Murphy Portable Generator A900 Series User Manual

A900-9025N

Revised 10-99

Section 40

(00-02-0197)

SERIES A900

MURPHYMATIC GENERATOR

ENGINE CONTROL SYSTEM

DESIGN, INSTALLATION

AND OPERATING MANUAL

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Table of Contents

Section 1: Introduction

1-1 System

page 1

1-2 Models

1-3 Purpose

1-4 Definitions

1-5 How To Use This Manual

Section 2: Specifications

2-1 Enclosure Type

2-2 Power Requirements

2-3 Input Ratings

2-4 Output Ratings

2-5 Field Wiring Connections

2-6 Operating Temperature

Section 3: Model Identification

3-1 Model Numbers

3-2 A901

3-3 A901-2

3-4 A902

3-5 A902-2

3-6 A903

3-7 A903-2

Section 4: Installation

4-1 Location

4-2 Wiring

4-3 Crank Disconnect

4-4 Pre-Operational Check-Out

Section 5: Operation

5-1 Operator Controls

5-2 Operating Modes

Section 6: Routine Maintenance and Operational Tests

6-1 Routine Maintenance

6-2 Operational Tests

Section 7: Troubleshooting and Repair

7-1 Tools Required

7-2 A900 SELECTRONIC^®Control Operation and Shutdown

7-3 A900 SELECTRONIC^®Control Alarm Circuit Operation

Section 8: Service Parts

8-1 Table 8-1: Replacement Components of the A900 Series Generator Controls

8-2 Table 8-2: Replacement Components of the A900 Controls for Detroit Diesel

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1-5 How to use this manual.

1-5.1 Section 1, 2, 4, 5, 6 and 7 contain general information that

applies to all A900 models.

1-5.2 Section 3, Model Identification, is broken into seven sub

sections. Section 3-1 allows you to chose the model that best

fits your requirements and Section 3-2 through 3-7 explain each

models features in detail.

Section 1: Introduction

1-1 System.

1-1.1 The MURPHYMATIC^®Generator Engine Control System,

Series A900 is designed to meet the requirements of the engine

control, shutdown and alarm section of NFPA-110 “Emergency

And Standby Power Systems” specification. The controller also

meets the minimum requirements of NFPA99 “Health Care

Facilities” and the Canadian standard CAN/CSA-C282-M89

“Emergency Electrical Power Supply for Buildings” for engine

Section 2: Specifications

control, shutdown and alarm systems. By combining one of the 2-1 Enclosure Type.

A900 series controls with generator instruments, a complete engine 2-1.1 The A900 Series enclosure is designed to be mounted in a

generator control panel meeting the above specifications can be standard electrical enclosure for indoor use.

provided.

1-2 Models.

2-2 Power Requirements.

2-2.1 The engine controls, shutdown circuits, alarm and shut-

down indicators are powered from the engine starting battery.

The A900 series is available in either 12 or 24 V, negative ground.

1-2.1 The Series A900 is available in three basic configurations:

1-2.1.1 Model A901 for automatic start and stop generator sets

which includes the minimum shutdowns and alarms per NFPA-

110 Level 1.

1-2.1.2 Model A902 for automatic start and stop generator sets

which includes the minimum shutdowns and alarms per NFPA-

110 Level 2.

2-2.2 The A900 is fused for 3 A maximum current.

2-3 Input Ratings.

2-3.1 All input switches should be dry contact type, maximum

current is 2 mA, 8 V DC or less.

2-3.2 Frequency signal for the speed sensing circuit requires a

1-2.1.3 Model A903 for automatic start and stop generator sets

minimum input of 2 V rms from a magnetic pickup (preferred) or

which includes the minimum shutdowns and alarms per NFPA-

from the tachometer terminal of the battery charging alternator.

110 Level 2 and seven unlabeled alarm lights for additional

2-3.2.1 Frequency range of the speed sensing circuits is 25 Hz to

10,000 Hz.

customer specified alarms.

1-2.2 All models are available for 12 or 24 V DC operation.

1-2.3 All models are available for use on either two cycle or four 2-4 Output Ratings.

cycle engines. Models for two cycle engines include an alarm 2-4.1 The A900 Control / Display Module has outputs for remote

light for “Air Damper Closed” and an “Overspeed Relay” to indication of alarm and shutdowns. These outputs are transistors

operate the air shutoff solenoid for overspeed shutdown.

that close to the negative supply (sink) and are rated at 1 amp, 30

1-2.4 Each model is made up of two parts, a Control/Display V DC maximum.

module and a Relay module.

2-4.2 The Control / Display Module also has an output for an

auxiliary starter contactor which is rated 1 A, 30 V DC maximum.

This is a transistor that closes to the positive supply (source).

2-4.3 The Relay Module includes 3 engine control relays with

contact ratings of 7 A, 30 V DC inductive. These powered

contacts must be supplied from an 8 A fuse or circuit breaker

(customer supplied). The 3 alarm relays have dry contacts, also

rated at 7 A, 30 V DC maximum.

1-3 Purpose.

1-3.1 This manual is directed to the installation, maintenance and

operating personnel who will be in day to day contact with the

A900 system. However the basic knowledge gained with this

material will allow those personnel to easily adjust to special

circumstances.

1-4 Definitions.

1-4.1 Throughout this manual, reference is made to organi- 2-5 Field Wiring Connections.

zations, trade names and trademarks which may not be familiar to 2-5.1 All field wiring connections are barrier terminal blocks, UL

the reader. Some of these are:

rated for 15 A, 300 V.

1-4.1.1 CSA: Canadian Standards Association.

1-4.1.2 CAN/CSA-C282-M89: The standard for Emergency

Electrical Power Supply for Buildings, 1989 Edition.

1-4.1.3 NFPA: National Fire Protection Association.

1-4.1.4 NFPA-70: The National Electrical Code.

1-4.1.5 NFPA-99-1990: The standard for Health Care Facilities,

1990 Edition.

2-6 Operating Temperature.

2-6.1 The operating temperature range of the A900 is -4°F to

158°F (-20°C to 70°C.)

Section 3: Model Identification

3-1 Model Numbers.

3-1.1 A901-12 and A901-24: These models are designed for an

automatic start four cycle engine driven generator, and

include the shutdown and alarm points recommended in NFPA-

110-1988 “Emergency and Standby Generator Systems” for Level

1 installations. These controllers also meet or exceed the

minimum requirements of NFPA99-1990 “Health Care Facilities”

and with the addition of a Low Water Level alarm, the Canadian

standard CAN/CSA-C282-M89 “Emergency Electrical Power

Supply for Buildings”. The suffix numbers -12 and -24 indicate

the engine starting battery voltage.

1-4.1.6 NFPA-110-1988: The standard for Emergency And

Standby Power Systems, 1988 Edition.

1-4.1.7 Several terms used in this manual are registered

trademarks of Frank W. Murphy Mfr.

(a) MURPHYMATIC^®: Refers to all Murphy automatic controls.

(b) SELECTRONIC^®: A name that is applied to all electronic

controls manufactured by Murphy.

(d) TATTLETALE^®: A term that refers to a shutdown indicating

device or circuit in the control panel.

3-1.2 A901-2-12 and A901-2-24: These models are designed for

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an automatic-start, two-cycle, engine-driven generator, and

include the shutdown and alarm points recommended in NFPA-

110-1988 “Emergency and Standby Generator Systems” for

Level 1 installations. These controllers also meet or exceed the

minimum requirements of NFPA-99-1990 “Health Care

Facilities” and with the addition of a Low Water Level alarm,

the Canadian standard CAN/CSA-C282-M89 “Emergency

Electrical Power Supply for Buildings”. The suffix numbers -12

and -24 indicate the engine starting battery voltage.

6-1/2 in.

(165 mm)

Low Water

Overcrank

Overspeed

Oil Pressure

Temperature

Loss of Speed

Signal

Lamp Test

3-1.2.1 The A901-2 series control includes an “Air Damper

Closed” light and “Overspeed Relay” to trip the air shut-off

solenoid on overspeed of a two-cycle engine.

Water

Temperature

AUTO

OFF

9-3/4 in.

(248 mm)

TEST

3-1.3 A902-12 and A902-24: These models are designed for an

automatic-start, four-cycle, engine-driven generator, and include

the shutdown and alarm points recommended in NFPA-110-

1988 “Emergency and Standby Generator Systems” for Level 2

installations. The suffix numbers -12 and -24 indicate the

engine starting battery voltage.

3-1.4 A902-2-12 and A902-2-24: These models are designed

for an automatic-start, two-cycle, engine-driven generator, and

include the shutdown and alarm points recommended in NFPA-

110-1988 “Emergency and Standby Generator Systems” for

Level 2 installations. The suffix numbers -12 and -24 indicate

the engine starting battery voltage.

Switch

Low Oil Pressure

PreAlarm

Not In AUTO

Low Fuel

Level

High Water Temp.

PreAlarm

Battery Charger

AC Failure

High Battery

Voltage

Low Battery

Voltage

Alarm Silence

3-1.4.1 The A902-2 series control includes an “Air Damper

Closed” light and “Overspeed Relay” to trip the air shut-off

solenoid on overspeed of a two-cycle engine.

3-1.5 A903-12 and A903-24: These models are designed for an

automatic-start, four-cycle, engine-driven generator, and include

the shutdown and alarm points recommended in NFPA-110-

1988 “Emergency and Standby Generator Systems” for Level 2

installations plus seven unlabeled alarms that the user may

specify and an “Alarm Silence Switch”. The suffix numbers -12

and -24 indicate the engine starting battery voltage.

Figure 3-2.1

A start signal is applied to the automatic control and the

engine start sequence begins.

3-2.1.2 Lamp Test Pushbutton: Tests the lights on the A901

module.

3-2.1.3 Alarm Silence Pushbutton: Turns off any audible alarm

that is connected to the Local or Remote Audible Alarm Relays.

The indicating light will remain on as long as the condition

exists. If the Alarm Silence pushbutton is not operated, the

audible alarm will turn off when the alarm contact clears.

3-2.1.4 The A901 SELECTRONIC^®Control Module includes

the following engine control features:

3-1.6 A903-2-12 and A903-2-24: These models are designed for

an automatic-start, two-cycle, engine driven generator, and

include the shutdown and alarm points recommended in NFPA-

110-1988 “Emergency and Standby Generator Systems” for

Level 2 installations plus seven unlabeled alarms that the user

may specify and an “Alarm Silence Switch”. The suffix numbers

-12 and -24 indicate the engine starting battery voltage.

(a) Cycle crank circuit; will crank the engine for 15 seconds

then rest for 15 seconds until the engine starts. The

crank/rest time can be selected for either 10, 15, 20, 25 or

30 seconds. If the engine false starts, goes above crank

disconnect speed then drops below that speed, the control

will rest for a fixed 10 second period before cranking again.

(b) Crank Disconnect Speed Switch; this circuit detects

engine speed and terminates cranking when engine speed

rises above the speed switch setting. The speed switch is

adjustable, 25 Hz to 2000 Hz, and is factory set at 1180

Hz. This would be 600 RPM on an engine with 118 teeth

on the flywheel ring gear.

NFPA-110, is provided as a back up for the Crank

Disconnect Speed Switch. It is operated by an external

switch sensing either speed, generator voltage or some other

variable that could be used to terminate cranking. Either

circuit will disconnect the starter when the engine starts.

3-1.6.1 The A903-2 series control includes an “Air Damper

Closed” light and “Overspeed Relay” to trip the air shut-off

solenoid on overspeed of a two-cycle engine.

3-1.7 Table 3-1.7 illustrates the alarm and shutdown require-

ments of NFPA-110, NFPA99 and CAN/CSA-C282-M89 and

compares the features of the A900 series controls to those

requirements.

