AIR-COOLED
DIAGNOSTIC
REPAIR MANUAL
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www.guardiangenerators.com
AUTOMATIC HOME STANDBY GENERATORS
Models:
4389, 4758 (6 kW NG, 7 kW LP)
4456, 4759 (12 kW NG, 12 kW LP)
4390, 4760 (13 kW, 15 kW LP)
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ELECTRICAL FORMULAS
TO FIND
KNOWN VALUES
1-PHASE
3-PHASE
KILOWATTS (kW)
Volts, Current, Power Factor
E x I
1000
E x I x 1.73 x PF
1000
KVA
Volts, Current
E x I
1000
E x I x 1.73
1000
AMPERES
WATTS
kW, Volts, Power Factor
kW x 1000
E
kW x 1000
E x 1.73 x PF
Volts, Amps, Power Factor
Frequency, RPM
Volts x Amps
E x I x 1.73 x PF
NO. OF ROTOR
POLES
2 x 60 x Frequency
RPM
2 x 60 x frequency
RPM
FREQUENCY
RPM
RPM, No. of Rotor Poles
Frequency, No. of Rotor Poles
Motor Horsepower, Efficiency
Volts, Amperes
RPM x Poles
2 x 60
RPM x Poles
2 x 60
2 x 60 x Frequency
Rotor Poles
2 x 60 x Frequency
Rotor Poles
kW (required for
Motor)
HP x 0.746
Efficiency
HP x 0.746
Efficiency
RESISTANCE
E
I
E
I
VOLTS
Ohm, Amperes
Ohms, Volts
I x R
I x R
AMPERES
E
R
E
R
E = VOLTS
I = AMPERES
R = RESISTANCE (OHMS)
PF = POWER FACTOR
Page 1
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SPECIFICATIONS
GENERATOR
Models 04389, 04758
6,000 NG/7,000 LP
120/240
Models 04456, 04759
12,000 NG/12,000 LP
120/240
Model 04390, 04760
13,000 NG/15,000 LP
120/240
Rated Max. Continuous Power Capacity (Watts*)
Rated Voltage
Rated Max. Continuous Load Current (Amps)
120 Volts**
50.0 NG/58.3 LP
100.0 NG/100.0 LP
108.3 NG/125.0 LP
240 Volts
25.0 NG/29.2 LP
50.0 NG/50.0 LP
54.2 NG/62.5 LP
Main Line Circuit Breaker
Phase
Number of Rotor Poles
Rated AC Frequency
Power Factor
30 Amp
50 Amp
60 Amp/70 Amp
1
2
1
2
1
2
60 Hz
1
60 Hz
1
60 Hz
1
Battery Requirement
Group 26/26R
12 Volts and
Group 26/26R
12 Volts and
Group 26/26R
12 Volts and
350 Cold-cranking
Amperes Minimum
550 Cold-cranking
Amperes Minimum
550 Cold-cranking
Amperes Minimum
Weight
452 Pounds
68 db (A)
470 Pounds
70.5db (A)
-20 F (-28.8 C) to 104 F (40 C)
487 Pounds
71.5 db (A)
Output Sound Level @ 23 ft (7m) at full load
Normal Operating Range
* Maximum wattage and current are subject to and limited by such factors as fuel Btu content, ambient temperature, altitude, engine power and condition, etc. Maximum power
decreases about 3.5 percent for each 1,000 feet above sea level; and also will decrease about 1 percent for each 6 C (10 F) above 16 C (60 F) ambient temperature.
** Load current values shown for 120 volts are maximum TOTAL values for two separate circuits. The maximum current in each circuit must not exceed the value stated for 240 volts.
15,000 watt with upgrade kit 04578-0. Kit includes power harnesses and 70 amp 2-pole circuit breaker.
ENGINE
Models 04389, 04758
GH-410
Models 04456, 04759
GT-990
Models 04390, 04760
GT-990
Type of Engine
Number of Cylinders
Rated Horsepower
Displacement
1
2
2
14.5 @ 3,600 rpm
410cc
26 @ 3,600 rpm
992cc
30 @ 3,600 rpm
992cc
Cylinder Block
Aluminum w/Cast
Iron Sleeve
Aluminum w/Cast
Iron Sleeve
Aluminum w/Cast
Iron Sleeve
Valve Arrangement
Ignition System
Recommended Spark Plug
Spark Plug Gap
Compression Ratio
Starter
Overhead Valves
Solid-state w/Magneto
RC12YC
0.76 mm (0.030 inch)
8.6:1
Overhead Valves
Solid-state w/Magneto
RC12YC
0.5 mm (0.020 inch)
9.5:1
Overhead Valves
Solid-state w/Magneto
RC12YC
0.5 mm (0.020 inch)
9.5:1
12 Vdc
12 Vdc
12Vdc
Oil Capacity Including Filter
Recommended Oil Filter
Recommended Air Filter
Operating RPM
Approx. 1.5 Qts
Generac Part # 070185
Generac Part # 0C8127
3,600
Approx. 1.7 Qts
Generac Part # 070185
Generac Part # 0C8127
3,600
Approx. 1.7 Qts
Generac Part # 070185
Generac Part # 0C8127
3,600
FUEL CONSUMPTION
Model #
Natural Gas*
LP Vapor**
Full Load
1/2 Load
74
Full Load
105
1/2 Load
0.91/33
1.34/48.9
1.73/63.2
04389, 04758
04556, 04759
04390, 04760
1.21/44.1
2.17/79.0
2.80/102.3
114
185
148.5
240
* Natural gass is in cubic feet per hour. **LP is in gallons per hour/cubic feet per hour.
STATOR WINDING RESISTANCE VALUES / ROTOR RESISTANCE
Model 04692
Models 04389
04679, 04758
Models 04456
04759
Models 04390
04760
Power Winding: Across 11 & 22
Power Winding: Across 33 & 44
Excitation Winding: Across 2 & 6
Engine Run Winding: Across 55 & 66A
Battery Charge Winding: Across 66 & 77
Rotor Resistance
0.190-0.208 ohms
0.190-0.208 ohms
1.442-1.670 ohms
0.104-0.120 ohms
0.137-0.158 ohms
15.42-17-85 ohms
0.223-0.259 ohms
0.223-0.259 ohms
1.53-1.77 ohms
0.100-0.169 ohms
0.146-0.169 ohms
11.88-13.76 ohms
0.115 ohms
0.115 ohms
0.745 ohms
0.109 ohms
0.164 ohms
15.9 ohms
0.08/0.08 ohms
0.08/0.08 ohms
0.705 ohms
0.087 ohms
0.130 ohms
19.8 ohms
Page 2
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SPECIFICATIONS
MOUNTING DIMENSIONS
Page 3
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SPECIFICATIONS
MOUNTING DIMENSIONS
Page 4
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SPECIFICATIONS
MAJOR FEATURES
7 kW, Single Cylinder GH-410 Engine
12 kW and 15 kW, V-twin GT-990 Engine
Page 5
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TABLE OF CONTENTS
PART
1.1
TITLE
Generator Identification
1.2
Prepackaged Installation Basics
Preparation Before Use
PART 1
GENERAL
INFORMATION
1.3
1.4
Testing, Cleaning and Drying
Engine-Generator Protective Devices
Operating Instructions
1.5
1.6
1.7
Automatic Operating Parameters
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
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SECTION 1.1
GENERATOR IDENTIFICATION
GENERAL INFORMATION
PART 1
INTRODUCTION
This Diagnostic Repair Manual has been prepared
especially for the purpose of familiarizing service
personnel with the testing, troubleshooting and repair
of air-cooled, prepackaged automatic standby
generators. Every effort has been expended to
ensure that information and instructions in the manual
are both accurate and current. However, Generac
reserves the right to change, alter or otherwise
improve the product at any time without prior
notification.
The manual has been divided into ten PARTS. Each
PART has been divided into SECTIONS. Each
SECTION consists of two or more SUBSECTIONS.
It is not our intent to provide detailed disassembly and
reassemble instructions in this manual. It is our intent
to (a) provide the service technician with an
understanding of how the various assemblies and
systems work, (b) assist the technician in finding the
cause of malfunctions, and (c) effect the expeditious
repair of the equipment.
ITEM NUMBER:
Many home standby generators are manufactured to
the unique specifications of the buyer. The Model
Number identifies the specific generator set and its
unique design specifications.
Figure 1. A Typical Data Plate
SERIAL NUMBER:
Used for warranty tracking purposes.
Page 1.1-1
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SECTION 1.2
PREPACKAGED INSTALLATION BASICS
GENERAL INFORMATION
PART 1
The pressure at which LP gas is delivered to the
generator fuel solenoid valve may vary considerably,
depending on ambient temperatures. In cold weather,
supply pressures may drop to "zero". In warm
weather, extremely high gas pressures may be
encountered. A primary regulator is required to
maintain correct gas supply pressures.
INTRODUCTION
Information in this section is provided so that the
service technician will have a basic knowledge of
installation requirements for prepackaged home
standby systems. Problems that arise are often
related to poor or unauthorized installation practices.
Recommended gaseous fuel pressure at the inlet side
of the generator fuel solenoid valve is (a) a minimum
of 11 inches water column (6.38 ounces per square
inch), and (b) a maximum of 14 inches water column
(8 ounces per square inch). A primary regulator is
required to ensure that proper fuel supply pressures
are maintained.
A typical prepackaged home standby electric system
is shown in Figure 1 (next page). Installation of such a
system includes the following:
❏Selecting a Location
❏Grounding the generator.
❏Providing a fuel supply.
❏Mounting the load center.
DANGER: LP AND NATURAL GAS ARE BOTH
HIGHLY EXPLOSIVE. GASEOUS FUEL LINES
MUST BE PROPERLY PURGED AND TESTED
FOR LEAKS BEFORE THIS EQUIPMENT IS
PLACED INTO SERVICE AND PERIODICALLY
THEREAFTER. PROCEDURES USED IN
GASEOUS FUEL LEAKAGE TESTS MUST
COMPLY STRICTLY WITH APPLICABLE FUEL
GAS CODES. DO NOT USE FLAME OR ANY
SOURCE OF HEAT TO TEST FOR GAS
LEAKS. NO GAS LEAKAGE IS PERMITTED.
LP GAS IS HEAVIER THAN AIR AND TENDS
TO SETTLE IN LOW AREAS. NATURAL GAS
IS LIGHTER THAN AIR AND TENDS TO
SETTLE IN HIGH PLACES. EVEN THE
❏Connecting power source and load lines.
❏Connecting system control wiring.
❏Post installation tests and adjustments.
SELECTING A LOCATION
Install the generator set as close as possible to the
electrical load distribution panel(s) that will be powered
by the unit, ensuring that there is proper ventilation for
cooling air and exhaust gases. This will reduce wiring
and conduit lengths. Wiring and conduit not only add to
the cost of the installation, but excessively long wiring
runs can result in a voltage drop.
GROUNDING THE GENERATOR
SLIGHTEST SPARK CAN IGNITE THESE
FUELS AND CAUSE AN EXPLOSION.
The National Electric Code requires that the frame
and external electrically conductive parts of the
generator be property connected to an approved
earth ground. Local electrical codes may also require
proper grounding of the unit. For that purpose, a
grounding lug is attached to the unit. Grounding may
be accomplished by attaching a stranded copper wire
of the proper size to the generator grounding lug and
to an earth-driven copper or brass grounding-rod
(electrode). Consult with a local electrician for
grounding requirements in your area.
Use of a flexible length of hose between the
generator fuel line connection and rigid fuel lines is
required. This will help prevent line breakage that
might be caused by vibration or if the generator shifts
or settles. The flexible fuel line must be approved for
use with gaseous fuels.
Flexible fuel line should be kept as straight as
possible between connections. The bend radius for
flexible fuel line is nine (9) inches. Exceeding the
bend radius can cause the fittings to crack.
THE FUEL SUPPLY
Prepackaged units with air-cooled engine were
operated, tested and adjusted at the factory using
natural gas as a fuel. These air-cooled engine units can be
converted to use LP (propane) gas by making a few
adjustments for best operation and power.
THE TRANSFER SWITCH / LOAD CENTER
A transfer switch is required by electrical code, to
prevent electrical feedback between the UTILITY and
STANDBY power sources, and to transfer electrical
loads from one power supply to another safely.
LP (propane) gas is usually supplied as a liquid in
pressure tanks. Both the air-cooled and the liquid
cooled units require a "vapor withdrawal" type of fuel
supply system when LP (propane) gas is used. The
vapor withdrawal system utilizes the gaseous fuel
vapors that form at the top of the supply tank.
PREPACKAGED TRANSFER SWITCHES:
Instructions and information on prepackaged transfer
switches may be found in Part 3 of this manual.
Page 1-2.1
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SECTION 1.2
PREPACKAGED INSTALLATION BASICS
GENERAL INFORMATION
PART 1
Figure 1. Typical Prepackaged Installation
Page 1.2-2
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SECTION 1.2
PREPACKAGED INSTALLATION BASICS
GENERAL INFORMATION
PART 1
POWER SOURCE AND LOAD LINES
SYSTEM CONTROL INTERCONNECTIONS
The utility power supply lines, the standby (generator)
supply lines, and electrical load lines must all be
connected to the proper terminal lugs in the transfer
switch. The following rules apply:In 1-phase systems
with a 2-pole transfer switch, connect the two utility
source hot lines to Transfer Switch Terminal Lugs N1
and N2. Connect the standby source hot lines (E1,
E2) to Transfer Switch Terminal Lugs E1 and E2.
Connect the load lines from Transfer Switch Terminal
Lugs T1 and T2 to the electrical load circuit. Connect
UTILITY, STANDBY and LOAD neutral lines to the
neutral block in the transfer switch.
Prepackaged home standby generators are equipped
with a terminal board identified with the following
terminals: (a) UTILITY 1, (b) UTILITY 2, (c) 23, and (d)
194. Prepackaged load centers house an identically
marked terminal board. When these four terminals are
properly interconnected, dropout of utility source
voltage below a preset value will result in automatic
generator startup and transfer of electrical loads to the
"Standby" source. On restoration of utility source
voltage above a preset value will result in retransfer
back to that source and generator shutdown.
Figure 2. Proper Fuel Installation
Page 1-2.3
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SECTION 1.3
PREPARATION BEFORE USE
GENERAL INFORMATION
PART 1
GENERAL
ENGINE OIL RECOMMENDATIONS
The installer must ensure that the home standby
generator has been properly installed. The system
must be inspected carefully following installation. All
applicable codes, standards and regulations
pertaining to such installations must be strictly
complied with. In addition, regulations established by
the Occupational Safety and Health Administration
(OSHA) must be complied with.
The primary recommended oil for units with air-cooled,
single cylinder or V-Twin engines is synthetic oil.
Synthetic oil provides easier starts in cold weather and
maximum engine protection in hot weather. Use high
quality detergent oil that meets or exceeds API
(American Petroleum Institute) Service class SG, SH,
or SJ requirements for gasoline engines. The following
chart lists recommended viscosity ranges for the lowest
anticipated ambient temperatures.
Prior to initial startup of the unit, the installer must
ensure that the engine-generator has been properly
prepared for use. This includes the following:
❏An adequate supply of the correct fuel must be
available for generator operation.
Engine crankcase oil capacities for the engines
covered in this manual can be found in the
specifications section at the beginning of the book.
LOWEST ANTICIPATED
AMBIENT TEMPERATURE RECOMMENDED OIL
Above 60 F. (16 C.)
20 -59 F. (-7 to 15 C.)
Below 20 F. (-7 C.)
For all seasons
AIR COOLED ENGINE
❏The engine must be properly serviced with the
recommended oil.
Use SAE 30 oil
Use SAE 10W-30 oil
SAE 5W-20/5W-30 oil
Use SAE 5W-30
Synthetic oil
FUEL REQUIREMENTS
Generators with air-cooled engine have been factory
tested and adjusted using natural gas as a fuel. If LP
(propane) gas is to be used at the installation site,
adjustment of the generator fuel regulator will be
required for best performance. Refer to Test 63,
"Check Fuel Regulator" on Page 4.4-16 for fuel
regulator adjustment procedures.
❏When natural gas is used as a fuel, it should be
rated at least 1000 BTU’s per cubic foot.
❏When LP (propane) gas is used as a fuel, it should
be rated at 2520 BTU’s per cubic foot.
Page 1.3-1
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SECTION 1.4
TESTING, CLEANING AND DRYING
GENERAL INFORMATION
PART 1
VISUAL INSPECTION
When it becomes necessary to test or troubleshoot a
generator, it is a good practice to complete a
thorough visual inspection. Remove the access
covers and look closely for any obvious problems.
Look for the following:
❏Burned or broken wires, broken wire connectors,
damaged mounting brackets, etc.
❏Loose or frayed wiring insulation, loose or dirty
connections.
❏Check that all wiring is well clear of rotating parts.
❏Verify that the Generator properly connected for the
correct rated voltage. This is especially important
on new installations. See Section 1.2, "AC
Connection Systems".
❏Look for foreign objects, loose nuts, bolts and other
fasteners.
❏Clean the area around the Generator. Clear away
paper, leaves, snow, and other objects that might
blow against the generator and obstruct its air
openings.
Figure 1. Digital VOM
MEASURING AC VOLTAGE
METERS
An accurate AC voltmeter or a VOM may be used to
read the generator AC output voltage. The following
apply:
Devices used to measure electrical properties are
called meters. Meters are available that allow one to
measure (a) AC voltage, (b) DC voltage, (c) AC
frequency, and (d) resistance In ohms. The following
apply:
1. Always read the generator AC output voltage only at the
unit's rated operating speed and AC frequency.
❏To measure AC voltage, use an AC voltmeter.
2. The generator voltage regulator can be adjusted for
correct output voltage only while the unit is operating at
its correct rated speed and frequency.
❏To measure DC voltage, use a DC voltmeter.
❏Use a frequency meter to measure AC frequency In
"Hertz" or "cycles per second".
❏Use an ohmmeter to read circuit resistance, in "ohms".
3. Only an AC voltmeter may be used to measure AC
voltage. DO NOT USE A DC VOLTMETER FOR THIS
PURPOSE.
THE VOM
A meter that will permit both voltage and resistance to
be read is the "volt-ohm-milliammeter" or "VOM".
Some VOM’s are of the analog type (not shown).
These meters display the value being measured by
physically deflecting a needle across a graduated
scale. The scale used must be interpreted by the user.
DANGER!: GENERATORS PRODUCE HIGH
AND DANGEROUS VOLTAGES. CONTACT
WITH HIGH VOLTAGE TERMINALS WILL
RESULT IN DANGEROUS AND POSSIBLY
LETHAL ELECTRICAL SHOCK.
Digital VOM’s (Figure 1) are also available and are
generally very accurate. Digital meters display the
measured values directly by converting the values to
numbers.
NOTE: Standard AC voltmeters react to the
AVERAGE value of alternating current. When working
with AC, the effective value is used. For that reason a
different scale is used on an AC voltmeter. The scale
is marked with the effective or "rms" value even
though the meter actually reacts to the average value.
That is why the AC voltmeter will give an Incorrect
reading if used to measure direct current (DC).
MEASURING DC VOLTAGE
A DC voltmeter or a VOM may be used to measure
DC voltages. Always observe the following rules:
1. Always observe correct DC polarity.
a. Some VOM’s may be equipped with a
polarity switch.
b. On meters that do not have a polarity
switch, DC polarity must be reversed by
reversing the test leads.
Page 1.4-1
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SECTION 1.4
TESTING, CLEANING AND DRYING
GENERAL INFORMATION
PART 1
2. Before reading a DC voltage, always set the meter to a
higher voltage scale than the anticipated reading. if in
doubt, start at the highest scale and adjust the scale
downward until correct readings are obtained.
3. The design of some meters is based on the "current flow"
theory while others are based on the "electron flow" theory.
a. The "current flow" theory assumes that
direct current flows from the positive (+) to
the negative (-).
b. The "electron flow" theory assumes that
current flows from negative (-) to positive
(+).
NOTE: When testing generators, the "current flow"
theory is applied. That is, current is assumed to flow
from positive (+) to negative (-).
MEASURING AC FREQUENCY
Figure 2. Clamp-On Ammeter
The generator AC output frequency is proportional to
rotor speed. Generators equipped with a 2-pole rotor
must operate at 3600 rpm to supply a frequency of 60
Hertz. Units with 4-pole rotor must run at 1800 rpm to
deliver 60 Hertz.
Correct engine and rotor speed is maintained by an
engine speed governor. For models rated 60 Hertz,
the governor is generally set to maintain a no-load
frequency of about 62 Hertz with a corresponding
output voltage of about 124 volts AC line-to-neutral.
Engine speed and frequency at no-load are set
slightly high to prevent excessive rpm and frequency
droop under heavy electrical loading.
MEASURING CURRENT
To read the current flow, in AMPERES, a clamp-on
ammeter may be used. This type of meter indicates
current flow through a conductor by measuring the
strength of the magnetic field around that conductor.
The meter consists essentially of a current
transformer with a split core and a rectifier type
instrument connected to the secondary. The primary
of the current transformer is the conductor through
which the current to be measured flows. The split
core allows the Instrument to be clamped around the
conductor without disconnecting it.
Figure 3. A Line-Splitter
NOTE: If the physical size of the conductor or
ammeter capacity does not permit all lines to be
measured simultaneously, measure current flow in
each individual line. Then, add the Individual
readings.
Current flowing through a conductor may be
measured safely and easily. A line-splitter can be
used to measure current in a cord without separating
the conductors.
MEASURING RESISTANCE
The volt-ohm-milliammeter may be used to measure
the resistance in a circuit. Resistance values can be
very valuable when testing coils or windings, such as
the stator and rotor windings.
When testing stator windings, keep in mind that the
resistance of these windings is very low. Some
meters are not capable of reading such a low
resistance and will simply read CONTINUITY.
Page 1.4-2
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SECTION 1.4
TESTING, CLEANING AND DRYING
GENERAL INFORMATION
PART 1
If proper procedures are used, the following
conditions can be detected using a VOM:
❏A "short-to-ground" condition in any stator or rotor
winding.
❏Shorting together of any two parallel stator windings.
❏Shorting together of any two isolated stator windings.
❏An open condition in any stator or rotor winding.
Component testing may require a specific resistance
value or a test for INFINITY or CONTINUITY.
INFINITY is an OPEN condition between two
electrical points, which would read as no resistance
on a VOM. CONTINUITY is a CLOSED condition
between two electrical points, which would be
indicated as very low resistance or ZERO on a VOM.
ELECTRICAL UNITS
AMPERE:
Figure 4. Electrical Units
OHM'S LAW
The rate of electron flow in a circuit is represented by
the AMPERE. The ampere is the number of electrons
flowing past a given point at a given time. One
AMPERE is equal to just slightly more than six
thousand million billion electrons per second.
A definite and exact relationship exists between
VOLTS, OHMS and AMPERES. The value of one can
be calculated when the value of the other two are
known. Ohm’s Law states that in any circuit the current
will increase when voltage increases but resistance
remains the same, and current will decrease when
resistance Increases and voltage remains the same.
With alternating current (AC), the electrons flow first
in one direction, then reverse and move in the
opposite direction. They will repeat this cycle at
regular intervals. A wave diagram, called a "sine
wave" shows that current goes from zero to maximum
positive value, then reverses and goes from zero to
maximum negative value. Two reversals of current
flow is called a cycle. The number of cycles per
second is called frequency and is usually stated in
"Hertz".
VOLT:
The VOLT is the unit used to measure electrical
PRESSURE, or the difference in electrical potential
that causes electrons to flow. Very few electrons will
flow when voltage is weak. More electrons will flow as
voltage becomes stronger. VOLTAGE may be
considered to be a state of unbalance and current
flow as an attempt to regain balance. One volt is the
amount of EMF that will cause a current of 1 ampere
to flow through 1 ohm of resistance.
Figure 5.
OHM:
If AMPERES is unknown while VOLTS and OHMS
are known, use the following formula:
The OHM is the unit of RESISTANCE. In every circuit
there is a natural resistance or opposition to the flow
of electrons. When an EMF is applied to a complete
circuit, the electrons are forced to flow in a single
direction rather than their free or orbiting pattern. The
resistance of a conductor depends on (a) its physical
makeup, (b) its cross-sectional area, (c) its length,
and (d) its temperature. As the conductor’s
temperature increases, its resistance increases in
direct proportion. One (1) ohm of resistance will
permit one (1) ampere of current to flow when one (1)
volt of electromotive force (EMF) is applied.
VOLTS
OHMS
AMPERES =
If VOLTS is unknown while AMPERES and OHMS
are known, use the following formula:
VOLTS = AMPERES x OHMS
If OHMS is unknown but VOLTS and AMPERES are
known, use the following:
VOLTS
AMPERES
=
OHMS
Page 1.4-3
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SECTION 1.4
TESTING, CLEANING AND DRYING
GENERAL INFORMATION
PART 1
TESTING ROTOR INSULATION:
INSULATION RESISTANCE
Apply a voltage of 500 volts across the rotor positive
(+) slip ring (nearest the rotor bearing), and a clean
frame ground (i.e. the rotor shaft). DO NOT EXCEED
500 VOLTS AND DO NOT APPLY VOLTAGE
LONGER THAN 1 SECOND. FOLLOW THE
MEGGER MANUFACTURER’S INSTRUCTIONS
CAREFULLY.
The insulation resistance of stator and rotor windings
is a measurement of the integrity of the insulating
materials that separate the electrical windings from the
generator steel core. This resistance can degrade over
time or due to such contaminants as dust, dirt, oil,
grease and especially moisture. In most cases, failures
of stator and rotor windings is due to a breakdown in
the insulation. And, in many cases, a low insulation
resistance is caused by moisture that collects while the
generator is shut down. When problems are caused by
moisture buildup on the windings, they can usually be
corrected by drying the windings. Cleaning and drying
the windings can usually eliminate dirt and moisture
built up in the generator windings.
ROTOR MINIMUM INSULATION RESISTANCE:
1.5 megohms
CAUTION: Before attempting to measure
Insulation resistance, first disconnect and
Isolate all leads of the winding to be tested.
Electronic components, diodes, surge
protectors, relays, voltage regulators, etc., can
be destroyed if subjected to high megger
voltages.
THE MEGOHMMETER
GENERAL:
A megohmmeter, often called a "megger", consists of
a meter calibrated in megohms and a power supply.
Use a power supply of 500 volts when testing stators
or rotors. DO NOT APPLY VOLTAGE LONGER
THAN ONE (1) SECOND.
HI-POT TESTER:
A "Hi-Pot" tester is shown in Figure 1. The model
shown is only one of many that are commercially
available. The tester shown is equipped with a
voltage selector switch that permits the power supply
voltage to be selected. It also mounts a breakdown
lamp that will illuminate to indicate an insulation
breakdown during the test.
TESTING STATOR INSULATION:
All parts that might be damaged by the high megger
voltages must be disconnected before testing. Isolate
all stator leads (Figure 2) and connect all of the stator
leads together. FOLLOW THE MEGGER
MANUFACTURER’S INSTRUCTIONS CAREFULLY.
Use a megger power setting of 500 volts. Connect
one megger test lead to the junction of all stator
leads, the other test lead to frame ground on the
stator can. Read the number of megohms on the
meter.
The MINIMUM acceptable megger reading for stators
MINIMUM INSULATION
RESISTANCE
(in "Megohms")
GENERATOR RATED VOLTS
__________________________
=
+1
1000
may be calculated using the following formula:
EXAMPLE: Generator is rated at 120 volts AC. Divide
"120" by "1000" to obtain "0.12". Then add "1" to
obtain "1.12" megohms. Minimum Insulation
resistance for a 120 VAC stator is 1.12 megohms.
Figure 1. One Type of Hi-Pot Tester
STATOR INSULATION RESISTANCE TEST
If the stator insulation resistance is less than the
calculated minimum resistance, clean and dry the
stator. Then, repeat the test. If resistance is still low,
replace the stator.
Use the Megger to test for shorts between isolated
windings as outlined "Stator Insulation Tests .
GENERAL:
Units with air-cooled engines are equipped with (a)
dual stator AC power windings, (b) an excitation or
DPE winding, (c) a battery charge winding and (d) an
engine run winding. Insulation tests of the stator
consist of (a) testing all windings to ground, (b) testing
between isolated windings, and (c) testing between
parallel windings. Figure 2 is a pictorial representation
of the various stator leads on units with air-cooled
engine.
Also test between parallel windings. See "Test
Between Parallel Windings" on this page.
Page 1.4-4
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SECTION 1.4
TESTING, CLEANING AND DRYING
GENERAL INFORMATION
PART 1
TESTING ALL STATOR WINDINGS TO GROUND:
6. Now proceed to the C2 connector. Each winding will be
individually tested for a short to ground. Insert a large
paper clip (or similar item) into the C2 connector at the
following pin locations:
1. Disconnect stator output leads 11 and 44 from the
generator main line circuit breaker.
2. Remove stator output leads 22 and 33 from the neutral
connection and separate the two leads.
Pin
Wire
Number
Winding
Location
1
2
3
4
5
6
7
8
77
66
66A
55
22
11
6
Battery Charge
Battery Charge
Engine Run
3. Disconnect C2 connector from the side of the control
panel. The C2 connector is the closest to the back
panel.
Engine Run
Sense Lead Power
Sense Lead Power
Excitation
2
Excitation
Next refer to Steps 5a through 5c of the Hi-Pot procedure.
Example: Insert paper clip into Pin 1, Hi-Pot from Pin
1 (Wire 77) to ground. Proceed to Pin 2, Pin 3, etc.
through Pin 8.
Figure 2. Stator Winding Leads
4. Connect the terminal ends of Wires 11, 22, 33 and 44
together. Make sure the wire ends are not touching any
part of the generator frame or any terminal.
Figure 3. C2 Connector Pin Location Numbers
(Female Side)
5. Connect the red test probe of the Hi-Pot tester to the
joined terminal ends of stator leads 11, 22, 33 and 44.
