PI Manufacturing Portable Generator AC generators User Manual

Installation, Service & Maintenance

Manual

AC generators with the following for prefixes:

UCI; UCM; UCD 224 & 274 .

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ELECTROMAGNETIC COMPATIBILITY

Additional Information

FOREWORD

The function of this book is to provide the user of the

Stamford generator with an understanding of the

principles of operation, the criteria for which the generator

has been designed, and the installation and maintenance

procedures. Specific areas where the lack of care or use

of incorrect procedures could lead to equipment damage

and/or personal injury are highlighted, with WARNING

and/or CAUTION notes, and it is important that the

contents of this book are read and understood before

proceeding to fit or use the generator.

European Union

Council Directive 89/336/EEC

For installations within the European Union, electrical

products must meet the requirements of the above

directive, and STAMFORD ac generators are supplied on

the basis that:

•

They are to be used for power-generation or related

function.

STAMFORD Service, Sales and Technical staff of are

always ready to assist and reference to the company for

advice is welcomed.

They are to be applied in one of the following

environments:

Incorrect

installation,

operation,

Portable (open construction - temporary site supply)

servicing or replacement of parts can

result in severe personal injury or

death, and/or equipment damage.

Service personnel must be qualified

to perform electrical and mechanical

service.

Portable (enclosed

temporary site supply)

Containerised (temporary or permanent site supply)

Ship-borne below decks (marine auxiliary power)

Commercial vehicle (road transport / refrigeration

etc) Rail transport (auxiliary power)

Industrial vehicle (earthmoving, cranes etc)

Fixed installation (industrial - factory / process plant)

Fixed installation (residential, commercial and light

industrial - home / office / health)

Warning !

EC DECLARATION OF INCORPORATION

All Stamford generators are supplied with a declaration of

incorporation for the relevant EC legislation, typically in

the form of a label as below.

Energy management (Combined heat and power

and/or peak lopping)

Alternative energy schemes^.

•

The standard generators are designed to meet the

‘industrial’ emissions and immunity standards.

Where the generator is required to meet the

residential, commercial and light industrial emissions

and immunity standards reference should be made

to document reference N4/X/011, as additional

equipment may be required.

•

The installation earthing scheme involves connection

of the generator frame to the site protective earth

conductor using a minimum practical lead length.

Maintenance and servicing with anything other than

factory supplied genuine STAMFORD parts will

invalidate warranty and our liability for EMC

compliance.

•

Installation, maintenance and servicing is carried out

by adequately trained personnel fully aware of the

requirements of the relevant EC directives

Under the EC Machinery Directive section 1.7.4. It is the

responsibility of the generator set builder to ensure the

generator identity is clearly displayed on the front cover

of this book.

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CONTENTS

SAFETY PRECAUTIONS

FOREWORD

CONTENTS

SECTION 1

2&3

INTRODUCTION

1.1

1.2

1.3

INTRODUCTION

DESIGNATION

SERIAL NUMBER LOCATION

AND IDENTITY NUMBER LOCATION

RATING PLATE AND CE MARKING

PRINCIPLE OF OPERATION

SELF-EXCITED AVR CONTROLLED GENERATORS

PERMANENT MAGNET GENERATOR (PMG) EXCITED -

AVR CONTROLLED GENERATORS

AVR ACCESSORIES

TRANSFORMER CONTROLLED GENERATORS

APPLICATION OF THE GENERATOR

INSTALLATION - PART 1

LIFTING

1.4

SECTION 2

2.1

2.2

2.3

2.4

SECTION 3

SECTION 4

4.1

4.2

ASSEMBLY

4.2.1

4.2.2

4.2.3

4.3

NO FOOT OPTION

TWO BEARING GENERATORS

SINGLE BEARING GENERATORS

EARTHING

4.4

PRE-RUNNING CHECKS

INSULATION CHECK

DIRECTION OF ROTATION

VOLTAGE AND FREQUENCY

AVR SETTINGS

TYPE SX460 AVR

TYPE SX440 AVR

TYPE SX421 AVR

TYPE MX341 AVR

4.4.1

4.4.2

4.4.3

4.4.4

4.4.4.1

4.4.4.2

4.4.4.3

4.4.4.4

4.4.4.5

4.4.5

TYPE MX321 AVR

TRANSFORMER CONTROLLED

EXCITATION SYSTEM (Series 5)