3-2 A901.

3-2.1 Control / Display Module. The Control / Display Module,

figure 3-2.1, includes the control and test switches, the solid state

logic elements, shutdown and alarm TATTLETALE^®lights that

make up the generator engine control for a four-cycle engine.

3-2.1.1 Mode Selector Switch, OFF-AUTO-TEST:

(a) OFF; turns off the control system and resets any shutdown

circuits.

(b) AUTO; turns on the engine controls and shutdown circuits.

System is on standby waiting for a contact closure to start

engine.

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Table 3-1.7

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(d) Overcrank circuit; will stop automatic cranking and

indicate overcrank if engine fails to start after 3 attempts.

The number of cranks are selectable for 1, 2, 3, 4 or 5

cycles before shutdown. The overcrank circuit may also

be turned off so no overcrank shutdown occurs.

activated by the frequency input, it prevents the engine

from running without overspeed protection.

(g) Remote Shutdown; this circuit is provided to shutdown

the engine generator from a remote location. No

indicating light is provided.

(e) Shutdown Time Delay Bypass; this delay prevents the oil 3-2.1.6 Nine (9) Alarm Indicating Circuits; provide indication of

pressure, water temperature and loss of speed signal cause of alarm. These circuits activate the alarm relays. Alarm

shutdown circuits from operating for 15 seconds after the circuits are active as long as power is applied to the A901. All are

engine starts as detected by the crank disconnect circuit. active when the engine is running, shutdown or on standby except

This same delay also locks out the Low Oil Pressure Pre- Low Oil Pressure Pre- alarm and High Water Temperature Pre-

alarm and High Water Temperature Pre-alarm circuits alarm. Nine (9) Amber Alarm Indicating Lights are provided.

when the engine is not running.

(f) Overspeed Speed Switch;

(a) Low Water Temperature; operated by low water temp-

erature SWICHGAGE^®.

1. Provides a signal to the overspeed shutdown circuit if

the engine exceeds the preset speed. The factory

setting is approximately 3894 Hz, or 1980 RPM on an

engine with 118 teeth on the flywheel ring gear. The

adjustment range is 300 Hz to 10,000 Hz.

(b) Spare Alarm; operated by an external switch. This circuit

is provided for an additional alarm that may be required by

the user.

TEST mode selector switch.

2. A push-to-test switch is provided to allow testing of the

overspeed circuit without overspeeding the engine.

When switch is depressed, the set point of the speed

switch is lowered approximately 10%.

3. The push-to-test switch can also be used to set the

overspeed switch at approximately 110% of running

speed. Hold the switch depressed while adjusting the

setting until the overspeed trips. When switch is

released, the set point will be 10% above normal running

speed. This is the method used to make the factory

setting. With engine speed at 1800 RPM or 3540 Hz.

(d) Low Fuel Level; operated by level switch on fuel tank.

(e) High Battery Voltage; operated by relay contact in

battery charger.

(f) Low Battery Voltage; operated by low voltage sensing

device in battery charger.

(g) Low Oil Pressure Pre-alarm; operated by pre-alarm

switch in oil pressure SWICHGAGE^®.

(h) High Water Temperature Pre-alarm; operated by pre

alarm switch in water temperature SWICHGAGE^®.

(i) Battery Charger AC Failure: operated by a relay contact in

the Battery Charger.

(g) Cooldown circuit; this circuit keeps the engine running 3-2.2 Relay Module. The Relay Module, figure 3-2.2, includes

for five minutes after the transfer switch has removed all of the control, alarm and shutdown relays that are required to

the load from the generator and signaled the A901 to make up the generator engine control. Relays are available for

stop the engine. This feature may be selected (turned operation on either 12 or 24 volt battery systems. Five (5) relays

On, standard setting is Off) with a switch on the back of are included for:

the Control / Display Module.

3-2.2.1 Fuel Relay; this relay provides two outputs, one to

3-2.1.5 Seven (7) First-out Shutdown Circuits; provide first-out energize the engine fuel solenoid and a separate circuit to

indication of cause of shutdown. These circuits deactivate the

fuel relay and lockout the A901 until reset. Shutdown circuits

Figure 3-2.2

are activated by the crank disconnect circuit and are not active

when the engine is stopped. Six (6) Red Shutdown Indicating

Lights are provided. The Remote Shutdown circuit does not

have an indicator light.

3A Fuse

(a) Overcrank; tripped by the overcrank sensing circuit which

counts the number of cranking attempts.

RH2V2

-U

(b) Overspeed; tripped by overspeed switch when engine

exceeds a preset speed.

if pressure drops below preset point while the engine is

running.

DC12V

6-1/4 in.

(159 mm)

RH2V2

-U

DC12V

RH2V2

-U

DC12V

(d) Water Temperature; tripped by the water temperature

SWICHGAGE^®if engine coolant temperature exceeds the

switch setting.

(e) Spare Shutdown; tripped by an external switch. This

circuit is provided for an additional shutdown that may be

recommended by the engine supplier.

RH2V2

-U

DC12V

(f) Loss of Speed Signal; tripped by an internal sensing

circuit that detects the loss of the Magnetic Pickup

frequency signal for the speed switches while the engine

is still running. Since the Overspeed shutdown circuit is

4-1/2 in.

(114 mm)

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energize the battery charging alternator field.

crank/rest time is selectable for either 10, 15, 20, 25 or 30

seconds. If the engine false starts, goes above crank

disconnect speed then drops below that speed, the control

will rest for a fixed 10 second period before cranking again.

(b) Crank Disconnect Speed Switch; this circuit detects

engine speed and terminates cranking when engine speed

rises above the speed switch setting. The speed switch is

adjustable, 25 Hz to 2000 Hz, and is factory set at 1180

Hz. This would be 600 RPM on an engine with 118 teeth

on the flywheel ring gear.

3-2.2.2 Shutdown Relay; this relay is operated by the shutdown

circuits of the Control / Display Module and provides an output

that can be used to trip the generator circuit breaker on an

emergency shutdown.

3-2.2.3 Local Audible Alarm Relay; provides a contact closure

to operate a local audible alarm as required by NFPA-110, Level

1 and Level 2.

3-2.2.4 Remote Audible Alarm Relay; provides a contact

closure to operate a remote audible alarm as required by NFPA-

110, Level 1.

3-2.2.5 Remote Visual Alarm Relay; provides a contact closure

to operate a remote visual alarm as required by NFPA- 110,

Level 1.

6-1/2 in.

(165 mm)

3-2.3 Status Signals. The relay module also includes three

outputs that can be used with external circuits for signaling or

control functions.

3-2.3.1 The Control On function at terminal 12 is on (closed

to negative) as long as the Mode Selector Switch is in either

Auto or Test. When the Mode Selector is turned Off, the

Control On signal is open. This can be used to signal switch

position or to reset an external circuit when the Mode Selector

is turned Off.

Low Water

Overcrank

Overspeed

Oil Pressure

Temperature

Loss of Speed

Signal

Lamp Test

Water

Temperature

AUTO

OFF

9-3/4 in.

(248 mm)

TEST

3-2.3.2 The System Ready signal at terminal 13 is on (closed

to negative) as long as the Mode Selector Switch is in either

Auto or Test and no shutdown Tattletale circuit is latched on.

This can be used to signal that the generator engine is ready to

automatically start or is running in Test.

3-2.3.3 The Control On function at terminal 14 is on (closed

to positive) as long as the Mode Selector Switch is in either

Auto or Test. When the Mode Selector is turned Off, the

Control On signal is open. This can be used to signal switch

position or to reset an external circuit when the Mode Selector

is turned Off.

Air Damper

Closed

Switch

Low Oil Pressure

PreAlarm

Not In AUTO

Low Fuel

Level

High Water Temp.

PreAlarm

Battery Charger

AC Failure

High Battery

Voltage

Low Battery

Voltage

Alarm Silence

3-3 A901-2.

3-3.1 Control / Display Module. The Control / Display Module,

figure 3-3.1, includes the control and test switches, the solid state

logic elements, shutdown and alarm TATTLETALE^®lights that

make up the generator engine control for a two-cycle engine.

3-3.1.1 Mode Selector Switch, OFF-AUTO-TEST:

(a) OFF; turns off the control system and resets any shutdown

circuits.

(b) AUTO; turns on the engine controls and shutdown

circuits. System is on standby waiting for a contact

closure to start engine.

A start signal is applied to the automatic control and the

engine start sequence begins.

3-3.1.2 Lamp Test Pushbutton: Tests the lights on the A- 901-2

module.

3-3.1.3 Alarm Silence Pushbutton: Turns off any audible alarm

that is connected to the Local or Remote Audible Alarm Relays.

The indicating light will remain on as long as the condition

exists. If the Alarm Silence pushbutton is not operated, the

audible alarm will turn off when the alarm contact clears.

3-3.1.4 The A901-2 SELECTRONIC^®Control Module includes

the following engine control features:

Figure 3-3.1

NFPA-110, is provided as a back up for the Crank Discon-

nect Speed Switch. It is operated by an external switch

sensing either speed, generator voltage or some other

variable that could be used to terminate cranking. Either

circuit will disconnect the starter when the engine starts.

(d) Overcrank circuit; will stop automatic cranking and

indicate overcrank if engine fails to start after 3 attempts.

The number of cranks are selectable for 1, 2, 3, 4 or 5

cycles before shutdown. The overcrank circuit may also

be turned off so no overcrank shutdown occurs.

(e) Shutdown Time Delay Bypass; this delay prevents the oil

pressure, water temperature and loss of speed signal

shutdown circuits from operating for 15 seconds after the

engine starts as detected by the crank disconnect circuit.

This same delay also locks out the Low Oil Pressure Pre-

alarm and High Water Temperature Pre-alarm circuits

when the engine is not running.

(a) Cycle crank circuit; will crank the engine for 15 seconds

then rest for 15 seconds until the engine starts. The

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(f) Overspeed Speed Switch;

(b) Air Damper Closed; operated by an external switch or by

the Overspeed Relay circuit. This circuit is provided with

a selector switch to allow the user to determine the source

of the signal.

TEST mode selector switch.

1. Provides a signal to the overspeed shutdown circuit if

the engine exceeds the preset speed. The factory

setting is approximately 3894 Hz, or 1980 RPM on an

engine with 118 teeth on the flywheel ring gear. The

adjustment range is 300 Hz to 10,000 Hz.

2. A push to test switch is provided to allow testing of the

overspeed circuit without overspeeding the engine.

When switch is depressed, the set point of the speed

switch is lowered approximately 10%.

3. The push to test switch can also be used to set the

overspeed switch at approximately 110% of running

speed. Hold the switch depressed while adjusting the

setting until the overspeed trips. When switch is

released, the set point will be 10% above normal running

speed. This is the method used to make the factory

setting. With engine speed at 1800 RPM or 3540 Hz.

(d) Low Fuel Level; operated by level switch on fuel tank.

(e) High Battery Voltage; operated by relay contact in battery

charger.

(f) Low Battery Voltage; operated by low voltage sensing

device in battery charger.

(g) Low Oil Pressure Pre-alarm; operated by pre-alarm

switch in oil pressure SWICHGAGE^®.

(h) High Water Temperature Pre-alarm; operated by pre-

alarm switch in water temperature SWICHGAGE^®.

(i) Battery Charger AC Failure; operated by relay contact in

Battery Charger.