Connect the black tester lead to a clean frame ground
on the stator can. With tester leads connected in this
manner, proceed as follows:
TEST BETWEEN WINDINGS:
1. Insert a large paper clip into Pin Location 1 (Wire 77).
Connect the red tester probe to the paper clip. Connect
the black tester probe to Stator Lead 11. Refer to Steps
5a through 5c of “TESTING ALL STATOR WINDINGS
TO GROUND” on the previous page.
a.Turn the Hi-Pot tester switch OFF.
b.Plug the tester cord into a 120 volt AC wall
socket and set its voltage selector switch to
"1500 volts".
2. Repeat Step 1 at Pin Location 3 (Wire 66A) and Stator
Lead 11.
c. Turn the tester switch "On" and observe the
breakdown lamp on tester. DO NOT APPLY
VOLTAGE LONGER THAN 1 SECOND. After
one (1) second, turn the tester switch OFF.
3. Repeat Step 1 at Pin Location 7 (Wire 6). and Stator
Lead 11.
If the breakdown lamp comes on during the one-
second test, the stator should be cleaned and dried.
After cleaning and drying, repeat the insulation test. If,
after cleaning and drying, the stator fails the second
test, the stator assembly should be replaced.
4. Connect the red test probe to Stator Lead 33. Connect
the black test probe to Stator Lead 11. Refer to Steps
5a through 5c of “TESTING ALL STATOR WINDINGS
TO GROUND” on the previous page.
Page 1.4-5
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SECTION 1.4
TESTING, CLEANING AND DRYING
GENERAL INFORMATION
PART 1
5. Insert a large paper clip into Pin Location No. 1 (Wire
77). Connect the red tester probe to the paper clip.
Connect the black tester probe to Stator Lead 33. Refer
to Steps 5a through 5c of “TESTING ALL STATOR
WINDINGS TO GROUND” on the previous page.
6. Observe the breakdown lamp, then turn the tester
switch OFF. DO NOT APPLY VOLTAGE LONGER
THAN ONE (1) SECOND.
If the breakdown lamp came on during the one (1)
second test, cleaning and drying of the rotor may be
necessary. After cleaning and drying, repeat the
insulation breakdown test. If breakdown lamp comes
on during the second test, replace the rotor assembly.
6. Repeat Step 5 at Pin Location 3 (Wire 66A) and Stator
Lead 33.
7. Repeat Step 5 at Pin Location 7 (Wire 6) and Stator
Lead 33.
For the following steps (8 through 10) an additional
large paper clip (or similar item) will be needed:
8. Insert a large paper clip into Pin Location 1 (Wire 77).
Connect the red tester probe to the paper clip. Insert the
additional large paper clip into Pin Location 3 (Wire
66A). Connect the black tester probe to this paper clip.
Refer to Steps 5a through 5c of “TESTING ALL
STATOR WINDINGS TO GROUND” on the previous
page.
9. Insert a large paper clip into Pin Location 1 (Wire 77).
Connect the red tester probe to the paper clip. Insert the
additional large paper clip into Pin Location 7 (Wire 6).
Connect the black tester probe to this paper clip. Refer
to Steps 5a through 5c of “TESTING ALL STATOR
WINDINGS TO GROUND” on the previous page.
Figure 4. Testing Rotor Insulation
CLEANING THE GENERATOR
Caked or greasy dirt may be loosened with a soft
brush or a damp cloth. A vacuum system may be
used to clean up loosened dirt. Dust and dirt may also
be removed using dry, low-pressure air (25 psi
maximum).
10.Insert a large paper clip into Pin Location 3 (Wire 66A).
Connect the red tester probe to the paper clip. Insert the
additional large paper clip into Pin Location 7 (Wire 6).
Connect the black tester probe to this paper clip. Refer
to Steps 5a through 5c of “TESTING ALL STATOR
WINDINGS TO GROUND” on the previous page.
CAUTION: Do not use sprayed water to clean
the generator. Some of the water will be
retained on generator windings and terminals,
and may cause very serious problems.
ROTOR INSULATION RESISTANCE TEST
Before attempting to test rotor insulation, the brush
holder must be completely removed. The rotor must
be completely isolated from other components before
starting the test. Attach all leads of all stator windings
to ground.
DRYING THE GENERATOR
To dry a generator, proceed as follows:
1. Open the generator main circuit breaker. NO
ELECTRICAL LOADS MUST BE APPLIED TO THE
GENERATOR WHILE DRYING.
1. Connect the red tester lead to the positive (+) slip ring
(nearest the rotor bearing).
2. Connect the black tester probe to a clean frame ground,
such as a clean metal part of the rotor shaft.
2. Disconnect all Wires 4 from the voltage regulator.
3. Provide an external source to blow warm, dry air
through the generator interior (around the rotor and
stator windings. DO NOT EXCEED 185° F. (85° C.).
3. Turn the tester switch OFF.
4. Plug the tester into a 120 volts AC wall socket and set
the voltage switch to "1500 volts".
4. Start the generator and let it run for 2 or 3 hours.
5. Turn the tester switch "On" and make sure the pilot light
has turned on.
5. Shut the generator down and repeat the stator and rotor
insulation resistance tests.
Page 1.4-6
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SECTION 1.5
ENGINE-GENERATOR PROTECTIVE DEVICES
GENERAL INFORMATION
PART 1
above.
GENERAL
Standby electric power generators will often run
unattended for long periods of time. Such operating
parameters as (a) engine oil pressure, (b) engine
temperature, (c) engine operating speed, and (d)
engine cranking and startup are not monitored by an
operator during automatic operation. Because engine
operation will not be monitored, the use of engine
protective safety devices is required to prevent engine
damage in the event of a problem.
Prepackaged generator engines mount several engine
protective devices. These devices work in conjunction
with a circuit board, to protect the engine against such
operating faults as (a) low engine oil pressure, (b) high
temperature, (c) overspeed, and (d) overcrank. On
occurrence of any one or more of those operating faults,
circuit board action will effect an engine shutdown.
LOW OIL PRESSURE SHUTDOWN:
See Figure 1. An oil pressure switch is mounted on
the engine oil filter adapter. This switch has normally
closed contacts that are held open by engine oil
pressure during cranking and startup. Should oil
pressure drop below approximately 10 psi, the switch
contacts will close. On closure of the switch contacts,
a Wire 86 circuit from the circuit board will be
connected to ground. Circuit board action will then de-
energize a "run relay" (on the circuit board). The run
relay’s normally open contacts will then open and a
12 volts DC power supply to a Wire 14 circuit will then
be terminated. This will result in closure of a fuel
shutoff solenoid and loss of engine ignition.
Figure 1. Engine Protective Switches on an
Air-Cooled Engine
OVERCRANK SHUTDOWN:
Automatic engine cranking and startup normally
occurs when the circuit board senses that utility
source voltage has dropped below approximately 60
percent of its nominal rated voltage and remains at
that low level longer than fifteen (15) seconds. At the
end of fifteen (15) seconds, circuit board action will
energize a crank relay and a run relay (both relays
are on the circuit board). On closure of the crank relay
contacts, circuit board action will deliver 12 volts DC
to a starter contactor relay (SCR, for v-twin models)
or a starter contactor (SC, for single cylinder models).
The control contactor will energize and battery power
will be delivered to the starter motor (SM). The engine
will then crank.
HIGH OIL TEMPERATURE SHUTDOWN:
An oil temperature switch (Figure 1) is mounted on
the engine block. The thermal switch has normally
open contacts that will close if oil temperature should
exceed approximately 284 F (140 C). This will result
in the same action as a low oil pressure shutdown.
During a manual startup (AUTO-OFF-MANUAL
switch at MANUAL), action is the same as during an
automatic start, except that cranking will begin
immediately when the switch is set to MANUAL.
OVERSPEED SHUTDOWN:
During engine cranking and operation, the circuit board
receives AC voltage and frequency signals from the
generator engine run windings, via Wire 66A. Should the
AC frequency exceed approximately 72Hz (4320 rpm),
circuit board action will de-energize a "run relay"
(mounted on the circuit board). The relay’s contacts will
open, to terminate engine ignition and close a fuel shutoff
solenoid. The engine will then shut down. This feature
protects the engine-generator against damaging
overspeeds.
Circuit board action (during both a manual and an
automatic start) will hold the crank relay energized for
15 seconds on. The relay will then de-energize for 15
seconds off. It will then energize for seven (7)
seconds on and de-energize for seven (7) seconds
off. It will repeat this same cycle for another 45
seconds.
If the engine has not started after approximately 90
seconds of these crank-rest cycles, cranking will
automatically terminate and shutdown will occur. The
circuit board uses AC signals from the stator engine
run winding as an indication that the engine has
started.
NOTE: The circuit board also uses engine run
winding output to terminate engine cranking at
approximately 30 Hz (1800 rpm). In addition, the
engine run winding output is used by the circuit board
as an "engine running" signal The circuit board will
not initiate transfer of electrical loads to the "Standby"
source unless the engine is running at 30 Hz or
Page 1.5-1
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SECTION 1.6
OPERATING INSTRUCTIONS
GENERAL INFORMATION
PART 1
circuit board action will initiate engine cranking
and startup.
CONTROL PANEL
GENERAL:
d.Following engine startup, circuit board action
will initiate transfer of electrical loads to the
"Standby" source side.
See Figure 1. The front face of this panel mounts (a)
an hourmeter, (b) an AUTO-OFF-MANUAL switch ,(c)
a 15 amp fuse, (d) a 5 amp fuse, (e) a set exercise
switch and (f) the protection systems.
e.On restoration of utility source voltage above a
preset level, circuit board action will initiate
retransfer back to the "Utility Source" side.
HOURMETER:
Equipped on some models only. The hourmeter
indicates engine-generator operating-time, in hours
and tenths of hours. Use the meter in conjunction with
the periodic maintenance schedule for the applicable
generator set. circuit board action turns the hourmeter
on at startup, via the same (Wire 14) circuit that
powers the engine ignition system and the fuel shutoff
solenoid.
f. Following retransfer, circuit board will shut the
engine down and will then continue to monitor
utility source voltage.
2. OFF Position:
a.Set the switch to OFF to stop an operating
engine.
b.To prevent an automatic startup from occurring,
set the switch to OFF.
3. MANUAL Position:
a.Set switch to MANUAL to crank and start unit
manually.
b.Engine will crank cyclically and start (same as
automatic startup, but without transfer). The unit
WILL transfer if utility voltage is not available.
DANGER: WHEN THE GENERATOR IS
INSTALLED IN CONJUNCTION WITH AN
AUTOMATIC TRANSFER SWITCH, ENGINE
CRANKING AND STARTUP CAN OCCUR AT
ANY TIME WITHOUT WARNING (PROVIDING
THE AUTO-OFF-MANUAL SWITCH IS SET TO
AUTO). TO PREVENT AUTOMATIC STARTUP
AND POSSIBLE INJURY THAT MIGHT BE
CAUSED BY SUCH STARTUP, ALWAYS SET
THE AUTO-OFF-MANUAL SWITCH TO ITS
OFF POSITION BEFORE WORKING ON OR
AROUND THIS EQUIPMENT.
Figure 1. Control Panel
15 AMP FUSE:
This fuse protects the DC control circuit (including the
circuit board) against overload. If the fuse element
has melted open due to an overload, engine cranking
or running will not be possible. Should fuse
replacement become necessary, use only an identical
15 amp replacement fuse.
AUTO-OFF-MANUAL SWITCH:
Use this switch to (a) select fully automatic operation,
(b) to crank and start the engine manually, and (c) to
shut the unit down or to prevent automatic startup.
1. AUTO position:
a.Select AUTO for fully automatic operation.
5 AMP FUSE:
b.When AUTO is selected, circuit board will
monitor utility power source voltage.
This fuse protects the battery charge circuit against
overload. If the fuse element has melted open due to
an overload, battery charge will not occur. Should
fuse replacement become necessary, use only an
identical 5 amp replacement fuse.
c. Should utility voltage drop below a preset level
and remain at such a low level for a preset time,
Page 1.6-1
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SECTION 1.6
OPERATING INSTRUCTIONS
GENERAL INFORMATION
PART 1
THE SET EXERCISE SWITCH:
To select automatic operation when a prepackaged
transfer switch is installed along with a prepackaged
home standby generator, proceed as follows:
The air-cooled, prepackaged automatic standby
generator will start and exercise once every seven (7)
days, on a day and at a time of day selected by the
owner or operator. The set exercise time switch is
provided to select the day and time of day for system
exercise.
1. Check that the prepackaged transfer switch main
contacts are at their UTILITY position, i.e., the load is
connected to the utility power supply. If necessary,
manually actuate the switch main contacts to their
UTILITY source side. See Part 5 of this manual, as
appropriate, for instructions.
See Page 5.1-3 ("The 7-Day Exercise Cycle") for
instructions on how to set exercise time.
2. Check that utility source voltage is available to transfer
switch terminal lugs N1 and N2 (2-pole, 1-phase
transfer switches).
DANGER: THE GENERATOR WILL CRANK
AND START WHEN THE SET EXERCISE TIME
SWITCH IS SET TO "ON". DO NOT ACTUATE
THE SWITCH TO "ON" UNTIL AFTER YOU
HAVE READ THE INSTRUCTIONS IN PART 5.
3. Set the generator AUTO-OFF-MANUAL switch to its
AUTO position.
4. Actuate the generator main line circuit breaker to its "On"
or "Closed" position. With the preceding Steps 1 through
4 completed, a dropout in utility supply voltage below a
preset level will result in automatic generator cranking
and start-up. Following startup, the prepackaged transfer
switch will be actuated to its "Standby" source side, i.e.,
loads powered by the standby generator.
PROTECTION SYSTEMS:
Unlike an automobile engine, the generator may have
to run for long periods of time with no operator
present to monitor engine conditions. For that reason,
the engine is equipped with the following systems that
protect it against potentially damaging conditions:
❏ Low Oil Pressure Sensor
❏ High Temperature Sensor
❏ Overcrank
MANUAL TRANSFER TO "STANDBY" AND
MANUAL STARTUP
❏ Overspeed
To transfer electrical loads to the "Standby"
(generator) source and start the generator manually,
proceed as follows:
There are LED readouts on the control panel to notify
you that one of these faults has occurred. There is
also a System Set LED that is lit when all of the
following conditions are true:
1. On the generator panel, set the AUTO-OFF-MANUAL
switch to OFF.
1. The AUTO-OFF-MANUAL switch is set to the AUTO
position.
2. On the generator, set the main line circuit breaker to it's
OFF or "Open" position.
2. The NOT IN AUTO dip switch is set to the OFF position
on the control board.
3. Turn OFF the utility power supply to the transfer switch,
using whatever means provided (such as a utility source
line circuit breaker).
3. No alarms are present.
4. Manually actuate the transfer switch main contacts to
their “Standby” position, i.e., loads connected to the
“Standby” power source side.
TO SELECT AUTOMATIC OPERATION
The following procedure applies only to those
installations in which the air-cooled, prepackaged
automatic standby generator is installed in
conjunction with a prepackaged transfer switch.
Prepackaged transfer switches do not have an
intelligence circuit of their own, as do Generac "GTS"
type transfer switches. Instead, automatic operation
on prepackaged transfer switch and generator
combinations is controlled by circuit board action.
NOTE: For instructions on manual operation of
prepackaged transfer switches, see Part 5.
5. On the generator panel, set the AUTO-OFF-MANUAL
switch to MANUAL. The engine should crank and start.
6. Let the engine warm up and stabilize for a minute or two
at no-load.
Page 1.6-2
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SECTION 1.6
OPERATING INSTRUCTIONS
GENERAL INFORMATION
PART 1
7. Set the generator main line circuit breaker to its "On" or
"Closed" position. The generator now powers the
electrical loads.
MANUAL SHUTDOWN AND RETRANSFER
BACK TO "UTILITY"
To shut the generator down and retransfer electrical
loads back to the UTILITY position, proceed as
follows:
1. Set the generator main line circuit breaker to its OFF or
"Open" position.
2. Let the generator run at no-load for a few minutes, to cool.
3. Set the generator AUTO-OFF-MANUAL switch to OFF.
Wait for the engine to come to a complete stop.
4. Turn off the utility power supply to the transfer switch
using whatever means provided (such as a utility source
main line circuit breaker)
5. Manually actuate the prepackaged transfer switch to its
UTILITY source side, i.e., load connected to the utility
source.
6. Turn on the utility power supply to the transfer switch,
using whatever means provided.
7. Set the generator AUTO-OFF-MANUAL switch to
AUTO.
Page 1.6-3
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SECTION 1.7
AUTOMATIC OPERATING PARAMETERS
GENERAL INFORMATION
PART 1
PHASE 4-ENGINE STARTUP AND RUNNING:
INTRODUCTION
The circuit board senses that the engine is running by
receiving a voltage/frequency signal from the engine
run windings.
When the prepackaged generator is installed in
conjunction with a prepackaged transfer switch, either
manual or automatic operation is possible. Manual
transfer and engine startup, as well as manual
shutdown and retransfer are covered in Section 1.6.
Selection of fully automatic operation is also
discussed in that section. This section will provide a
step-by-step description of the sequence of events
that will occur during automatic operation of the
system.
When generator AC frequency reaches approximately
30 Hz, an engine warm-up timer on the circuit board
turns on. That timer will run for about ten (10)
seconds.
The engine warm-up timer lets the engine warm-up
and stabilize before transfer to the "Standby" source
can occur.
NOTE: The engine can be shut down manually at any
time, by setting the AUTO-OFF-MANUAL switch to
OFF.
AUTOMATIC OPERATING SEQUENCES
PHASE 1 - UTILITY VOLTAGE AVAILABLE:
PHASE 5- TRANSFER TO "STANDBY":
With utility source voltage available to the transfer
switch, that source voltage is sensed by a circuit
board in the generator panel and the circuit board
takes no action.
When the circuit board’s engine warm-up timer has
timed out and AC voltage has reached 50 percent of
the nominal rated voltage, circuit board action
completes a transfer relay circuit to ground. The
transfer relay is housed in the prepackaged transfer
switch enclosure.
Electrical loads are powered by the utility source and
the AUTO-OFF-MANUAL switch is set to AUTO.
The transfer relay energizes and transfer of loads to
the "Standby" power source occurs. Loads are now
powered by standby generator AC output.
PHASE 2- UTILITY VOLTAGE DROPOUT:
If a dropout in utility source voltage should occur
below about 60 percent of the nominal utility source
voltage, a 15 second timer on the circuit board will
start timing. This timer is required to prevent false
generator starts that might be caused by transient
utility voltage dips.
PHASE 6- "UTILITY" POWER RESTORED:
When utility source voltage is restored above about
80 percent of the nominal supply voltage, a 15
second timer on the circuit board starts timing. If utility
voltage remains sufficiently high at the end of 15
seconds, retransfer can occur.
PHASE 3- ENGINE CRANKING:
When the circuit board’s 15 second timer has finished
timing and if utility source voltage is still below 60
percent of the nominal source voltage, circuit board
action will energize a crank relay and a run relay.
Both of these relays are mounted on the circuit board.
PHASE 7- RETRANSFER BACK TO "UTILITY":
At the end of the 15 second delay, circuit board action
will open a circuit to a transfer relay (housed in the
transfer switch). The transfer relay will then de-
energize and retransfer back to the utility source will
occur. Loads are now powered by utility source
power. On retransfer, an engine cool-down timer
starts timing and will run for about one (1) minute.
If the engine starts, cranking will terminate when
generator AC output frequency reaches
approximately 30 Hz.
PHASE 8- GENERATOR SHUTDOWN:
When the engine cool-down timer has finished timing,
and if the minimum run timer has timed out, engine
shutdown will occur.
Page 1.7-1
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SECTION 1.7
AUTOMATIC OPERATING PARAMETERS
GENERAL INFORMATION
PART 1
AUTOMATIC OPERATING SEQUENCES CHART
SEQ. CONDITION
ACTION
SENSOR, TIMER OR OTHER
1
2
3
4
Utility source voltage is
No action
Voltage Dropout Sensor on circuit
circuit board.
available.
Utility voltage dropout below
60% of rated voltage occurs.
A 15-second timer on circuit
board turns on.
Voltage Dropout Sensor and 15
second timer on circuit board.
Utility voltage is still below
60% of rated voltage.
15-second timer runs for 15
seconds, then stops.
Voltage Dropout Sensor and 15
second timer.
Utility voltage is still low after
15 seconds.
Circuit board action energizes a Circuit board crank and run
crank relay and a run relay.
See NOTE 1.
relays.
5
6
Utility voltage still low and
the engine has started.
Circuit board s engine warmup Engine Warmup Timer (10 seconds)
timer runs for 10 seconds.
Engine running and engine
warmup timer times out.
AC output voltage above
50% nominal voltage.
Circuit board action energizes a
transfer relay in transfer switch
and transfer to Standby occurs.
Circuit board transfer relay circuit
Transfer switch transfer relay.
7
8
9
Engine running and load is
powered by Standby power.
No further action
Circuit board voltage pickup
sensor continues to seek an
acceptable Utility voltage.
Utility source voltage is
restored above 80% of rated
Circuit board voltage pickup
sensor reacts and a re-transfer Return to Utility Timer (15 seconds)
time delay turns on.
Voltage Pickup Sensor (80%)
Utility voltage still high after 15
seconds.
Return to Utility Timer times out Return to Utility Timer
10 Utility voltage still high.
Circuit board action opens the
transfer relay circuit to ground.
Transfer relay de-energizes and
retransfer to Utility occurs.
Circuit board transfer relay circuit
Transfer switch transfer relay.
11 Engine still running, loads are
powered by Utility source.
Circuit board engine cool down Circuit board Engine Cool down
timer starts running. Timer (1 minute)
12
After 1 minute, engine cool down Engine Cool down Timer
timer stops and circuit board s
run relay de-energizes. Engine
shuts down.
Circuit board Run Relay.
13 Engine is shut down, loads are
powered by Utility source.
Return to Sequence 1.
No action.
Voltage Dropout Sensor on circuit
circuit board.
Page 1.7-2
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TABLE OF CONTENTS
PART
2.1
TITLE
Description and Components
Operational Analysis
2.2
PART 2
2.3
Troubleshooting Flow Charts
Diagnostic Tests
2.4
AC GENERATORS
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
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SECTION 2.1
DESCRIPTION & COMPONENTS
AC GENERATORS
PART 2
directly coupled to the engine crankshaft (see Figure
1), and mounted in an enclosure. Both the engine and
generator rotor are driven at approximately 3600 rpm,
to provide a 60 Hz AC output.
INTRODUCTION
The air-cooled, pre-packaged automatic standby
system is an easy to install, fully enclosed and self-
sufficient electric power system. It is designed
especially for homeowners, but may be used in other
applications as well. On occurrence of a utility power
failure, this high performance system will (a) crank
and start automatically, and (b) automatically transfer
electrical loads to generator AC output.
THE AC GENERATOR
Figure 1 shows the major components of the AC
generator.
The generator revolving field (rotor) is driven by an
air-cooled engine at about 3600 rpm.
The generator may be used to supply electrical power
for the operation of 120 and/or 240 volts, 1phase, 60
Hz, AC loads.
A 2-pole, "V-Type", prepackaged transfer switch is
shipped with the unit (see Part 3). Prepackaged
transfer switches do not include an "intelligence
circuit" of their own. Instead, automatic startup,
transfer, running, retransfer and shutdown operations
are controlled by a solid state circuit board in the
generator control panel.
ROTOR ASSEMBLY
The 2-pole rotor must be operated at 3600 rpm to
supply a 60 Hertz AC frequency. The term "2-pole"
means the rotor has a single north magnetic pole and
a single south magnetic pole. As the rotor rotates, its
lines of magnetic flux cut across the stator assembly
windings and a voltage is induced into the stator
windings. The rotor shaft mounts a positive (+) and a
negative (-) slip ring, with the positive (+) slip ring
nearest the rear bearing carrier. The rotor bearing is
pressed onto the end of the rotor shaft. The tapered
rotor shaft is mounted to a tapered crankshaft and is
held in place with a single through bolt.
ENGINE-GENERATOR DRIVE SYSTEM
The generator revolving field is driven by an air-
cooled, horizontal crankshaft engine. The generator is
Figure 1. AC Generator Exploded View
Page 2.1-1
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SECTION 2.1
DESCRIPTION & COMPONENTS
AC GENERATORS
PART 2
Wire 4 connects to the positive (+) brush and Wire 0 to
the negative (-) brush. Wire 0 connects to frame
ground. Rectified and regulated excitation current, as
well as current from a field boost circuit, are delivered
to the rotor windings via Wire 4, and the positive (+)
brush and slip ring. The excitation and field boost
current passes through the windings and to frame
ground via the negative (-) slip ring and brush, and
Wire 0. This current flow creates a magnetic field
around the rotor having a flux concentration that is
proportional to the amount of current flow.
Figure 2. The 2-Pole Rotor Assembly
STATOR ASSEMBLY
The stator can houses and retains (a) dual AC power
windings, (b) excitation winding, (c) battery charge
winding and (d) engine run winding. A total of twelve
(12) stator leads are brought out of the stator can as
shown in Figure 3.
The stator can is sandwiched between an engine
adapter and a rear bearing carrier. It is retained in
that position by four stator studs.
Figure 4. Brush Holder and Brushes
OTHER AC GENERATOR COMPONENTS
Some AC generator components are housed in the
generator control panel enclosure, and are not shown
in Figure 1. These are (a) an excitation circuit breaker,
(b) a voltage regulator, and (c) a main line circuit
breaker.
EXCITATION CIRCUIT BREAKER:
The excitation circuit breaker (CB2) is housed in the
generator panel enclosure and electrically connected
in series with the excitation (DPE) winding output to
the voltage regulator. The breaker is self-resetting, i.e.;
its contacts will close again when excitation current
drops to a safe value.
Figure 3 Stator Assembly Leads
BRUSH HOLDER AND BRUSHES
The brush holder is retained to the rear bearing carrier
by means of two #10-32 x 9/16 Taptite screws. A
positive (+) and a negative (-) brush are retained in the
brush holder, with the positive (+) brush riding on the
slip ring nearest the rotor bearing.
If the circuit breaker has failed open, excitation current
flow to the voltage regulator and, subsequently, to the
rotor windings will be lost. Without excitation current
flow, AC voltage induced into the stator AC power
windings will drop to a value that is commensurate with
the rotor residual magnetism (see Figure 5).
Page 2.1-2
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SECTION 2.1
DESCRIPTION & COMPONENTS
AC GENERATORS
PART 2
Figure 5. Excitation Circuit Breaker
VOLTAGE REGULATOR:
Figure 6. Typical Voltage Regulator
A typical voltage regulator is shown in Figure 6.
Unregulated AC output from the stator excitation
winding is delivered to the regulator’s DPE terminals,
via Wire 2, the excitation circuit breaker, Wire 162,
and Wire 6. The voltage regulator rectifies that
current and, based on stator AC power winding
sensing, regulates it. The rectified and regulated
excitation current is then delivered to the rotor
windings from the positive (+) and negative (-)
regulator terminals, via Wire 4 and Wire 1. Stator AC
power winding sensing is delivered to the regulator
"SEN" terminals via Wires 11 and 22.
A single red lamp (LED) glows during normal
operation. The lamp will become dim if excitation
winding AC output diminishes. It will go out on
occurrence of an open condition in the sensing AC
output circuit.
An adjustment potentiometer permits the stator AC
power winding voltage to be adjusted. Perform this
adjustment with the generator running at no-load, and
with a 62 Hz AC frequency (62 Hz equals 3720 rpm).
At the stated no-load frequency, adjust to obtain a
line-to-line AC voltage of about 252 volts.
The regulator provides "over-voltage" protection, but
does not protect against "under-voltage". On
occurrence of an "over-voltage’ condition, the
regulator will "shut down" and complete loss Of
excitation current to the rotor will occur. Without
excitation current, the generator AC output voltage
will drop to approximately one-half (or lower) of the
unit’s rated voltage.
MAIN LINE CIRCUIT BREAKER:
The main line circuit breaker protects the generator
against electrical overload. See Specifications on
Page 1 for amp ratings.
Page 2.1-3
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SECTION 2.2
OPERATIONAL ANALYSIS
AC GENERATORS
PART 2
Field boost voltage is reduced from that of battery
voltage by the resistor action and, when read with a
DC voltmeter, will be approximately 9 or 10 volts DC.
ROTOR RESIDUAL MAGNETISM
The generator revolving field (rotor) may be
considered to be a permanent magnet. Some
’residual" magnetism is always present in the rotor.
This residual magnetism is sufficient to induce a
voltage into the stator AC power windings that is
approximately 2-12 volts AC.
FIELD BOOST
FIELD BOOST CIRCUIT:
When the engine is cranking, direct current flow is
delivered from a circuit board to the generator rotor
windings, via Wire 4.
The field boost system is shown schematically in
Figure 2. Manual and automatic engine cranking is
initiated by circuit board action, when that circuit
board energizes a crank relay (K1). Battery voltage is
then delivered to field boost Wire 4 (and to the rotor),
via a field boost resistor and diode. The crank relay,
field boost resistor and diode are all located on the
circuit board.
Notice that field boost current is available only while
the crank relay (K1) is energized, i.e., while the
engine is cranking.
Figure 2. Field Boost Circuit Schematic
Figure 1. Operating Diagram of AC Generator
Page 2.2-1
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SECTION 2.2
OPERATIONAL ANALYSIS
AC GENERATORS
PART 2
Initially, the AC power winding voltage sensed by the
regulator is low. The regulator reacts by increasing
the flow of excitation current to the rotor until voltage
increases to a desired level. The regulator then
maintains the desired voltage. For example, if voltage
exceeds the desired level, the regulator will decrease
the flow of excitation current. Conversely, if voltage
drops below the desired level, the regulator responds
by increasing the flow of excitation current.