GENERATOR SET TESTING

TEST METERING/CABLING

INITIAL START-UP

4.5

4.5.1

4.6

4.7

4.7.1

4.7.1.1

LOAD TESTING

AVR CONTROLLED GENERATORS - AVR ADJUSTMENTS

UFRO (Under Frequency Roll Off)

(AVR Types SX460, SX440, SX421, MX341 and MX321)

EXC TRIP (Excitation Trip)

OVER/V (Over Voltage)

TRANSIENT LOAD SWITCHING ADJUSTMENTS

RAMP BUILD UP TIME

TRANSFORMER CONTROLLED GENERATORS -

TRANSFORMER ADJUSTMENT

ACCESSORIES

INSTALLATION - PART 2

GENERAL

GLANDING

EARTHING

PROTECTION

4.7.1.2

4.7.1.3

4.7.1.4

4.7.1.5

4.7.2

4.8

SECTION 5

5.1

5.2

5.3

5.4

5.5

COMMISSIONING

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CONTENTS

SECTION 6

ACCESSORIES

REMOTE VOLTAGE ADJUST (ALL AVR TYPES)

PARALLEL OPERATION

DROOP

SETTING PROCEDURE

ASTATIC CONTROL

MANUAL VOLTAGE REGULATOR (MVR) -

MX341 and MX321 AVR

6.1

6.2

6.2.1

6.2.1.1

6.2.2

6.3

6.4

OVERVOLTAGE DE-EXCITATION BREAKER

SX421 and MX321 AVR

6.4.1

6.5

6.5.1

6.6

RESETTING THE BREAKER

CURRENT LIMIT - MX321 AVR

SETTING PROCEDURE

POWER FACTOR CONTROLLER (PFC3)

SERVICE AND MAINTENANCE

WINDING CONDITION

WINDING CONDITION ASSESSMENT

METHODS OF DRYING OUT GENERATORS

BEARINGS

SECTION 7

7.1

7.1.1

7.1.2

7.2

7.3

7.3.1

7.4

7.4.1

7.4.2

7.4.3

7.4.4

7.4.5

7.4.6

7.4.7

7.5

AIR FILTERS

CLEANING PROCEDURE

FAULT FINDING

SX460 AVR - FAULT FINDING

SX440 AVR - FAULT FINDING

SX421 AVR - FAULT FINDING

TRANSFORMER CONTROL - FAULT FINDING

MX341 AVR - FAULT FINDING

MX321 AVR - FAULT FINDING

RESIDUAL VOLTAGE CHECK

SEPARATE EXCITATION TEST PROCEDURE

GENERATOR WINDINGS, ROTATING DIODES and

PERMANENT MAGNET GENERATOR (PMG)

BALANCED MAIN TERMINAL VOLTAGES

UNBALANCED MAIN TERMINAL VOLTAGES

EXCITATION CONTROL TEST

AVR FUNCTION TEST

RANSFORMER CONTROL

REMOVAL AND REPLACEMENT OF COMPONENT

ASSEMBLIES

REMOVAL OF PERMANENT MAGNET GENERATOR (PMG)

REMOVAL OF BEARINGS

REMOVAL OF ENDBRACKET AND EXCITER STATOR

REMOVAL OF THE ROTOR ASSEMBLY

RETURNING TO SERVICE

7.5.1

7.5.1.1

7.5.1.2

7.5.2

7.5.2.1

7.5.2.2

7.5.3

7.5.3.1

7.5.3.2

7.5.3.3

7.5.3.4

7.6

SECTION 8

SECTION 9

SPARES AND AFTER SALES SERVICE

RECOMMENDED SPARES

AFTER SALES SERVICE

PARTS IDENTIFICATION

TYPICAL SINGLE BEARING GENERATOR (Fig. 11)

TYPICAL TWO BEARING GENERATOR (Fig. 12)

8.1

8.2

TYPICAL TWO BEARING (SERIES 5) GENERATOR (Fig. 13) 37

ROTATING RECTIFIER ASSEMBLY (Fig. 14) 38

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SECTION 1

INTRODUCTION

1.4 RATING PLATE

1.1 INTRODUCTION

The generator has been supplied with a self adhesive rating

plate label to enable fitting after final assembly and painting.