(g) Cooldown circuit; this circuit keeps the engine running 3-3.2 Relay Module. The Relay Module, figure 3-3.2, includes

for five minutes after the transfer switch has removed all of the control, alarm and shutdown relays that are required to

the load from the generator and signaled the A901-2 to make up the generator engine control. Relays are available for

stop the engine. This feature may be selected (turned operation on either 12 or 24 volt battery systems. Six (6) relays

On, standard setting is Off) with a switch on the back of are included for:

the Control / Display Module.

3-3.1.5 Seven (7) First-out Shutdown Circuits; provide first-out

indication of cause of shutdown. These circuits deactivate the

fuel relay and lockout the A901-2 until reset. Shutdown circuits

are activated by the crank disconnect circuit and are not active

when the engine is stopped. Six (6) Red Shutdown Indicating

3A Fuse

Lights are provided. The Remote Shutdown circuit does not

have an indicator light.

(a) Overcrank; tripped by the overcrank sensing circuit which

DC12V

counts the number of cranking attempts.

(b) Overspeed; tripped by overspeed switch when engine

exceeds a preset speed.

pressure drops below preset point while the engine is running.

(d) Water Temperature; tripped by the water temperature

SWICHGAGE^®if engine coolant temperature exceeds the

switch setting.

6-1/4 in.

(159 mm)

(e) Spare Shutdown; tripped by an external switch. This

circuit is provided for an additional shutdown that may be

recommended by the engine supplier.

(f) Loss of Speed Signal; tripped by an internal sensing

circuit that detects the loss of the Magnetic Pickup

frequency signal for the speed switches while the engine

is still running. Since the Overspeed shutdown circuit is

activated by the frequency input, it prevents the engine

from running without overspeed protection.

4-1/2 in.

(114 mm)

Figure 3-3.2

(g) Remote Shutdown; this circuit is provided to shutdown

the engine generator from a remote location. No

indicating light is provided.

3-3.1.6 Nine (9) Alarm Indicating Circuits; provide indication

of cause of alarm. These circuits activate the alarm relays.

Alarm circuits are active as long as power is applied to the

A901-2. All are active when the engine is running, shutdown or

on standby except Low Oil Pressure Pre- alarm and High Water

Temperature Pre-alarm. Nine (9) Amber Alarm Indicating

Lights are provided.

3-3.2.1 Fuel Relay; this relay provides two outputs, one to

energize the engine fuel solenoid and a separate circuit to

energize the battery charging alternator field.

3-3.2.2 Shutdown Relay; this relay is operated by the shutdown

circuits of the Control / Display Module and provides an output

that can be used to trip the generator circuit breaker on an

emergency shutdown.

3-3.2.3 Overspeed Relay; operates only on an Overspeed

shutdown. This relay provides an output to trip an air shut off

solenoid to close the air damper on a two-cycle engine.

3-3.2.4 Local Audible Alarm Relay; provides a contact closure

(a) Low Water Temperature; operated by low water temp-

erature SWICHGAGE^®.

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to operate a local audible alarm as required by NFPA- 110,

Level 1 and Level 2.

3-3.2.5 Remote Audible Alarm Relay; provides a contact

closure to operate a remote audible alarm as required by NFPA-

110, Level 1.

3-3.2.6 Remote Visual Alarm Relay; provides a contact closure

to operate a remote visual alarm as required by NFPA- 110,

Level 1.

on the flywheel ring gear.

by NFPA-110, is provided as a back up for the Crank

Disconnect Speed Switch. It is operated by an external

switch sensing either speed, generator voltage or some

other variable that could be used to terminate cranking.

Either circuit will disconnect the starter when the engine

starts.

3-3.3 Status Signals. The relay module also includes three

outputs that can be used with external circuits for signaling or

control functions.

3-3.3.1 The Control On function at terminal 12 is on (closed

to negative) as long as the Mode Selector Switch is in either

Auto or Test. When the Mode Selector is turned Off, the

Control On signal is open. This can be used to signal switch

position or to reset an external circuit when the Mode Selector

is turned Off.

(d) Overcrank circuit; will stop automatic cranking and

indicate overcrank if engine fails to start after 3 attempts.

The number of cranks are selectable for 1, 2, 3, 4 or 5

cycles before shutdown. The overcrank circuit may also

be turned off so no overcrank shutdown occurs.

6-1/2 in.

(165 mm)

3-3.3.2 The System Ready signal at terminal 13 is on (closed

to negative) as long as the Mode Selector Switch is in either

Auto or Test and no shutdown Tattletale circuit is latched on.

This can be used to signal that the generator engine is ready to

automatically start or is running in Test.

Low Water

Overcrank

Temperature

Loss of Speed

Overspeed

Signal

Lamp Test

Oil Pressure

3-3.3.3 The Control On function at terminal 14 is on (closed

to positive) as long as the Mode Selector Switch is in either

Auto or Test. When the Mode Selector is turned Off, the

Control On signal is open. This can be used to signal switch

position or to reset an external circuit when the Mode Selector

is turned Off.

Water

Temperature

AUTO

OFF

9-3/4 in.

(248 mm)

TEST

3-4 A902.

3-4.1 Control / Display Module. The Control / Display

Module, figure 3-4.1, includes the control and test switches, the

solid state logic elements, shutdown and alarm TATTLETALE^®

lights that make up the generator engine control for a four-cycle

engine.

3-4.1.1 Mode Selector Switch, OFF-AUTO-TEST:

(a) OFF; turns off the control system and resets any shutdown

circuits.

(b) AUTO; turns on the engine controls and shutdown

circuits. System is on standby waiting for a contact

closure to start engine.

A start signal is applied to the automatic control and the

engine start sequence begins.

3-4.1.2 Lamp Test Pushbutton: Tests the lights on the A902

module.

3-4.1.3 The A902 SELECTRONIC^®Control Module includes

the following engine control features:

Figure 3-4.1

(e) Shutdown Time Delay Bypass; this delay prevents the oil

pressure, water temperature and loss of speed signal

shutdown circuits from operating for 15 seconds after the

engine starts as detected by the crank disconnect circuit.

(f) Overspeed Speed Switch;

(a) Cycle crank circuit; will crank the engine for 15 seconds

then rest for 15 seconds until the engine starts. The

crank/rest time is selectable for either 10, 15, 20, 25 or 30

seconds. If the engine false starts, goes above crank

disconnect speed then drops below that speed, the control

will rest for a fixed 10 second period before cranking

again.

(b) Crank Disconnect Speed Switch; this circuit detects

engine speed and terminates cranking when engine speed

rises above the speed switch setting. The speed switch is

adjustable, 25 Hz to 2000 Hz, and is factory set at 1180

Hz. This would be 600 RPM on an engine with 118 teeth

1. Provides a signal to the overspeed shutdown circuit if

the engine exceeds the preset speed. The factory

setting is approximately 3894 Hz, or 1980 RPM on an

engine with 118 teeth on the flywheel ring gear. The

adjustment range is 300 Hz to 10,000 Hz.

2. A push to test switch is provided to allow testing of the

overspeed circuit without overspeeding the engine.

When switch is depressed, the set point of the speed

switch is lowered approximately 10%.

3. The push to test switch can also be used to set the

overspeed switch at approximately 110% of running

speed. Hold the switch depressed while adjusting the

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setting until the overspeed trips. When switch is that can be used to trip the generator circuit breaker on an

released, the set point will be 10% above normal emergency shutdown.

running speed. This is the method used to make the

factory setting. With engine speed at 1800 RPM or

3540 Hz.

(g) Cooldown circuit; this circuit keeps the engine running

for five minutes after the transfer switch has removed the

load from the generator and signaled the A902 to stop

the engine. This feature may be selected (turned On,

standard setting is Off) with a switch on the back of the

3A Fuse

DC12V

Control / Display Module.

3-4.1.4 Seven (7) First-out Shutdown Circuits; provide first-out

indication of cause of shutdown. These circuits deactivate the

fuel relay and lockout the A902 until reset. Shutdown circuits

are activated by the crank disconnect circuit and are not active

when the engine is stopped. Six (6) Red Shutdown Indicating

Lights are provided. The Remote Shutdown circuit does not

have an indicator light.

6-1/4 in.

(159 mm)

(a) Overcrank; tripped by the overcrank sensing circuit which

counts the number of cranking attempts.

(b) Overspeed; tripped by overspeed switch when engine

exceeds a preset speed.

pressure drops below preset point while the engine is

running.

4-1/2 in.

(114 mm)

(d) Water Temperature; tripped by the water temperature

SWICHGAGE^®if engine coolant temperature exceeds the

switch setting.

(e) Spare Shutdown; tripped by an external switch. This

circuit is provided for an additional shutdown that may be

recommended by the engine supplier.

(f) Loss of Speed Signal; tripped by an internal sensing

circuit that detects the loss of the Magnetic Pickup

frequency signal for the speed switches while the engine

is still running. Since the Overspeed shutdown circuit is

activated by the frequency input, it prevents the engine

from running without overspeed protection.

(g) Remote Shutdown; this circuit is provided to shutdown

the engine generator from a remote location. No

indicating light is provided.

3-4.1.5 Two (2) Alarm Indicating Circuits; provide indication

of cause of alarm. These circuits activate the alarm relay. Alarm

circuits are active as long as power is applied to the A902. All

are active when the engine is running, shutdown or on standby.

Two (2) Amber Alarm Indicating Lights are provided.

(a) Low Water Temperature; operated by low water

temperature SWICHGAGE^®.

(b) Spare Alarm; operated by an external switch. This circuit

is provided for an additional alarm that may be required

by the user.

3-4.2 Relay Module. The Relay Module, figure 3-4.2, includes

all of the control, alarm and shutdown relays that are required to

make up the generator engine control. Relays are available for

operation on either 12 or 24 volt battery systems. Three (3)

relays are included for:

3-4.2.1 Fuel Relay; this relay provides two outputs, one to

energize the engine fuel solenoid and a separate circuit to

energize the battery charging alternator field.

Figure 3-4.2

3-4.2.3 Local Audible Alarm Relay; provides a contact closure

to operate a local audible alarm as required by NFPA- 110, Level

1 and Level 2.

3-4.3 Status Signals. The relay module also includes three

outputs that can be used with external circuits for signaling or

control functions.

3-4.3.1 The Control On function at terminal 12 is on (closed to

negative) as long as the Mode Selector Switch is in either Auto

or Test. When the Mode Selector is turned Off, the Control On

signal is open. This can be used to signal switch position or to

reset an external circuit when the Mode Selector is turned Off.

3-4.3.2 The System Ready signal at terminal 13 is on (closed

to negative) as long as the Mode Selector Switch is in either

Auto or Test and no shutdown TATTLETALE^®circuit is

latched on. This can be used to signal that the generator engine

is ready to automatically start or is running in Test.

3-4.3.3 The Control On function at terminal 14 is on (closed to

positive) as long as the Mode Selector Switch is in either Auto

or Test. When the Mode Selector is turned Off, the Control On

signal is open. This can be used to signal switch position or to

reset an external circuit when the Mode Selector is turned Off.

3-5 A902-2.

3-5.1 Control / Display Module. The Control / Display Module,

figure 3-5.1, includes the control and test switches, the solid state

logic elements, shutdown and alarm TATTLETALE^®lights that

make up the generator engine control for a two-cycle engine.

3-5.1.1 Mode Selector Switch, OFF-AUTO-TEST:

(a) OFF; turns off the control system and resets any shutdown

circuits.

(b) AUTO; turns on the engine controls and shutdown circuits.

System is on standby waiting for a contact closure to start

engine.

3-4.2.2 Shutdown Relay; this relay is operated by the shutdown

circuits of the Control / Display Module and provides an output

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6-1/2 in.

(165 mm)

be turned off so no overcrank shutdown occurs.