OPERATION
STARTUP:
When the engine is started, residual plus field boost
magnetism from the rotor induces a voltage into (a)
the stator AC power windings, (b) the stator excitation
or DPE windings, (c) the stator battery charge, and (d)
engine run winding. In an "on-speed" condition,
residual plus field boost magnetism are capable of
creating approximately one-half the unit’s rated
voltage.
AC POWER WINDING OUTPUT:
A regulated voltage is induced into the stator AC
power windings. When electrical loads are connected
across the AC power windings to complete the circuit,
current can flow in the circuit. The regulated AC
power winding output voltage will be in direct
proportion to the AC frequency. For example, on units
rated 120/240 volts at 60 Hz, the regulator will try to
maintain 240 volts (line-to-line) at 60 Hz. This type of
regulation system provides greatly improved motor
starting capability over other types of systems.
ON-SPEED OPERATION:
As the engine accelerates, the voltage that is induced
into the stator windings increases rapidly, due to the
increasing speed at which the rotor operates.
FIELD EXCITATION:
An AC voltage is induced into the stator excitation
(DPE) windings. The DPE winding circuit is completed
to the voltage regulator, via Wire 2, excitation circuit
breaker, Wire 162, and Wire 6. Unregulated
alternating current can flow from the winding to the
regulator.
BATTERY CHARGE WINDING OUTPUT:
A voltage is induced into the battery charge windings.
Output from these windings is delivered to a battery
charger, via Wires 66 and 77. The resulting direct
current from the battery charger is delivered to the
unit battery, via Wire 15, a 15 amp fuse, and Wire 13.
This output is used to maintain battery state of charge
during operation.
The voltage regulator "senses" AC power winding
output voltage and frequency via stator Wires 11 and
22.
The regulator changes the AC from the excitation
winding to DC. In addition, based on the Wires 11 and
22 sensing signals, it regulates the flow of direct
current to the rotor.
ENGINE RUN WINDING OUTPUT:
A voltage is induced into the engine run winding and
delivered to a solid state circuit board , via Wire 66A.
This output "tells" the circuit board that the engine has
started and what its operating speed is. The circuit
board uses these signals from the engine run winding
to (a) terminate cranking, and (b) turn on various
timing circuits that control automatic operation. See
Part 4, "DC Control".
The rectified and regulated current flow from the
regulator is delivered to the rotor windings, via Wire 4,
and the positive brush and slip ring. This excitation
current flows through the rotor windings and is
directed to ground through the negative (-) slip ring
and brush, and Wire 0.
The greater the current flow through the rotor
windings, the more concentrated the lines of flux
around the rotor become.
The more concentrated the lines of flux around the
rotor that cut across the stationary stator windings,
the greater the voltage that is induced into the stator
windings.
Page 2.2-2
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SECTION 2.3
TROUBLESHOOTING FLOWCHARTS
AC GENERATORS
PART 2
GENERAL
Use the Flow Charts in conjunction with the detailed
instructions in Section 2.4. Test numbers used in the
flow charts correspond to the numbered tests in
Section 2.4.
The first step in using the flow charts is to correctly
identify the problem. Once that has been done, locate
the problem on the following pages. For best results,
perform all tests in the exact sequence shown in the
flow charts.
Page 2.3-1
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SECTION 2.3
TROUBLESHOOTING FLOWCHARTS
AC GENERATORS
PART 2
Page 2.3-2
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SECTION 2.3
TROUBLESHOOTING FLOWCHARTS
AC GENERATORS
PART 2
Page 2.3-3
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SECTION 2.3
TROUBLESHOOTING FLOWCHARTS
AC GENERATORS
PART 2
Page 2.3-4
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
PROCEDURE:
INTRODUCTION
The generator main circuit breaker is located on the
control panel. If loads are not receiving power, make
sure the breaker is set to "On" or "Closed".
If you suspect the breaker may have failed, it can be
tested as follows (see Figure 1):
This section is provided to familiarize the service
technician with acceptable procedures for the testing
and evaluation of various problems that could be
encountered on prepackaged standby generators with
air-cooled engine. Use this section of the manual in
conjunction with Section 2.3, "Troubleshooting Flow
Charts". The numbered tests in this section
correspond with those of Section 2.3.
1. Set a volt-ohm-milliammeter (VOM) to its "R x 1" scale
and zero the meter.
2. With the generator shut down, disconnect all wires from
the main circuit breaker terminals, to prevent interaction.
Test procedures in this section do not require the use
of specialized test equipment, meters or tools. Most
tests can be performed with an inexpensive volt-ohm-
milliammeter (VOM). An AC frequency meter is
required, where frequency readings must be taken. A
clamp-on ammeter may be used to measure AC
loads on the generator.
Testing and troubleshooting methods covered in this
section are not exhaustive. We have not attempted to
discuss, evaluate and advise the home standby
service trade of all conceivable ways in which service
and trouble diagnosis might be performed. We have
not undertaken any such broad evaluation.
Accordingly, anyone who uses a test method not
recommended herein must first satisfy himself that
the procedure or method he has selected will
jeopardize neither his nor the product’s safety.
3. With the generator shut down, connect one VOM test
probe to the Wire 11 terminal of the breaker and the
other test probe to the Wire E1 terminal.
4. Set the breaker to its "On" or "Closed" position. The
VOM should read CONTINUITY.
5. Set the breaker to its OFF or "Open" position and the
VOMshould indicate INFINITY.
6. Repeat Steps 4 and 5 with the VOM test probes
connected across the breaker's Wire 44 terminal and
the E2 terminal.
RESULTS:
1. If the circuit breaker tests good, go on to Test 2.
SAFETY
2. If the breaker tests bad, it should be replaced.
Service personnel who work on this equipment must
be made aware of the dangers of such equipment.
Extremely high and dangerous voltages are present
that can kill or cause serious injury. Gaseous fuels
are highly explosive and can be ignited by the
slightest spark. Engine exhaust gases contain deadly
carbon monoxide gas that can cause
unconsciousness or even death. Contact with moving
parts can cause serious injury. The list of hazards is
seemingly endless.
When working on this equipment, use common sense
and remain alert at all times. Never work on this
equipment while you are physically or mentally
fatigued. If you don’t understand a component, device
or system, do not work on it.
TEST 1- CHECK MAIN CIRCUIT BREAKER
DISCUSSION:
Often the most obvious cause of a problem is
overlooked. If the generator main line circuit breaker
is set to OFF or "Open", no electrical power will be
supplied to electrical loads. If loads are not receiving
power, perhaps the main circuit breaker is open or
has failed.
Figure 1. Generator Main Circuit Breaker Test Points
Page 2.4-1
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
current units with air-cooled engine, "field boost"
current flow is available to the rotor only during
engine cranking.
TEST 2- CHECK AC OUTPUT VOLTAGE
DISCUSSION:
A volt-ohm-milliammeter (VOM) may be used to
check the generator output voltage. Output voltage
may be checked at the unit’s main circuit breaker
terminals. Refer to the unit’s DATA PLATE for rated
line-to-line and line-to-neutral voltages.
TEST 3- TEST EXCITATION CIRCUIT
BREAKER
DISCUSSION:
DANGER: USE EXTREME CAUTION DURING
THIS TEST. THE GENERATOR WILL BE
RUNNING. HIGH AND DANGEROUS
Unregulated excitation current is delivered to the
voltage regulator from the stator excitation (DPE)
winding, via Wire 2, an excitation circuit breaker
(CB2), Wire 162, and Wire 6. If the excitation circuit
breaker has failed open, excitation current will not be
available to the voltage regulator or to the rotor.
Stator AC power winding output will then be reduced
to a voltage that is the product of residual magnetism
alone.
VOLTAGES WILL BE PRESENT AT THE TEST
TERMINALS. CONNECT METER TEST CLAMPS
TO THE HIGH VOLTAGE TERMINALS WHILE
THE GENERATOR IS SHUT DOWN. STAY
CLEAR OF POWER TERMINALS DURING THE
TEST. MAKE SURE METER CLAMPS ARE
SECURELY ATTACHED AND WILL NOT SHAKE
LOOSE.
PROCEDURE:
1. With the generator shut down for at least two minutes,
locate the excitation circuit breaker in the generator
panel. Disconnect wires from the breaker, to prevent
interaction.
PROCEDURE:
1. With the engine shut down, connect the AC voltmeter
test leads across the Wires 11 and 44 terminals of the
generator main circuit breaker (see Figure 1). These
connections will permit line-to-line voltages to be read.
2. Set a volt-ohm-milliammeter (VOM) to its "R x 1'scale
and zero the meter.
3. Connect the VOM test probes across the circuit breaker
terminals. The meter should read CONTINUITY.
2. Set the generator main circuit breaker to its OFF or
"Open" position. This test will be conducted with the
generator running at no-load.
RESULTS:
1. Replace circuit breaker if defective (meter reads
“OPEN”). Then proceed to Test 4.
3. Start the generator, let it stabilize and warm up for a
minute or two.
2. If circuit breaker is good, go on to Test 4.
4. Take the meter reading. On unit's having a rated line-to-
line voltage of 240 volts, the no-load voltage should be
about 242-252 volts AC.
5. Shut the engine down and remove the meter test leads.
RESULTS:
1. If zero volts or residual voltage is indicated, go on to
Test 3.
2. If the voltage reading is higher than residual, but is lower
than the stated limits, go to Test 11.
3. If a high voltage is indicated, go on to Test 11.
NOTE: "Residual" voltage may be defined as the
voltage that is produced by rotor residual magnetism
alone. The amount of voltage induced into the stator
AC power windings by residual voltage alone will be
approximately 2 to 16 volts AC, depending on the
characteristics of the specific generator. If a unit is
supplying residual voltage only, either excitation
current is not reaching the rotor or the rotor windings
are open and the excitation current cannot pass. On
Figure 2. Excitation Circuit Breaker
Page 2.4-2
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
TEST 4- FIXED EXCITATION TEST
/ROTOR AMP DRAW TEST
DISCUSSION:
Supplying a fixed DC current to the rotor will induce a
magnetic field in the rotor. With the generator
running, this should create a proportional voltage
output from the stator windings.
PROCEDURE:
1. Disconnect Wire 4 from the voltage regulator, 3rd
terminal from the top. See Figure 3.
2. Connect a jumper wire to the disconnected Wire 4 and
to the 12 volt fused battery supply Wire 15. (located at
15A fuse).
Figure 3. Voltage Regulator
3. Set VOM to AC volts.
4. Disconnect Wire 2 from the excitation circuit breaker
(CB2) and connect one meter test lead to that wire.
Disconnect Wire 6 from the voltage regulator and
connect the other meter test lead to that wire. (5th
terminal from top, double check wire number).
5. Set the AUTO-OFF-MANUAL switch to MANUAL. Once
the engine starts, record the AC voltage.
6. Set the AUTO-OFF-MANUAL switch to OFF.
Reconnect Wire 2 and Wire 6.
7. Disconnect Wire 11 from the voltage regulator and
connect one meter test lead to that wire. Disconnect
Wire 22 from the voltage regulator and connect the
other meter test lead to that wire (both wires are located
at the top two terminals of the voltage regulator, see
Figure 3).
Page 2.4-3
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
8. Set the AUTO-OFF-MANUAL switch to MANUAL. Once
the engine starts, record the AC voltage.
RESULTS:
If CONTINUITY was NOT measured across each wire, repair
or replace the wires as needed.
9. Set the AUTO-OFF-MANUAL switch to OFF.
Reconnect Wire 11 and Wire 22.
TEST 6 - CHECK FIELD BOOST
10.Set VOM to DC amperage.
11.Remove jumper lead connected to Wire 4 and Wire 15.
DISCUSSION:
12.Connect one meter test lead to battery positive twelve-
volt supply Wire 15, located at the 15A fuse. Connect
the other meter test lead to Wire 4 (still disconnected
from previous tests). Measure and record static rotor
amp draw.
See "Field Boost Circuit" on Page 2.2-1. Field boost current
(from the circuit board) is available to the rotor only while the
engine is cranking. Loss of field boost output to the rotor may
or may not affect power winding AC output voltage. The
following facts apply:
13.Set the AUTO-OFF-MANUAL switch to the MANUAL
position. Once the engine starts, repeat step 12.
Measure and record running rotor amp draw with the
engine running.
o A small amount of voltage must be induced into the DPE
winding to turn the voltage regulator on.
o If rotor residual magnetism is sufficient to induce a voltage
into the DPE winding that is high enough to turn the voltage
regulator on, regulator excitation current will be supplied
even if field boost has failed. Normal AC output voltage will
then be supplied.
14.Set the Auto-Off -Manual switch to OFF. Reconnect
Wire 4 to the voltage regulator.
RESULTS:
o If rotor residual magnetism has been lost or is not sufficient
to turn the regulator on, and field boost has also been lost,
excitation current will not be supplied to the rotor. Generator
AC output voltage will then drop to zero or nearly zero.
Refer to Chart on Page 2.4-3: “Results - Fixed Excitation
Test/Rotor Amp Draw Test.”.
TEST 5: WIRE CONTINUITY
PROCEDURE:
DISCUSSION:
1. Locate Wire 4 that is routed from the circuit board and
connects to the voltage regulator terminal, third from the
top (see Figure 3). Disconnect that wire from the voltage
regulator terminal.
The voltage regulator receives unregulated alternating
current from the stator excitation winding, via Wires 2, 6,
and 162. It also receives voltage sensing from the stator
AC power windings, via Wires 11 and 22. The regulator
rectifies the AC from the excitation winding and based on
the sensing signals, regulates the DC current flow to the
rotor. The rectified and regulated current flow is delivered
to the rotor brushes via Wires 4 (positive) and 0 (negative).
This test will verify the integrity of Wires 0 and 162.
2. Set a VOM to read DC volts. Disconnect Connector C2
from the control panel (C2 is the closest to the back
panel).
3. Connect the positive (+) VOM test probe to the terminal
end of disconnected Wire 4.
4. Connect the common (-) VOM test probe to the
grounding lug.
PROCEDURE:
1. Set VOM to its "R x 1" scale.
5. Crank the engine while observing the VOM reading. While
the engine is cranking, the VOM should read
approximately 9-10 volts DC. When engine is not
cranking, VOM should indicate "zero" volts (see Figure 4).
2. Remove Wire 0 from the voltage regulator, 4th terminal
from the top. Also voltage regulator is labeled (-) next to
terminal.
3. Connect one test lead to Wire 0, connect the other test
lead to a clean frame ground. The meter should read
CONTINUITY.
RESULTS:
1. If normal field boost voltage is indicated in Step 5,
replace the voltage regulator.
4. Disconnect Wire 162 from the voltage regulator, 6th
terminal from the top. Disconnect the other end of Wire 162
from the excitation circuit breaker. Connect one test lead to
one end of Wire 162, and the other test lead to the other
end of Wire 162. The meter should read CONTINUITY.
2. If normal field boost voltage is NOT indicated in Step 5,
check Wire 4 (between regulator and circuit board) for
open or shorted condition. If wire is good, replace the
circuit board.
Page 2.4-4
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
from each other and are not touching the frame during
the test.
5. Set a VOM to its "R x 1" scale and zero the meter.
6. Refer to Figure 5 for pin locations of Connector C2. Use
a large paper clip or similar metallic object to access
pins in connector C2.
Note: Pins 9, 10, 11 & 12 are not used for this test.
Figure 5. C2 Connector
Pin Locations
Figure 6. C2 Connector
Pin Locations
Figure 4. Field Boost Test Points
(Female Side)
(Male Side)
7. Connect one test lead to stator lead Wire 11. Connect
the other test lead to stator lead Wire 22 (power
winding). Note the resistance reading and compare to
the specifications on Page 2.
TEST 7: TESTING THE STATOR WITH A VOM
DISCUSSION:
A Volt-OHM-Milliammmeter (VOM) can be used to test the
stator windings for the following faults:
8. Connect one test lead to stator lead Wire 33. Connect
the other test lead to stator lead Wire 44 (power
winding). Note the resistance reading and compare to
the specifications on Page 2.
❏ An open circuit condition
❏ A "short-to-ground" condition
❏ A short circuit between windings
9. Connect one test lead to Pin 1. Connect the other test
lead to Pin 2 (battery charge winding). Note the
resistance reading, compare to specifications on Page 2.
Note: The resistance of stator windings is very low.
Some meters will not read such a low resistance, and
will simply indicate CONTINUITY. Recommended is a
high quality, digital type meter capable of reading very
low resistances.
10.Connect one test lead to Pin 3. Connect the other test
lead to Pin 4 (engine run winding). Note the resistance
reading, compare to specification Page 2.
PROCEDURE:
1. Disconnect stator leads 11 and 44 from the main circuit
breaker.
11.Connect one test lead to Pin 5. Connect the other test
lead to Pin 6 (power winding-sense leads). Note the
resistance reading, compare to specification Page 2.
2. Disconnect stator leads 22 and 33 from the neutral
connection separate the leads.
12.Connect on test lead to Pin 7. Connect the other test
lead to Pin 8 (excitation winding). Note the resistance
reading, compare to specification Page 2.
3. Disconnect Connector C2 from the side of the control
panel (C2 is the closest to the back panel).
4. Make sure all off the disconnected leads are isolated
Page 2.4-5
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
TEST WINDINGS FOR A SHORT TO GROUND:
13. Make sure all leads are isolated from each other and
are not touching the frame.
35. Connect one meter test lead to Pin 7 of the C2
connector, connect the other test lead to Wire 6 at the
voltage regulator. CONTINUITY should be measured.
36. Connect one meter test lead to Pin 8 of the C2
connector, connect the other test lead to Wire 2 at CB2
(DPE circuit breaker). CONTINUITY should be
measured.
14. Set a VOM to its "R x 10,000" or "R x 1K" scale and
zero the meter
15. Connect one test lead to a clean frame ground.
Connect the other test lead to stator lead Wire 11.
a. The meter should read INFINITY
RESULTS:
1. Stator winding resistance values is a test of winding
continuity and resistance. If a very high resistance or
INFINITY is indicated, the winding is open or partially
open.
b. Any reading other than INFINITY indicates a
"short-to-ground" condition.
16. Repeat Step 15 using stator lead Wire 33.
17. Repeat Step 15 using Pin 1.
18. Repeat Step 15 using Pin 3
2. Testing for a "grounded" condition: Any upscale
movement of the meter needle or dial indicates the
winding is grounded.
19. Repeat Step 15 using Pin 5
20. Repeat Step 15 using Pin 7
3. Testing for a "shorted" condition: Any upscale
movement of the VOM needle or dial indicates the
winding is shorted.
TEST FOR A SHORT CIRCUIT BETWEEN WINDINGS:
21. Set a VOM to its "R x 10,000" or "R x 1K" scale and
zero the meter.
4. If the stator tests good and wire continuity tests good ,
perform “Insulation Resistance Test” on page 1.4-4.
22. Connect one test lead to stator lead Wire 11. Connect
the other test lead to stator lead Wire 33.
5. If any test of wire continuity failed in control panel failed,
repair or replace the wire, terminal or pin connectors for
that associated wire as needed.
a. The meter should read INFINITY.
b. Any reading other than INFINITY indicates a short
circuit between windngs.
NOTE: Read section 1.4, "Testing, Cleaning and
Drying" carefully. If the winding tests good, perform an
insulation resistance test. If the winding fails the
insulation resistance test, clean and dry the stator as
outlined in Section 1.4. Then, repeat the insulation
resistance test. If the winding fails the second
resistance test (after cleaning and drying), replace
the stator assembly.
23. Repeat Step 22 using stator lead Wire 11; Pin 1
24. Repeat Step 22 using stator lead Wire 11; Pin 3
25 Repeat Step 22 using stator lead Wire 11; Pin 7
26. Repeat Step 22 using stator lead Wire 33; Pin 1
27. Repeat Step 22 using stator lead Wire 33; Pin 3
28. Repeat Step 22 using stator lead Wire 33; Pin 7
29. Repeat Step 22 using Pin 1; Pin 3
30. Repeat Step 22 using Pin 1; Pin 7
TEST 8 - RESISTANCE CHECK
OF ROTOR CIRCUIT
31. Repeat Step 22 using Pin 3; Pin 7
DISCUSSION:
TEST CONTROL PANEL WIRES FOR CONTINUITY:
32.Set a VOM to its "Rx1" scale.
To verify the zero current draw reading and measure the
rotor circuit.
33.Disconnect the C2 connector from the control panel. (C2
is the closest to the back panel). Refer to Figure 6 for
pin locations.
PROCEDURE:
1. Disconnect Wire 4 from the voltage regulator. It is
located 3rd terminal from the top of the volt regulator.
33.Connect one meter test lead to Pin 5 of the C2
connector, connect the other test lead to Wire 22 at the
voltage regulator. CONTINUITY should be measured.
2. Set VOM to the "Rx1" scale.
34. Connect one meter test lead to Pin 6 of the C2
connector, connect the other test lead to Wire 11 at the
voltage regulator. CONTINUITY should be measured.
3. Connect one test lead to Wire 4. Connect the other test
lead to a clean frame ground. Note the resistance
reading. Compare to specifications on Page 2.
Page 2.4-6
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
RESULTS:
5. Wire 0 from the negative (-) brush terminal connects to
Pin 9 of the C2 connector.
1. If the resistance reading is correct, check your VOM
meters fuse and repeat Test 4.
Test this wire for an open condition. Remove wire 0
from the brush assembly. Connect one meter test lead
to wire 0. Connect the other test lead to Pin 9 (wire 0)
of the C2 connector ( female side). CONTINUITY
should be measured. If INFINITY is measured repair or
replace wire 0 between the brush assembly and the C2
connector.
2. If INFINITY is measured on your VOM meter, go to Test 9.
TEST 9 - CHECK BRUSHES
AND SLIP RINGS
DISCUSSION:
The function of the brushes and slip rings is to provide for
passage of excitation current from stationary components to the
rotating rotor. Brushes are made of a special long lasting
material and seldom wear out or fail. However, slip rings can
develop a tarnish or film that can inhibit or offer a resistance to
the flow of electricity. Such a non-conducting film usually
develops during non-operating periods. Broken or disconnected
wiring can also cause loss of excitation current to the rotor.
6. Wire 4 from the positive (+) brush terminal connects to
Pin 10 of the C2 connector.Test this wire for an open
condition. Remove wire 4 from the brush assembly.
Connect one meter test lead to Wire 4. Connect the
other meter test lead to Pin 10 (wire 0) of the C2
connector (female side). CONTINUITY should be
measured. If INFINITY is measured repair or replace
wire 4 between the brush assembly and the C2
connector.
7. Connect one meter test lead to wire 4 Connect the
other meter test lead to frame ground. INFINITY should
be measured. If CONTINUITY is measured a short to
ground exists on wire 4 repair or replace wire 4
between the brush assembly and the C2 connector.
8. If continuity was measured in steps 5 and 6 proceed to
step 9.
9. Disconnect wires 0 and 4 from the brush assembly.
Remove the brush assembly from the bearing carrier.
Inspect the brushes for excessive wear,damage.
Figure 7. Checking Brushes and Slip Rings
10. Inspect the rotor slip rings. If they appear dull or
tarnished, they may be polished with a fine sandpaper.
DO NOT USE METALLIC GRIT TO POLISH SLIP
RINGS.
PROCEDURE:
1. Disconnect connector C2 (deutsch connector closest to
the back panel). Refer to figure 5 and figure 6 on page
2.4-5.
11. If brush assembly and slip rings look good proceed to
Test 10 ( Test Rotor assembly)
2. Set a VOM to measure resistance.
3. Connect one meter test lead to Pin 9 (Wire 0) of the C2
connector (female side). Connect the other meter test
lead to Pin 10 (Wire 4) of the C2 connector (female
side). Rotor resistance should be measured see
specifications on page 2. If rotor resistance is not
measured proceed to step 4. If rotor resistance is
measured proceed to step 12.
12. Wire 0 connects from the C2 connector to the control
panel ground lug. Connect one meter test lead to Pin 9
(Wire 0) of the C2 connector (male side). Connect the
other meter test lead to the ground terminal in the
control panel. CONTINUITY should be measured. If
INFINITY is measured repair or replace wire 0 between
the C2 connector and the ground terminal.
4. See figure 7. Carefully inspect brush wires; make sure
they are properly and securely connected.
13. Remove wire 4 from the voltage regulator.
Page 2.4-7
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
14. Connect one meter test lead to Pin 10 (wire 4) of the
C2 connector (male side). Connect the other meter test
lead to Wire 4 removed from the Voltage regulator.
CONTINUITY should be measured. If INFINITY is
measured repair or replace wire 4 between the C2
connector and the voltage regulator.
RESULTS:
1. Repair, replace or reconnect wires as necessary.
2. Replace any damaged slip rings or brush holder.
3. Clean and polish slip rings as required.
Figure 8. The Rotor Assembly
TEST 11 - CHECK AC OUTPUT FREQUENCY
TEST 10 - TEST ROTOR ASSEMBLY
DISCUSSION:
DISCUSSION:
The generator AC frequency is proportional to the operating
speed of the rotor. The 2-pole rotor will supply a 60 Hertz
AC frequency at 3600 rpm. The unit's AC output voltage is
proportional to the AC frequency. For example, a unit rated
240 volts (line-to-line) will supply that rated voltage (plus or
minus 2 percent) at a frequency of 60 Hertz. If, for any
reason, the frequency should drop to 30 Hertz, the line-to-
line voltage will drop to a matching voltage of 120 volts AC.
Thus, if the AC voltage output is high or low and the AC
frequency is correspondingly high or low, the engine speed
governor may require adjustment.
A rotor having completely open windings will cause loss of
excitation current flow and, as a result, generator AC output
voltage will drop to "residual" voltage. A "shorted" rotor
winding can result in a low voltage condition.
PROCEDURE:
I. Disconnect the brush wires or remove the brush holder,
to prevent interaction.
2. Set a VOM to its "R x 1" scale and zero the meter.
3. Connect the positive (+) VOM test lead to the positive
(+) rotor slip ring (nearest the rotor bearing); and the
common (-) test lead to the negative (-) slip ring. The
meter should read approximately 10-20 ohms. Compare
to “Specifications,” Page 1.
PROCEDURE:
1. Connect an accurate AC frequency meter across the
Wires 11 and 44 terminals of the generator main line
circuit breaker (see Figure 1, Page 2.4-1).
2. Start the engine, let it stabilize and warm up at no-load.
4. Now, set the VOM to a high resistance scale (such as
"R x 10,000" or "R x 1K"). Again, zero the meter.
3. When engine has stabilized, read the frequency meter.
The no-load frequency should be about 61-63 Hertz.
5. Connect the positive (+) VOM test lead to the positive
(+) slip ring and the common (-) test lead to a clean
frame ground. The meter should indicate INFINITY.
RESULTS:
1. If the AC frequency is high or low, go on to Test 12.
2. If frequency is good, but voltage is high or low, go to
Test 13.
3. If frequency and voltage are both good, tests may be
discontinued.
RESULTS:
1. Replace rotor assembly if it is open or shorted.
2. If rotor tests good, perform “Insulation Resistance Test”
on Page 1.4-6.
TEST 12 - CHECK AND ADJUST ENGINE
GOVERNOR
NOTE: Be sure to read Section 1.4, "Testing, Cleaning
and Drying", carefully. If the rotor tests good, try
performing an insulation resistance test. Clean and dry
the rotor if it fails that test. Then, repeat the test. If the
rotor fails the second insulation resistance test, it
should be replaced.
DISCUSSION:
The generator AC frequency output is directly proportional
to the speed of the rotor. A two-pole rotor (having a single
north and a single south magnetic pole) will produce an AC
frequency of 60 hertz at 3600 RPM.
The generator is equipped with a "voltage over frequency"
type AC voltage regulator. The units AC output voltage is
Page 2.4-8
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
generally proportional to AC frequency. A low or high governor
speed will result in a correspondingly low or high AC frequency
and voltage output. The governed speed must be adjusted
before any attempt to adjust the voltage regulator is made.
PROCEDURE (12/15 KW UNITS):
1. Loosen governor clamp bolt (See Figure 10).
2. Completely remove the idle spring.
3. With governor arm at wide open throttle position, rotate
governor shaft fully clockwise. Tighten clamp bolt to 84
inch-pounds.
PROCEDURE (7KW UNITS):
1. Loosen the governor clamp bolt (Figure 9).
4. Start unit and apply full load. Use full load speed adjust
screw (Figure 11) to adjust frequency to 58 Hz.
2. Hold the governor lever at its wide open throttle position,
and rotate the governor shaft clockwise as far as it will
go. Then, tighten the governor lever clamp bolt to 70
inch-pounds (8 N-m).
5. Remove load, stop engine, loosen the idle adjust screw
and reconnect the idle spring.
3. Start the generator; let it stabilize and warm up at no-load.
6. Using your hand, push the governor arm to the closed
throttle position. Make sure the idle spring does not
stretch at all.
4. Connect an AC frequency meter across the generators
AC output leads.
7. Restart the unit.
5. Turn the speed adjust nut to obtain a frequency reading
of 62 Hz.
8. Slowly turn the idle adjust screw to adjust the no-load
idle speed to 62.5 Hz.
6. When frequency is correct at no load, check the AC
voltage reading. If voltage is incorrect, the voltage
regulator may require adjustment.
9. The governor is now set.
Figure 11. Full Load Speed Adjust
ScrewV-twin Engines
Figure 9. Engine Governor Adjustment Single
Cylinder Engines
RESULTS:
1. If, after adjusting the engine governor, frequency and
voltage are good, tests may be discontinued.
2. If frequency is now good, but voltage is high or low, go
to Test 13.
3. If engine was overspeeding, check linkage and throttle
for binding. If no governor response is indicated refer to
engine service manual.
4. If engine appears to run rough and results in low
frequency, proceed tp Problem 11, Page 4.3-3.
Figure 10. Engine Governor Adjustment
V-twin Engines
Page 2.4-9
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SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
PART 2
PROCEDURE:
1. Connect an accurate AC frequency meter and an AC
voltmeter across the stator AC power winding leads.