The UC22/27 range of generators is of brushless rotating field

design, available up to 660V/50Hz (1500 rpm) or 60Hz (1800

rpm), and built to meet BS5000 Part 3 and international

standards.

All the UC22/27 range are self-excited with excitation power

derived from the main output windings, using either the

SX460/SX440/SX421 AVR. The UC22 is also available with

specific windings and a transformer controlled excitation

system.

It is intended that this label will be stuck to the outside of the

terminal box on the left hand side when viewed from the

N.D.E. To assist with squarely positioning the label, location

protrusions have been made in the sheet metalwork.

A CE Mark label is also supplied loose for fitment after final

assembly and painting. This should be attached to an external

surface of the Generator at a suitable location where it will not

be obscured by the customer's wiring or other fittings.

A permanent magnet generator (PMG) powered excitation

system is available as an option using either the MX341 or

MX321 AVR.

The surface in the area where a label is to be stuck must be

flat, clean, and any paint finish be fully dry before attempting

to attach label. Recommended method for attaching label is

peel and fold back sufficient of the backing paper to expose

some 20 mm of label adhesive along the edge which is to be

located against the sheet metal protrusions. Once this first

section of label has been carefully located and stuck into

position the backing paper can be progressively removed, as

the label is pressed down into position. The adhesive will

achieve a permanent bond in 24 hours.

Detailed specification sheets are available on request.

1.2 DESIGNATION

1.3 SERIAL NUMBER LOCATION AND IDENTITY

NUMBER LOCATION

Each generator is metal stamped with it’s own unique serial

number, the location of this number is described below.

UCI and UCM generators have their serial number stamped

into the upper section of the drive end frame to end bracket

adaptor ring, shown as item 31 in the parts lists at the back of

this book.

UCD generators have their serial number stamped into the

top of the drive end adaptor /fan shroud casting. If for any

reason this casting is removed, it is imperative that care is

taken to refit it to the correct generator to ensure correct

identification is retained.

Inside the terminal box two adhesive rectangular labels have

been fixed, each carrying the generators unique identity

number. One label has been fixed to the inside of the terminal

box sheet metal work, and the second label fixed to the main

frame of the generator.

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SECTION 2

PRINCIPLE OF OPERATION

The PMG system provides a constant source of excitation

2.1 SELF-EXCITED AVR CONTROLLED

power irrespective of main stator loading and provides high

motor starting capability as well as immunity to waveform

distortion on the main stator output created by non linear

loads, e.g. thyristor controlled dc motor.

The MX341 AVR senses average voltage on two phases

ensuring close regulation. In addition it detects engine speed

and provides an adjustable voltage fall off with speed, below a

pre-selected speed (Hz) setting, preventing over-excitation at

low engine speeds and softening the effect of load switching

to relieve the burden on the engine. It also provides over-

excitation protection which acts following a time delay, to de-

excite the generator in the event of excessive exciter field

voltage.

The main stator provides power for excitation of the exciter

field via the SX460 (SX440 or SX421) AVR which is the

controlling device governing the level of excitation provided to

the exciter field. The AVR responds to a voltage sensing

signal derived from the main stator winding. By controlling the

low power of the exciter field, control of the high power

requirement of the main field is achieved through the rectified

output of the exciter armature.

The MX321 provides the protection and engine relief features

of the MX341 and additionally incorporates 3 phase rms

sensing and over-voltage protection.

The detailed function of all the AVR circuits is covered in the

load testing (subsection 4.7).

2.3 AVR ACCESSORIES

The SX440, SX421, MX341 and MX321 AVRs incorporate

circuits which, when used in conjunction with accessories, can

provide for parallel operation either with 'droop' or 'astatic'

control, VAR/PF control and in the case of the MX321 AVR,

short circuit current limiting.