(e) Shutdown Time Delay Bypass; this delay prevents the oil

pressure, water temperature and loss of speed signal

shutdown circuits from operating for 15 seconds after the

engine starts as detected by the crank disconnect circuit.

(f) Overspeed Speed Switch;

Low Water

Temperature

Overcrank

Overspeed

Oil Pressure

Loss of Speed

Signal

1. Provides a signal to the overspeed shutdown circuit if

the engine exceeds the preset speed. The factory

setting is approximately 3894 Hz, or 1980 RPM on an

engine with 118 teeth on the flywheel ring gear. The

adjustment range is 300 Hz to 10,000 Hz.

Lamp Test

Water

Temperature

AUTO

OFF

9-3/4 in.

(248 mm)

TEST

2. A push to test switch is provided to allow testing of the

overspeed circuit without overspeeding the engine.

When switch is depressed, the set point of the speed

switch is lowered approximately 10%.

Air Damper

Closed

3. The push to test switch can also be used to set the

overspeed switch at approximately 110% of running

speed. Hold the switch depressed while adjusting the

setting until the overspeed trips. When switch is

released, the set point will be 10% above normal

running speed. This is the method used to make the

factory setting. With engine speed at 1800 RPM or

3540 Hz.

(g) Cooldown circuit; this circuit keeps the engine running

for five minutes after the transfer switch has removed

the load from the generator and signaled the A902-2 to

stop the engine. This feature may be selected (turned

On, standard setting is Off) with a switch on the back of

the Control / Display Module.

3-5.1.4 Seven (7) First-out Shutdown Circuits; provide first-out

indication of cause of shutdown. These circuits deactivate the

fuel relay and lockout the A902-2 until reset. Shutdown circuits

are activated by the crank disconnect circuit and are not active

when the engine is stopped. Six (6) Red Shutdown Indicating

Lights are provided. The Remote Shutdown circuit does not

have an indicator light.

Figure 3-5.1

A start signal is applied to the automatic control and the

engine start sequence begins.

3-5.1.2 Lamp Test Pushbutton: Tests the lights on the A- 902-2

module.

3-5.1.3 The A902-2 SELECTRONIC^®Control Module includes

the following engine control features:

(a) Cycle crank circuit; will crank the engine for 15 seconds

then rest for 15 seconds until the engine starts. The

crank/rest time is selectable for either 10, 15, 20, 25 or 30

seconds. If the engine false starts, goes above crank

disconnect speed then drops below that speed, the control

will rest for a fixed 10 second period before cranking

again.

(a) Overcrank; tripped by the overcrank sensing circuit which

counts the number of cranking attempts.

(b) Overspeed; tripped by overspeed switch when engine

exceeds a preset speed.

if pressure drops below preset point while the engine is

running.

(b) Crank Disconnect Speed Switch; this circuit detects

engine speed and terminates cranking when engine speed

rise above the speed switch setting. The speed switch is

adjustable, 25 Hz to 2000 Hz, and is factory set at 1180

Hz. This would be 600 RPM on an engine with 118 teeth

on the flywheel ring gear.

(d) Water Temperature; tripped by the water temperature

SWICHGAGE^®if engine coolant temperature exceeds the

switch setting.

(e) Spare Shutdown; tripped by an external switch. This

circuit is provided for an additional shutdown that may be

recommended by the engine supplier.

by NFPA-110, is provided as a back up for the Crank

Disconnect Speed Switch. It is operated by an external

switch sensing either speed, generator voltage or some

other variable that could be used to terminate cranking.

Either circuit will disconnect the starter when the engine

starts.

(d) Overcrank circuit; will stop automatic cranking and

indicate overcrank if engine fails to start after 3 attempts.

The number of cranks are selectable for 1, 2, 3, 4 or 5

cycles before shutdown. The overcrank circuit may also

(f) Loss of Speed Signal; tripped by an internal sensing

circuit that detects the loss of the Magnetic Pickup

frequency signal for the speed switches while the engine

is still running. Since the Overspeed shutdown circuit is

activated by the frequency input, it prevents the engine

from running without overspeed protection.

(g) Remote Shutdown; this circuit is provided to shutdown

the engine generator from a remote location. No

indicating light is provided.

3-5.1.5 Two (2) Alarm Indicating Circuits; provide indication

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of cause of alarm. These circuits activate the alarm relay. reset an external circuit when the Mode Selector is turned Off.

Alarm circuits are active as long as power is applied to the 3-5.3.2 The System Ready signal at terminal 13 is on (closed

A902-2. All are active when the engine is running, shutdown or to negative) as long as the Mode Selector Switch is in either

on standby. Two (2) Amber Alarm Indicating Lights are Auto or Test and no shutdown TATTLETALE^®circuit is

provided.

(a) Low Water Temperature; operated by low water engine is ready to automatically start or is running in Test.

temperature SWICHGAGE^®.

3-5.3.3 The Control On function at terminal 14 is on (closed to

latched on. This can be used to signal that the generator

(b) Air Damper Closed; operated by an external switch or by positive) as long as the Mode Selector Switch is in either Auto

the Overspeed Relay circuit. This circuit is provided with or Test. When the Mode Selector is turned Off, the Control On

a selector switch to allow the user to determine the source signal is open. This can be used to signal switch position or to

of the signal.

reset an external circuit when the Mode Selector is turned Off.

3-5.2 Relay Module. The Relay Module, figure 3-5.2, includes

all of the control, alarm and shutdown relays that are required to

make up the generator engine control. Relays are available for

operation on either 12 or 24 volt battery systems. Four (4)

relays are included for:

3-6 A903.

3-6.1 Control / Display Module. The Control / Display Module,

figure 3-6.1, includes the control and test switches, the solid

state logic elements, shutdown and alarm TATTLETALE^®lights

that make up the generator engine control for a four cycle

engine. This module is the same as Model A- 901 except 7 of

the alarm circuits are un-labeled. This allows the customer to

specify labels other than those recommended in NFPA-110.

This model has shutdown and alarm circuits labeled to meet the

requirements of NFPA-110, Level 2.

3A Fuse

DC12V

6-1/4 in.

(159 mm)

4-1/2 in.

(114 mm)

Figure 3-5.2

3-5.2.1 Fuel Relay; this relay provides two outputs, one to

energize the engine fuel solenoid and a separate circuit to

energize the battery charging alternator field.

3-5.2.2 Shutdown Relay; this relay is operated by the shutdown

circuits of the Control / Display Module and provides an output

that can be used to trip the generator circuit breaker on an

emergency shutdown.

3-5.2.3 Overspeed Relay; operates only on an Overspeed

shutdown. This relay provides an output to trip an air shut off

solenoid to close the air damper on a two-cycle engine.

3-5.2.4 Local Audible Alarm Relay; provides a contact closure

to operate a local audible alarm as required by NFPA- 110, Level

1 and Level 2.

3-5.3 Status Signals. The relay module also includes three

outputs that can be used with external circuits for signaling or

control functions.

3-5.3.1 The Control On function at terminal 12 is on (closed to

negative) as long as the Mode Selector Switch is in either Auto

or Test. When the Mode Selector is turned Off, the Control On

signal is open. This can be used to signal switch position or to

Figure 3-6.1

3-6.1.1 Mode Selector Switch, OFF-AUTO-TEST:

(a) OFF; turns off the control system and resets any shutdown

circuits.

(b) AUTO; turns on the engine controls and shutdown circuits.

System is on standby waiting for a contact closure to start

engine.

A start signal is applied to the automatic control and the

engine start sequence begins.

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3-6.1.2 Lamp Test Pushbutton: Tests the lights on the A903

module.

3-6.1.3 Alarm Silence Pushbutton: Turns off any audible alarm

that is connected to the Local or Remote Audible Alarm Relays.

the load from the generator and signaled the A903 to

stop the engine. This feature may be selected (turned

On, standard setting is Off) with a switch on the back of

the Control / Display Module.

The indicating light will remain on as long as the condition 3-6.1.5 Seven (7) First-out Shutdown Circuits; provide first-

exists. If the Alarm Silence pushbutton is not operated, the out indication of cause of shutdown. These circuits deactivate

audible alarm will turn off when the alarm contact clears.

3-6.1.4 The A903 SELECTRONIC^®Control Module includes circuits are activated by the crank disconnect circuit and are not

the following engine control features: active when the engine is stopped. Six (6) Red Shutdown

the fuel relay and lockout the A903 until reset. Shutdown

(a) Cycle crank circuit; will crank the engine for 15 seconds Indicating Lights are provided. The Remote Shutdown circuit

then rest for 15 seconds until the engine starts. The does not have an indicator light.

crank/rest time is selectable for either 10, 15, 20, 25 or 30

seconds. If the engine false starts, goes above crank

disconnect speed then drops below that speed, the control

will rest for a fixed 10 second period before cranking

again.

(a) Overcrank; tripped by the overcrank sensing circuit

which counts the number of cranking attempts.

(b) Overspeed; tripped by overspeed switch when engine

exceeds a preset speed.

if pressure drops below preset point while the engine is

running.

(b) Crank Disconnect Speed Switch; this circuit detects

engine speed and terminates cranking when engine speed

rises above the speed switch setting. The speed switch is

adjustable, 25 Hz to 2000 Hz, and is factory set at 1180

Hz. This would be 600 RPM on an engine with 118 teeth

on the flywheel ring gear.

by NFPA-110, is provided as a back up for the Crank

Disconnect Speed Switch. It is operated by an external

switch sensing either speed, generator voltage or some

other variable that could be used to terminate cranking.

Either circuit will disconnect the starter when the engine

starts.

(d) Water Temperature; tripped by the water temperature

SWICHGAGE^®if engine coolant temperature exceeds

the switch setting.

(e) Spare Shutdown; tripped by an external switch. This

circuit is provided for an additional shutdown that may

be recommended by the engine supplier.

(f) Loss of Speed Signal; tripped by an internal sensing

circuit that detects the loss of the Magnetic Pickup

frequency signal for the speed switches while the engine

is still running. Since the Overspeed shutdown circuit is

activated by the frequency input, it prevents the engine

from running without overspeed protection.

(g) Remote Shutdown; this circuit is provided to shutdown

the engine generator from a remote location. No

indicating light is provided.

(d) Overcrank circuit; will stop automatic cranking and

indicate overcrank if engine fails to start after 3 attempts.

The number of cranks are selectable for 1, 2, 3, 4 or 5

cycles before shutdown. The overcrank circuit may also

be turned off so no overcrank shutdown occurs.

3-6.1.6 Nine (9) Alarm Indicating Circuits; provide indication

(e) Shutdown Time Delay Bypass; this delay prevents the oil of cause of alarm. These circuits activate the alarm relays.

pressure, water temperature and loss of speed signal Alarm circuits are active as long as power is applied to the

shutdown circuits from operating for 15 seconds after the A903. All are active when the engine is running, shutdown or

engine starts as detected by the crank disconnect circuit. on standby except alarm circuit #7 and #8 which are locked out

This same delay also locks out alarm circuit #7 and #8 until the engine is running. Nine (9) Amber Alarm Indicating

when the engine is not running.

(f) Overspeed Speed Switch;

Lights are provided however only two circuits are labeled. The

other 7 are for customer specified alarms.

1. Provides a signal to the overspeed shutdown circuit if

the engine exceeds the preset speed. The factory

setting is approximately 3894 Hz, or 1980 RPM on an

engine with 118 teeth on the flywheel ring gear. The

adjustment range is 300 Hz to 10,000 Hz.

(a) Low Water Temperature; operated by low water

temperature SWICHGAGE^®.

(b) #2 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

2. A push to test switch is provided to allow testing of

the overspeed circuit without overspeeding the

engine. When switch is depressed, the set point of the

speed switch is lowered approximately 10%.