TEST 13 - CHECK AND ADJUST
VOLTAGE REGULATOR
DISCUSSION:
2. Start the engine, let it stabilize and warm-up.
For additional information, refer to description and
components Page 2.1-3.
3. Apply electrical loads to the generator equal to the rated
capacity of the unit.
PROCEDURE:
4. Check the AC frequency and voltage. Frequency should
not drop below approximately 58-59 Hertz. Voltage
should not drop below about 230 volts (plus or minus 2
percent).
With the frequency between 61-62 Hertz, slowly turn the
slotted potentiometer (Figure 12) until line voltage reads
244-252 volts.
NOTE: You must remove the access panel on top of the
control panel to adjust the voltage regulator.
RESULTS:
1. If frequency and voltage drop excessively under load, go
to Test 15.
NOTE: The voltage regulator is housed above the
generator control panel. The regulator maintains a
voltage in direct proportion to frequency at a 2-to-1
ratio. For example, at 62 Hertz, line-to-neutral voltage
will be 124 volts.
2. If frequency and voltage under load are good,
discontinue tests.
TEST 15 - CHECK FOR OVERLOAD CONDITION
DISCUSSION:
An "overload' condition is one in which the generator rated
wattage/amperage capacity has been exceeded. To test for
an overload condition on an installed unit, the best method is
to use an ammeter. See "Measuring Current" on Page 1.4-2.
PROCEDURE:
Use a clamp-on ammeter to measure load current draw, with
the generator running and all normal electrical loads turned on.
RESULTS:
1. If the unit is overloaded, reduce loads to the unit's rated
capacity.
Figure 12. Voltage Adjustment Potentiometer
2. If unit is not overloaded, but rpm and frequency drop
excessively when loads are applied, go to Test 16.
RESULTS:
1. If the frequency and voltage are now good, discontinue
tests.
TEST 16 - CHECK ENGINE CONDITION
DISCUSSION:
2. If frequency is now good but voltage is high or low, go to
Problem 1, Test 4.
If engine speed and frequency drop excessively under load, the
engine may be under-powered. An under-powered engine can
be the result of a dirty air cleaner, loss of engine compression,
faulty carburetor settings, incorrect ignition timing, etc.
TEST 14 - CHECK VOLTAGE AND
FREQUENCY UNDER LOAD
PROCEDURE:
DISCUSSION:
For engine testing, troubleshooting and repair procedures
refer to Problem 11 on Page 4.3-3. For further engine repair
information refer to the following manuals:
It is possible for the generator AC output frequency and
voltage to be good at no-load, but they may drop excessively
when electrical loads are applied. This condition, in which
voltage and frequency drop excessively when loads are
applied, can be caused by (a) overloading the generator, (b)
loss of engine power, or (c) a shorted condition in the stator
windings or in one or more connected loads.
• P/N 0C1103 - Service and Repair Manual for Single
Cylinder GN Engines.
• P/N 0E2081 - Service Manual for GTV-990/760 V-Twin
OHVI Engines.
Page 2.4-10
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TABLE OF CONTENTS
PART
3.1
TITLE
Description and Components
Operational Analysis
PART 3
V-TYPE
PREPACKAGED
TRANSFER
SWITCHES
3.2
3.3
Troubleshooting Flow Charts
Diagnostic Tests
3.4
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
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SECTION 3.1
DESCRIPTION & COMPONENTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
GENERAL
ENCLOSURE
The prepackaged, V-Type transfer switch is rated
100 amps at 250 volts maximum. It is available in 2-
pole configuration only and, for that reason, is
useable with 1-phase systems only.
The standard prepackaged, V-Type transfer switch
enclosure is a NEMA 1 type ("NEMA" stands for
"National Electrical Manufacturer’s Association").
Based on NEMA Standard 250, the NEMA 1
enclosure may be defined as one that is intended for
indoor use primarily to provide a degree of protection
against contact with the enclosed equipment and
where unusual service conditions do not exist.
Prepackaged transfer switches do not have an
intelligence system of their own. Instead, automatic
operation of these transfer switches is controlled by a
circuit board housed in the generator control panel.
ITEM DESCRIPTION
1
BOX GTS LOAD CENTER
2
3
4
5
6
7
8
9
COVER, 12 POSITION GTS LOAD CENTER
TRANSFER SWITCH HOME STANDBY 100A2P250V
SCREW TAPTITE M5-0.8 X 10 BP
SCREW TAPTITE 1/4-20 X 5/8 BP
LOCK WASHER, SPECIAL-1/4"
RELAY PANEL 12VDC DPDT 10A@240VA
BASE, MOUNTING 12 CIRCUIT 125A/240V
SCREW TAPTITE M4-0.7X10 BP
RIVET POP .156 X .160-.164/#20
WASHER FLAT 1/4 ZINC
PLUG
HARNESS ADAPTER PLATE
PANEL-SUB BREAKER BASE
TRIM VINYL BLACK 1/8GP
WASHER LOCK #10
NUT WING M6-1.0
HANDLE, TRANSFER SWITCH HOME STANDBY
HOLDER CABLE TIE
LUG DIS QK NI-S 10X45 DEG BR/T
SCREW PPHM #10-32 X 1/4
LUG SLDLSS 1/0-#14X9/16 AL/CU
BLOCK TERMINAL 20A 5 X 6 X 1100V
TIE WRAP 3.9" X .10" NAT'L UL
WASHER FLAT #8 ZINC
COVER, RELAY & TERM BLOCK
WIRE HARNESS,GTS LOAD CENTER (NOT SHOWN FOR CLARITY)
FUSE HOLDER
10
11
12
13
14
15
16
17
18
19
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
ASSEMBLY FUSE 5A X BUSS HLDR73591
PCB SUPPORT SNAP-IN 1-3/8"
CIRCT BRK 20 X 1 HOM120
CIRCT BRK 20 X 2 HOM220
CIRCT BRK 15 X 1 HOM115
CIRCT BRK 30 X 2 HOM230
COVER - HARNESS ENTRY
HARNESS, GTS TO EXT CONN BOX
WASHER LOCK M4
SCREW SW 1/4-20X5/8 N WA JS500
SCREW SWAGE 1/4-20 X 1/2 ZINC
SCREW PPHM M4-0.7 X 10
HARNESS,GTS TO MAIN PANEL
Figure 1. Exploded View of V-Type Prepackaged Transfer Switch
Page 3.1-1
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SECTION 3.1
DESCRIPTION & COMPONENTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
the circuit and spring force will complete the
retransfer to STANDBY. A bridge rectifier, which
changes the utility source alternating current (AC) to
direct current (DC), is sealed in the coil wrappings. If
coil or bridge rectifier replacement becomes
necessary, the entire coil and bridge assembly should
be replaced.
TRANSFER MECHANISM
The 2-pole transfer mechanism consists of a pair of
moveable LOAD contacts, a pair of stationary
UTILITY contacts, and a pair of stationary STANDBY
contacts. The load contacts can be connected to the
utility contacts by a utility closing coil; or to the
standby contacts by a standby closing coil. In
addition, the load contacts can be actuated to either
the UTILITY or STANDBY side by means of a manual
transfer handle. See Figures 2 and 3.
STANDBY CLOSING COIL C2:
Coil C2 is energized by rectified standby source
power, to actuate the load contacts to their "Standby"
source side. Energizing the coil moves the load
contacts to an overcenter position; limit switch action
then opens the circuit and spring force will complete
the transfer action to "Standby". This coil’s bridge
rectifier is also sealed in the coil wrappings. Replace
the coil and bridge rectifier as a unit.
LIMIT SWITCHES XA1 AND XB1:
Switches are mechanically actuated by load contacts
movement. When the load contacts are connected to
the utility contacts, limit switch XA1 opens the utility
circuit to utility closing coil C1 and limit switch XB1
closes the standby circuit to standby closing coil C2.
The limit switches "arm" the system for retransfer
back to UTILITY when the load contacts are
connected to the STANDBY side. Conversely, when
the load contacts are connected to the UTILITY side,
the switches "arm" the system for transfer to
STANDBY. An open condition in limit switch XA1 will
prevent retransfer to "Utility". An open switch XB1 will
prevent transfer to STANDBY.
Figure 2. Load Connected to Utility Power Source
Figure 3. Load Connected to Standby Power Source
UTILITY CLOSING COIL C1:
See Figure 4. This coil is energized by rectified utility
source power, to actuate the load contacts to the
UTILITY power source side. When energized, the coil
will move the main contacts to an "overcenter"
position. A limit switch will then be actuated to open
Figure 4. The "V-Type" Transfer Mechanism
Page 3.1-2
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SECTION 3.1
DESCRIPTION & COMPONENTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
4. When the "engine warm-up timer" has timed out, circuit
board action completes the Wire 23 circuit to ground.
TRANSFER RELAY
Transfer relay operation is controlled by a circuit
board. That circuit board is a part of a control panel
assembly, mounted on the standby generator set.
a.The transfer relay then energizes.
b.The relay’s normally-closed contacts open and
its normally open contacts close.
Figure 5 shows the transfer relay pictorially and
schematically. Relay operation may be briefly
described as follows:
c. When the normally open contacts close,
standby source power is delivered to the
standby closing coil and transfer to "Standby"
occurs.
1. Generator battery voltage (12 volts DC) is available to
the transfer relay coil from the generator circuit board,
via Wire 194 and relay terminal A.
5. When the generator circuit board "senses" that utility
source voltage has been restored above a preset level,
the board will open the Wire 23 circuit to ground.
a.The 12 volts DC circuit is completed through the
transfer relay coil and back to the generator
circuit board, via Wire 23.
a.The transfer relay will de-energize, its normally-
closed contacts will close and its normally open
contacts will open.
b.Circuit board action normally holds the Wire 23
circuit open to ground and the relay is de-
energized.
b.When the normally-closed relay contacts close,
utility source voltage is delivered to the utility
closing coil to energize that coil.
c. When de-energized, the relay’s normally open
contacts are open and its normally-closed
contacts are closed.
c. Retransfer back to UTILITY occurs.
d.The normally-closed relay contacts will deliver
utility source power to the utility closing circuit of
the transfer mechanism.
NEUTRAL LUG
The standby generator is equipped with an
UNGROUNDED neutral. The neutral lug in the
transfer switch is isolated from the switch enclosure.
e.The normally open relay contacts will deliver
standby source power to the transfer
mechanism’s standby closing circuit.
MANUAL TRANSFER HANDLE
The manual transfer handle is retained in the transfer
switch enclosure by means of a wing stud. Use the
handle to manually actuate the transfer mechanism
load contacts to either the UTILITY or STANDBY
source side.
Instructions on use of the manual transfer handle may
be found in Part 5, "Operational Tests and
Adjustments".
TERMINAL BLOCK
During system installation, this 5-point terminal block
must be properly interconnected with an identically
labeled terminal block in the generator control panel
assembly.
Figure 5. Transfer Relay Schematic
2. During automatic system operation, when the generator
circuit board "senses" that utility source voltage has
dropped out, the circuit board will initiate engine
cranking and startup.
3. When the circuit board "senses" that the engine has
started, an "engine warm-up timer" on the circuit board
starts timing.
Page 3.1-3
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SECTION 3.1
DESCRIPTION & COMPONENTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
FUSE HOLDER
The fuse holder holds two (2) fuses, designated as
fuses F1 and F2. Each fuse is rated 5 amperes.
FUSES F1, F2:
These two fuses protect the terminal board UTILITY 1
and 2 circuit against overload.
Figure 6. Transfer Switch Terminal Block
Terminals used on the terminal block are identified as
Utility 1 and 2; 23 and 194.
UTILITY 1 AND 2:
Interconnect with identically labeled terminals in the
generator control panel assembly. This is the utility
voltage signal to the circuit board. The signal is
delivered to a step-down transformer in the control
module assembly and the resultant reduced voltage is
then delivered to the circuit board. UTILITY 1 and 2
power is used by the circuit board as follows:
Figure 7. The Fuse Holder
❏If utility source voltage should drop below a preset
level, circuit board action will initiate automatic
cranking and startup, followed by automatic transfer
to the standby source.
❏Utility source voltage is used to operate a battery
trickle charge circuit which helps to maintain battery
state of charge during non-operating periods.
TERMINALS 23 AND 194:
These terminals connect the transfer relay to the
generator circuit board. See "Transfer Relay" on Page
3.1-2.
Page 3-1.4
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
OPERATIONAL ANALYSIS
Figure 1 is a schematic and wiring diagram for a typical V-Type transfer switch.
Figure 1. Wiring Diagram and Schematic
Page 3.2-1
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
UTILITY SOURCE VOLTAGE AVAILABLE
Figure 2 is a schematic representation of the transfer switch with utility source power available. The circuit
condition may be briefly described as follows:
❏Utility source voltage is available to terminal lugs N1 and N2 of the transfer mechanism, transfer switch is in the
UTILITY position and source voltage is available to T1, T2 and customer load.
❏Utility source voltage is available to limit switch (XA1) via the normally-closed transfer relay contacts (1 and 7)
and Wire 126. However, XA1 is open and the Circuit to the utility closing coil is open.
❏Utility voltage "sensing" signals are delivered to a circuit board on the generator, via Wire N1A, a 5 amp fuse
(F1), transfer switch terminal N1, generator terminal N1 and a sensing transformer. The second line of the utility
voltage "sensing" circuit is via Wire N2A, a 5 amp Fuse (F2), transfer switch terminal N2, generator terminal
N2, and the sensing transformer.
Figure 2. Utility Source Power Available
Page 3.2-2
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
UTILITY SOURCE VOLTAGE FAILURE
If utility source voltage should drop below a preset value, the generator circuit board will sense the dropout. That
circuit board will then initiate generator cranking and startup after a time delay circuit times out.
Figure 3 is a schematic representation of the transfer switch with generator power available, waiting to transfer.
❏Generator voltage available E1, E2.
❏Circuit board action holding Wire 23 open to ground.
❏Power available to standby coil C2, upon closure of TR, normally open contacts (9 & 6) will close and initiate a
transfer.
Figure 3. Generator Power Available, Waiting to Transfer.
Page 3.2-3
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V-TYPE PREPACKAGED
TRANSFER SWITCHES
SECTION 3.2
OPERATIONAL ANALYSIS
PART 3
TRANSFER TO STANDBY
The generator circuit board delivers 12 volts DC to the transfer relay, via terminal 194 and back to the circuit
board via terminal 23. However, circuit board action holds the Wire 23 circuit open and the transfer relay remains
de-energized. On generator startup, an "engine warm-up timer" on the generator circuit board starts timing. When
that timer has timed out, circuit board action completes the Wire 23 circuit to ground. The transfer relay then
energizes, its normally open contacts close, and standby source voltage is delivered to the standby closing coil
via Wires E1 and E2, the transfer relay (TR) contacts, limit switch (XB1), Wire "B". and a bridge rectifier. The
standby closing coil energizes and the main contacts actuate to their "Standby" side.
Figure 4. Transfer Action to Standby Position
Page 3-2.4
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
TRANSFER TO STANDBY
When the standby coil is energized it pulls the transfer switch mechanism to a overcenter position towards the
standby power source side, the transfer switch mechanically snaps to the STANDBY position. On closure of the
main contacts to the standby power source side, limit switches XA1 and XB1 are mechanically actuated to "arm"
the circuit for re- transfer to utility power source side.
Generator power from E1 and E2 is now connected to the customer load through T1 and T2.
Figure 5. Generator Powering Load.
Page 3.2-5
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
UTILITY RESTORED
Utility voltage is restored and is available to terminals N1 and N2. The utility voltage is sensed by the generators
circuit board. If it is above a preset value for a preset time interval a transfer back to utility power will occur.
Figure 6. Utility Restored, Generator Still Providing Output to Load.
Page 3.2-6
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
UTILITY RESTORED, TRANSFER SWITCH DE-ENERGIZED
After the preset time interval expires the circuit board will open the Wire 23 circuit to ground. The transfer relay
de-energizes, it’s normally closed contacts close, and utility source voltage is delivered to the utility closing coil
(C1), via Wires N1A and N2A, closed Transfer Relay Contacts 1 and 7, and Limit Switch XA1.
Figure 7. Utility Restored, Transfer Relay De-energized.
Page 3.2-7
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
UTILITY RESTORED, RETRANSFER BACK TO UTILITY
As the utility coil pulls the transfer switch to an OVER CENTER position, the switch mechanically snaps to
UTILITY. On closure of the main contacts to the utility power source side, Limit Switches XA1 and XB1 are
mechanically actuated to arm the circuit for transfer to STANDBY.
Figure 8. Utility Restored, Retransfer Back to Utility.
Page 3.2-8
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SECTION 3.2
OPERATIONAL ANALYSIS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
TRANSFER SWITCH IN UTILITY
When the transfer switch returns to the UTILITY side, generator shutdown occurs after approximately one (1)
minute.
Figure 9. Transfer Switch in UTILITY.
Page 3.2-9
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SECTION 3.3
TROUBLESHOOTING FLOW CHARTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
INTRODUCTION TO TROUBLESHOOTING
The first step in troubleshooting is to correctly identify the problem. Once that is done, the cause of the problem
can be found by performing the tests in the appropriate flow chart.
Test numbers assigned in the flow charts are identical to test numbers in section 3.4, Diagnostic Tests. Section
Page 3.3-1
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SECTION 3.3
TROUBLESHOOTING FLOW CHARTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
Page 3.3-2
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
PROCEDURE:
GENERAL
1. If the generator engine has started automatically (due to
a utility power source outage) and is running, check the
position of the generator main circuit breaker. The
circuit breaker must be set to its "On" or "Closed"
position. When you are sure the generator main circuit
breaker is set to "On" or 'Closed", check the voltage at
transfer mechanism terminal lugs E1 and E2 with an
accurate AC voltmeter or with an accurate volt-ohm-
milliammeter (VOM). The generator line-to line voltage
should be indicated.
Test numbers in this section correspond to the
numbered tests in Section 3.3, "Troubleshooting Flow
Charts". When troubleshooting, first identify the
problem. Then, perform the diagnostic tests in the
sequence given in the flow charts.
TEST 21- CHECK VOLTAGE AT TERMINAL
LUGS E1, E2
DISCUSSION:
In automatic mode, the standby closing coil (C2) must
be energized by standby generator output if transfer
to the "Standby" source is to occur. Transfer to
"Standby" cannot occur unless that power supply is
available to the transfer switch.
2. If the generator has been shut down, proceed as
follows:
a.On the generator control panel, set the AUTO-
OFF-MANUAL switch to OFF.
b.Turn OFF all power voltage supplies to the
transfer switch. Both the utility and standby
power supplies must be positively turned off
before proceeding.
DANGER: BE CAREFUL! HIGH AND
DANGEROUS VOLTAGES ARE PRESENT AT
TERMINAL LUGS E1 AND E2 WHEN THE
GENERATOR IS RUNNING. AVOID CONTACT
WITH HIGH VOLTAGE TERMINALS OR
DANGEROUS AND POSSIBLY LETHAL
ELECTRICAL SHOCK MAY RESULT. DO NOT
PERFORM THIS VOLTAGE TEST WHILE
STANDING ON WET OR DAMP GROUND,
WHILE BAREFOOT, OR WHILE HANDS OR
FEET ARE WET.
c. Check the position of the transfer mechanism
main contacts. The moveable LOAD contacts
must be connected to the stationary UTILITY
source contacts. If necessary, manually actuate
the main contacts to the "Utility" power source
side.
Figure 1. The “V-Type” Transfer Mechanism
Page 3.4-1
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
d.Actuate the generator main line circuit breaker
to its "On" or "Closed" position. The utility power
supply to the transfer switch must be turned
OFF.
2. Set the generators AUTO-OFF-MANUAL switch to the
OFF position.
3. Set your VOM to measure AC voltage.
e.Set the generator AUTO-OFF-MANUAL switch to
AUTO.
DANGER: BE CAREFUL! HIGH AND
DANGEROUS VOLTAGES ARE PRESENT AT
TERMINAL LUGS WHEN THE GENERATOR IS
RUNNING. AVOID CONTACT WITH HIGH
VOLTAGE TERMINALS OR DANGEROUS AND
POSSIBLY LETHAL ELECTRICAL SHOCK MAY
RESULT. DO NOT PERFORM THIS VOLTAGE
TEST WHILE STANDING ON WET OR DAMP
GROUND, WHILE BAREFOOT, OR WHILE
HANDS OR FEET ARE WET.
(1) The generator should crank and start.
(2) When the generator starts, an "engine
warm-up timer" should start timing. After
about 15 seconds, the transfer relay should
energize and transfer to the "Standby"
source should occur.
f. If transfer to "Standby" does NOT occur, check
the voltage across transfer switch terminal lugs
E1 and E2. The generator line-to-line voltage
should be indicated.
4. Disconnect Wire E2 from the standby closing coil (C2).
Connect one meter test Lead to Wire E2. Use a suitable
and safe connection to this wire, such as an alligator
clip that attaches to the meter test probe. Isolate this
wire and test probe from any other potential source or
ground.
RESULTS:
1. If normal transfer to "Standby" occurs, discontinue tests.
2. If transfer to "Standby" does NOT occur and no voltage
is indicated across terminal lugs E1/E2, determine why
generator AC output has failed.
5. If necessary, repeat Step 2 under "Procedure" of Test
21. The system must be in automatic operating mode,
with engine running, and standby source voltage
available to terminal lugs E1 and E2.
3. If transfer to "Standby" does NOT occur and voltage
reading across terminal lugs E1/E2 is good, go on to
Test 22.
6. Locate on the standby closing coil the terminal that Wire
B is connected to. (Figure 1, previous page). Connect
the other meter test lead to this terminal. Generator line
to line voltage should be indicated. If generator voltage
is NOT indicated, proceed to Step 7.
TEST 22 - CHECK VOLTAGE AT STANDBY
CLOSING COIL C2
DISCUSSION:
7. With Wire E2 still connected to one test probe, connect
the other meter test lead to Wire 205 on Limit Switch
XB1(see Figure 1 on previous page). Generator line to
line voltage should be measured.
Standby source voltage is used to energize the
standby closing coil and actuate the main contacts to
their "Standby" source side. Standby source
alternating current (AC) is changed to direct current
(DC) by a bridge rectifier before reaching the closing
coil. This test will determine if standby voltage is
available to the closing coil.
RESULTS:
1. If generator line-to-line voltage is indicated in
“Procedure, Step 6,” but transfer does NOT occur,
proceed to Test 24.
If normal standby source voltage is available to the
terminals of the standby closing coil but transfer to
"Standby" does NOT occur, look for (a) binding or
sticking in the transfer mechanism, (b) a defective
coil, or (c) a bad bridge rectifier. The coil and the
bridge rectifier must be replaced as a unit.
2. If generator line-to-line voltage is NOT indicated in
“Procedure, Step 7,” proceed to Test 33.
3. If generator line-to-line voltage is indicated in
“Procedure, Step 7,” proceed to Test 25.
PROCEDURE:
1. Set the generator main line circuit breaker to the OFF or
“Open” position.
Page 3.4-2
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
TEST 23 - TEST TRANSFER RELAY TR
DISCUSSION:
In automatic operating mode, the transfer relay must
be energized by circuit board action or standby
source power will not be available to the standby
closing coil. Without standby source power, the
closing coil will remain de-energized and transfer to
"Standby" will not occur. This test will determine if the
transfer relay is functioning normally.
PROCEDURE:
1. See Figure 2. Disconnect all wires from the transfer
relay, to prevent interaction.
2. Set a VOM to its "R x 1" scale and zero the meter.
Figure 2. Transfer Relay Test Points
3. Connect the VOM test leads across Relay Terminals 6
and 9 with the relay de-energized. The VOM should
read INFINITY.
5. Now, connect the VOM test leads across Relay
Terminals 1 and 7.
a.Energize the relay and the meter should
indicate INFINITY.
b.De-energize the relay and the VOM should read
CONTINUITY.
RESULTS:
4. Using jumper wires, connect the positive (+) post of a 12
volt battery to relay Terminal “A” and the negative (-)
battery post to Relay Terminal "B". The relay should
energize and the VOM should read CONTINUITY.
1. Replace transfer relay if it is defective.
2. If transfer relay checks good go to Test 26.
TEST 24- CHECK MANUAL TRANSFER
SWITCH OPERATION
Figure 3. Manual Transfer Switch Operation
Page 3.4-3
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
DISCUSSION:
7. Finally, actuate the main contacts to their UTILITY power
source side, i.e., load contacts against the UTILITY
contacts (upward movement of the operating lever).
In automatic operating mode, when utility source
voltage drops below a preset level, the engine should
crank and start. On engine startup, an "engine warm-up
timer" on the generator circuit board should start timing.
When that timer has timed out (about 15 seconds), the
transfer relay should energize to deliver utility source
power to the standby closing coil terminals. If normal
utility source voltage is available to the standby closing
coil terminals, but transfer to STANDBY does not occur,
the cause of the failure may be (a) a failed standby
closing coil and/or bridge rectifier, or (b) a seized or
sticking actuating coil or load contact. This test will help
you evaluate whether any sticking or binding is present
in the transfer mechanism.
RESULTS:
1. If there is no evidence of binding, sticking, excessive
force required, replace the appropriate closing coil.
2. If evidence of sticking, binding, excessive force required
to move main contacts, find cause of binding or sticking
and repair or replace damaged part(s).
TEST 25- TEST LIMIT SWITCH XB1
DISCUSSION:
PROCEDURE:
Standby power source voltage must be available to
the standby closing coil in order for a TRANSFER TO
STANDBY action to occur. To deliver that source
voltage to the coil, limit switch XB1 must be closed to
the "Standby" power source side. If the limit switch
did not get actuated or has failed open, the source
voltage will not be available to the closing coil and
transfer to "Standby" will not occur.
1. With the generator shut down, set the generator AUTO-
OFF-MANUAL switch to OFF.
2. Set the generator main circuit breaker to OFF or "Open".
3. Turn off the utility power supply to the transfer switch,
using whatever means provided (such as a utility source
main line breaker).
PROCEDURE:
DANGER: DO NOT ATTEMPT MANUAL
TRANSFER SWITCH OPERATION UNTIL ALL
POWER VOLTAGE SUPPLIES TO THE
SWITCH HAVE BEEN POSITIVELY TURNED
OFF. FAILURE TO TURN OFF ALL POWER
VOLTAGE SUPPLIES MAY RESULT IN
EXTREMELY HAZARDOUS AND POSSIBLY
LETHAL ELECTRICAL SHOCK.
With the generator shut down, the generator main
circuit breaker turned OFF, and with the utility power
supply to the transfer switch turned OFF, test limit
switch XB1 as follows:
1. To prevent interaction, disconnect Wire 205 and Wire B
from the limit switch terminals.
2. Set a VOM to its "R x 1" scale and zero the meter.
4. In the transfer switch enclosure, locate the manual
transfer handle. Handle is retained in the enclosure with
a wing nut. Remove the wing nut and handle.
3. See Figure 1. Connect the VOM test probes across
the two outer terminals from which the wires were
disconnected.
5. See Figure 3. Insert the un-insulated end of the handle
over the transfer switch operating lever.
4. Manually actuate the main contacts to their "Standby"
position. The meter should read INFINITY.
a.Move the transfer switch operating lever up to
actuate the load contacts to the UTILITY
position, i.e., load connected to the utility source.
5. Manually actuate the main contacts to their UTILITY
position. The meter should read CONTINUITY.
b.Actuate the operating lever down to move the
load contacts against the standby contacts, i.e.,
load connected to the STANDBY source.
6. Repeat Steps 4 and 5 several times and verify the VOM
reading at each switch position.
6. Repeat Step 5 several times. As the transfer switch
operating lever is moved slight force should be needed
until the lever reaches its center position. As the lever
moves past its center position, an over-center spring
should snap the moveable load contacts against the
stationary STANDBY or UTILITY contacts.
RESULTS:
1. If Limit Switch XB1 fails the test, remove and replace the
switch or adjust switch until it is actuated properly.
2. If limit switch is good, repair or replace Wire B between
limit switch and Standby Coil (C2).
Page 3.4-4
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
a.Generator starts and transfer occurs,
discontinue tests.
TEST 26 - CHECK 23 AND 194
WIRING/CONNECTIONS
b.Generator starts and transfer does NOT occur.
With the generator running and utility OFF,
ground Wire 23 in the control panel at
interconnection terminals (ICT) or at the terminal strip.
If transfer occurs replace circuit board.
DISCUSSION:
An open circuit in the transfer switch control wiring
can prevent a transfer action from occurring. In the
auto mode, the circuit board supplies +12 VDC to
Wire 194. This DC voltage is supplied to the transfer
relay (TR) at Terminal Location A . The opposite
side of the transfer relay (TR) coil (Terminal B) is
connected to Wire 23. Positive 12VDC is present on
this also. Circuit board action will allow current to flow
through the circuit and the (TR) is energized.
9. Connect the negative (-) test lead to the ground lug in the
generator control panel. Connect the positive (+) test
lead to Wire 194 in the generator control panel at the
interconnection terminals (ICT) or at the terminal strip
.
a.If the voltage is present, repair wiring between
ICT (or terminal strip) and transfer switch
PROCEDURE/RESULTS:
b.If voltage is NOT present, proceed to Step 10.
1. Set VOM to DC volts
10.Connect the positive (+) test lead to Wire 194 located in
the J1 connector Pin Location 4, connected to the circuit
board (see Figure 3, Page 4.1-2).
2. Place generator AUTO-OFF-MANUAL switch to the
AUTO position. Utility power should be present; the
generator should not start.
a.If voltage is present, repair wiring between J1
connector and ICT (or terminal strip).
3. Connect the negative (-) test lead to a suitable frame
ground in the transfer switch.
b.If voltage is NOT present, replace circuit board.
4. Connect the positive (+) test lead to Wire 194 at the
terminal strip in the transfer switch.
TEST 27- CHECK VOLTAGE AT TERMINAL
LUGS N1, N2
a.If voltage is present, proceed to Step 5.
b.If voltage is NOT present, proceed to Step 9.