The SX460 or SX440 AVR senses average voltage on two

phases ensuring close regulation. In addition it detects engine

speed and provides voltage fall off with speed, below a pre-

selected speed (Hz) setting, preventing over-excitation at low

engine speeds and softening the effect of load switching to

relieve the burden on the engine.

Function and adjustment of the accessories which can be

fitted inside the generator terminal box are covered in the

accessories section of this book.

The SX421 AVR in addition to the SX440 features has three

phase rms sensing and also provides for over voltage

protection when used in conjunction with an external circuit

breaker (switchboard mounted).

Separate instructions are provided with other accessories

available for control panel mounting.

2.2 PERMANENT MAGNET GENERATOR (PMG)

EXCITED - AVR CONTROLLED GENERATORS

2.4 TRANSFORMER CONTROLLED GENERATORS

The main stator provides power for excitation of the exciter

field via a transformer rectifier unit. The transformer combines

voltage and current elements derived from the main stator

output to form the basis of an open-loop control system, which

is self regulating in nature. The system inherently

compensates for load current magnitude and power factor

and provides short circuit maintenance in addition to a good

motor starting performance.

Three phase generators normally have a three phase

transformer control for improved performance with

unbalanced loads but a single phase transformer option is

available.

No accessories can be provided with this control system.

The permanent magnet generator (PMG) provides power for

excitation of the exciter field via the AVR (MX341 or MX321)

which is the controlling device governing the level of excitation

provided to the exciter field. The AVR responds to a voltage

sensing signal derived, via an isolating transformer in the

case of MX321 AVR, from the main stator winding. By

controlling the low power of the exciter field, control of the

high power requirement of the main field is achieved through

the rectified output of the exciter armature.

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SECTION 3

APPLICATION OF THE GENERATOR

The generator is supplied as a component part for installation

in a generating set. It is not, therefore, practicable to fit all the

necessary warning/hazard labels during generator

manufacture. The additional labels required are packaged

with this Manual, together with a drawing identifying their

locations. (See below).

The generators are of air-ventilated screen protected drip-

proof design and are not suitable for mounting outdoors

unless adequately protected by the use of canopies. Anti-

condensation heaters are recommended during storage and

for standby duty to ensure winding insulation is maintained in

good condition.

When installed in a closed canopy it must be ensured that the

ambient temperature of the cooling air to the generator does

not exceed that for which the generator has been rated.

The canopy should be designed such that the engine air

intake to the canopy is separated from the generator intake,

particularly where the radiator cooling fan is required to draw

air into the canopy. In addition the generator air intake to the

canopy should be designed such that the ingress of moisture

is prohibited, preferably by use of a 2 stage filter.

The air intake/outlet must be suitable for the air flow given in

the following table with additional pressure drops less than or

equal to those given below :

Air Flow

50Hz

Additional

(intake/outlet)

Pressure Drop

6mm water gauge

(0.25”)

Frame

60Hz

0.216m³/sec

458cfm

0.281m³/sec

595cfm

UC22

0.25m³/sec

530cfm

0.514m³/sec

1090cfm

0.31m³/sec

657cfm

0.617m³/sec

1308cfm

6mm water gauge

(0.25”)

6mm water gauge

(0.25”)

UCD22

UC27

0.58m³/sec

1230cfm

0.69m³/sec

1463cfm

6mm water gauge

(0.25”)

UCD27

Important ! Reduction in cooling air flow or inadequate

protection to the generator can result in

damage and/or failure of windings.

Dynamic balancing of the generator rotor assembly has been

carried out during manufacture in accordance with BS 6861

Part 1 Grade 2.5 to ensure vibration limits of the generator are

in accordance with BS 4999 Part 142.

The main vibration frequencies produced by the component

generator are as follows:- :

4 pole

1500 rpm

1800 rpm

25 Hz

30 Hz

However, vibrations induced by the engine are complex and

contain frequencies of 1.5, 3, 5 or more times the fundamental

frequency of vibration. These induced vibrations can result in

generator vibration levels higher than those derived from the

generator itself. It is the responsibility of the generating set

designer to ensure that the alignment and stiffness of the

bedplate and mountings are such that the vibration limits of

BS5000 Part 3 are not exceeded.

It is the responsibility of the generating set manufacturer to

ensure that the correct labels are fitted, and are clearly visible.