3. The push to test switch can also be used to set the

overspeed switch at approximately 110% of running

speed. Hold the switch depressed while adjusting the

setting until the overspeed trips. When switch is

released, the set point will be 10% above normal

running speed. This is the method used to make the

factory setting. With engine speed at 1800 RPM or

3540 Hz.

TEST mode selector switch.

(d) #4 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(e) #5 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(f) #6 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(g) #7 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(g) Cooldown circuit; this circuit keeps the engine running

for five minutes after the transfer switch has removed

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(h) #8 Spare Alarm; operated by an external switch. This positive) as long as the Mode Selector Switch is in either Auto

circuit is provided for an additional alarm that may be or Test. When the Mode Selector is turned Off, the Control On

required by the user.

signal is open. This can be used to signal switch position or to

(i) #9 Spare Alarm; operated by an external switch. This reset an external circuit when the Mode Selector is turned Off.

circuit is provided for an additional alarm that may be

required by the user.

3-6.2 Relay Module. The Relay Module, figure 3-6.2, includes

3-7 A903-2.

3-7.1 Control / Display Module. The Control / Display Module,

figure 3-7.1, includes the control and test switches, the solid

all of the control, alarm and shutdown relays that are required to

state logic elements, shutdown and alarm TATTLETALE^®lights

make up the generator engine control. Relays are available for

that make up the generator engine control for a two-cycle

operation on either 12 or 24 volt battery systems. Three (3)

engine. This module is the same as Model A901-2 except 6 of

the alarm circuits are un-labeled. This allows the customer to

relays are included for:

specify labels other than those recommended in NFPA-110.

This model has shutdown and alarm circuits labeled to meet the

requirements of NFPA-110, Level 2.

3A Fuse

DC24V

6-1/4 in.

(159 mm)

4-1/2 in.

(114 mm)

Figure 3-6.2

3-6.2.1 Fuel Relay; this relay provides two outputs, one to

energize the engine fuel solenoid and a separate circuit to

energize the battery charging alternator field.

3-6.2.2 Shutdown Relay; this relay is operated by the shutdown

circuits of the Control / Display Module and provides an output

that can be used to trip the generator circuit breaker on an

emergency shutdown.

3-6.2.3 Local Audible Alarm Relay; provides a contact closure

to operate a local audible alarm as required by NFPA- 110, Level

1 and Level 2.

3-6.3 Status Signals. The relay module also includes three

outputs that can be used with external circuits for signaling or

control functions.

3-6.3.1 The Control On function at terminal 12 is on (closed to

negative) as long as the Mode Selector Switch is in either Auto

or Test. When the Mode Selector is turned Off, the Control On

signal is open. This can be used to signal switch position or to

reset an external circuit when the Mode Selector is turned Off.

3-6.3.2 The System Ready signal at terminal 13 is on (closed

to negative) as long as the Mode Selector Switch is in either

Auto or Test and no shutdown TATTLETALE^®circuit is

latched on. This can be used to signal that the generator

engine is ready to automatically start or is running in Test.

3-6.3.3 The Control On function at terminal 14 is on (closed to

Figure 3-7.1

3-7.1.1 Mode Selector Switch, OFF-AUTO-TEST:

(a) OFF; turns off the control system and resets any shutdown

circuits.

(b) AUTO; turns on the engine controls and shutdown

circuits. System is on standby waiting for a contact

closure to start engine.

A start signal is applied to the automatic control and the

engine start sequence begins.

3-7.1.2 Lamp Test Pushbutton: Tests the lights on the A- 903-2

module.

3-7.1.3 Alarm Silence Pushbutton: Turns off any audible alarm

that is connected to the Local or Remote Audible Alarm Relays.

The indicating light will remain on as long as the condition

exists. If the Alarm Silence pushbutton is not operated, the

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audible alarm will turn off when the alarm contact clears.

are provided. The Remote Shutdown circuit does not have an

3-7.1.4 The A903-2 SELECTRONIC^®Control Module includes indicator light.

the following engine control features:

(a) Overcrank; tripped by the overcrank sensing circuit which

(a) Cycle crank circuit; will crank the engine for 15 seconds

then rest for 15 seconds until the engine starts. The

crank/rest time is selectable for either 10, 15, 20, 25 or 30

seconds. If the engine false starts, goes above crank

disconnect speed then drops below that speed, the control

will rest for a fixed 10 second period before cranking again.

(b) Crank Disconnect Speed Switch; this circuit detects

engine speed and terminates cranking when engine speed

rises above the speed switch setting. The speed switch is

adjustable, 25 Hz to 2000 Hz, and is factory set at 1180

Hz. This would be 600 RPM on an engine with 118 teeth

on the flywheel ring gear.

counts the number of cranking attempts.

(b) Overspeed; tripped by overspeed switch when engine

exceeds a preset speed.

pressure drops below preset point while the engine is

running.

(d) Water Temperature; tripped by the water temperature

SWICHGAGE^®if engine coolant temperature exceeds the

switch setting.

(e) Spare Shutdown; tripped by an external switch. This

circuit is provided for an additional shutdown that may be

recommended by the engine supplier.

NFPA-110, is provided as a back up for the Crank

Disconnect Speed Switch. It is operated by an external

switch sensing either speed, generator voltage or some other

variable that could be used to terminate cranking. Either

circuit will disconnect the starter when the engine starts.

(d) Overcrank circuit; will stop automatic cranking and

indicate overcrank if engine fails to start after 3 attempts.

The number of cranks are selectable for 1, 2, 3, 4 or 5

(f) Loss of Speed Signal; tripped by an internal sensing

circuit that detects the loss of the Magnetic Pickup

frequency signal for the speed switches while the engine is

still running. Since the Overspeed shutdown circuit is

activated by the frequency input, it prevents the engine

from running without overspeed protection.

(g) Remote Shutdown; this circuit is provided to shutdown

the engine generator from a remote location. No

indicating light is provided.

cycles before shutdown. The overcrank circuit may also 3-7.1.6 Nine (9) Alarm Indicating Circuits; provide indication

be turned off so no overcrank shutdown occurs. of cause of alarm. These circuits activate the alarm relays.

(e) Shutdown Time Delay Bypass; this delay prevents the oil Alarm circuits are active as long as power is applied to the

pressure, water temperature and loss of speed signal A903-2. All are active when the engine is running, shutdown or

shutdown circuits from operating for 15 seconds after the on standby except alarm circuit #7 and #8 which are locked out

engine starts as detected by the crank disconnect circuit. until the engine is running. Nine (9) Amber Alarm Indicating

This same delay also locks out alarm circuit #7 and #8 Lights are provided however only three circuits is labeled. The

when the engine is not running.

other 6 are for customer specified alarms.

(f) Overspeed Speed Switch;

(a) Low Water Temperature; operated by low water

1. Provides a signal to the overspeed shutdown circuit if

the engine exceeds the preset speed. The factory

setting is approximately 3894 Hz, or 1980 RPM on an

engine with 118 teeth on the flywheel ring gear. The

adjustment range is 300 Hz to 10,000 Hz.

temperature SWICHGAGE^®.

(b) Air Damper Closed; operated by an external switch or by

the Overspeed Relay circuit. This circuit is provided with

a selector switch to allow the user to determine the source

of the signal.

2. A push to test switch is provided to allow testing of the

overspeed circuit without overspeeding the engine.

When switch is depressed, the set point of the speed

switch is lowered approximately 10%.

TEST mode selector switch.

(d) #4 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(e) #5 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(f) #6 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(g) #7 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

(h) #8 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

3. The push to test switch can also be used to set the

overspeed switch at approximately 110% of running

speed. Hold the switch depressed while adjusting the

setting until the overspeed trips. When switch is

released, the set point will be 10% above normal running

speed. This is the method used to make the factory

setting. With engine speed at 1800 RPM or 3540 Hz.

(g) Cooldown circuit; this circuit keeps the engine running

for five minutes after the transfer switch has removed the

load from the generator and signaled the A903-2 to stop

the engine. This feature may be selected (turned On,

standard setting is Off) with a switch on the back of the

Control / Display Module.

3-7.1.5 Seven (7) First-out Shutdown Circuits; provide first-out

indication of cause of shutdown. These circuits deactivate the

fuel relay and lockout the A903 until reset. Shutdown circuits are

(i) #9 Spare Alarm; operated by an external switch. This

circuit is provided for an additional alarm that may be

required by the user.

activated by the crank disconnect circuit and are not active when 3-7.2 Relay Module. The Relay Module, figure 3-7.2, includes

the engine is stopped. Six (6) Red Shutdown Indicating Lights all of the control, alarm and shutdown relays that are required to

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make up the generator engine control. Relays are available for

operation on either 12 or 24 volt battery systems. Four (4)

relays are included for:

Section 4: Installation

4-1 Location.

4-1.1 The A900 series is designed to mount in a

MURPHYMATIC^®Generator Control panel with the Control /

Display module on the front panel and the Relay module on the

inside bottom surface. Other types of installation is possible as

long as the relationship of the two modules are maintained.

4-1.2 Clearance for Installation and Service; The modules must

be accessible for wiring to the terminal blocks and adjustment of

the user controls on the back of the Control / Display module.

Figure 4-1.2 shows the mounting dimensions and the minimum

clearances recommended for installation.

3A Fuse

DC12V

4-1.3 Wiring Terminals; Terminal blocks are provided on both

sides of the Control / Display enclosure and the Relay Module.

Torque all terminal screws to 12 inch pound maximum.

6-1/4 in.

(159 mm)

4-2 Wiring.

4-2.1 After the A900 has been located and installed, the wiring

connections can be made. This work should be done with all

electrical power disconnected from the engine. BE SURE THAT

THE BATTERY IS DISCONNECTED.

4-2.2 All electrical installation work should be done in

accordance with the National Electrical Code, NFPA-70, and all

applicable local codes.

4-2.3 In general, the following connections will be made:

(a) Battery positive and negative. An 8 A fuse or circuit

breaker must be provided to protect powered relay contact

circuits.

4-1/2 in.

(114 mm)

Figure 3-7.2

3-7.2.1 Fuel Relay; this relay provides two outputs, one to

energize the engine fuel solenoid and a separate circuit to

energize the battery charging alternator field.

(b) Engine run device, such as a fuel shutoff solenoid.

tachometer output of a battery charging alternator.

3-7.2.2 Shutdown Relay; this relay is operated by the shutdown

circuits of the Control / Display Module and provides an output

that can be used to trip the generator circuit breaker on an

emergency shutdown.

3-7.2.3 Overspeed Relay; operates only on an Overspeed

shutdown. This relay provides an output to trip an air shut off

solenoid to close the air damper on a two-cycle engine.

3-7.2.4 Local Audible Alarm Relay; provides a contact closure

to operate a local audible alarm as required by NFPA- 110, Level

1 and Level 2.

(d) Auxiliary crank disconnect device, such as a voltage

sensing relay contact wired to the generator output.

(e) Engine starter circuit; an auxiliary starter solenoid is

required to handle most starter solenoid requirements.

(f) Remote start contact. This is normally from the automatic

transfer switch but other sources are possible.

(g) Alarm and shutdown sensing switches as required.

4-2.3.1 The complete wiring of a Model A901 control is shown

in figure 4-2.3.1. Provision is made in the A900 series to

operate remote lights for all of the alarm and shutdown circuits

however these circuits do not have to be wired for the A900 to

function. Alarm input switches are not required but the alarm

circuits will not work without them.

3-7.3 Status Signals. The relay module also includes three

outputs that can be used with external circuits for signaling or

control functions.