DISCUSSION:
5. Connect the positive (+) test lead to Wire 23 at the
terminal strip in the transfer switch.
If retransfer to the "Utility" power source side is to
occur, utility source voltage must be available to
terminal lugs N1 and N2 of the transfer mechanism.
In addition, If that source voltage is not available to
NI/N2 terminals, automatic startup and transfer to
"Standby" will occur when the generator manual-off-
auto switch is set to AUTO. This test will prove that
"Utility" voltage is available to those terminals, or is
not available. It is the first test in a series of tests that
should be accomplished when (a) retransfer back to
’Utility" does not occur, or (b) startup and transfer
occurs unnecessarily.
a.If voltage is present, proceed to Step 6.
b.If voltage is NOT present, repair wiring between
terminal strip and transfer relay (TR).
6. Connect the negative (-) test lead to the ground lug in the
generator control panel. Connect the positive (+) test
lead to Wire 23 in the generator control panel at the
interconnection terminals (ICT) or at the terminal strip.
a.If voltage is present, proceed to Step 7.
b.If voltage is NOT present, repair wiring between
transfer switch and generator control panel.
DANGER: PROCEED WITH CAUTION! HIGH
AND DANGEROUS VOLTAGES ARE PRESENT
AT TERMINAL LUGS N1/N2. CONTACT WITH
HIGH VOLTAGE TERMINALS WILL RESULT IN
DANGEROUS AND POSSIBLY LETHAL
ELECTRICAL SHOCK. DO NOT ATTEMPT THIS
TEST WHILE STANDING ON WET OR DAMP
GROUND, WHILE BAREFOOT, OR WHILE
HANDS OR FEET ARE WET.
7. Connect the positive (+) test lead to Wire 23 located in
the J1 connector Pin Location 3, connected to the circuit
board (see Figure 3, Page 4.1-2).
a.If voltage is present, proceed to Step 8.
b.If voltage is NOT present, repair wiring between
(ICT and J1connector).
8. Turn off utility power to transfer switch, simulating a
utility failure.
Page 3.4-5
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
PROCEDURE:
RESULTS:
1. Make sure that all main line circuit breakers in the utility
line to the transfer switch are “On” or “Closed.”
1. If voltage reading across the "Utility I" and "Utility 2"
terminals is zero, go to Test 30.
2. Test for utility source line-to-line voltage across terminal
lugs N1 and N2 (see Figure 1). Normal utility source
voltage should be indicated.
2. If voltage reading is good, go to Test 29.
3. For Problem 14 ONLY; if voltage is good, repair N1/N2
open wiring between Transfer Switch and Generator.
RESULTS:
TEST 29- CHECK VOLTAGE AT UTILITY
CLOSING COIL C1
1. If low or no voltage is indicated, find the cause of the
problem and correct.
2. If normal utility source voltage is indicated, go on to
Test 28.
DISCUSSION:
Utility source voltage is required to energize utility
closing coil C1 and effect retransfer back to the
"Utility" source. This voltage is delivered to the utility
closing coil via Wires N1A and N2A, the transfer
relay’s normally-closed contacts (relay de-energized),
Wire 126, Limit Switch XA1, and a bridge rectifier.
3. For Problem 14 ONLY, if voltage is good, repair or
replace Wire N1A/N2A between Transfer Switch Lugs
N1/N2 and Fuse Holder connections.
TEST 28 - CHECK VOLTAGE AT UTILITY 1 AND
UTILITY 2 TERMINALS
PROCEDURE:
The UTILITY 1 and UTILITY 2 terminals in the transfer
switch deliver utility voltage sensing to a circuit board.
If voltage at the terminals is zero or low, standby
generator startup and transfer to the Standby source
will occur automatically as controlled by the circuit
board. A zero or low voltage at these terminals will also
prevent retransfer back to the Utility source.
1. On the generator control panel, set the AUTO-OFF-
MANUAL switch to OFF.
2. Turn OFF the utility power supply to the transfer switch,
using whatever means provided (such as a utility source
main line circuit breaker).
3. Set the generator main line circuit breaker to its OFF or
"Open" position.
PROCEDURE:
With utility source voltage available to terminal lugs
N1 and N2, use an AC voltmeter or a VOM to test for
utility source line-to-line voltage across terminal block
Utility 1 and Utility 2 terminals. Normal line-to-line
utility source voltage should be indicated.
4. Check the position of the transfer mechanism main
contacts. The moveable load contacts must be
connected to the stationary utility contacts. If necessary,
manually actuate the main contacts to their "Utility
source side (load connected to the "Utility' source).
DANGER: BE CAREFUL! HIGH AND
DANGEROUS VOLTAGES ARE PRESENT AT
TERMINAL LUGS WHEN THE GENERATOR IS
RUNNING. AVOID CONTACT WITH HIGH
VOLTAGE TERMINALS OR DANGEROUS AND
POSSIBLY LETHAL ELECTRICAL SHOCK MAY
RESULT. DO NOT PERFORM THIS VOLTAGE
TEST WHILE STANDING ON WET OR DAMP
GROUND, WHILE BAREFOOT, OR WHILE
HANDS OR FEET ARE WET.
5. Disconnect Wire N2A from the utility closing coil (C1).
Connect one meter test Lead to Wire N2A. Use a suitable
and safe connection to this wire, such as an alligator clip
that attaches to the meter test probe. Isolate this wire and
test probe from any other potential source or ground.
Figure 4. Transfer Switch Terminal Block
Page 3.4-6
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
6. Set the generator main line circuit breaker to its "On" or
"Closed" position.
7. Set the generator AUTO-OFF-MANUAL switch to
AUTO.
a.The generator should crank and start.
b.About 15 seconds after engine startup, the
transfer relay should energize and transfer to
the ’Standby" source should occur.
8. When you are certain that transfer to "Standby" has
occurred, turn ON the utility power supply to the transfer
switch. After a 15 seconds, retransfer back to the
"Utility" source should occur.
9. Locate on the utility closing coil the terminal that Wire A
is connected to (see Figure 1, Page 3.4-1). Connect the
other meter test lead to this terminal. Generator line to
line voltage should be indicated. If generator voltage
is NOT indicated, proceed to Step 10.
Figure 5. Fuse Holder and Fuses
PROCEDURE:
1. On the generator panel, set the AUTO-OFF-MANUAL
switch to OFF.
10.With Wire N2A still connected to one test probe, connect
the other meter test lead to Wire 126 on Limit Switch
XA1 (see Figure 1, Page 3.4-1). Generator line to line
voltage should be measured.
2. Turn off the utility power supply to the transfer switch,
using whatever means provided.
3. Remove fuses F1 and F2 from the fuse holder (see
Figure 5).
RESULTS:
1. In Step 7, if the generator does NOT crank or start, refer
to Part 4, "DC Control".
4. Inspect and test fuses for blown condition.
2. In Step 7, if transfer to the "Standby" source does NOT
occur, go to Problem 1.
RESULTS:
1. Replace blown fuse(s) and proceed to Test 34.
3. In Step 9, if normal utility source line-to-line voltage is
indicated but retransfer back to "Utility" does NOT
occur, go to Test 24.
2. For Problem 7 (DC Control section), go to Test 27.
TEST 31 - TEST LIMIT SWITCH XA1
4. If normal utility source line-to-line voltage is NOT
indicated in Step 9, but is indicated in Step 10,
proceed to Test 31.
DISCUSSION:
When the transfer switch main contacts are actuated
to their "Utility" position, limit switch XA1 should be
mechanically actuated to its open position. On
transfer to the "Standby" position, the limit switch
should actuate to its closed position. If the switch
does not actuate to its closed position, retransfer back
to "Utility" will not occur.
5. If normal utility source line-to-line voltage is NOT
indicated in Step 8, and is NOT indicated in Step 9,
proceed to Test 32.
TEST 30 - CHECK FUSES F1 AND F2
DISCUSSION:
PROCEDURE:
Fuses F1 and F2 are connected in series with the
Utility 1 and Utility 2 circuits, respectively. A blown
fuse will open the applicable circuit and will result in
(a) generator startup and transfer to "Standby", or (b)
failure to retransfer back to the UTILITY source.
1. With the standby generator shut down, set its AUTO-
OFF-MANUAL switch to OFF.
2. Turn OFF the utility power supply to the transfer switch,
using whatever means provided.
Page 3.4-7
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
CONTINUITY. If wiring tests good, proceed to Test 23.
3. To prevent interaction, disconnect Wire 126 and Wire
"A" from the limit switch terminals.
TEST 33 - CONTINUITY TEST OF WIRING (C2)
4. Set a VOM to its "R x 1 " scale and zero the meter.
DISCUSSION:
5. Connect the VOM test leads across the two limit switch
terminals from which Wires A and 126 were removed.
This test will ensure that all control wiring has continuity.
1. See Test 32, Step 1
6. Manually actuate the main contacts to their "Standby"
position. The VOM should indicate CONTINUITY.
2. See Test 32, Step 2
3. See Test 32, Step 3
4. See Test 32, Step 4
7. Manually actuate the main contacts to their "Utility"
position. The VOM should read INFINITY.
RESULTS:
5. Disconnect Wire E2 from the standby coil (C2) and
connect one test lead to it. Connect the other test lead
to Terminal Lug E2 of the transfer switch. CONTINUITY
should be read. Reconnect Wire E2.
Replace limit switch XA1 if it checks bad.
NOTE: Problems with transfer switch operation can
also be caused by (a) defective wiring between the
generator and transfer switch, or (b) a defective
component in the generator circuit board. See Part 4,
"DC Control".
6. Disconnect Wire 205 from transfer relay (TR) Terminal 6
and connect one test lead to it. Connect the other test
lead to limit switch XB1 top terminal Wire 205.
CONTINUITY should be read. Reconnect Wire 205.
TEST 32 - CONTINUITY TEST OF WIRING (C1)
7. Disconnect Wire E1 from Transfer Relay (TR) Terminal
9 and connect one test lead to it. Connect the other test
lead to terminal lug E1 of the transfer switch.
CONTINUITY should be read. Reconnect Wire E1.
DISCUSSION:
This test will ensure that all control wiring has continuity.
1. Set the AUTO-OFF-MANUAL switch to the OFF
position.
RESULTS:
2. Turn the generator main circuit breaker to the off position.
Repair any defective wiring that does not read
CONTINUITY. If wiring tests good, proceed to Test 23.
3. Turn off the utility power supply to the transfer switch
using whatever means provided. (Such as utility source
main line circuit breaker).
TEST 34 - CHECK N1 AND N2 WIRING
4. Set your VOM to the "R x 1" scale.
DISCUSSION:
5. Disconnect Wire N2A from the Utility Coil C1 and
connect one test lead to it. Connect the other test lead
to terminal lug N2 of the transfer switch. CONTINUITY
should be read. Reconnect Wire N2A.
A shorted Wire N1 or N2 to ground can cause fuse F1
or F2 to blow.
PROCEDURE:
1. On the generator panel, set the AUTO-OFF-MANUAL
switch to OFF.
6. Disconnect Wire 126 from transfer relay (TR) and
connect one test lead to it. Connect the other test lead
to limit switch XA1 bottom terminal Wire 126.
CONTINUITY should be read. Reconnect Wire 126.
2. Turn off the utility power supply to the transfer switch,
using whatever means are provided.
3. Remove fuses F1 and F2 from the fuse holder (see Figure 5).
7. Disconnect Wire N1A from transfer relay (TR) terminal
and connect one test lead to it. Connect the other test
lead to F1 top fuse terminal Wire N1A. CONTINUITY
should be read. Reconnect Wire N1A.
4. Remove the generator control panel cover. Disconnect
wire N1 and wire N2 from the interconnection terminal in
the control panel, or the terminal strip.
5. Set your VOM to the 'R x 1" scale. Connect the positive
meter test lead to wire N1.
RESULTS:
Repair any defective wiring that does not read
Page 3.4-8
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
a. Connect the negative meter lead to the
ground lug. INFINITY should be measured.
RESULTS:
If a short is indicated in steps 5 through 9, repair
wiring and re-test. If utility line to line voltage is
measured in Step 14, proceed to Test 35.
b. Connect the negative meter lead to Wire 23
at ICT or terminal strip. INFINITY should be
measured.
TEST 35 - CHECK TRANSFORMER (TX)
c. Connect the negative meter lead to Wire
194 at ICT or terminal strip. INFINITY
should be measured.
DISCUSSION:
The transformer is a step down type and has two
functions. It supplies approximately 16VAC to the
control board for utility sensing. It also supplies
approximately 16 VAC to the battery charger when
utility is available for trickle charge. A shorted
transformer can result in fuse F1 or F2 blowing.
d. Connect the negative meter lead to the neutral
connection. INFINITY should be measured.
6. Set your VOM to the 'R x 1" scale. Connect the positive
meter test lead to wire N2.
a. Connect the negative meter lead to the
ground lug. INFINITY should be measured.
PROCEDURE:
1. On the generator panel, set the AUTO-OFF-MANUAL
switch to OFF.
b. Connect the negative meter lead to Wire 23
at ICT or terminal strip. INFINITY should be
measured.
2. Turn off the utility power supply to the transfer switch,
using whatever means is provided.
c. Connect the negative meter lead to Wire
No. 194 at ICT or terminal strip. INFINITY
should be measured.
3. See Figure 6. Disconnect Wires N1, N2, 224, 225,
224A, 225A from transformer (TX).
d. Connect the negative meter lead to the
neutral connection. INFINITY should be
measured.
4. Set a VOM to the "R x 1" scale.
5. Connect one test lead to TX terminal 1. Connect the
other test lead to TX terminal 5. Approximately 38.5
ohms should be measured
7. Disconnect wire N1 and wire N2 from transformer TX.
8. Connect one test lead to wire N1 removed in step 7, and
the other test lead to the ground terminal. INFINITY
should be measured.
6. Connect one test lead to TX terminal 10. Connect the
other test lead to TX terminal 9. Approximately 1.5
ohms should be measured.
9. Connect one test lead to wire N2 removed in step 7, and
the other test lead to the ground terminal. INFINITY
should be measured.
7. Connect one test lead tot TX terminal 7. Connect the
other test lead to TX terminal 6. Approximately 0.3
ohms should be measured.
10.If no short is indicated in steps 5 through 9, proceed with
steps 11 through 15. If a short is indicated in steps 5
through 9, repair shorted wiring.
8. Connect one test lead to TX terminal 1. Connect the
other test lead to the transformer case. INFINITY
should be measured.
11.Reconnect wires N1 and N2 to the interconnection
terminal or terminal strip.
9. Connect one test lead to TX terminal 7. Connect the
other test lead to the transformer case. INFINITY
should be measured.
12.Replace fuses F1 and F2 in the fuse holder.
13.Turn on the utility power supply to the transfer switch
using whatever means is provided.
10.Connect one test lead to TX terminal 9. Connect the
other test lead to the transformer case. INFINITY
should be measured.
14.Set VOM to measure AC voltage. Connect one test
lead to wire N1 and the other test lead to wire N2.
Utility line to line voltage should be measured.
11.Connect one test lead to TX terminal 1. Connect the
other test lead to TX terminal 10. INFINITY should be
measured.
15.Turn off the utility power supply to the transfer switch
using whatever means is provided.
Page 3.4-9
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SECTION 3.4
DIAGNOSTIC TESTS
V-TYPE PREPACKAGED
TRANSFER SWITCHES
PART 3
12.Connect one test lead to TX terminal 1. Connect the
other test lead to TX terminal 7. INFINITY should be
measured.
13.Connect one test lead to TX terminal 10. Connect the
other test lead t TX terminal 7. INFINITY should be
measured.
RESULTS:
For steps 5, 6, and 7, replace transformer if an open
is indicated, or if the resistance value indicated is
zero. If the resistance value is not within the
approximate range, proceed to test 65.
For steps 8 through 13, replace the transformer if it
fails any of these steps.
Figure 6. Transformer (TX)
Page 3.4-10
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TABLE OF CONTENTS
PART
4.1
TITLE
Description and Components
Operational Analysis
Troubleshooting Flow Charts
Diagnostic Tests
4.2
PART 4
DC CONTROL
4.3
4.4
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
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SECTION 4.1
DESCRIPTION AND COMPONENTS
3DC CONTROL
PART 4
GENERAL
TRANSFORMER (TX)
This section will familiarize the reader with the various
components that make up the DC control system.
Major DC control system components that will be
covered include the following:
❏A Terminal Strip / Interconnection Terminal
❏A Transformer (TX)
❏A Circuit Board.
❏An AUTO-OFF-MANUAL Switch.
❏A 15 Amp Fuse.
The control panel assembly’s transformer is a step-
down type. The line-to-line voltage from the Utility
1/Utility 2 terminals is delivered to the transformer’s
primary winding. Transformer action then induces a
reduced voltage (about 12 to 16 volts) into both
secondary transformer windings. Reduced voltage
from one secondary winding is delivered to the circuit
board as "Utility" source sensing voltage. Reduced
voltage from the other secondary winding is delivered
to the battery charger for trickle charging.
If the Utility sensing voltage drops below a preset
value, circuit board action will initiate automatic
generator startup and transfer to the "Standby"
source side.
❏A 5 Amp Fuse.
TERMINAL STRIP / INTERCONNECTION
TERMINAL
The sensing transformer is shown in Figure 2, both
pictorially and schematically.
The terminals of this terminal strip are connected to
identically numbered terminals on a prepackaged
transfer switch terminal board. The terminal board
connects the transfer switch to the circuit board and
transformer.
The terminal board provides the following connection
points:
A. Utility 1 and Utility 2
1.Connect to identically marked terminals on a
prepackaged transfer switch terminal board.
2.The circuit delivers "Utility" power source
voltage to the transformer (TX) located in the
control panel assembly.
B. 23 and 194
1.Connect to identically numbered terminals on
the terminal board of the prepackaged transfer
switch.
Figure 2. The Transformer
CIRCUIT BOARD
2.This circuit connects the circuit board to the
transfer relay coil in the prepackaged transfer
switch.
The circuit board controls all standby electric system
operations including (a) engine startup, (b) engine
running, (c) automatic transfer, (d) automatic
retransfer, and (e) engine shutdown. In addition, the
circuit board performs the following functions:
❏Delivers "field boost" current to the generator rotor
windings (see "Field Boost Circuit" on Page 2.2-1).
❏Starts and "exercises" the generator once every
seven days.
❏Provides automatic engine shutdown in the event of
low oil pressure, high oil temperature, or overspeed.
A 17-pin and a 5-pin connector are used to
interconnect the circuit board with the various circuits
of the DC systems. Connector pin numbers,
associated wires and circuit functions are listed in the
CHART on the next page.
Figure 1. Terminal Board
Page 4.1-1
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SECTION 4.1
DESCRIPTION AND COMPONENTS
DC CONTROL
PART 4
J1 PIN
WIRE
4
CIRCUIT FUNCTION
1
2
Field boost current to rotor (about 9-10 volts DC).
86
Low oil pressure shutdown. Automatic shutdown occurs when Wire 85 is grounded by loss of oil
pressure to the LOP.
3
4
5
6
7
23
194
56
Switched to ground for Transfer Relay (TR) operation.
12 VDC output from the circuit board for transfer relay, present in AUTO or MANUAL operation.
Energized (12 volts DC) by circuit board’s crank relay (K1) to crank the engine.
Engine shutdown. Circuit is grounded by circuit board action to ground the engine
18
14
12 VDC output for engine run condition. Used for fuel solenoid (FS), battery charge relay (BCR),
and hourmeter if equipped.
8
66A
239
15A
17
AC input to the board for crank terminate and overspeed protection.
B+ input when SW1 is in the MANUAL position.
B+ input into the board for source voltage when SW1 is in the AUTO or MANUAL position.
B+ output to SW1 for manual start operation.
12VDC source voltage for the circuit board. Also runs timer for exerciser.
Common ground.
9
10
11
12
13
14
15
16
17
15
0
225
224
Transformer reduced "Utility" source sensing voltage.
Transformer reduced "Utility" source sensing voltage.
NOT USED
NOT USED
J2 PIN
WIRE
CIRCUIT FUNCTION
1
2
3
4
5
NOT USED
85
High temperature oil engine safety.
Input set exercise. Signal to ground to set.
Output for remote alarm relay, optional.
Output for remote alarm relay, optional.
351
15B
229
Figure 3. Circuit Board
Page 4.1-2
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SECTION 4.1
DESCRIPTION AND COMPONENTS
DC CONTROL
PART 4
The circuit board mounts a crank relay (K1) and a run
relay (K2, see Figure 4). Crank relay (K1) is
energized by circuit board action during both manual
and automatic startup to crank the engine. Cranking
is accomplished in crank-rest cycles, with the first
cycle being 15 seconds on and 15 seconds off. After
the first crank-rest cycle, the remaining cycles will be
in equal 7-9 second durations. This cyclic cranking
action continues until either (a) the engine starts, or
(b) approximately 90 seconds of the crank-rest cycles
have elapsed.
15 AMP FUSE
This fuse protects the circuit board against excessive
current. If the fuse has blown, engine cranking and
operation will not be possible. Should fuse
replacement become necessary, use only an identical
15-amp replacement fuse.
5 AMP FUSE
This fuse protects the battery charger against
excessive current. If the fuse has blown, battery
charge operation will not be possible. Should fuse
replacement become necessary, use only an identical
5-amp replacement fuse.
The run relay is energized by circuit board action at
the same time as the crank relay, to energize and
open a fuel solenoid valve.
DANGER: THE GENERATOR ENGINE WILL
CRANK AND START WHEN THE 7-DAY
EXERCISER SWITCH IS ACTUATED. THE
UNIT WILL ALSO CRANK AND START
EVERY 7 DAYS THEREAFTER, ON THE
DAY AND AT THE TIME OF DAY THE
SWITCH WAS ACTUATED.
AUTO-OFF-MANUAL SWITCH
This 3-position switch permits the operator to (a)
select fully automatic operation, (b) start the
generator manually, or (c) stop the engine and
prevent automatic startup. Switch terminals are
shown pictorially and schematically in Figure 5,
below.
Figure 5. 15 Amp Fuse
Figure 4. The AUTO-OFF-MANUAL Switch
Page 4.1-3
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SECTION 4.1
DESCRIPTION AND COMPONENTS
DC CONTROL
PART 4
Figure 6. Control Panel Component Identification
Page 4.1-4
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
INTRODUCTION
This "Operational Analysis" is intended to
familiarize the service technician with the
operation of the DC control system on
prepackaged units with air-cooled engine. A
thorough understanding of how the system
works is essential to sound and logical
troubleshooting. The DC control system
illustrations on the following pages include a "V-
Type" prepackaged transfer switch.
UTILITY SOURCE VOLTAGE AVAILABLE
See Figure 1, above. The circuit condition with
the AUTO-OFF-MANUAL switch set to AUTO
and with "Utility" source power available can be
briefly described as follows:
"Utility" source voltage is available to transfer
switch terminal lugs N1/N2. With the transfer
switch main contacts at their "Utility" side, this
source voltage is available to terminal lugs
T1/T2 and to the "Load" circuits.
"Utility" voltage is delivered to the primary
winding of a sensing transformer (TX), via
transfer switch wires N1/N2, fuses F1/F2,
connected wiring, and Control Panel "Utility
1/Utility 2" terminals. A resultant voltage
(about 16 volts AC) is induced into the
transformer secondary windings and then
delivered to the circuit board via Wires
224/225. The circuit board uses this reduced
"Utility" voltage as sensing voltage. Wires
224A/225A supply 16 VAC to the battery
charger.
Figure 1. Circuit Condition - Utility Source Voltage Available
Battery output is delivered to the circuit board
with the AUTO-OFF-MANUAL switch (SW1) set
to AUTO, as shown.
Page 4.2-1
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
Page 4.2-2
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
INITIAL DROPOUT OF
UTILITY SOURCE VOLTAGE
Refer to Figure 2, above. Should a "Utility"
power source failure occur, circuit condition may
be briefly described as follows:
The circuit board constantly senses for an
acceptable "Utility" source voltage, via
transfer switch fuses F1/F2, transfer switch
"Utility 1/Utility 2" terminals, connected wiring,
control panel "Utility 1/Utility 2" terminals, the
sensing transformer (TX), and Wires 224/225.
Should "Utility" voltage drop below
approximately 60 percent of the nominal
source voltage, a 15-second timer on the
circuit board will turn on.
In Figure 2, the 15-second timer is still timing
and engine cranking has not yet begun.
The AUTO-OFF-MANUAL switch is shown in
its AUTO position. Battery voltage is available
to the circuit board, via Wire 13, 15 amp fuse
(F1), Wire 15, the AUTO-OFF-MANUAL
switch (SW1), Wire 15A, and Pin 10 of the
circuit board connector.
Figure 2. Circuit Condition -
Initial Dropout of Utility Source Voltage
Page 4.2-3
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
Page 4.2-4
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
UTILITY VOLTAGE DROPOUT AND
ENGINE CRANKING
After fifteen (15) seconds and when the circuit
board’s 15-second timer has timed out, if
"Utility" voltage is still below 60 percent of
nominal, circuit board action will energize the
circuit board’s crank and run relays (K1 and
K2) simultaneously.
The crank relay (K1) will remain energized for
about 15 seconds on the first crank cycle. The
relay will then de-energize for 7 seconds and
will again energize. This time it will remain
energized for 7 seconds. Thus, the engine will
crank cyclically for 7 second crank-rest
cycles. This cyclic cranking will continue until
either the engine starts or until about ninety
(90) seconds of crank-rest cycles have been
used up.
When the crank relay (K1) is energized, circuit
board action delivers 12 volts DC to a starter
contactor relay (SCR), via Wire 56. When the
SCR energizes, its contacts close and battery
power is delivered to a starter contactor (SC).
When the SC energizes, its contacts close
and battery power is delivered to the starter
motor (SM).The engine cranks.
When the circuit board’s run relay (K2)
energizes, 12 volts DC is delivered to a fuel
solenoid (FS), via Wire 14. The fuel solenoid
(FS) energizes open and fuel is available to
the engine. Wire 14 also energizes the
hourmeter for operation (if so equipped) .
Wire 14 energizes the battery charge relay
(BCR), which will allow the BCR to power the
battery charger.
Figure 3. Circuit Condition - Engine Cranking
As the engine cranks, magnets on the engine
flywheel induce a high voltage into the engine
ignition modules (IM1/IM2). A spark is
produced that jumps the spark plug
(SP1/SP2) gap.
During cranking, Wire 4 supplies 2-3 VDC (8-
9 VDC isolated) to the rotor for field flash.
With ignition and fuel flow available the
engine can start.
Page 4.2-5
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
Page 4.2-6
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
ENGINE STARTUP AND RUNNING
With the fuel solenoid open and ignition
occurring, the engine starts. Engine startup and
running may be briefly described as follows:
An AC voltage/frequency signal is delivered to
the circuit board from the generator engine
run winding, via Wire 66A. When AC
frequency reaches approximately 30 Hz, the
circuit board (a) terminates cranking, and (b)
turns on an "engine warm-up timer".
The "engine warm-up timer" will run for about
15 seconds. When this timer finishes timing,
board action will initiate transfer to the
"Standby" power source. As shown in Figure
4 (above), the timer is still running and
transfer has not yet occurred.
Generator AC output is available to transfer
switch terminal lugs E1/E2 and to the
normally open contacts of a transfer relay.
However, the transfer relay is de-energized
and its contacts are open.
Figure 4. Circuit Condition - Engine Startup and Running
Page 4.2-7
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
Page 4.2-8
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
INITIAL TRANSFER TO THE
"STANDBY" SOURCE
The generator is running, the circuit board’s
"engine warm-up timer" is timing, and generator
AC output is available to transfer switch terminal
lugs E1 and E2 and to the open contacts on the
transfer relay. Initial transfer to the "Standby"
power supply may be briefly described as
follows:
The circuit board delivers a 12 volts DC
output to the transfer relay (TR) actuating coil,
via Wire 194, and terminal A of the transfer
relay (TR) in the transfer switch. This 12 volts
DC circuit is completed back to the board, via
transfer relay terminal B, and Wire 23.
However, circuit board action holds the Wire
23 circuit open to ground and the transfer
relay (TR) is de-energized.
When the circuit board’s "engine warm-up
timer" times out, circuit board action
completes the Wire 23 circuit to ground. The
transfer relay then energizes and its normally
open contacts close.
"Standby" power is now delivered to the
standby closing coil (C2), via Wires E1 /E2,
the normally open transfer relay contacts,
Wire 205, limit switch XB1, Wire B, and a
bridge rectifier. The standby closing coil
energizes and the main current carrying
contacts of the transfer switch are actuated to
their ’Standby" source side.
Figure 5. Circuit Condition - Initial Transfer to Standby
As the main contacts move to their "Standby"
source side, a mechanical interlock actuates
limit switch XB1 to its open position and limit
switch XA1 to its "Utility" side position. When
XB1 opens, standby closing coil C2 3 de-
energizes.
"Standby" power is delivered to the "Load"
terminals (T1/T2) of the transfer switch.
Page 4.2-9
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
Page 4.2-10
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
UTILITY VOLTAGE RESTORED / RE-
TRANSFER TO UTILITY
The "Load" is powered by the "Standby" power
supply. The circuit board continues to seek an
acceptable "Utility" source voltage. On
restoration of "Utility" source voltage, the
following events will occur:
On restoration of utility source voltage above
80 percent of the nominal rated voltage, a
"retransfer time delay" on the circuit board
starts timing. The timer will run for about
fifteen (15) seconds.
At the end of fifteen (15) seconds, the
"retransfer time delay" will stop timing and
circuit board action will open the Wire 23
circuit to ground. The transfer relay (TR) will
then de-energize.
When the transfer relay (TR) de-energizes, its
normally-closed contacts close. "Utility"
source voltage is then delivered to the utility
closing coil (C1), via Wires N1A/N2A, the
closed TR contacts, Wire 126, limit switch
XA1, and a bridge rectifier.