The generators have been designed for use in a maximum

ambient temperature of 40°C and altitude less than 1000m

above sea level in accordance with BS5000.

Ambients in excess of 40°C and altitudes above 1000m can

be tolerated with reduced ratings - refer to the generator

nameplate for rating and ambient. In the event that the

generator is required to operate in an ambient in excess of the

nameplate value or at altitudes in excess of 1000 metres

above sea level, refer to the factory.

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In standby applications where the running time is limited and

reduced life expectancy is accepted, higher levels than

specified in BS5000 can be tolerated, up to a maximum of

18mm/sec.

The terminal box is constructed with removable panels for

easy adaptation to suit specific glanding requirements. Within

the terminal box there are insulated terminals for line and

neutral connections and provision for earthing. Additional

earthing points are provided on the generator feet.

Two bearing generators open coupled require a substantial

bedplate with engine/generator mounting pads to ensure a

good base for accurate alignment. Close coupling of engine to

generator can increase the overall rigidity of the set. For the

purposes of establishing set design the bending moment at

the engine flywheel housing to generator adaptor interface

should not exceed 1000ft.lb. (140 kgm). A flexible coupling,

designed to suit the specific engine/generator combination, is

recommended to minimise torsional effects.

The neutral is NOT connected to the frame.

The main stator winding has leads brought out to the

terminals in the terminal box.

No earth connections are made on the

generator

regulations for earthing must be made.

Incorrect earthing or protection

and

reference

site

Belt driven applications of two bearing generators require the

pulley diameter and design to be such that the side load or

force applied to the shaft is central to the extension and does

not exceed the values given in the table below : -

arrangements can result in personal

injury or death.

Warning !

Fault current curves (decrement curves), together with

generator reactance data, are available on request to assist

the system designer to select circuit breakers, calculate fault

currents and ensure discrimination within the load network.

Shaft

Extension

Side Load

Frame

kgf

408

510

Incorrect

installation,

service

UC22

UC27

4000

5000

110

140

replacement of parts can result in severe

personal injury or death, and/or

equipment damage. Service personnel

must be qualified to perform electrical

and mechanical service.

In instances where shaft extensions greater than specified in

the table have been supplied reference must be made to the

factory for appropriate loadings.

Warning !

Alignment of single bearing generators is critical and vibration

can occur due to the flexing of the flanges between the engine

and generator. As far as the generator is concerned the

maximum bending moment at this point must not exceed

1000ft.lb.

(140kgm).

substanial

bedplate

with

engine/generator mounting pads is required.

It is expected that the generator will be incorporated into a

generating set operating in an environment, where the

maximum shock load experienced by the generator will not

exceed 3g. in any plane. If shock loads in excess of 3g are to

be encountered, anti-vibration mountings must be

incorporated into the generating set to ensure they absorb the

excess.

The maximum bending moment of the engine flange must be

checked with the engine manufacturer.

Generators can be supplied without a foot, providing the

option for customers own arrangement. See SECTION 4.2.1

for assembly procedure.

Torsional vibrations occur in all engine-driven shaft systems

and may be of a magnitude to cause damage at certain

critical speeds.

It is therefore necessary to consider the torsional vibration

effect on the generator shaft and couplings. It is the

responsibility of the generator set manufacturer to ensure

compatibility, and for this purpose drawings showing the shaft

dimensions and rotor inertias are available for customers to

forward to the engine supplier. In the case of single bearing

generators coupling details are included.

Important ! Torsional incompatibility and/or excessive

vibration levels can cause damage or failure

of generator and/or engine components.

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SECTION 4

INSTALLATION - PART 1

Once the bar is removed, to couple the rotor to engine, the

4.1 LIFTING

Warning !

rotor is free to move in the frame, and care is needed during

coupling and alignment to ensure the frame is kept in the

horizontal plane.

Incorrect lifting or inadequate lifting

capacity can result in severe personal

injury or equipment damage. MINIMUM

LIFTING CAPACITY REQUIRED IS 750Kg.

Generator lifting lugs should NOT be used

for lifting the complete generator set.