3-7.3.1 The Control On function at terminal 12 is on (closed to

negative) as long as the Mode Selector Switch is in either Auto

or Test. When the Mode Selector is turned Off, the Control On

signal is open. This can be used to signal switch position or to

reset an external circuit when the Mode Selector is turned Off.

3-7.3.2 The System Ready signal at terminal 13 is on (closed

to negative) as long as the Mode Selector Switch is in either

Auto or Test and no shutdown TATTLETALE^®circuit is

latched on. This can be used to signal that the generator

engine is ready to automatically start or is running in Test.

3-7.3.3 The Control On function at terminal 14 is on (closed to

positive) as long as the Mode Selector Switch is in either Auto

or Test. When the Mode Selector is turned Off, the Control On

signal is open. This can be used to signal switch position or to

reset an external circuit when the Mode Selector is turned Off.

4-2.3.2 Figure 4-2.3.2 is for wiring of the A902 control. The

same provisions as for the A901 are made.

4-2.3.3 The A903 wiring is shown in figure 4-2.3.3.

4-2.3.4 Wire Termination; the terminal blocks that are supplied

requires that all wires be terminated with #6 stud size forked

spade solderless wire connectors or stripped and inserted under

the captive terminal plates. Torque all terminal screws to 12

inch pound maximum.

4-2.3.5 All inductive loads (relays-soleniods-coils-etc.) that are

connected to the A900 must have reverse diodes wired across

the coil to supress reverse voltage that is generated whenever the

inductive load is de-energized. This will protect the electronic

components in the A900 and should prevent operating

malfunction due to noise. The “rule of thumb” for sizing the

reverse diode is to use one with a PIV (Peak Inverse Voltage)

rating equal to the operating voltage, or at least 100 volts and a

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Figure 4-1.2.5: Mounting Dimensions

6 in.

(152 mm)

3 in.

(76 mm)

2-13/16 in.

(71 mm)

A900 Series

Module

5-5/8 in.

(143 mm)

1-1/2 in.

(38 mm)

clearance

Mounting

Holes

1/8 in.

(3 mm)

diameter

6-3/4 in.

(171 mm)

9-3/8 in.

(238 mm)

3-3/8 in.

(86 mm)

4-15/32 in.

(114 mm)

5 in. (127 mm) maximum

between A-900 Series module

& relay module when mounting

Relay Module

3/16 in.

(5 mm) dia.

4 places

5-1/2 in.

(140 mm)

3-3/4 in.

(95 mm)

1-7/8 in. (48 mm)

clearance

1-7/8 in. (48 mm)

clearance

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Figure 4-2.3.1: A901 wiring

Hourmeter

Voltmeter

B+

Input

Output

Barrier

Terminal

Blocks

Barrier

Terminal

Blocks

AUTO START

MODULE

15 B+ OUT

ALARM SILENCE 35

AUDIBLE ALARM

HOURMETER

B-

OVERCRANK 37

Remove jumper from

4 and 27 to use

manual start switch

MANUAL START

OVERSPEED

28 START

PICKUP

OIL PRESSURE 39

HI WATER TEMP. 40

REMOTE SHUTDOWN 41

SPARE SHUTDOWN 42

LOSS OF SPEED 43

29 PICKUP

30 OIL PRESSURE

31 LO WATER TEMP.

32 HI WATER TEMP.

33 REMOTE S.D.

34 SPARE ALARM

LO WATER TEMP. 44

SPARE ALARM 45

SWITCH NOT IN AUTO 46

LOW FUEL LEVEL

HIGH BATTERY VOLTAGE

LOW BATTERY VOLTAGE

LOW OIL PRESSURE PREALARM

HI WATER TEMP. PREALARM

BATTERY CHARGER AC FAILURE

LEVEL 1 ALARM

Optional

Air damper closed

on a 2-cycle engine

Battery

NOTE 2

Auxiliary Starter

Solenoid

Red

Blk

Starter

+ -

J1 A B C D E F G H I J K L M N J2

Circuit

Breaker

NOTE 2

100K

MDQ3

B+

B-

3A Fuse

Auxiliary crank

disconnect

relay

Energize to Stop solenoid

Energize to Run solenoid

NOTE 2

Local

Fuel

Relay

Audible

Crank relay

Alarm

Alternator Excitor

Optional Run relay and Remote signal

Local audible alarm

J1G

Alternator

Breaker Shunt trip coil

Fuel Pressure Switch

Shut

Down

Relay

Remote

Audible

Alarm

NOTE 1

NOTE 2

Power supply

Spare shutdown

Remote audible alarm

Control on sink 200 mA MAX

System ready sink 200 mA MAX

Çontrol on source 200 mA MAX

Power supply

Over

Speed

Relay

Remote

Visual

Alarm

To Battery +

Remote visual alarm

Air Damper

Solenoid

Power supply

NOTE 1: Fuel Pressure Switch and Air Damper Solenoid

are used on a 2-cycle engine

NOTE 2: Place Reverse Bias Diodes across inductive loads.

Drawing Revision C

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Figure 4-2.3.2: A902 wiring

Hourmeter

Voltmeter

B+

Input

Output

Barrier

Terminal

Blocks

Barrier

Terminal

Blocks

AUTO START

MODULE

15 B+ OUT

ALARM SILENCE 35

AUDIBLE ALARM

HOURMETER

OVERCRANK 37

B-

Remove jumper from

4 and 27 to use

manual start switch

MANUAL START

OVERSPEED

28 START

PICKUP

OIL PRESSURE 39

HI WATER TEMP. 40

REMOTE SHUTDOWN 41

SPARE SHUTDOWN 42

LOSS OF SPEED 43

29 PICKUP

30 OIL PRESSURE

31 LO WATER TEMP.

32 HI WATER TEMP.

33 REMOTE S.D.

34 SPARE ALARM

LO WATER TEMP. 44

SPARE ALARM 45

Optional

LEVEL 2 ALARM

Air damper closed

on a 2-cycle engine

Battery

NOTE 2

Auxiliary Starter

Solenoid

Red

Blk

Starter

+ -

J1 A B C D E F G H I J K L M N J2

Circuit

Breaker

NOTE 2

100K

MDQ3

B+

B-

3A Fuse

Auxiliary crank

disconnect

relay

Energize to Stop solenoid

Energize to Run solenoid

NOTE 2

Local

Fuel

Relay

Audible

Crank relay

Alarm

Alternator Excitor

Optional Run relay and Remote signal

Local audible alarm

J1G

Alternator

Breaker Shunt trip coil

Fuel Pressure Switch

Shut

Down

Relay

Remote

Audible

Alarm

NOTE 1

NOTE 2

Power supply

Spare shutdown

Remote audible alarm

Control on sink 200 mA MAX

System ready sink 200 mA MAX

Çontrol on source 200 mA MAX

Power supply

Over

Speed

Relay

Remote

Visual

Alarm

To Battery +

Remote visual alarm

Air Damper

Solenoid

Power supply

NOTE 1: Fuel Pressure Switch and Air Damper Solenoid

are used on a 2-cycle engine

NOTE 2: Place Reverse Bias Diodes across inductive loads.

Drawing Revision C

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Figure 4-2.3.3: A903 wiring

Hourmeter

Voltmeter

B+

Input

Output

Barrier

Terminal

Blocks

Barrier

Terminal

Blocks

AUTO START

MODULE

15 B+ OUT

ALARM SILENCE 35

AUDIBLE ALARM

HOURMETER

B-

OVERCRANK 37

Remove jumper from

4 and 27 to use

manual start switch

MANUAL START

OVERSPEED

28 START

PICKUP

OIL PRESSURE 39

HI WATER TEMP. 40

REMOTE SHUTDOWN 41

SPARE SHUTDOWN 42

LOSS OF SPEED 43

29 PICKUP

30 OIL PRESSURE

31 LO WATER TEMP.

32 HI WATER TEMP.

33 REMOTE S.D.

34 SPARE ALARM

LO WATER TEMP. 44

SPARE ALARM 45

SWITCH NOT IN AUTO 46

SPARE

LEVEL 2 ALARM

Optional

Air damper closed

on a 2-cycle engine

NOTE 2

Battery

Auxiliary Starter

Solenoid

Red

Blk

Starter

+ -

J1 A B C D E F G H I J K L M N J2

Circuit

Breaker

NOTE 2

100K

MDQ3

B+

B-

3A Fuse

Auxiliary crank

disconnect

relay

Energize to Stop solenoid

Energize to Run solenoid

Local

Fuel

Relay

Audible

Crank relay

Alarm

Alternator Excitor

Optional Run relay and Remote signal

Local audible alarm

J1G

NOTE 2

Alternator

Breaker Shunt trip coil

Fuel Pressure Switch

Shut

Down

Relay

Remote

Audible

Alarm

NOTE 1

NOTE 2

Power supply

Spare shutdown

Remote audible alarm

Control on sink 200 mA MAX

System ready sink 200 mA MAX

Çontrol on source 200 mA MAX

Power supply

Over

Speed

Relay

Remote

Visual

Alarm

To Battery +

Remote visual alarm

Air Damper

Solenoid

Power supply

NOTE 1: Fuel Pressure Switch and Air Damper Solenoid

are used on a 2-cycle engine

NOTE 2: Place Reverse Bias Diodes across inductive loads.

Drawing Revision C

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current rating that is equal to or greater than the forward current determine if the frequency of the speed switches must be

that the coil draws to operate. For example, a relay less than 1 A, changed, calculate the required setting using the following

use a 1 A diode since they are readily available. The wiring formulas:

shown in Figures 4-2.3.1, 4-2.3.2 and 4-2.3.3 have examples of

the places that a reverse diode is required.

No. of Gear Teeth x RPM set points

Set point

frequency in HZ

4-3 Crank Disconnect.

4-3.1 A magnetic pickup is recommended to supply the speed

signal for the A900 series primary crank termination circuit and

for the overspeed switch. This pickup will be mounted in the

flywheel housing in line with the ring gear on the flywheel and

wired to the A900 using either a twisted pair or a shielded cable

to reduce the possibility of electrical noise pickup in the wiring.

4-3.1.1 The tachometer terminal, of the battery charging

alternator, may be used for the speed signal but a broken drive

belt will disable this source and some alternators have electrical

noise which will cause the speed switches to operate at speeds

well below the desired RPM.

4-3.2 An auxiliary crank disconnect circuit, required by

NFPA-110, is provided in the A900. Any signal that detects

when the engine is running and provides a contact closure

between Terminals 4 and 16 can be used. This circuit

terminates cranking even if the speed signal fails. The “Loss

Of Speed” shutdown / alarm on the A900 will indicate if the

speed signal is lost while the engine is running by either

shutdown of the engine or operation of the alarm circuit.

“Loss Of Speed” alarm will only operate if the auxiliary crank

disconnect circuit is used. Provision is also made for a second

N.C. contact between Terminals 17 and 18 to interrupt the

output to the auxiliary starter solenoid. This would disconnect

cranking even if both crank disconnect circuits in the A900

should fail. If this contact is not provided, you must jumper

Terminals 17 and 18 for the start signal to reach the auxiliary

starter solenoid. A voltage sensing relay wired to one output

phase of the generator is one way to provide both of these

contacts.

Pulley ratio x No. of Alternator Poles x RPM set points

Set point

frequency in HZ

Refer to Table 4-4.1 to determine if the speed switch settings are

below the factory settings listed. If required frequency will be

higher than the standard, increase the setting before proceeding.

Turn The Crank Disconnect Set and Overspeed Set pots

clockwise to increase setting. The adjustments are 20 turn

controls without stops at either end.

4-4.1.1 Be sure to have a fully charged battery to do these tests.

Low battery voltage can cause improper results during the tests.