The utility closing coil (C1) energizes and
moves the main current carrying contacts to
their "Neutral" position. The main contacts
move to an over center position past "Neutral"
and spring force closes them to their "Utility"
side. "Load" terminals are now powered by
the "Utility" source.
Movement of the main contacts to ’Utility"
actuates limit switches XA1/XB1. XA1 opens
and XB1 actuates to its "Standby" source
side.
Figure 6. Circuit Condition - Utility Voltage Restored
The generator continues to run.
Page 4.2-11
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
Page 4.2-12
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
ENGINE SHUTDOWN
Following retransfer back to the "Utility" source,
an "engine cool-down timer" on the circuit board
starts timing. When that timer has timed out
(approximately one minute), circuit board action
will de-energize the circuit board’s run relay
(K2). The following events will then occur:
The DC circuit to Wire 14 and the fuel
solenoid (FS) will be opened. The fuel
solenoid (FS) will de-energize and close to
terminate the engine fuel supply.
The hourmeter (if equipped) connected to
Wire 14 will be opened and clock function of
the hourmeter will stop.
The battery charge relay (BCR) connected to
Wire 14 will be de-energized. This will cause
transformer (TX) voltage to power the battery
charger again.
Circuit board action will connect the engine’s
ignition shutdown module (ISM) to ground, via
Wire 18, circuit board Pin 13, and Wire 0.
Ignition will be terminated.
Without fuel flow and without ignition, the
engine will shut down.
Figure 7. Circuit Condition -
Retransfer to “Utility” and Engine Shutdown
Page 4.2-13
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SECTION 4.2
OPERATIONAL ANALYSIS
DC CONTROL
PART 4
Page 4.2-14
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SECTION 4.3
TROUBLESHOOTING FLOW CHARTS
DC CONTROL
PART 4
Page 4.3-1
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SECTION 4.3
TROUBLESHOOTING FLOW CHARTS
DC CONTROL
PART 4
Page 4.3-2
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SECTION 4.3
TROUBLESHOOTING FLOW CHARTS
DC CONTROL
PART 4
Page 4.3-3
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SECTION 4.3
TROUBLESHOOTING FLOW CHARTS
DC CONTROL
PART 4
Page 4.3-4
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SECTION 4.3
TROUBLESHOOTING FLOW CHARTS
DC CONTROL
PART 4
Page 4.3-5
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SECTION 4.3
TROUBLESHOOTING FLOW CHARTS
DC CONTROL
PART 4
Page 4.3-6
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SECTION 4.3
TROUBLESHOOTING FLOW CHARTS
DC CONTROL
PART 4
Page 4.3-7
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
INTRODUCTION
TEST 42 - TRY A MANUAL START
Perform these "Diagnostic Tests" in conjunction with
the "Troubleshooting Flow Charts" of Section 4.3.
DISCUSSION:
The first step in troubleshooting for an "engine won’t
crank" condition is to determine if the problem is
peculiar to automatic operations only or if the engine
won’t crank manually either.
The test procedures and methods presented in this
section are not exhaustive. We could not possibly
know of, evaluate and advise the service trade of all
conceivable ways in which testing and trouble
diagnosis might be performed. We have not
undertaken any such broad evaluation.
PROCEDURE:
1. On the generator panel, set the AUTO-OFF-MANUAL
switch to OFF.
2. Set the generator main line circuit breaker to its OFF or
open position.
TEST 41 - CHECK POSITION OF AUTO-OFF-
MANUAL SWITCH
3. Set the generator AUTO-OFF-MANUAL switch to
MANUAL.
DISCUSSION:
If the standby system is to operate automatically, the
generator AUTO-OFF-MANUAL switch must be set to
AUTO. That is, the generator will not crank and start
on occurrence of a "Utility" power outage unless that
switch is at AUTO. In addition, the generator will not
exercise every seven (7) days as programmed unless
the switch is at AUTO.
a.The engine should crank cyclically through it s
"crank-rest" cycles until it starts.
b.Let the engine stabilize and warm up for a few
minutes after it starts.
RESULTS:
1. If the engine cranks manually but does NOT crank
automatically, go to Test 43.
PROCEDURE:
With the AUTO-OFF-MANUAL switch set to "AUTO,
test automatic operation. Testing of automatic
operation can be accomplished by turning OFF the
Utility power supply to the transfer switch. When the
utility power is turned OFF, the standby generator
should crank and start. Following startup, transfer to
the standby source should occur. Refer to Section 1.8
in this manual. An "Automatic Operating Sequences
Chart" is provided on Page 1.7-2. Use the chart as a
guide in evaluating automatic operation.
2. If the engine does NOT crank manually, proceed to
Problem 9 in the "Troubleshooting Flow Charts".
TEST 43- TEST AUTO-OFF-MANUAL SWITCH
DISCUSSION:
When the AUTO-OFF-MANUAL switch is set to AUTO
position, battery voltage (12 volts DC) is delivered to the
circuit board via Wire 15A, the closed switch terminal,
Wire 15A, and Pin 10 of the circuit board connector.
This voltage is needed to operate the circuit board.
Following generator startup and transfer to the
standby source, turn ON the utility power supply to the
transfer switch. Retransfer back to the "Utility" source
should occur. After an "engine cool down timer" has
timed out, generator shutdown should occur.
Setting the switch to its "Manual" position delivers
battery voltage to the circuit board for its operation. In
addition, when the switch is set to "Manual", 12 volts
DC is supplied to the circuit board via Pin 11 of the
board, Wire 239, the closed switch contacts, Wire 17
and Pin 9 of the circuit board connector.
RESULTS:
1. If normal automatic operation is obtained, discontinue
tests.
2. If engine does NOT crank when "Utility" power is turned
off, proceed to Test 42.
3. If engine cranks but won't start, go to Problem 10 in
Section 4.3.
4. If engine cranks and starts, but transfer to "Standby"
does NOT occur, go to Problem 5 in Section 3.3.
5. If transfer to "Standby" occurs, but retransfer back to
"Utility" does NOT occur when utility source voltage is
restored, go to Problem 6 in Section 3.3.
Figure 1. Schematic of AUTO-OFF-MANUAL Switch
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
PROCEDURE:
TEST 44- CHECK WIRE 15/15A/17/239 VOLTAGE
Disconnect all wires from switch terminals, to prevent
interaction. Then, use a volt-ohm-milliammeter (VOM)
to test for continuity across switch terminals as shown
in the following chart. Reconnect all wires and verify
correct positions when finished.
DISCUSSION:
The circuit board will not turn on unless battery
voltage is available to the board via wire 15, the
AUTO-OFF-MANUAL switch and Wire 15A. If battery
voltage is not available, automatic or manual
operation will not be possible.
TERMINALS
2 and 3
SWITCH POSITION
READING
Battery voltage is available to wire 17 from pin location
11 of the J1 connector on the circuit board. When the
AUTO-OFF-MANUAL switch is in the MANUAL position,
wire 239 supplies battery voltage to pin location 9 of the
circuit board, and engine cranking occurs.
AUTO
MANUAL
OFF
CONTINUITY
INFINITY
INFINITY
2 and 1
5 and 6
5 and 4
AUTO
MANUAL
OFF
INFINITY
CONTINUITY
INFINITY
PROCEDURE:
AUTO
MANUAL
OFF
CONTINUITY
INFINITY
INFINITY
(For Problem 1 flow chart, do Steps 1-5 and Step 9 only)
(For Problem 2 flow chart, do all steps)
1. Set a VOM to measure DC voltage.
AUTO
MANUAL
OFF
INFINITY
CONTINUITY
INFINITY
2. Connect the positive (+) test lead to the AUTO-OFF-
MANUAL switch Terminal 2, Wire 15. Connect the
negative (-) test lead to a clean frame ground. Battery
voltage should be measured (See Figure. 2).
RESULTS:
1. Replace AUTO-OFF-MANUAL switch, if defective.
2. For Problem 8 Only: If the switch passes the tests,
verify the REMOTE NOT AUTO dipswitch is set to OFF
on the circuit board (see Figure 3, page 4.1-2) then
proceed to Test 44.
3. Connect the positive (+) test lead to the AUTO-OFF-
MANUAL switch terminal 1, Wire 15A. Connect the
negative (-) test lead to a clean frame ground. Set the
AUTO-OFF-MANUAL switch to MANUAL. Battery
voltage should be measured.
3. For Problem 9 Only: If the switch passes the tests,
proceed to Test 60.
4. Connect the positive (+) test lead to Pin location 12 Wire
15 at the J1 connector on the circuit board. Connect the
negative (-) test lead to a clean frame ground. Battery
voltage should be measured.
5. Connect the positive (+) test lead to pin location 10, wire
15A at the J1 connector on the circuit board. Connect
the negative test lead to a clean frame ground. Set the
AUTO-OFF-MANUAL switch to the MANUAL position.
Battery voltage should be measured. Repeat Step 5.
This time set the AUTO-OFF-MANUAL switch to AUTO.
Battery voltage should be measured.
6. Connect the positive (+) test lead to pin location 9, wire
239 at the J1 connector on the circuit board. Connect the
negative (-) test lead to a clean frame ground. Set the
AUTO-OFF-MANUAL switch to the MANUAL position.
Battery voltage should be measured. If battery voltage
is measured, stop and proceed to results. If battery
voltage is NOT measured, proceed to Step 7.
Figure 2. AUTO-OFF-MANUAL Switch Test Points
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SECTION 4.4
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DC CONTROL
PART 4
7. Connect the positive (+) test lead to the AUTO-OFF-
MANUAL switch Terminal 4, Wire 17/178. Connect the
negative (-) test lead to a clean frame ground. Battery
voltage should be measured.
TEST 45- CHECK 15 AMP FUSE
DISCUSSION:
The 15 amp fuse is located on the generator console.
A blown fuse will prevent battery power from reaching
the circuit board, with the same result as setting the
AUTO-OFF-MANUAL switch to OFF.
8. Connect the positive (+) test lead to Pin location 11, wire
17 at the J1 connector on the circuit board. Connect the
negative (-) test lead to a clean frame ground. Battery
voltage should be measured.
PROCEDURE:
Remove the 15 amp fuse (F1) by pushing in on fuse
holder cap and turning the cap counterclockwise.
Inspect the fuse visually and with a VOM for an open
condition.
9. Set a VOM to measure resistance "R x 1" scale. Connect
one meter test lead to a clean frame ground. Connect the
other test lead to Pin location 13, Wire 0 at the J1 connector
on the circuit board. CONTINUITY should be measured.
RESULTS:
RESULTS:
1. If the fuse if good, go on to Test 46.
1. No battery voltage in Step 2. Go to test 45 or
repair/replace Wire 15 from F1 to SW1.
2. If the fuse is bad, it should be replaced. Use only an
identical 15 amp replacement fuse.
2. No battery voltage in Step 3. Go to Test 43 or repair or
replace Wire 15A from Terminal 1 to Terminal 3 of SW1.
3. If fuse continues to blow, go to Problem 16.
3. No battery voltage in Step 4. Verify Step 2 and repair or
replace wire 15 from SW1 to J1 connector.
TEST 46- CHECK BATTERY
4. No battery voltage in Step 5. Go to Test 43 or repair or
replace Wire 15A from SW1 to J1 connector.
DISCUSSION:
Battery power is used to (a) crank the engine and (b)
to power the circuit board. Low or no battery voltage
can result in failure of the engine to crank, either
manually or during automatic operation.
5. If battery voltage is available in Step 8 but NOT in Step
7, repair or replace Wire 17 from SW1 to J1 connector.
6. If battery voltage is available in Step 7 but NOT in Step
6, go to Test 43.
PROCEDURE:
7. If CONTINUITY is NOT measured in Step 9, repair or
replace Wire 0 between the J1 connector and the 8-tab
ground terminal.
A. Inspect Battery Cables:
1.Visually inspect battery cables and battery
posts.
8. If battery voltage is available in Steps 1-5 but NOT in
Step 8 of Problem 2 flow chart, replace or repair the
circuit board.
2.If cable clamps or terminals are corroded, clean
away all corrosion.
9. If battery voltage is available in Steps 1-5 for Problem 1
flow chart, replace the circuit board.
3.Install battery cables, making sure all cable
clamps are tight. The red battery cable from the
starter contactor (SC) must be securely
attached to the positive (+) battery post; the
black cable from the frame ground stud must be
tightly attached to the negative (-) battery post.
B. Test Battery State of Charge:
1.Use an automotive type battery hydrometer to
test battery state of charge.
2.Follow the hydrometer manufacturer’s
instructions carefully. Read the specific gravity
of the electrolyte fluid in all battery cells.
3.If the hydrometer does not have a "percentage
of charge" scale, compare the reading obtained
to the following:
Figure 3. Wires 15A
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SECTION 4.4
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DC CONTROL
PART 4
a. An average reading of 1.260 indicates the
battery is 100% charged.
circuit board connector J1. Connect the common (-) test
lead to a clean frame ground. Then, repeat Step 2.
b. An average reading of 1.230 means the
battery is 75% charged.
a.The circuit board’s crank and run relays should
energize.
c. An average reading of 1.200 means the
battery is 50% charged.
b.The meter should read battery voltage.
d. An average reading of 1.170 indicates the
battery is 25% charged.
C. Test Battery Condition:
1.If the difference between the highest and lowest
reading cells is greater than 0.050 (50 points),
battery condition has deteriorated and the
battery should be replaced.
2.However, if the highest reading cell has a
specific gravity of less than 1.230, the test for
condition is questionable. Recharge the battery
to a 100 percent state of charge, then repeat the
test for condition.
Figure 4. The Wire 56 Circuit
RESULTS:
RESULTS:
1. Remove the battery and recharge with an automotive
battery charger, if necessary.
1. If battery voltage is indicated in Step 3, but NOT in Step
2, Wire 56 (between the circuit board and starter
contactor relay or starter contactor) is open. Repair or
replace this wire as required.
2. If battery condition is bad, replace the battery with a
new one.
2. If battery voltage is NOT indicated in Step 3, go to Test
43.
TEST 47 - CHECK WIRE 56 VOLTAGE
3. If battery voltage is indicated in both Steps 2 and 3, but
engine does NOT crank, go on to Test 49.
DISCUSSION:
During an automatic start or when starting manually, a
crank relay (K1) on the circuit board should energize.
Each time the crank relay energizes, the circuit board
should deliver 12 volts DC to a starter contactor
relay(SCR) and the engine should crank. This test will
verify (a) that the crank relay on the circuit board is
energizing, and (b) that circuit board action is
delivering 12 volts DC to the starter contactor relay.
TEST 48- TEST STARTER CONTACTOR
RELAY (V-TWIN ONLY)
DISCUSSION:
The starter contactor relay (SCR) located in the
control panel must be energized for cranking to occur.
Once the SCR is energized, it s normally open
contacts will close and battery voltage will be
available to Wire 16 and to the starter contactor (SC).
PROCEDURE:
1. Connect the positive (+) test probe of a DC voltmeter (or
VOM) to the Wire 56 connector of the starter contactor
relay (SCR, on models with v-twin engines) or the starter
contactor (SC, on models with single cylinder engines).
Connect the common (-) test probe to frame ground.
2. Observe the meter. Then, actuate the AUTO-OFF-
MANUAL switch to MANUAL position.
a.The circuit board crank and run relays should
energize.
b.The meter should indicate battery voltage.
3. Insert the positive (+) meter test lead into Pin 5 of the
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DC CONTROL
PART 4
Figure 5. The Starter Contactor Relay
ground. Battery voltage (12 volts DC) should be indicated.
2. Now, connect the positive (+) meter test lead to the
starter contactor stud to which the starter motor cable
attaches (see Figure 6 or 7). Connect the common (-)
test lead to frame ground.
PROCEDURE:
1 Set a VOM to measure DC voltage.
2. Connect the positive (+) meter test lead to the Wire 13
connector. Connect the negative (-) meter test lead to a
clean frame ground. Battery voltage should be measured.
a.No voltage should be indicated initially.
3. Connect the positive (+) meter test lead to the Wire 16
connector. Connect the negative (-) meter test lead to a
clean frame ground.
b.Set the AUTO-OFF-MANUAL switch to MANUAL.
The meter should now indicate battery voltage
as the starter contactor energizes.
4. Set the AUTO-OFF-MANUAL switch to MANUAL.
Observe the meter reading. Battery voltage should
measured. If battery voltage is NOT measured, proceed
to Step 5.
5. Set the VOM to it’s “R x 1” scale to measure ohms.
6. Connect one test lead to the Wire 0 connector. Connect
the other test lead to a clean frame ground.
CONTINUITY should be measured.
RESULTS:
1 If battery voltage is NOT measured in Step 2, repair or
replace wiring between starter contactor relay and fuse
(F2).
2. If battery voltage is NOT measured in Step 4 and
CONTINUITY is measured in Step 6, replace the starter
contactor relay.
3. If battery voltage is measured in Step 4. proceed to
Test 49.
Figure 6. The Starter Contactor (Single Cylinder Units)
TEST 49- TEST STARTER CONTACTOR
DISCUSSION:
The starter contactor (SC) must energize and its heavy
duty contacts must close or the engine will not crank.
This test will determine if the starter contactor is in
working order.
PROCEDURE:
Carefully inspect the starter motor cable that runs from
the battery to the starter motor. Cable connections must
be clean and tight. If connections are dirty or corroded,
remove the cable and clean cable terminals and
terminal studs. Replace any cable that is defective or
badly corroded.
Use a DC voltmeter (or a VOM) to perform this test.
Test the starter contactor as follows:
1. Connect the positive (+) meter test lead to the starter
contactor stud (to which the red battery cable connects).
Connect the common (-) meter test lead to a clean frame
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SECTION 4.4
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DC CONTROL
PART 4
Figure 7. The Starter Contactor (V-twin Units)
to engage (pinion engaged), but engine did NOT crank,
check for mechanical binding of the engine or rotor.
RESULTS:
If engine turns over slightly, go to Test 62 Check and
Adjust Valves. Compression release on single
cylinder engines may not be working, or mechanical
binding is occurring.
1. If battery voltage was indicated in Step 1, but NOT in
Step 2b, replace the starter contactor.
2. If battery voltage was indicated in Step 2b, but the
engine did NOT crank, go on to Test 50.
TEST 50- TEST STARTER MOTOR
CONDITIONS AFFECTING STARTER MOTOR
PERFORMANCE:
1. A binding or seizing condition in the starter motor bearings.
2. A shorted, open or grounded armature.
a.Shorted, armature (wire insulation worn and
wires touching one another). Will be indicated
by low or no RPM.
b.Open armature (wire broken) will be indicated
by low or no RPM and excessive current draw.
Figure 8. Starter Motor (V-Twin Engines)
c. Grounded armature (wire insulation worn and wire
touching armature lamination or shaft). Will be
indicated by excessive current draw or no RPM.
3. A defective starter motor switch.
4. Broken, damaged or weak magnets.
5. Starter drive dirty or binding.
DISCUSSION:
Test 47 verified that circuit board action is delivering
DC voltage to the starter contactor relay (SCR). Test
48 verified the operation of the SCR. Test 49 verified
the operation of the starter contactor (SC). Another
possible cause of an "engine won’t crank" problem is
a failure of the starter motor.
Figure 9. Starter Motor (Single Cylinder Engines)
PROCEDURE:
CHECKING THE PINION:
The battery should have been checked prior to this
test and should be fully charged.
When the starter motor is activated, the pinion gear
should move and engage the flywheel ring gear. If the
pinion does not move normally, inspect the pinion for
binding or sticking.
Set a VOM to measure DC voltage (12 VDC).
Connect the meter positive (+) test lead to the starter
contactor stud which has the small jumper wire
connected to the starter. Connect the common (-) test
lead to the starter motor frame.
Set the Start-Stop Switch to its "START" position and
observe the meter. Meter should Indicate battery voltage,
starter motor should operate and engine should crank.
RESULTS:
1. If battery voltage is indicated on the meter but starter
motor did NOT operate, remove and bench test the
starter motor (see following test).
2. If battery voltage was indicated and the starter motor tried
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SECTION 4.4
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DC CONTROL
PART 4
Figure 10. Check Pinion Gear Operation (V-Twin)
Figure 12. Clamp-On Ammeter
TACHOMETER:
A tachometer is available from your Generac Power
Systems source of supply. Order as P/N 042223. The
tachometer measures from 800 to 50,000 RPM,
Figure 13.
Figure 11. Check Pinion Gear Operation
(Single Cylinder)
TOOLS FOR STARTER PERFORMANCE TEST:
The following equipment may be used to complete a
performance test of the starter motor:
❏A clamp-on ammeter.
Figure 13. Tachometer
TEST BRACKET:
❏A tachometer capable of reading up to 10,000 rpm.
❏A fully charged 12-volt battery.
A starter motor test bracket may be made as shown
in Figure 14. A growler or armature tester is available
from an automobile diagnostic service supplier.
MEASURING CURRENT:
To read the current flow, in AMPERES, a clamp-on
ammeter may be used. This type of meter indicates
current flow through a conductor by measuring the
strength of the magnetic field around that conductor.
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DC CONTROL
PART 4
Figure 14. Test Bracket
REMOVE STARTER MOTOR:
It is recommended that the starter motor be removed
from the engine when testing starter motor
performance. Assemble starter to test bracket and
clamp test bracket in vise, Figure 15.
TESTING STARTER MOTOR:
1. A fully charged 12 volt battery is required.
2. Connect jumper cables and clamp-on ammeter as
shown in Figure 15.
3. With the starter motor activated (jump the terminal on the
starter contactor to battery voltage), note the reading on
the clamp-on ammeter and on the tachometer (rpm).
Note: Take the reading after the ammeter and
tachometer are stabilized, approximately 2-4
seconds.
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SECTION 4.4
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❏The gaseous fuel system must be properly tested
4. A starter motor in good condition will be within the
following specifications:
for leaks following installation and periodically
thereafter. No leakage is permitted. Leak test
methods must comply strictly with gas codes.
Single Cylinder
V-twin
4500
50
Minimum rpm
800
9
DANGER: GASEOUS FUELS ARE HIGHLY
EXPLOSIVE. DO NOT USE FLAME OR HEAT
TO TEST THE FUEL SYSTEM FOR LEAKS.
NATURAL GAS IS LIGHTER THAN AIR,
TENDS TO SETTLE IN HIGH PLACES. LP
(PROPANE) GAS IS HEAVIER THAN AIR,
TENDS TO SETTLE IN LOW AREAS. EVEN
THE SLIGHTEST SPARK CAN IGNITE THESE
GASES AND CAUSE AN EXPLOSION.
Maximum Amps
PROCEDURE:
A water manometer or a gauge that is calibrated in
"ounces per square inch" may be used to measure
the fuel pressure. Fuel pressure at the inlet side of the
fuel solenoid valve should be between 11 - 14 inches
water column as measured with a manometer, or
6.38-8.00 ounces per square inch as measure with a
pressure gauge.
The fuel pressure can be checked using a pressure
tester kit (Generac p/n 0C7977). See Figure 16 for
the gas pressure test point on the fuel regulator.
NOTE: Where a primary regulator is used to establish
fuel inlet pressure, adjustment of that regulator is
usually the responsibility of the fuel supplier or the
fuel supply system installer.
RESULTS:
Figure 15. Testing Starter Motor Performance
1. If fuel supply and pressure are adequate, but engine will
not start, go on to Test 53.
TEST 51 - CHECK FUEL SUPPLY AND
PRESSURE
2. If generator starts but runs rough or lacks power, repeat
the above procedure with the generator running and
under load. The fuel system must be able to maintain
11”-14” water column at all load requirements. If proper
fuel supply and pressure is maintained, go to Test 55.
DISCUSSION:
The air-cooled prepackaged generator was factory
tested and adjusted using natural gas as a fuel. If
desired, LP (propane) gas may be used. However,
when changing over to propane, some minor
adjustments are required. The following facts apply:
❏An adequate gas supply and sufficient fuel pressure
must be available or the engine will not start.
❏Minimum recommended gaseous fuel pressure at
the generator fuel inlet connection is 11 inches
water column (6.38 ounces per square inch).
❏Maximum gaseous fuel pressure at the generator
fuel inlet connection is 14 inches water column (8
ounces per square inch).
❏When propane gas is used, only a "vapor withdrawal"
system may be used. "This type of system utilizes the
gas that form above the liquid fuel the vapor pressure
must be high enough engine operation.
Figure 16. Air Cooled Engine Fuel System
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SECTION 4.4
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PART 4
3. While observing the meter, set the AUTO-OFF-MANUAL
switch to MANUAL.
TEST 52 - TEST FUEL SOLENOID
Note: This test is for fuel regulators equipped with idle
circuit port only. See Figure 16. These units have an
additional 1/4” fuel hose.
a.The circuit board’s crank and run relays should
energize and the engine should crank and start.
b.The meter should indicate battery voltage.
DISCUSSION:
c. If battery voltage is indicated, proceed to Step 4.
If battery voltage is NOT indicated, proceed to
Test 53 results.
When the Fuel Solenoid (FS) is energized, gas
pressure is available internally to the on demand Fuel
Regulator. Gas pressure will then be available to the
idle circuit port of the Fuel Regulator.
4. Disconnect Wire 14 at the Fuel Solenoid (FS).
a.Connect the positive (+) test lead to Wire 14. Connect
the negative test lead to a clean frame ground. Set
the AUTO-OFF-MANUAL switch to MANUAL. Battery
voltage should be measured. If battery voltage is
indicated, proceed to Step 5.
PROCEDURE:
1. Disconnect Wire 56 from the starter contactor relay
(SCR). This will disable the unit from cranking. For
single cylinder units, disconnect from the starter
contactor (SC) and isolate it from ground.
b. Connect the positive (+) test lead to Wire 14 at the 4-tab
terminal block in the control panel, see Figure 17.
Connect the negative (-) test lead to frame ground. While
observing the meter, set the AUTO-OFF-MANUAL
switch to MANUAL. Battery voltage should be measured.
2. Remove the fuel hose from the idle circuit port barbed
fitting.
3. Attach a manometer (Generac P/N 0C7977) to the idle
circuit port barbed fitting.
4. Set the AUTO-OFF-MANUAL switch to MANUAL. The
engine will not crank, but gas pressure should be
observed on the manometer at 11”-14” of water column.
5. Set the AUTO-OFF-MANUAL switch to OFF. Remove
the manometer. Re-attach the fuel hose to the idle circuit
port barbed fitting. Re-connect Wire 56 to the starter
contactor relay or starter contactor.
RESULTS:
1. If gas pressure was measured, proceed to Test 55.
2. If gas pressure was NOT measured, replace the fuel
solenoid (FS).
Figure 17. 4-Tab Terminal Block
5. Set the VOM to it’s “R x 1” scale.
TEST 53 - CHECK CIRCUIT BOARD WIRE 14
OUTPUT
6. Disconnect Wire 0 from the Fuel Solenoid (FS). Connect
one test lead to Wire 0 and the other test lead to a clean
frame ground. CONTINUITY should be measured.
DISCUSSION:
During any cranking action, the circuit board’s crank
relay (K1) and run relay (K2) both energize
simultaneously. When the run relay energizes, its
contacts close and 12 volts DC is delivered to Wire 14
and to a fuel solenoid. The solenoid energizes open
to allow fuel flow to the engine. This test will
determine if the circuit board is working properly.
RESULTS:
1. If the engine cranks but does not start and battery voltage
was NOT measured in Step 3, replace the circuit board.
2. If the engine cranks and battery voltage was measured
in Step 3, but there was no battery voltage in Step 4(a),
repair or replace Wire 14 between 4-tab terminal block
and the Fuel Solenoid (FS).
PROCEDURE:
1. Set the AUTO-OFF-MANUAL switch to OFF.
3. If the engine cranks and battery voltage was measured
in step 3 and no battery voltage is measured in step 4b,
repair or replace Wire 14 between the J1 connector on
the circuit board and the 4-tab terminal block.
2. Connect the positive (+) test lead of a DC voltmeter (or
VOM) into Pin 7 (Wire 14) of the circuit board connector
J1. Connect the common (-) test lead to frame ground.
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PART 4
RESULTS:
4. If the engine cranks but does not start and battery
voltage was measured in Steps 2, 3 and 4, and
CONTINUITY was NOT measured in Step 6, repair or
replace Wire 0 between the Control Panel ground
connection and the Fuel Solenoid terminal. If
CONTINUITY was measured in Step 6, proceed to Test
52 or test 54 depending on the model.
1. If solenoid actuates, go to Test 55.
2. Replace the solenoid if it does not actuate.
TEST 55 - CHECK FOR IGNITION SPARK
DISCUSSION:
If the engine cranks but will not start, perhaps an
ignition system failure has occurred. A special "spark
tester" (Generac P/N 0C5969) can be used to check
for ignition spark.
TEST 54 - CHECK FUEL SOLENOID
DISCUSSION:
In Test 53, if battery voltage was delivered to Wire 14,
the fuel solenoid should have energized open. This test
will verify whether or not the fuel solenoid is operating.
Fuel Solenoid Nominal Resistance 27-33 ohms.
Figure 19. Spark Tester
PROCEDURE:
1. Remove spark plug leads from the spark plugs
(Figure 20).
2. Attach the clamp of the spark tester to the engine
cylinder head.
Figure 18. The Fuel Solenoid (FS)
PROCEDURE:
1. Disconnect Wire 56 from the starter contactor relay
(SCR). This will disable the unit from cranking. For
single cylinder units, disconnect from the starter
contactor (SC) and isolate it from ground.
2. Place one hand on the Fuel Solenoid (FS). Cycle the
AUTO-OFF-MANUAL switch from MANUAL to OFF.
You should be able to feel the solenoid actuate as well
as hear it actuate. If a small screwdriver is placed on the
solenoid and then gently pulled away, a magnetic field
should be felt.
Figure 20. Checking Ignition Spark
3. Set the AUTO-OFF-MANUAL switch to OFF. Reconnect
Wire 56 to starter contactor relay or starter contactor.
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SECTION 4.4
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DC CONTROL
PART 4
by defective spark plug(s).
PROCEDURE:
1. Remove spark plugs and clean with a penknife or use a
wire brush and solvent.
3. Attach the spark plug lead to the spark tester terminal.
4. Crank the engine while observing the spark tester. If
spark jumps the tester gap, you may assume the engine
ignition system is operating satisfactorily.
NOTE: The engine flywheel must rotate at 350 rpm
(or higher) to obtain a good test of the solid state
ignition system.
2. Replace any spark plug having burned electrodes or
cracked porcelain.
3. Set gap on new or used spark plugs to 0.030 inch for
single cylinder engines and 0.020 inch for v-twin engines.
To determine if an engine miss is ignition related,
connect the spark tester in series with the spark plug
wire and the spark plug (Figure 21). Then, crank and
start the engine. A spark miss will be readily
apparent. If spark jumps the spark tester gap
regularly but the engine miss continues, the problem
is in the spark plug or in the fuel system.
RESULTS:
1. Clean, re-gap or replace spark plugs as necessary.
2. If spark plugs are good, go to Test 62.
NOTE: A sheared flywheel key may change ignition
timing but sparking will still occur across the spark
tester gap.
Figure 22. Checking Spark Plug Gap
TEST 57- CHECK ENGINE COMPRESSION
DISCUSSION:
Lost or reduced engine compression can result in (a)
failure of the engine to start, or (b) rough operation.
One or more of the following will usually cause loss of
compression:
Figure 21. Checking Engine Miss
RESULTS:
1. If no spark or very weak spark occurs, go to Test 58.
❏Blown or leaking cylinder head gasket.
❏Improperly seated or sticking-valves.
2. If sparking occurs but engine still won't start, go to
Test 56.
❏Worn Piston rings or cylinder. (This will also result
in high oil consumption).
3. When checking for engine miss, if sparking occurs at
regular intervals but engine miss continues, go to Test 16.
NOTE: For the single cylinder engine, the minimum
allowable compression pressure for a cold engine is
60 psi.
4. When checking for engine miss, if a spark miss is
readily apparent, go to Test 59.
NOTE: It is extremely difficult to obtain an accurate
compression reading without special equipment. For
that reason, compression values are not published for
the V-Twin engine. Testing has proven that an
accurate compression indication can be obtained using
the following method.
TEST 56 - CHECK SPARK PLUGS
DISCUSSION:
If the engine will not start and Test 55 indicated good
ignition spark, perhaps the spark plug(s) are fouled or
otherwise damaged. Engine miss may also be caused
PROCEDURE:
Page 4.4-12
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SECTION 4.4
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DC CONTROL
PART 4
1. Remove both spark plugs.
3. If spark now occurs with Wire 18 removed, check for a
short to ground. Set the AUTO-OFF-MANUAL switch to
OFF. Remove the 17 pin connector J1 from the circuit
board.
2. Insert a compression gauge into either cylinder.
3. Crank the engine until there is no further increase in
pressure.
4. Set a VOM to measure resistance. Connect one test
lead to Wire 18 from the control panel. Connect the
other test lead to a clean frame ground. INFINITY
should be measured.
4. Record the highest reading obtained.
5. Repeat the procedure for the remaining cylinder and
record the highest reading.
5. Reconnect the J1 connector to the circuit board.
RESULTS:
6. Set a VOM to measure resistance. Connect one test
lead to Wire 18 from the control panel. Connect the
other test lead to a clean frame ground. Set the AUTO-
OFF-MANUAL switch to MANUAL. During cranking the
meter should read INFINITY.
The difference in pressure between the two cylinders
should not exceed 25 percent. If the difference is
greater than 25 percent, loss of compression in the
lowest reading cylinder is indicated.
Example 1: If the pressure reading of cylinder #1 is 65
psi and of cylinder #2, 60 psi, the difference is 5 psi.
Divide "5" by the highest reading (65) to obtain the
percentage of 7.6 percent.
RESULTS:
1. If INFINITY was NOT measured in Step 4, repair or
replace shorted ground Wire 18 between the J1
connector from the circuit board to the stud or bullet
connector.
Example 2:
No. 1 cylinder reads 75 psi; No. 2 cylinder
reads 55 psi. The difference is 20 psi. Divide "20" by
"75" to obtain "26.7" percent. Loss of compression in
No. 2 cylinder is indicated.
2. If INFINITY was NOT measured in Step 6 during
cranking, replace the circuit board and retest for spark.
If compression is poor, look for one or more of the
following:
3. If ignition spark still has not occurred, proceed to
Test 59.
Loose cylinder head bolts.
Failed cylinder head gasket.
Burned valves or valve seats.
Insufficient valve clearance.
Warped cylinder head.
TEST 59 - CHECK AND ADJUST IGNITION
MAGNETOS
DISCUSSION:
In Test 55, a spark tester was used to check for
engine ignition. If sparking or weak spark occurred,
one possible cause might be the ignition magneto(s).
This test consists of adjusting the air gap between the
ignition magneto(s) and the flywheel. The flywheel
and flywheel key will also be checked during this test.
Warped valve stem.
Worn or broken piston ring(s).
Worn or damaged cylinder bore.
Broken connecting rod.
Worn valve seats or valves.
PROCEDURE:
Note: The air gap between the ignition magneto and
the flywheel on single cylinder engines is non-
adjustable. Proceed directly to Steps 15,16 and 17 for
single cylinder engines. For V-twin engines, proceed
as follows.
TEST 58 - CHECK SHUTDOWN WIRE
DISCUSSION:
Circuit board action during shutdown will ground Wire
18. Wire 18 is connected to the Ignition Magneto(s).
The grounded magneto will not be able to produce
spark.
1. See Figure 23. Rotate the flywheel until the magnet is
under the module (armature) laminations.
PROCEDURE:
2. Place a 0.008-0.012 inch (0.20-0.30mm) thickness
gauge between the flywheel magnet and the module
laminations.
1. On v-twin generators, remove Wire 18 from the stud
located above the oil cooler. On single cylinder
generators, disconnect Wire 18 at the bullet connector.
3. Loosen the mounting screws and let the magnet pull the
magneto down against the thickness gauge.
2. Perform Test 55.
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
4. Tighten both mounting screws.
5. To remove the thickness gauge, rotate the flywheel.
6. Repeat the above procedure for the second magneto.
Figure 25. Diode Failure Diagnosis
11.Connect the positive (+) test lead to Connector ”A” (as
shown in Figure 26). Connect the negative (-) test lead
to Connector “B.”
a.If meter Beeps once and displays voltage
drop, then the diode is good.
b.If the meter makes a continuous tone, the diode
is bad (shorted) and the harness must be
replaced.
c. If the meter displays OL, the diode is defective
(open) and the harness must be replaced.
Figure 23. Setting Ignition Magneto (Armature)
Air Gap
7. Repeat Test 55 and check for spark across the spark
tester gap.
8. If air gap was not out of adjustment, test ground wires.
9. Set the VOM to the diode test position. The meter will
display forward voltage drop across the diode. If the
voltage drop is less than 0.7 volts, the meter will “Beep”
once as well as display the voltage drop. A continuous
tone indicates CONTINUITY (shorted diode). An
incomplete circuit (open diode) will be displayed as
“OL.”
10.Disconnect the engine wire harness from the ignition
magnetos and stud connector (Figure 24).
Figure 24. Engine Ground Harness
Figure 26. Engine Ground Harness Test Points
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SECTION 4.4
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DC CONTROL
PART 4
12.Now repeat Step 11 with the negative meter test lead
connected to Connector “C” (Figure 26).
13.Now check the flywheel magnet by holding a
screwdriver at the extreme end of its handle and with its
point down. When the tip of the screwdriver is moved to
within 3/4 inch (19mm) of the magnet, the blade should
be pulled in against the magnet.
14.Now check the flywheel key. The flywheel’s taper is
locked on the crankshaft taper by the torque of the
flywheel nut. A keyway is provided for alignment only
and theoretically carries no load.
Figure 27. Oil Pressure Switch
Note: If the flywheel key becomes sheared or even
partially sheared, ignition timing can change. Incorrect
timing can result in hard starting or failure to start.
PROCEDURE:
Note: For Problem 9 Flow Chart, perform Steps 3a, 4
and 5 only. For Problem 12 Flow Chart perform all
steps.
15.As stated earlier, the armature air gap is fixed for single
cylinder engine models and is not adjustable. Visually
inspect the armature air gap and hold down bolts.
1. Check engine crankcase oil level.
16.Disconnect the shutdown ground wire from the armature
and retest for spark, Test 55.
a.Check engine oil level.
b.If necessary, add the recommended oil to the
dipstick FULL mark. DO NOT OVERFILL
ABOVE THE FULL MARK.
17.Perform Steps 13 and 14.
RESULTS:
2. With oil level correct, try starting the engine.
If sparking still does not occur after adjusting the
armature air gap, testing the ground wires and
performing the basic flywheel test, replace the ignition
magneto(s).
a.If engine still cranks and starts, but then shuts
down, go to Step 3.
b.If engine does not crank go to Step 6.
c. If engine cranks and starts normally, discontinue
tests.
TEST 60- CHECK OIL PRESSURE SWITCH
AND WIRE 86
3. Do the following:
a.Disconnect Wire 86 and Wire 0 from the oil
pressure switch terminals. Remove the switch
and install an oil pressure gauge in its place.
DISCUSSION:
If the oil pressure switch contacts have failed in their
closed position, the engine will probably crank and
start. However, shutdown will then occur within about
5 (five) seconds. If the engine cranks and starts, then
shuts down almost immediately with a LOP fault light,
the cause may be one or more of the following:
b.Connect Wire 86 to Wire 0 for starting purposes
only. After engine starts, remove Wire 86 from
Wire 0.
c. Start the engine while observing the oil pressure
reading on gauge.
❏Low engine oil level.
d.Note the oil pressure.
❏Low oil pressure.
(1) Normal oil pressure is approximately 35-40
psi with engine running. If normal oil
pressure is indicated, go to Step 4 of this
test.
❏A defective oil pressure switch.
If the oil pressure switch contacts have failed open or
Wire 86 does not have continuity to ground at
starting, the engine will not crank. If the engine does
not crank, the cause may be one of the following:
(2) If oil pressure is below about 4.5 psi, shut
engine down immediately. A problem exists
in the engine lubrication system.
❏A defective oil pressure switch stuck open.
Note: The oil pressure switch is rated at 10 psi for v-
twin engines, and 8 psi for single cylinder engines.
❏An open Wire 86 to Circuit Board.
4. Remove the oil pressure gauge and reinstall the oil
pressure switch. Do NOT connect Wire 86 or Wire 0 to
Page 4.4-15
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
PROCEDURE:
the switch terminals.
1. Verify that the engine has cooled down (engine block is
cool to the touch). This will allow the contacts in the
High Oil Temperature Switch to close.
a. Set a VOM to its "R x 1" scale and zero the meter.
b.Connect the VOM test leads across the switch
terminals. With engine shut down, the meter
should read CONTINUITY.
2. Check the installation and area surrounding the
generator. There should be at least three feet of clear
area around the entire unit. Make sure that there are no
obstructions preventing incoming and outgoing air.
c. Connect Wire 86 to Wire 0 for starting purposes
only. After engine starts, remove Wire 86 from
Wire 0.
d. Crank and start the engine. The meter should
read INFINITY.
3. Disconnect Wire 85 and Wire 0 from the High Oil
Temperature Switch.
5. Perform Steps 4a and 4b. If INFINITY is measured with
the engine shutdown, replace the LOP switch.
4. Set a VOM to measure resistance. Connect the test
leads across the switch terminals. The meter should
read INFINITY.
6. Set a VOM to it’s “R x 1” scale.
a. Connect one test lead to Wire 86 (disconnected from
LOP). Connect the other test lead to Pin Location 2
(Wire 86) of the J1 connector at the Circuit Board.
CONTINUITY should be measured. If CONTINUITY
is NOT measured, repair or replace Wire 86 between
the LOP switch and the J1 Connector.
5. If the switch tested good in Step 4, and a true over-
temperature condition has not occurred, check Wire 85
for a short to ground. Remove Connector J2 (5-pin) from
the circuit board. Set the VOM to measure resistance.
Connect one test lead to Wire 85 (disconnected from High
Oil Temperature Switch). Connect the other test lead to a
clean frame ground. INFINITY should be measured.
b. Connect one test lead to Wire 0 ( disconnected from
LOP). Connect the other test lead to a clean frame
ground. CONTINUITY should be measured. If
CONTINUITY is NOT measured repair or replace
Wire 0 between the LOP and and the ground terminal
connection on the engine mount.
TESTING HIGH OIL TEMPERATURE SWITCH:
6. Remove the High Oil Temperature Switch.
7. Immerse the sensing tip of the switch in oil as shown in
Figure 28, along with a suitable thermometer.
7. If the LOP switch tests good in Step 4 and oil pressure is
good in Step 3 but the unit still shuts down with a LOP
fault, check Wire 86 for a short to ground. Set a VOM to
it’s “R x 1” scale. Disconnect the J1 Connector from the
circuit board. Remove Wire 86 from the LOP switch.
Connect one test lead to Wire 86. Connect the other test
lead to a clean frame ground. INFINITY should be
measured. If CONTINUITY is measured, repair or replace
Wire 86 between the LOP switch and the J1 Connector.
RESULTS:
1. If switch tests good for Problem 9, proceed to Test 44.
2. Replace switch if it fails the test.
TEST 61- CHECK HIGH OIL TEMPERATURE
SWITCH
DISCUSSION:
Figure 28. Testing the Oil Temperature Switch
If the temperature switch contacts have failed in a closed
position, the engine will not crank or start. If it tries to
start, it will immediately fault out on OVERTEMP. If the
unit is in an overheated condition, the switch contacts will
close at 284”F. This will normally occur from inadequate
airflow through the generator.
8. Set a VOM to measure resistance. Then, connect the
VOM test leads across the switch terminal and the
switch body. The meter should read INFINITY.
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SECTION 4.4
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PART 4
9. Heat the oil in the container. When the thermometer
reads approximately 274°-294° F. (134°-146° C.), the
VOM should indicate CONTINUITY.
4. When the valve clearance is correct, hold the pivot ball
stud with the allen wrench and tighten the rocker arm
jam nut. Torque the jam nut to 174 inch pounds. After
tightening the jam nut, recheck the valve clearance to
make sure it did not change.
RESULTS:
1. If the switch fails Step 4, or Steps 8-9, replace the
switch.
5. Re-install the rocker cover gasket, rocker cover and the
four (4) screws.
2. If INFINITY was NOT measured in Step 5, repair or
replace Wire 85 between the Circuit Board and the High
Oil Temperature Switch.
RESULTS:
Adjust valve clearance as necessary, the retest.
TEST 63 - CHECK FUEL REGULATOR
TEST 62 - CHECK AND ADJUST VALVES
DISCUSSION:
DISCUSSION:
The fuel regulator is rarely the cause of a HARD
START or NO START condition. The most common
causes are insufficient fuel pressure supplied to the
unit, or the adjustment screws on the fuel regulator
being out of adjustment. The fuel regulator is an ON
DEMAND type. During cranking and running,
negative pressure from the airbox or carburetor
unseats the fuel regulator diaphragms and allows fuel
flow through the regulator.
Improperly adjusted valves can cause various engine
related problems including, but not limited to, hard
starting, rough running and lack of power. The valve
adjustment procedure for both the single cylinder and
the V-twin engines is the same.
PROCEDURE (INTAKE AND EXHAUST):
Make sure that the piston is at Top Dead Center
(TDC) of it s compression stroke (both valves closed).
The valve clearance should be 0.05-0.1mm (0.002-
0.004 in) cold.
PROCEDURE:
Note: Step 1 of this procedure pertain to V-twin
engines only. Single cylinder engines begin at Step 2.
1. If the adjustment screw settings are in question, reset as
follows:
Check and adjust the valve to rocker arm clearance
as follows:
1. Remove the four (4) screws from the rocker cover.
2. Remove the rocker cover and rocker cover gasket.
a.Turn adjustment screws clockwise all the way
in, then turn out counterclockwise two and one
half full turns. This will provide a starting point
for further adjustment.
2. Turn off utility power to the main distribution panel in the
house. This can be done by switching the service main
breaker to the OFF or “Open” position.
3. Allow the generator to start. Before loading the
generator, confirm that the No Load Frequency, with the
roof open and the door off, is set to 63-63.5 Hz.
Transfer load to emergency circuits.
4. Turn on appliances. lights, pumps, etc., that are on the
emergency circuits in an attempt to fully load the
generator. Be cautious not to overload the generator.
Use the following chart as a guide:
Unit
7 kW
12 kW
15 kW
120 Volts
50.0 amps
100.0 amps
108.3 amps
240 Volts
25.0 amps
50.0 amps
54.1 amps
Figure 29
3. Loosen the rocker arm jam nut. Use a 10mm allen
wrench to turn the pivot ball stud and check the
clearance between the rocker arm and the valve stem
with a flat feeler gauge (see Figure 29).
5. When full load has been achieved, connect a frequency
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
meter to the output lugs of the generator main line
circuit breaker.
7. Turn utility power to the main distribution panel back on.
This can be done by switching the service main breaker
to the “ON” or closed position. Allow the generator to
shut down.
The fuel regulator is fitted with one (7 kW), or two (12 &
15 kW) adjustment screws. While watching the
frequency meter, slowly turn the adjustment screw(s)
clockwise or counterclockwise one at a time until
highest frequency is read on the meter.
Do not make any unnecessary adjustments. Factory
settings are correct for most applications. However,
when making adjustments, be careful to avoid
overspeeding the engine.
Note: Only limited adjustment is available between
the set pins on 7 kW fuel regulators. Under no
circumstance should any of the pins be removed (see
Figures 30 & 31).
6. When the highest frequency is reached, maximum
power has been set. From this point turn the adjustment
screw(s) 1/4 turn counterclockwise. The regulator is
now set.
TEST 64 - CHECK BATTERY CHARGE
OUTPUT
DISCUSSION:
The battery charging system is a two amp trickle
charge. It is capable of maintaining a charge on a
functional battery. It is not intended to, nor capable of
charging a completely dead battery.
The system will charge when utility source power is
available to the generator or if the generator is
running. The system consists of a transformer (TX),
battery charge relay (BCR), battery charger (BC), and
a battery charge winding. The BCR contacts allow AC
voltage to the battery charger. When the BCR is de-
energized, voltage from the TX is available to the
battery charger. When the generator starts, Wire 14
energizes the BCR. This allows battery charge
winding AC output to power the battery charger.
Figure 30
PROCEDURE:
1. Check the 5 amp fuse (F2).
2. Set the AUTO-OFF-MANUAL switch to OFF.
Note: Utility source voltage MUST be available to the
generator.
3. Set a VOM to measure DC amps.
4. Disconnect Wire 13A (purple) from the 5 amp fuse (F2).
5. Connect the positive (+) test lead to Wire 13A, and
connect the negative (-) test lead to the fuse (F2)
terminal from which Wire 13A was removed. The VOM
should measure 50 milliamps to 2.5 amps, depending
upon the state of the charge of the battery.
6. Repeat Step 5. This time set the AUTO-OFF-MANUAL
switch to MANUAL. Allow the generator to start and
then measure the current again as in Step 5.
Figure 31
RESULTS:
Follow the Flow Chart on Page 4.3-5.
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SECTION 4.4
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PART 4
RESULTS:
TEST 65 - CHECK TRANSFORMER (TX)
VOLTAGE OUTPUT
1. If line-to-line voltage was NOT measured in Step 2, go
to Problem 7, Page 3.3-2.
DISCUSSION:
2. If correct voltage was measured in Step 2, and no
voltage was measured in Step 3, replace the
Transformer.
The Transformer (TX) is a STEP DOWN type and
has two functions. It supplies approximately 16 VAC to
the control panel circuit board for utility sensing. It also
supplies approximately 16 VAC to the battery charger
for trickle charging. A defective transformer will:
3. If correct voltage was measured in Step 2, and no
voltage was measured in Step 4, replace the
Transformer.
a.not supply AC to the battery charger, and
4. If voltage output was correct for Step 3 and for Step 4,
refer back to the Flow Chart (Page 4.3-5).
b.not supply sensing voltage to the circuit board.
TEST 66 - CHECK AC VOLTAGE AT BATTERY
CHARGER
DISCUSSION:
The battery charger needs to be supplied with
approximately 16 VAC. When the generator is not
running and utility source power is available, the
battery charger still receives voltage from the
Transformer (TX). When the generator is running,
voltage is supplied to the battery charger from the
battery charge winding.
PROCEDURE:
1. Set the AUTO-OFF-MANUAL switch to OFF.
Note: Utility source voltage MUST be available to the
generator.
2. Set a VOM to measure AC voltage.
Figure 32. Transformer (TX)
3. Disconnect the two pin connector (Wire 224B and Wire
225B) at the battery charger.
PROCEDURE:
1. Set a VOM to measure AC voltage.
4. Connect one meter test lead to Wire 224B at the two pin
connector. Connect the other test lead to Wire 225B at
the two pin connector. Approximately 16 VAC should be
measured.
2. Connect one meter test lead to the Transformer (TX)
Terminal 5, Wire N1. Connect the other meter test lead
to the Transformer (TX) Terminal 1, Wire N2. Utility line-
to-line voltage (240 VAC) should be measured.
5. Verify that the battery charge relay (BCR) is wired
correctly (Figure 33).
3. Connect one meter test lead to the Transformer (TX)
Terminal 6 with Wire 225A removed. Connect the other
meter test lead to the Transformer (TX) Terminal 7 with
Wire 224A removed. This output supplies power to the
battery charger. The VOM should measure
approximately 16 VAC.
6. Connect one meter test lead to Terminal 1, Wire 224A
on the BCR. Connect the other test lead to Terminal 3,
Wire 225A. Approximately 16 VAC should be measured.
RESULTS:
4. Connect one meter test lead to the Transformer (TX)
Terminal 9 with Wire 224 removed. Connect the other
meter test lead to the Transformer (TX) Terminal 10
with Wire 224 removed. This AC output is used as utility
sensing, and is supplied to the circuit board. The VOM
should measure approximately 16 VAC.
1. If voltage was NOT measured in Step 6, but was
measured in Test 65, repair or replace Wire 224A and
Wire 225B between the transformer (TX) and the
battery charge relay (BCR).
2. If voltage was not measured in Step 4, go to Test 67.
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SECTION 4.4
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DC CONTROL
PART 4
RESULTS:
1. Replace the battery charge relay if it fails any of the
steps in this chart.
2. If the BCR tests good, but still does not function during
generator operation, check Wire 14 and Wire 0
connected to the BCR.
a.Set a VOM to measure DC volts. Disconnect
Wire 14 from BCR Terminal A. Connect the
positive (+) test lead to Wire 14. Connect the
negative (-) test lead to a clean frame ground.
Set the AUTO-OFF-MANUAL switch to
MANUAL. Battery voltage should be measured.
If battery voltage is not measured, repair or
replace Wire 14 between the BCR and the 4-tab
terminal block.
Figure 33. Battery Charge Relay Test Points
TEST 67 - CHECK BATTERY CHARGE RELAY
(BCR)
DISCUSSION:
The battery charge relay is used to switch the AC
source delivered to the battery charger. When the
BCR is de-energized, the Normally Closed (NC)
contacts deliver AC power from the transformer.
When the BCR is energized by Wire 14, the Normally
Open (NO) contacts close and battery charge winding
AC source is delivered to the battery charger.
b.If voltage was measured in a, set the VOM to
measure resistance. Disconnect Wire 0 from
BCR Terminal B. Connect one test lead to Wire
0. Connect the other test lead to a clean frame
ground. CONTINUITY should be measured. If
CONTINUITY was not measured, repair or
replace Wire 0 between the BCR and the ground
terminal.
PROCEDURE:
1. See Figure 33. Disconnect all wires from the battery
charge relay, to prevent interaction.
TEST 68 - CHECK BATTERY CHARGE
WINDING HARNESS
2. Set a VOM to its "R x 1" scale and zero the meter.
DISCUSSION:
3. Follow the chart below and test each set of contacts.
Connect the VOM test leads to the relay terminals
indicated in the chart provided below.
This test will check the continuity of Wire 66 and Wire
77 between Connector C2 and the battery charge
relay.
4. To energize or de-energize the relay. Connect a jumper
wire to a positive (+)12VDC source and to relay
Terminal "A". Connect a jumper wire to the negative (-)
12VDC source and to relay Terminal "B". The relay will
ENERGIZE. Disconnect the positive jumper from
Terminal "A" of the relay and the relay will DE-
ENERGIZE.
PROCEDURE:
1. Disconnect Connector C2 from the side of the control
panel.
2. Disconnect Wire 66 from Terminal 6, and Wire 77 from
Terminal 4 of the BCR.
3. Set a VOM to measure resistance.
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PART 4
5. Connect one meter test lead to Wire 0 at the three pin
connector. Connect the other test lead to the ground
terminal. CONTINUITY should be measured.
RESULTS:
1. If CONTINUITY was NOT measured in Step 4, repair or
replace Wire 13A between the battery charger and fuse
F2.
2. If CONTINUITY was NOT measured in Step 5, repair or
replace Wire 0 between the battery charger and frame
ground.
TEST 70 - CHECK ENGINE RUN WINDING
Figure 34. C2 Connector Pin Locations (Male Side)
DISCUSSION:
4. Connect one test lead to Connector C2 Pin Location 1
(Wire 77). Connect the other test lead to the end of Wire
77 which was previously removed from the BCR.
CONTINUITY should be measured.
The engine run winding provides an AC input through
Wire 66A to the circuit board. This input is used for
overspeed sensing. If the input is not received by the
circuit board, immediate shutdown will occur.
PROCEDURE:
1. Set the AUTO-OFF-MANUAL switch to OFF.
5. Connect one test lead to Connector C2 Pin Location 2
(Wire 66). Connect the other test lead to the end of Wire
66 which was previously removed from the BCR.
CONTINUITY should be measured.
2. Set a VOM to measure resistance.
3. Disconnect Connector C2 from the side of the control
panel.
RESULTS:
4. Disconnect Connector J1 from the circuit board.
If CONTINUITY was NOT measured in Step 4 or Step
5, repair or replace defective wiring between
Connector C2 and the battery charge relay.
5. Connect one meter test lead to Connector C2 Pin
Location 3 (Wire 66A). Connect the other test lead to
Connector J1 Pin Location 8 (Wire 66A). CONTINUITY
should be measured.
TEST 69 - CHECK BATTERY CHARGER
WIRING
6. Connect one test lead to Connector C2 Pin Location 4
(Wire 55). Connect the other test lead to a clean frame
ground. CONTINUITY should be measured.
DISCUSSION:
7. Re-connect connector C2 to the control panel, and re-
connect connector J1 to the circuit board.
The three pin connector on the battery charger
connects the charger to ground and to battery power.
8. Set a VOM to measure AC Voltage.
PROCEDURE:
9. Connect the positive meter test lead to Pin Location 8,
Wire 66A of the J1 Connector on the circuit board.
Connect the negative meter test lead to the ground
terminal. Set the AUTO-OFF-MANUAL switch to
MANUAL. When the generator starts observe the
voltage output on the VOM. AC voltage should be 8-12
VAC.
1. Set the AUTO-OFF-MANUAL switch to OFF.
2. Disconnect the three pin connector from the battery
charger.
3. Set a VOM to measure resistance.
4. Connect one meter test lead to Wire 13A at the three pin
connector. Connect the other test lead to Wire 13A at
Fuse F2. CONTINUITY should be measured.
10.Set VOM to measure frequency. 62- 63 HZ should be
measured.
Page 4.4-21
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
RESULTS:
4. Connect one meter test lead to Pin Location J1-14
(Wire 225). Connect the other test lead to Pin Location
J1-15 (Wire 224). Approximately 14-16 VAC should be
measured.
1. If CONTINUITY is not measured in Step 5, repair or
replace Wire 66A between Connector C2 and
Connector J1 at the circuit board.
2. If CONTINUITY was not measured in Step 6, repair or
replace Wire 55 between Connector C2 and the ground
terminal.
RESULTS:
1. If voltage was measured in Step 4, replace the circuit
board.
3. If CONTINUITY was measured in both Step 5 and Step
6, go to Test 7.
2. If voltage was NOT measured in Step 4, repair or
replace Wire 224 and/or No. Wire 225 between
Transformer (TX) and Circuit Board Connector J1.
4. If AC voltage is not correct in Step 9, proceed to Test 7.
If frequency is not correct adjust no load frequency and
re-test.
TEST 73 - TEST SET EXERCISE SWITCH
TEST 71 - CHECK N1 AND N2 VOLTAGE
DISCUSSION:
If the Set Exercise Switch (SW2) fails closed, the unit
will start when in AUTO. In normal operation the
Normally Open contacts close when the switch is
depressed. This will ground Wire 351 and reset the
exercise time.
DISCUSSION:
Loss of utility source voltage to the generator will
initiate a startup and transfer by the generator.
Testing at the control panel terminal strip will divide
the system in two, thereby reducing troubleshooting
time.
PROCEDURE:
1. Set a VOM to measure resistance.
PROCEDURE:
2. Disconnect Wire 351 and Wire 0 from the Set Exercise
Switch (SW2).
Note: Verify that Utility Source Voltage is present.
1. Set the AUTO-OFF-MANUAL switch to OFF.
3. Connect one meter test lead to one terminal of SW2.
Connect the other test lead to the remaining terminal of
SW2. The meter should read INFINITY.
2. Set a VOM to measure AC voltage.
3. Connect one test lead to Wire N1 at the terminal strip in
the generator control panel. Connect the other test lead to
Wire N2. Utility line-to-line voltage should be measured.
4. With the meter test leads connected to SW2, depress
and hold the switch activated. The meter should read
CONTINUITY.