4-4.1.2 The “Air Damper Closed” alarm on A900 series for 2

cycle engines can be actuated by either an internal circuit that

senses the output to the overspeed relay, from the “Overspeed”

shutdown circuit or by an external switch wired to terminal 34

of the Control / Display Module. The “Air Damper Closed”

switch, Table 4-4.1 must be turned On for internal sensing and

Off for external switch. This circuit is a Spare alarm on A900

for 4 cycle engines and the switch must be turned Off to

prevent this circuit from operating with the “Overspeed”

shutdown.

4-4.1.3 All of the adjustments and controls shown in Table 4-4.1

are located on the rear of the control/display module. See Figure

4-4.1.3. Each light and switch is labeled for ease of

identification. The LED's are supplied as an aid in installation

and troubleshooting of the A900.

4-4.2 Crank Disconnect Speed Setting; to set this speed switch,

proceed as follows:

(a) Disconnect the run solenoid wire from terminal 6 on the

Relay Module.

4-4 Pre-operational Check-out.

(b) Check engine to be sure it is safe to crank.

4-4.1 After installation is complete, it is necessary to make

some adjustments to the A900 SELECTRONIC^®Control before

the system is operational. All shutdown and alarm circuits also

should be tested. Table 4-4.1 lists the standard factory setting of

the adjustable functions on the A900 series control. To

(d) Connect battery cables to a fully charged cranking battery.

(e) Turn Mode Selector switch to TEST position and watch

the lights on the A900 control module back panel.

1. The engine should start cranking and the “Fuel Relay”,

“Crank Relay”, and “Pickup Present” lights turn on.

2. If engine does not crank, check the lights. If green

light next to Mode Selector Switch on front panel is

not on, check the DC power input wiring and fuse.

3. If green light, “Fuel Relay” and “Crank Relay” lights

are on, check wiring from A900 Terminal 18 to

auxiliary start solenoid and than on to the starter on

engine.

Table 4-4.1

Standard

Setting

Adjustment

Range

Adjustment

Type

Function

Crank/Rest

Time

seconds

10, 15, 20, 25

and 30 Seconds

Switch

1, 2, 3, 4, 5, 6 and

No overcrank

Overcrank

3 cranks

1180 Hz

Crank

Disconnect

Turn CW

to increase

25 to 2 KHz

300 to 10 KHz

Fixed 5 minute

4. With engine cranking, check “Pickup Present” light. It

must be on. If off, check the wiring to magnetic

pickup and check gap between pickup face and ring

gear.

5. If “Crank Disconnect Speed” light comes on and

cranking stops, setting of Crank Disconnect Switch is

still to low. Turn Mode Selector switch OFF and turn

crank disconnect adjustment clockwise 1 or 2 turns

and repeat test.

Turn CW

to increase

3894 Hz

Overspeed

Cooldown

ON-OFF switch

Switch

OFF

Loss of speed

Signal

Shutdown or

Alarm

Shutdown

ON with

Overspeed

shutdown

Internal switch ON

External switch OFF

Air Damper Closed

Alarm on 2 Cycle

Engines only

Switch

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adjusted for proper running speed, turn Mode Selector

switch OFF. This gives the A900 Controller a stop signal.

(e) All lights on the back of the A900 should go off and the

engine stop. If engine does not stop, check run solenoid

to be sure it has returned to the stop position.

4-4.4 Automatic Start and Stop; to test the automatic-start and

stop function, proceed as follows:

(a) Turn Mode Selector switch to the AUTO position. Short

terminal 28 to 4 on the Control / Display module. This

gives the A900 Controller a start signal.

(b) Engine will crank, start and come up to governor speed.

between terminal 28 and 4. This gives the A900

Controller a stop signal.

(d) All lights on the back of the A900 should go off and the

engine stop.

4-4.5 Overspeed Switch Setting; To set the speed switch,

proceed as follows:

(a) Turn Mode Selector switch to the TEST position.

(b) Engine will crank, start and come up to governor speed.

to normal RPM.

(d) Depress and hold the Overspeed Test pushbutton.

(e) Slowly turn the Overspeed Set adjustment counter-

clockwise until the “Overspeed” and “Overspeed Relay”

lights on the A900 come on and the engine shuts down.

(f) Release pushbutton; check “Overspeed” light on front

panel to be sure it is on.

Figure 4-4.1.3

Fuel Relay

Torque

Scews to

12 In./lb.

Scews to

12 In./lb.

Crank Relay

SW1 = 1

SW2 = 2

SW3 = 3

SW4 = 4

SW5 = 5

SW6

Crank/Rest

Time

Number

of Cranks

SW1 = 10 s.

SW2 = 15 s.

SW3 = 20 s.

SW4 = 25 s.

SW5 = 30 s.

SW7 = None

Unused

Switch

SW6

Close Only One Switch

Crank

Pickup

Present

Disconnect Disconnect

Set

Speed

Overspeed Overspeed Overspeed Overspeed

Test Set Relay

Shutdown

Relay

Local Audible Alarm

Relay

Remote Visual Alarm

Relay

(g) Turn Mode Selector switch OFF to reset shutdown circuits;

then back to TEST.

(h) When engine starts, increase governor speed setting slowly

until engine shuts down on overspeed. This should occur

about 10% above governor speed.

(i) Turn Mode Selector switch OFF.

4-4.6 Overcrank setting; to test number of cranks before system

shuts down on overcrank;

(a) Disconnect the run solenoid wire from terminal 6 of the

Relay Module.

(b) Check number set on the “Number Of Cranks” switch on

A900 back panel. It is factory set at 3.

Remote Audible Alarm

Relay

Miscellaneous Program Switches

5 min. Cooldown

SW1 = Open

Unused Switches

Air Damper Closed

Light ON With

Overspeed Shutdown

SW7= Closed

SW2

Alarm

Shutdown

SW3 = Closed

SW4 = Open

SW5 = Open

SW6 = Closed

SW3 = Open

SW4 = Closed

SW5 = Closed

SW6 = Open

Loss of Speed Circuit

6. While engine is cranking, turn crank disconnect

adjustment counter clockwise slowly until “Crank

Disconnect Speed” light turns on and cranking stops.

7. Turn crank disconnect adjustment clockwise 1/4 turn.

This sets crank disconnect speed at approximately 125

RPM above cranking speed.

1. Engine will crank for 15 seconds.

2. Then rest for 15 seconds

3. This should repeat 3 times and then the “Overcrank”

light on the A900 will come on and engine will not

crank again.

8. Turn Mode Selector switch OFF.

(d) Turn Mode Selector switch OFF.

(e) Reconnect the run solenoid wire at terminal 6 of the Relay

Module.

4-4.7 Oil Pressure; to test oil pressure shutdown circuit:

(a) Turn Mode Selector switch to TEST. When engine starts,

wait 30 seconds then,

(b) Use a jumper wire and short from terminal 30 to 4.

(d) Turn Mode Selector switch OFF.

4-4.8 Water Temperature; to test the water temperature

shutdown circuit:

(a) Turn Mode Selector switch to TEST. When engine starts,

wait 30 seconds then,

(f) Reconnect the run solenoid wire at terminal 6 on Relay

Module.

4-4.3 Start and Stop Engine; to test the start and stop function,

proceed as follows:

(a) Double check all wiring to be sure it is connected.

(b) Turn Mode Selector switch to the TEST position. This

gives the A900 Controller a start signal.

1. Check “Crank Disconnect Speed” light; it should be on

and “Crank Relay” light should be off.

2. If lights are not correct, turn Mode Selector switch

OFF and review paragraph 4-4.2.

(d) When engine has come up to speed and governor has been

(b) Use a jumper wire and short from terminal 32 to 4.

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stop.

5-2.3.2 When the start signal is removed, the engine will stop.

It is now ready to restart.

(d) Turn Mode Selector switch OFF.

4-4.9 Low Water Temperature; to test the low water temperature 5-2.4 OFF or Not Operating; to prevent operation of the engine,

alarm circuit:

turn selector switch OFF.

(a) Engine does not have to be running.

(b) Use a jumper wire and short from terminal 31 to 4.

as the jumper maintains the circuit.

4-4.10 Other Alarm and/or Shutdowns; all other alarms and

shutdowns would be tested in the same manner.

(a) For shutdown circuits, the engine must be running for test.

(b) Most alarm only circuits can be tested without starting the

engine. Low Oil Pressure Pre-alarm and High Water

Temperature Pre-alarm are exceptions.

used to short out the switch contacts at the switch or if this

is not possible, the test can be run by shorting the input

terminal for that circuit, to ground, terminal 4.

(d) To test Low Oil Pressure Pre-alarm;

Section 6: Routine Maintenance

and Operational Tests

6-1 Routine Maintenance.

6-1.1 Due to the design and types of components used, very

little maintenance is required to the A900 Control.

6-1.2 Visual inspection of the internal wiring of the control

panel, along with checking wire connections for tightness,

should be done on a semiannual schedule for stand-by systems

or quarterly for prime power. Check wire bundles for chafing

and wear to the insulation of the wires where they contact the

panel or engine.

6-1.4 Shutdown and Alarm Circuits should be tested on a

monthly basis for prime power and quarterly for stand-by sets.

The same tests run during pre-operation check out, Section 4-4,

should be included.

1. Turn Mode Selector switch to TEST. When engine

starts, wait 30 seconds then,

2. Use a jumper wire and short from terminal 50 to 4;

“Low Oil Pressure Pre-alarm” light will come on as

long as the jumper maintains the circuit.

6-2 Operational Tests.

6-2.1 No special operational tests are required. The routine

operational tests for the generator set will exercise the control.

(e) To test High Water Temperature Pre-alarm;

1. Turn Mode Selector switch to TEST. When engine

starts, wait 30 seconds then,

Section 7: Troubleshooting and Repair

7-1 Tools Required.

7-1.1 Some of the tools necessary for troubleshooting are built

into the A900 Series controls.

2. Use a jumper wire and short from terminal 51 to 4;

“High Water Temperature Pre-alarm” light will come

on as long as the jumper maintains the circuit.

7-1.1.1 By observing the lights on the front and rear of the control

panel, clues to a problem and the possible source can be seen.

7-1.1.2 Operational problems with the automatic engine control

will show up by looking at the input and output lights on the rear

of the A900 SELECTRONIC^®Control / Display Module.

7-1.2 Other tools which may be required are:

7-1.2.l AC/DC Voltmeter for taking voltage readings and an

Ohmmeter for testing resistance of wires and connections.

7-1.2.2 Jumper wires with alligator clips to bypass or simulate

circuit closures.

Section 5: Operation

5-1 Operator Controls.

5-1.1 Mode Selector Switch; allows the operator to select either

manual (TEST), automatic operation (AUTO), or no operation

(OFF).

5-1.2 The OFF position on the mode selector also provides a

reset function for the shutdown circuits. If the engine is shut

down by the automatic control, the operator must turn selector

off and back on to reactivate the system.

5-1.3 Push to Test Lamps; this pushbutton tests the alarm and

shutdown indicator lights.

5-1.4 Alarm Silence Pushbutton; if so equipped, silences the

local and remote audible alarm. Visual indicator remains on

until reset or sensor switch contacts clear.

DO NOT USE THESE JUMPER WIRES TO CHECK IF

VOLTAGE IS PRESENT AT A TERMINAL BY DRAWING

AN ARC TO GROUND. THIS WILL DAMAGE OR

DESTROY EQUIPMENT IN THE A900 CONTROL PANEL.

7-2 A900 SELECTRONIC Control Operation And

Shutdown.