RESULTS:
1. If voltage was measured in Step 3, go to Test 65.
2. If voltage was not measured in Step 3, go to Test 28.
TEST 72 - CHECK UTILITY SENSING VOLTAGE
AT THE CIRCUIT BOARD
DISCUSSION:
If the generator starts and transfer to STANDBY
occurs in the automatic mode, even though an
acceptable UTILITY source voltage is available from
the Transformer (TX), the next step is to determine if
that sensing voltage is reaching the circuit board.
Figure 35. The Set Exercise Switch
PROCEDURE:
1. Set the AUTO-OFF-MANUAL switch to OFF.
5. Disconnect the five pin connector (J2) from the circuit
board.
2. Disconnect Connector J1 from the circuit board.
3. Set a VOM to measure AC voltage.
Page 4.4-22
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
RESULTS:
6. Connect one meter test lead to Wire 351 (previously
removed from SW2). Connect the other meter test lead
to Pin Location J3 (Wire 351). CONTINUITY should be
measured.
1. If CONTINUITY was measured in Step 5, a short exists
between Wire 178 and Wire 183. Repair or replace
Wire 178 and/or Wire 183 between terminal connector
and SW1.
7. Connect one meter test lead to Wire 351 (previously
removed from SW2). Connect the other meter test lead
to the ground terminal. INFINITY should be measured.
TEST 75 - CHECK BATTERY VOLTAGE
CIRCUIT
8. Connect one meter test lead to Wire 0 (previously
removed from SW2). Connect the other meter test lead to
the ground terminal. CONTINUITY should be measured.
DISCUSSION:
If the 15 amp fuse blows immediately after
replacement, Wire 15 should be checked for a fault.
RESULTS:
1. If the Set Exercise Switch (SW2) fails Step 3 or Step 4,
replace the switch.
PROCEDURE:
1. Set the AUTO-OFF-MANUAL switch to OFF.
2. If CONTINUITY was NOT measured in Step 6, OR if it
WAS measured in Step 7, repair or replace Wire 351
between SW2 and Connector J2.
2. Disconnect the 17-pin connector (J1) from the circuit
board.
3. Set a VOM to measure resistance.
3. If CONTINUITY was NOT measured in Step 8, repair or
replace Wire 0 between SW2 and the ground terminal.
4. Disconnect Wire 15 from the fuse holder (F1).
5. Connect one meter test lead to Wire 15 (removed from
fuse holder in previous step). Connect the other meter
test lead to the ground terminal. INFINITY should be
measured.
TEST 74 - CHECK REMOTE START WIRING
(IF EQUIPPED)
DISCUSSION:
RESULTS:
On some earlier models a remote start connection
was available. If these two wires are connected
together while the generator is in AUTO, the
generator will start.
1. If CONTINUITY was measured in Step 5, repair or
replace Wire 15 between the fuse holder (F1) and SW1,
or between SW1 and Connector J1.
2. If INFINITY was measured in Step 5, replace the circuit
board and retest.
PROCEDURE:
1. Set the AUTO-OFF-MANUAL switch to OFF.
2. Set a VOM to measure resistance.
TEST 76 - CHECK CRANKING AND RUNNING
CIRCUITS
3. Disconnect the 17-pin connector (J1) from the circuit
board.
4. If the remote start connections have been used,
disconnect the customer wires from the terminal
connector at Wire 178 and Wire 183.
DISCUSSION:
This test will check all of the circuits that are HOT
with battery voltage and which could cause the F1
Fuse to blow.
5. Connect one meter test lead to Wire 178 at the terminal
connector. Connect the other meter test lead to Wire 183
at the terminal connector. INFINITY should be measured.
PROCEDURE:
1. Set a VOM to measure resistance.
6. If the remote start connections have been used, connect
the meter test leads across customer supplied wiring. If
CONTINUITY is measured, customer supplied circuit is
causing startup.
2. Disconnect the 17-pin connector (J1) from the circuit board.
3. Connect one meter test lead to the ground terminal.
Connect the other meter test lead to each of the
following J1 Connector pin locations:
Page 4.4-23
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SECTION 4.4
DIAGNOSTIC TESTS
DC CONTROL
PART 4
J1-4, Wire 194
If
CONTINUITY
was
other meter test lead to the ground terminal. If
CONTINUITY or zero resistance was measured,
replace the SCR or SC. Coil resistance for the SCR is
155 ohms. Coil resistance for the SC is 4 ohms. If coil
resistance was measured, Wire 56 is shorted to ground
between Connector J1 and the SCR or SC. Repair or
replace the shorted wire.
measured, go to Step 4.
Average nominal resistance
reading: 110-120 ohms.
J1-5, Wire 56
If
CONTINUITY
was
measured, go to Step 5.
Average nominal resistance
reading V-twin (SCR): 150-
160 ohms, Single Cylinder
(SC): 4 ohms.
6. Disconnect and isolate each Wire 14 from the 4-tab
insulated terminal block. Repeat Step 3 for Pin Location
J1-7. If CONTINUITY was measured, repair or replace
Wire 14 between Connector J1 and the 4-tab terminal
block. If INFINITY was measured, proceed as follows:
J1-10, Wire 15A
J1-7, Wire 14
If
CONTINUITY
was
measured, repair or replace
shorted to ground Wire 15A
between Connector J1 and
switch SW1.
a.Disconnect Wire 14 from the following: fuel
solenoid (FS), battery charge relay (BCR) and
hourmeter (HM) if equipped.
If
CONTINUITY
was
measured, go to Step 6.
b.Connect the negative (-) meter test lead to the
ground terminal. Connect the positive (+) meter
test lead to each of the listed components at the
terminal from which Wire 14 was removed. If
CONTINUITY or zero resistance was measured,
the component has shorted to ground. Replace
the component. The average nominal resistance
value that should be measured for each
component is:
4. Disconnect Wire 194 from the terminal strip. Repeat
Step 3 at Pin Location J1-4.
a.If CONTINUITY was measured, Wire 194 is
shorted to ground between Connector J1 and
terminal strip.
b.If INFINITY was measured, disconnect Wire 194
from the transfer switch terminal strip. Connect
one meter test lead to the end of Wire 194
which was removed from the transfer switch
terminal strip. Connect the other meter test lead
to the ground terminal. If CONTINUITY was
measured, Wire 194 is shorted to ground
between the generator and the transfer switch.
Battery Charge Relay (BCR) - 112 ohms
Fuel Solenoid (FS) - 31 ohms
Hourmeter (HM) - 2 Mega ohms to infinity
c. If each component tests good, there is no short
to ground. The fault exists in one of the Wire 14
wires. Connect one meter test lead to the ground
terminal. Connect the other meter test lead to
each Wire 14 individually (on the end removed
from the BCR, FS or HM). The Wire 14 which
measures CONTINUITY is shorted to ground.
Repair or replace the affected wire between the
component and the 4-tab terminal block.
1) If INFINITY was measured, disconnect Wire
194 from the transfer relay (TR). Connect
one meter test lead to the transfer relay
terminal from which Wire 194 was previously
removed. Connect the other test lead to Wire
23 at the transfer switch terminal strip. If
CONTINUITY ZERO RESISTANCE was
measured, replace the transfer relay. Normal
coil resistance is approximately 113 ohms.
TEST 77 - TEST EXERCISE FUNCTION
2) If coil resistance of 113 ohms was
measured, the short is in Wire 194 between
the transfer relay and the terminal strip.
Repair or replace Wire 194.
DISCUSSION:
The following parameters must be met in order for the
weekly exercise to occur:
❏AUTO-OFF-MANUAL switch (SW1) set to AUTO.
5. Disconnect Wire 56 From the starter contactor relay
(SCR on V-twin) or the starter contactor (SC on single
cylinder). Connect one meter test lead to the SCR or SC
terminal from which Wire 56 was removed. Connect the
❏Circuit board DIP Switch 2 (REMOTE NOT AUTO)
set to OFF.
Page 4-4.24
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TABLE OF CONTENTS
PART
5.1
TITLE
System Functional Tests
PART 5
OPERATIONAL
TESTS
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
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SECTION 5.1
SYSTEM FUNCTIONAL TESTS
OPERATIONAL TESTS
AND ADJUSTMENTS
PART 5
DANGER: BE SURE TO TURN OFF ALL
POWER VOLTAGE SUPPLIES TO THE
TRANSFER SWITCH BEFORE ATTEMPTING
MANUAL OPERATION. FAILURE TO TURN
OFF POWER VOLTAGE SUPPLIES TO THE
TRANSFER SWITCH MAY RESULT IN
DANGEROUS AND POSSIBLY LETHAL
ELECTRICAL SHOCK.
INTRODUCTION
Following home standby electric system installation
and periodically thereafter, the system should be
tested Functional tests of the system include the
following:
❏Manual transfer switch operation.
❏System voltage tests.
4. Remove the manual transfer handle from the enclosure.
❏Generator Tests Under Load.
❏Testing automatic operation.
5. Place open end of the manual transfer handle over
transfer switch operating lever.
Before proceeding with functional tests, read
instructions and information on tags or decals affixed
to the generator and transfer switch. Perform all tests
in the exact order given in this section.
6. To connect "Load" terminal lugs to the "Standby" power
source, move, the handle upward.
7. To connect "Load" terminals to the Utility" power source,
move the handle downward.
MANUAL TRANSFER SWITCH OPERATION
8. Actuate the switch to "Utility" and to MANUAL several
times. Make sure no evidence of binding or interference
is felt.
"V-TYPE" TRANSFER SWITCHES:
1. On the generator panel, set the AUTO-OFF-MANUAL
switch to OFF.
9. When satisfied that manual transfer switch operation is
correct, actuate the main contacts to their "Utility"
position ("Load" connected to the "Utility" power supply).
2. Turn OFF the "Utility" power supply to the transfer
switch using whatever means provided (such as a
"Utility" main line circuit breaker).
ELECTRICAL CHECKS
3. Set the generator main line circuit breaker to OFF or
Complete electrical checks as follows:
1. Set the generator main circuit breaker to its OFF (or
open) position.
"Open".
Figure 1. Manual Operation “V-Type” Switch
Page 5.1-1
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SECTION 5.1
SYSTEM FUNCTIONAL TESTS
OPERATIONAL TESTS
AND ADJUSTMENTS
PART 5
2. Set the generator AUTO-OFF-MANUAL switch to the
“OFF “ position.
position. Let the engine run at no-load for a few minutes to
stabilize internal engine generator temperatures.
3. Turn off all loads connected to the transfer switch
terminals T1 and T2.
13.Set the generator AUTO-OFF-MANUAL switch to OFF.
The engine should shut down.
4. Turn on the utility power supply to the transfer switch
using the means provided (such as a utility main line
circuit breaker).
NOTE: It is important that you do not proceed until
you are certain that generator AC voltage and
frequency are correct and within the stated limits.
Generally, if both AC frequency and voltage are high
or low, the engine governor requires adjustment. If
frequency is correct, but voltage is high or low, the
generator voltage regulator requires adjustment.
DANGER
The transfer switch is now electrically hot.
Contact with hot parts will result in extremely
hazardous and possibly fatal electrical shock.
Proceed with caution.
GENERATOR TESTS UNDER LOAD
To test the generator set with electrical loads applied,
proceed as follows:
5. Use an accurate AC voltmeter to check utility power
source voltage across transfer switch terminals N1 and
N2. Nominal line-to-line voltage should be 240 volts AC.
1. Set generator main circuit breaker to its OFF (or open)
position.
6. Check utility power source voltage across terminals N1
and the transfer switch neutral lug; then across terminal
N2 and neutral. Nominal line-to-neutral voltage should
be 120 volts AC.
2. Turn OFF all loads connected to the Transfer Switch
Terminals T1 and T2.
3. Set the generator AUTO-OFF-MANUAL switch to OFF.
4. Turn off the utility power supply to the transfer switch,
using the means provided (such as a utility main line
circuit breaker).
7. When certain that utility supply voltage is compatible
with transfer switch and load circuit ratings, turn OFF
the utility power supply to the transfer switch.
8. On the generator panel, set the AUTO-OFF-MANUAL
switch to MANUAL. The engine should crank and start.
Do not attempt manual transfer switch
operation until all power voltage supplies to the
transfer switch have been positively turned off.
Failure to turn off all power voltage supplies
will result in extremely hazardous and possibly
fatal electrical shock.
9. Let the engine warm up for about five minutes to allow
internal temperatures to stabilize. Then, set the
generator main circuit breaker to its “ON” (or closed)
position.
DANGER
5. Manually set the transfer switch to the STANDBY
position, i.e., load terminals connected to the generator
E1/E2 terminals. The transfer switch operating lever
should be down.
Proceed with caution! Generator power voltage
is now supplied to the transfer switch. Contact
with live transfer switch parts will result in
dangerous and possibly fatal electrical shock.
6. Set the generator AUTO-OFF-MANUAL switch to
MANUAL. The engine should crank and start
immediately.
10.Connect an accurate AC voltmeter and a frequency
meter across transfer switch terminal lugs E1 and E2.
Voltage should be 242-252 volts; frequency should read
about 61-63 Hertz.
7. Let the engine stabilize and warm up for a few minutes.
8. Set the generator main circuit breaker to its ON (or
closed) position. Loads are now powered by the
standby generator.
11.Connect the AC voltmeter test leads across terminal lug
E1 and neutral; then across E2 and neutral. In both
cases, voltage reading should be 121-126 volts AC.
9. Turn ON electrical loads connected to transfer switch T1
12.Set the generator main circuit breaker to its OFF (or open)
Page 5.1-2
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SECTION 5.1
SYSTEM FUNCTIONAL TESTS
OPERATIONAL TESTS
AND ADJUSTMENTS
PART 5
sequence of operation.
and T2. Apply an electrical load equal to the full rated
wattage/amperage capacity of the installed generator.
With the generator running and loads powered by
generator AC output, turn ON the utility power supply
to the transfer switch. The following should occur:
❏After about six seconds, the switch should transfer
loads back to the utility power source.
❏About one minute after retransfer, the engine
should shut down.
10.Connect an accurate AC voltmeter and a frequency
meter across terminal lugs E1 and E2. Voltage should
be greater than 230 volts; frequency should be greater
than 58 Hertz.
11.Let the generator run at full rated load for 20-30
minutes. Listen for unusual noises, vibration or other
indications of abnormal operation. Check for oil leaks,
evidence of overheating, etc.
SETTING THE EXERCISE TIMER
Your generator is equipped with an exercise timer.
Once it is set, the generator will start and exercise
once every seven days, on the day of the week and at
the time of day you complete the following sequence.
During this exercise period, the unit runs for
approximately 12 minutes and then shuts down.
Transfer of loads to the generator output does not
occur during the exercise cycle.
12.When testing under load is complete, turn OFF electrical
loads.
13.Set the generator main circuit breaker to its OFF (or
open) position.
14.Let the engine run at no-load for a few minutes.
15.Set the AUTO-OFF-MANUAL switch to OFF. The engine
should shut down.
A switch on the control panel (see Figure 1, Page 1.6-1)
allows you to select the day and time for system
exercise. To select the desired day and time of day, you
must perform the following sequence at that time.
CHECKING AUTOMATIC OPERATION
To check the system for proper automatic operation,
proceed as follows:
1. Verify that the AUTO-OFF-MANUAL switch is set
to AUTO.
1. Set generator main circuit breaker to its OFF (or open)
position.
2. Hold down the set timer switch until the generator starts
(approximately 10 seconds) and then release.
2. Check that the AUTO-OFF-MANUAL switch is set to
OFF.
3. The generator will start and run for approximately 12
minutes and then shut down on its own. The exerciser
will then be set to run at that time of day every week.
3. Turn off the utility power supply to the transfer switch,
using means provided (such as a utility main line circuit
breaker).
NOTE: The exerciser will only work in the AUTO
mode and will not work unless this procedure is
performed. The exerciser will need to be reset every
time the 12 volt battery is disconnected and then
reconnected. The exerciser WILL NOT work if dip
switch 2 (REMOTE NOT AUTO) on the controller
printed circuit board is “ON.”
4. Manually set the transfer switch to the UTILITY position,
i.e., load terminals connected to the utility power source
side.
5. Turn ON the utility power supply to the transfer switch,
using the means provided (such as a utility main line
circuit breaker).
6. Set the AUTO-OFF-MANUAL switch to AUTO. The
system is now ready for automatic operation.
7. Turn OFF the utility power supply to the transfer switch.
With the AUTO-OFF-MANUAL switch at AUTO, the
engine should crank and start when the utility source
power is turned off. After starting, the transfer switch
should connect load circuits to the STANDBY side.
Let the system go through its entire automatic
Page 5.1-3
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TABLE OF CONTENTS
PART
6.1
TITLE
Major Disassembly
6.2
Torque Specifications
PART 6
DISASSEMBLY
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
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SECTION 6.1
MAJOR DISASSEMBLY
DISASSEMBLY
PART 6
Figure 1. Exhaust Side Enclosure Removed
MAJOR DISASSEMBLY
8. Remove Exhaust Pipe: Using a 13mm socket, loosen
the exhaust clamp and remove the exhaust pipe.
STATOR/ROTOR/ENGINE REMOVAL:
For stator removal, follow Steps 1-14. For rotor
removal, follow Steps 1-15. For Engine removal follow
Steps 1-16.
9. Remove Fan Housing Cover: Using a 10 mm socket,
remove the six (6) bolts from each side of the fan
housing cover. Remove the fan housing cover.
1. Remove door.
2. Set the AUTO-OFF-MANUAL switch to OFF. Disconnect
battery cables. Remove Fuse F1. Remove the utility
power source to the generator. Turn off fuel supply to
the generator.
10.Remove Rotor Bolt: Using a 9/16 socket, remove one
rotor bolt.
11.Remove Fan: Attach a steering wheel puller to the
fan using two (2) M8 X 1.25 bolts. Remove fan
from rotor.
3. Remove Control Panel Cover: Using a 10 mm socket,
remove the control panel cover. Remove two nuts
located on back panel using a 7mm socket. Remove
two control panel screws.
4. Disconnect Stator Leads/Connectors: Remove the
stator leads (Wire 11 and Wire 44) from the main circuit
breaker. Remove the stator leads (Wire 22 and Wire 33)
from the neutral lug. Unplug connectors C1 and C2 from
the control panel. For control panel removal only,
remove Wires N1/N2 and Wires 23/194 from the terminal
strip, and the ground and neutral wires from the control
panel.
5. Disconnect Fuel Hoses: Remove the two fuel hoses at
the air box assembly. Some models are equipped with
an additional third fuel hose. Remove it also if equipped.
Pull hoses back into the battery compartment. For
control panel removal only remove WireNos. 0 and 14
from the fuel solenoid.
Figure 2. Using a Steering Wheel Puller to
Remove Fan From Rotor
6. Remove Front and Back Exhaust Enclosure Covers:
Using a 10mm socket, remove the five bolts and four
nuts from the exhaust covers. Remove the covers.
Remove the nut and bolt attaching to the roof left side
folding support and bottom support bracket.
12.Remove Muffler Box/Side Cover and Alternator
panel Divider: Using a 10mm socket, remove the
three bolts from the top of the muffler box cover
that attach to the muffler side cover, and two bolts
from the side of the muffler box cover that attach
to the alternator divider plate. Remove the muffler
box cover.
7. Remove Exhaust Side Enclosure: Using a 10mm
socket with a 2 1/2” extension remove the four (4)
bottom enclosure bolts, and six (6) side enclosure bolts.
Remove the enclosure.
Remove the four bolts that attach the alternator divider
panel. Three are connected on the left side to the back
enclosure panel, and one is connected to the enclosure
base on the bottom right corner.
Remove the two bolts attaching the muffler side cover to
the back enclosure panel. They are located in the center
of the back panel. Remove the alternator panel and
muffler side cover as an assembly.
Page 6.1-1
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SECTION 6.1
MAJOR DISASSEMBLY
DISASSEMBLY
PART 6
Figure 3
13.Remove Muffler: Using a 13mm socket, remove the four
muffler hold down bolts. Remove the four exhaust
manifold nuts. Remove the muffler and muffler base
panel.
Figure 5. Rear Bearing Carrier Removed
14.Stator Removal: Using a 13mm socket, remove the
two nuts from the alternator mounting bracket/rubber
mounts. Lift the back end of the alternator up and place
a 2"x 4" piece of wood under the engine adapter.
Figure 6. Removing the Stator
15.Rotor Removal: Cut 2.5 inches from the rotor bolt. Slot
the end of the bolt to suit a flat blade screwdriver. Slide
the rotor bolt back through the rotor and use a
screwdriver to screw it into the crankshaft. Use a 3"
M12x1.75 bolt to screw into rotor. Apply torque to the
3" M12x1.75 bolt until taper breaks. If necessary, when
torque is applied to 3" M12x1.75 bolt, use a rubber
mallet on the end of the rotor shaft to break taper.
Figure 4. Engine Adapter Supported by
2”x4” Piece of Wood
Using a 1/4" socket, remove Wire 0 and Wire 4 from the
brush assembly. Remove the two brush assembly hold
down bolts. Remove the brushes.
Using a 13mm socket, remove the four stator hold down
bolts. Using a small rubber mallet remove the rear
bearing carrier. Remove the stator.
Page 6.1-2
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SECTION 6.1
MAJOR DISASSEMBLY
DISASSEMBLY
PART 6
Using a 10mm socket, remove the six (6) nuts attaching
the control panel to the side/back enclosure and the
engine divider panel. Remove the two (2) nuts
connected to the back enclosure located on the top side
of control panel. Remove the two (2) nuts located
underneath the middle of the control panel, connecting
to the back/side enclosure and the engine divider panel.
Remove the two (2) nuts from the front top side of the
control panel, connecting to the back/side enclosure
and the engine divider panel. Remove the control panel.
3. Remove Engine Divider Panel: Using a 10mm socket,
remove the remove the two (2) nuts attached to the
back enclosure. Remove the two bolts attached to the
base enclosure. Remove the engine divider panel.
Figure 7. Removing the Rotor
16.Remove Engine: Using a 13mm socket, remove the
two engine mount nuts, and ground wires.
Remove the engine.
4. Remove Intake manifolds: Using a 6mm allen wrench,
remove the four (4) socket head cap screws from the
intake manifolds. Remove the intake manifolds.
Remove the air intake snorkel.
17. Reverse the previous steps to re-assemble.
5. Remove Air Box: Using a 5/32 allen wrench, remove
the four (4) air box allen head shoulder bolts. While
removing the air box remove the four rubber washers
and disconnect the throttle linkage and anti-lash spring.
6. Unbolt Oil Cooler: Using a 10mm socket, remove the
four (4) oil cooler bolts.
7. Remove Blower Housing: Using an 8mm socket,
remove the nine (9) bolts around the blower housing.
Remove the blower housing.
8. Remove flywheel: Use a 36mm socket, a steering
wheel puller, two (2) M8x1.25 bolts and a 13 mm
socket. Remove the flywheel hex nut, remove the fan
plate and fan. Install the puller using the M8x1.25 bolts
and remove the flywheel.
Figure 8. Removing the Engine
FRONT ENGINE ACCESS
1. Follow Stator/Rotor/Engine removal procedures,
Steps 1-5.
TORQUE REQUIREMENTS (UNLESS OTHERWISE SPECIFIED)
FLYWHEEL NUT . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 FT-LBS
STATOR BOLTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 FT-LBS
ROTOR BOLT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 FT-LBS
ENGINE ADAPTER . . . . . . . . . . . . . . . . . . . . . . . . . 25 FT-LBS
EXHAUST MANIFOLD . . . . . . . . . . . . . . . . . . . . . . 18 FT-LBS
INTAKE MANIFOLD (TO CYLINDER HEAD) . . . . . 22 FT-LBS
M5-0.8 TAPTITE SCREW INTO ALUMINUM . . . 25-50 IN-LBS
M5-0.8 TAPTITE SCREW INTO PIERCED HOLE 25-50 IN-LBS
M6-1.0 TAPTITE SCREW INTO ALUMINUM . . . 50-96 IN-LBS
M6-1.0 TAPTITE SCREW INTO PIERCED HOLE 50-96 IN-LBS
M6-1.0 TAPTITE SCREW INTO WELDNUT . . . . 50-96 IN-LBS
M8-1.25 TAPTITE SCREW INTO ALUMINUM . . 12-18 FT-LBS
M6-1.0 NYLOK NUT ONTO STUD . . . . . . . . . . . 16-65 IN-LBS
2. Control Panel Removal: Using a 7mm socket remove
the eight bolts from male connectors C1 and C2.
Remove connectors engine divider panel.
Figure 9. C1 and C2 Connectors Located on the
Engine Divider Panel
NOTE: TORQUES ARE DYNAMIC VALUES WITH 10%
TOLERANCE UNLESS OTHERWISE NOTED.
Page 6.1-3
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TABLE OF CONTENTS
DWG #
TITLE
0D5700-C
0D5701-C
0C7830-C
0C7836-C
0D9013-C
0D9014-B
0D8500-B
WIRING DIAGRAM, 7 KW HSB
MODEL 4389-0
PART 7
ELECTRICAL
DATA
SCHEMATIC, 7 KW HSB
MODEL 4389-0
WIRING DIAGRAM, 12 & 15 KW HSB
MODEL 4456-0 & 4390-0
SCHEMATIC, 12 & 15 KW HSB
MODEL 4456-0 & 4390-0
WIRING DIAGRAM, 7 KW HSB
MODEL 4389-1
SCHEMATIC, 7 KW HSB
MODEL 4389-1
WIRING DIAGRAM, 12 & 15 KW HSB
MODEL 4456-1 & 4390-1
SCHEMATIC, 12 & 15 KW HSB
MODEL 4456-1 & 4390-1
0D8501-B
Air-cooled, Prepackaged
Automatic Standby Generators
Models:
04389, 04758 (6 kW NG, 7 kW LP)
04456, 04759 (12 kW NG, 12 kW LP)
04390, 04760 (13 kW NG, 15 kW LP)
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WIRING DIAGRAM, 7 KW HOME STANDBY
MODEL 4389-0
ELECTRICAL DATA
PART 7
DRAWING #0D5700-C
Page 7.1-1
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SCHEMATIC, 7 KW HOME STANDBY
ELECTRICAL DATA
PART 7
MODEL 4389-0
DRAWING #0D5701-C
Page 7.1-2
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WIRING DIAGRAM, 12 & 15 KW HOME STANDBY
MODEL 4456-0 & 4390-0
ELECTRICAL DATA
PART 7
DRAWING #0C7830-C
Page7.1-3
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SCHEMATIC, 12 & 15 KW HOME STANDBY
ELECTRICAL DATA
PART 7
MODEL 4456-0 & 4390-0
DRAWING #0C7836-C
Page 7.1-4
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WIRING DIAGRAM, 7 KW HOME STANDBY
MODEL 4389-1
ELECTRICAL DATA
PART 7
DRAWING #0D9013-C (1 OF 2)
Page 7.1-5
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WIRING DIAGRAM, 7 KW HOME STANDBY
ELECTRICAL DATA
PART 7
MODEL 4389-1
DRAWING #0D9013-C (2 OF 2)
Page 7.1-6
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SCHEMATIC, 7 KW HOME STANDBY
MODEL 4389-1
ELECTRICAL DATA
PART 7
DRAWING #0D9014-B (1 OF 2)
Page 7.1-7
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SCHEMATIC, 7 KW HOME STANDBY
ELECTRICAL DATA
PART 7
MODEL 4389-1
DRAWING #0D9014-B (2 OF 2)
Page 7.1-8
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WIRING DIAGRAM, 12 & 15 KW HOME STANDBY
MODEL 4456-1 & 4390-1
ELECTRICAL DATA
PART 7
DRAWING #0D8500-B (1 OF 2)
Page 7.1-9
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WIRING DIAGRAM, 12 & 15 KW HOME STANDBY
ELECTRICAL DATA
PART 7
MODEL 4456-1 & 4390-1
DRAWING #0D8500-B (2 OF 2)
Page 7.1-10
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SCHEMATIC, 12 & 15 KW HOME STANDBY
MODEL 4456-1 & 4390-1
ELECTRICAL DATA
PART 7
DRAWING #0D8501-B (1 OF 2)
Page 7.1-11
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SCHEMATIC, 12 & 15 KW HOME STANDBY
ELECTRICAL DATA
PART 7
MODEL 4456-1 & 4390-1
DRAWING #0D8501-B (2 OF 2)
Page 7.1-12
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NOTES
ELECTRICAL DATA
PART 7
Page 7.1-13
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NOTES
ELECTRICAL DATA
PART 7
Page 7.1-14
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NOTES
ELECTRICAL DATA
PART 7
Page 7.1-15
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PO Box 297
Whitewater, WI 53190
www.guardiangenerators.com
P/N OE3586/Printed in the USA/1.03/Rev. 3.04
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SECTION X.X
XXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
PART X
RESULTS:
1. Repair engine, or replace defective part(s), or adjust as
necessary.
2. If no engine problems are found, go to Test 7.
Page 149
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SECTION X.X
XXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
PART X
3.4 provides detailed instructions for performance of
each test.
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SECTION X.X
XXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
PART X
PROCEDURE:
1. Set the AUTO-OFF-MANUAL switch (SW1) to
MANUAL. The generator should start. Set SW1 back to
AUTO. Verify that SW1 has been in AUTO for weekly
exercise to function.
2. Verify that DIP Switch 2 (REMOTE NOT AUTO) on the
circuit board is set to the OFF position (see Figure 1,
Page 1.6-1).
3. Hold the Set Exercise switch until the generator starts
(approximately 10 seconds) and then release. The
generator will start and run for approximately 12
minutes and then shutdown on it’s own. The exerciser
will then be set to start and run at that time of that day
each week. If the unit does not start, go to Test 73.
Retest after performing Test 73. If the generator still will
not start, replace the circuit board. If the generator does
not start after depressing the Set Exercise switch, wait
one week and watch for exercise operation. If exercise
fails to operate, replace the circuit board.
Page 151
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SECTION X.X
XXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXX
PART X
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