7-2.1 The first step in troubleshooting any equipment is to

understand its normal operation. Table 7-2.1 contains normal

voltage readings taken at the terminals of the A901 with all

equipment shown on the standard drawing, connected.

(a) All voltage readings are DC, except at terminal 29, and

were taken with the negative lead of the meter connected

to ground at terminal 4. Voltage reading at terminal 29

was taken with negative lead grounded and the meter on

AC scale.

(b) The battery voltage, at the time readings were recorded,

was 13.8 V and 27.6 V. All readings will vary depending

on battery voltage, equipment supplied in the panel and

external devices connected to the A900 control. See notes

5-2 Operating Modes.

5-2.1 The A900 Generator Engine Control has two operating

modes: manual and automatic.

5-2.2 Manual Operation is provided for testing of the generator

set.

5-2.2.1 To initiate Manual Control, place the Mode Selector

switch in the TEST position. This provides the automatic

control a start signal.

5-2.2.2 To stop, turn selector switch to OFF. This removes start

signal and the engine will stop.

5-2.3 Automatic operation is the normal mode.

5-2.3.1 To initiate Automatic Control, place the Mode Selector

switch in the AUTOMATIC position. When a start signal is

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Table 7-2.1

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to the table for examples.

(b) Shutdown relay K-2 is energized, closing its contacts at

terminal 9. These contacts can be wired to a shunt trip

solenoid in the generator circuit breaker if required.

the run solenoid, terminal 6, and from the alternator

exciter, terminal 8. The circuits at terminal 5 and 7 will

close to reconnect the battery positive to these terminals.

(d) The run signal, terminal 19 turns off.

of the electronic components in the A900. Minor

variations, 1 or 2 volts, normally will have no effect on the

A900 operation.

(d) The AC voltage at terminal 29 must be a minimum of 2

VAC to drive the speed sensing circuits of the A900.

7-2.2 With power applied and the Mode Selector switch in

AUTO, the following occurs when a switch is closed from

terminal 28 to ground.

(e) If the shutdown is due to overspeed, the overspeed relay

operates and applies battery positive to terminal 10 to

close an air shutoff solenoid if the engine is so equipped.

7-2.2.1 The fuel relay is energized, which opens the circuits at

terminal 5 and 7, and closes the circuits at terminal 6 and 8. This 7-2.3.5 If the engine is shutdown by the remote stop circuit, no

applies battery power to the run solenoid and to the exciter TATTLETALE^®light is provided. Otherwise a TATTLETALE^®

terminal of the alternator.

light will show the cause of shutdown.

7-2.2.2 At the same time, the crank relay driver provides battery 7-2.3.6 In the A900, the Loss of Speed signal TATTLETALE^®

voltage at terminal 17, thru the auxiliary crank disconnect relay can be either a shutdown or an alarm. It is connected to a circuit

contact to the auxiliary starter solenoid. This output is controlled that monitors the magnetic pickup input at terminal 29. If the

by the crank and rest timer but it can be overridden by the crank input from the pickup fails, drops below the minimum voltage,

disconnect speed switch and / or the auxiliary crank disconnect or is disconnected while the engine is running, the Loss of Speed

circuit. The output will remain on until the crank time expires or Signal TATTLETALE^®circuit will activate and shutdown the

the crank disconnect circuits detect that the engine has started.

engine or operate the alarm circuit. It is recommended that the

7-2.2.3 If the engine does not start during the crank time, the shutdown circuit is used since this prevents the generator set

rest timer will prevent cranking until it has timed out. After the from running without overspeed protection. If this circuit is

rest time, the engine will begin cranking again. This sequence used as an alarm, the auxiliary crank disconnect input MUST be

will repeat until the engine starts or the overcrank shutdown supplied to prevent malfunction of the shutdown circuits.

circuit trips.

7-2.3.7 To reset the circuits, the Mode Selector switch must be

7-2.2.4 Engine speed is detected by an AC signal from a turned OFF and back on to either the AUTO or TEST position.

magnetic pickup wired to terminal 29. When this frequency 7-2.4 Normally, the engine will run until the start signal is

exceeds the setting of the crank disconnect speed switch,

(a) Cranking is terminated.

removed from terminal 28.

7-2.4.1 When the signal is removed, the following occurs to

(b) A time delay starts timing during which the oil pressure stop the engine;

and water temperature shutdown circuits are locked out.

(a) The fuel relay drops out, removing battery voltage from

the run solenoid, terminal 6, and from the alternator

exciter, terminal 8. The circuits at terminal 5 and 7 will

close to reconnect the battery positive to these terminals.

(b) The run signal, terminal 19 turns off.

locked out as soon as the fuel relay drops out. This

prevents any TATTLETALE^®from tripping while the

engine coasts to a stop.

(d) The overspeed shutdown circuit is activated.

7-2.2.5 An engine run signal closes to ground at terminal 19

when the engine starts.

7-2.3 With the engine running, the six shutdown TATTLETALE^®

circuits are activated and will operate anytime a switch closes

from ground to their inputs.

Circuit

Input

Output

(a) Remote Stop

(b) Oil Pressure

(d) Overspeed

(e) Loss of Speed Signal

(f) Spare Shutdown

Terminal 33

Terminal 30

Terminal 32

Int. Speed Switch

Int. Circuit

Terminal 41

Terminal 39

Terminal 40

Terminal 38

Terminal 43

Terminal 42

7-3 A900 SELECTRONIC^®Control Alarm Circuit

Operation.

7-3.1 The A900 alarm circuits perform the following functions;

(a) Turns on individual alarm lights based on input switch

closures.

Terminal 11

(b) Provides lamp test function for all alarm and shutdown lights.

remote visual alarm relay, K-6, or the local audible alarm

relay, K-4, the remote audible alarm relay, K-5, and the

remote visual alarm relay, K-6, depending on the

requirements of NFPA-110 1988 paragraph 3-5.5.1 (d).

(d) Provides the audible alarm silence circuit.

7-3.2 A contact closure to ground, at the alarm circuit

input terminal, will cause the associated TATTLETALE^®light to

turn on and an output transistor to close to ground and turn on a

remote indicating light.

7-2.3.1 Each circuit has a indicating light and a transistor output that

closes to ground to operate an individual remote indicating light.

7-2.3.2 When any of the six shutdown functions trip, the

shutdown relay K-2, pulls in and applies battery power to

terminal 9. At the same time, the fuel relay, K-1 drops out and if

the shutdown was due to overspeed, the overspeed relay, K-3

pulls in to signal an air shut off solenoid, terminal 10 to close.

7-2.3.3 The six shutdown circuits, paragraph 7-2.3, are first out

latching type TATTLETALE^®. That is, only one of the six may

trip at one time and it must be reset before the A900 will operate

again.

7-3.2.1 The alarm circuits also operate the three relays for local

audible alarm, remote audible alarm and remote visual alarm as

required by NFPA-110. The normally open dry relay contacts,

7-2.3.4 If one of the TATTLETALE^®circuits trip, the following

occurs to shutdown the engine and generator.

(a) The TATTLETALE^®light for that function turns on.

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local audible (K-4) terminal 20 and 21, remote audible (K-5) Module, a Relay Module and a number of Relays.

terminal 22 and 23 and remote visual (K- 6) terminal 24 and 25 8-1.2 There are no field replacement parts in the Control/Display

close to operate the alarm devices wired to them.

Module. The complete module must be replaced if it fails. All

7-3.3 An alarm silence pushbutton is wired between terminal 35 relays are individually replaceable in the Relay Module but the

and ground. This switch is provided on the A901 and can be module must be replaced if a failure of the circuit board occurs.

externally connected on the A902 series. When this switch is 8-2 Table 8-2 displays replaceable components for the A900 series

closed, the audible alarm relays K-4 and K-5 will drop out if they controls manufactured for Detroit Diesel Corporation.

are closed. This turns off the audible alarms but does not affect the These components have Murphy part numbers. In addition, they

individual alarm lights on the panel. The lights will remain on are OEM parts and are available only to Detroit Diesel and their

until the input switches open. If no alarm silence switch is distributors.

provided, the alarm relays will reset when the alarm and / or 8-2.1 The A900-DDC parts are the same as the Murphy A900

shutdown lights reset.

series that has been covered throughout the A900 manual except

the “Spare Shutdown” circuit is labeled “Low Water Level” and

the DDC logo is printed on the face plate.

Section 8: Service Parts

8-1 Table 8-1 covers all of the replaceable components of the

A900 Series Generator Engine Controls. The part numbers that are

shown are Frank W. Murphy Mfr. numbers, and may not appear on

the individual parts.

8-1.1 Each complete control is made up of a Control/Display

Table 8-1: Replacement Components for A900 Series Generator Engine Controls

Model Number

Part Number

40-02-0132

40-02-0137

40-02-0134

40-02-0140

40-02-0133

40-02-0145

40-02-0135

40-02-0148

40-02-0151

40-02-0152

40-02-0155

40-02-0156

Control/Display Module

40-00-0077

40-00-0078

40-00-0079

40-00-0080

40-00-0081

40-00-0082

Relay Module

40-00-0064

Relay Part Number

00-00-2952

00-00-2953

00-00-2952

00-00-2953

00-00-2952

00-00-2953

00-00-2952

00-00-2953

00-00-2952

00-00-2953

00-00-2952

00-00-2953

Relay Qty

A901-12

A901-24

A901-2-12

A901-2-24

A902-12

A902-24

A902-2-12

A902-2-24

A903-12

A903-24

A903-2-12

A903-2-24

Table 8-2: Replacement Components for A900 Series Controls for Detroit Diesel Corporation

Model Number

Part Number

Control/Display Module

Relay Module

Relay Part Number

Relay Qty

A901-12-DDC

A901-2-24-DDC

A902-12-DDC

A902-2-24-DDC

A903-12-DDC

40-35-0020

40-35-0029

40-35-0022

40-35-0037

40-35-0024

40-00-0083

40-00-0084

40-00-0085

40-00-0086

40-00-0087

40-00-0064

00-00-2952

00-00-2953

00-00-2952

00-00-2953

00-00-2952

A903-2-24-DDC

40-35-0043

40-00-0088

40-00-0064

00-00-2953

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In order to consistently bring you the highest quality, full featured products, we reserve the right to change our specifications and designs at any time.

CONTROL SYSTEMS & SERVICES DIVISION

P.O. Box 1819; Rosenberg, Texas 77471; USA

(281) 342-0297 fax (281) 341-6006

e-mail [email protected]

FRANK W. MURPHY, LTD.

MURPHY SWITCH OF CALIFORNIA

41343 12th Street West

Palmdale, California 93551-1442; USA

(661) 272-4700 fax (661) 947-7570

e-mail [email protected]

www.murphyswitch.com

Church Rd.; Laverstock, Salisbury SP1 1QZ; U.K.

+44 1722 410055 fax +44 1722 410088

e-mail [email protected]

FWMurphy

P.O. Box 470248

Tulsa, Oklahoma 74147 USA

(918) 627-3550

fax (918) 664-6146

e-mail [email protected]

www.fwmurphy.com

www.fwmurphy.co.uk

MURPHY DE MEXICO, S.A. DE C.V.

Blvd. Antonio Rocha Cordero 300, Fracción del Aguaje

San Luis Potosí, S.L.P.; México 78384

+52-48-206264 fax +52-48-206336

e-mail [email protected]

For Service in French:

Pour service en francais:

+44 1722 410697 fax +44 1722 410088

e-mail [email protected]

www.fwmurphy.co.uk/francais.htm

MACQUARRIE CORPORATION

1620 Hume Highway;

Campbellfield, Vic 3061; Australia

+61 3 9358-5555 fax +61 3 9358-5558

e-mail [email protected]

Printed in U.S.A.

0690040

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