Generators fitted with a PMG excitation system are not fitted

with retaining bar. Refer to frame designation to verify

generator type (subsection 1.2)

Two lifting lugs are provided for use with a shackle and pin

type lifting aid. Chains of suitable length and lifting capacity

must be used. Lifting points are designed to be as close to the

centre of gravity of the generator as possible, but due to

design restrictions it is not possible to guarantee that the

generator frame will remain horizontal while lifting. Care is

therefore needed to avoid personal injury or equipment

damage. The correct lifting arrangement is shown on the label

attached to the lifting lug. (See sample below).

4.2 ASSEMBLY

During the assembly of the generator to the engine it will be

necessary firstly to carefully align, then rotate, the combined

generator rotor - engine crankshaft assembly, as part of the

construction process, to allow location, insertion and

tightening of the coupling bolts. This requirement to rotate the

combined assemblies exists for both single and two bearing

units.

During the assembly of single bearing units it is necessary to

align the generator's coupling holes with the engine flywheel

holes; it is suggested that two diametrically opposite location

dowel pins are fitted to the engine flywheel, over which the

generator coupling can slide into final location into the engine

flywheel spigot recess. The dowels must be removed and

replaced by coupling bolts before the final bolt tightening

sequence.

While fitting and tightening the coupling bolts it will be

necessary to rotate the engine crankshaft - generator rotor

assembly. Care should be taken to ensure that rotation is

carried out in an approved manner that ensures safe working

practice when reaching inside the machine to insert or tighten

coupling bolts, and that no component of the assembly is

damaged by nonapproved methods of assembly rotation.

Engine manufacturers have available a proprietary tool or

acility designed to enable manual rotation of the crankshaft

assembly. This must always be used, having been

engineered as an approved method of assembly rotation,

engaging the manually driven pinion with the engine flywheel

starter ring-gear.

Before working inside the generator,

during the aligning and fitting of coupling

Caution !

bolts, care should be taken to lock the

assembly to ensure there is no possibility

of rotational movement.

Single bearing generators are supplied fitted with a rotor

retaining bar at the non-drive end of the shaft.

4.2.1 NO FOOT OPTION

To remove retaining bar :

Generators can be supplied without a foot providing the option

for customers own arrangement. For details of mounting this

arrangement, see the general arrangement drawing supplied

with the generator. Alternatively refer to the STAMFORD

factory for a copy of the latest general arrangement drawing

showing the 'NO FOOT OPTION' appropriate to your

generator.

1. Remove the four screws holding the sheet metal cover at

the non drive end and remove cover

2. Remove central bolt holding the retaining bar to the shaft

3. Refit sheet metal cover.

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1. Offer the a.c. generator to engine and engage both

coupling discs and housing spigots at the same time,

finally pulling home by using the housing and coupling

bolts. Use heavy gauge washers between bolt head and

discs on disc to flywheel bolts.

4.2.2 TWO BEARING GENERATORS

A flexible coupling should be fitted and aligned in accordance

with the coupling manufacturer's instruction. If a close

coupling adaptor is used the alignment of machined faces

must be checked by offering the generator up to the engine.

Shim the generator feet if necessary. Ensure adaptor guards

are fitted after generator/engine assembly is complete. Open

coupled sets require a suitable guard, to be provided by the

set builder. In the case of belt driven generators, ensure

alignment of drive and driven pulleys to avoid axial load on

the bearings. Screw type tensioning devices are

recommended to allow accurate adjustment of belt tension

whilst maintaining pully alignment. Side loads should not

exceed values given in SECTION 3. Belt and pulley guards

must be provided by the set builder.

1. Tighten coupling disc to flywheel. Refer to engine manual

for torque setting of disc to flywheel bolts.

1. Remove wooden wedges.

Incorrect guarding and/or generator

Caution !

alignment can result in personal injury

and/or equipment damage.

4.3 EARTHING

Important ! Incorrect belt tensioning will result in

excessive bearing wear.

The generator frame should be solidly bonded to the

generating set bedplate. If antivibration mounts are fitted

between the generator frame and its bedplate a suitably rated

earth conductor (normally one half of the cross sectional area

of the main line cables) should bridge across the antivibration

mount.

Incorrect guarding and/or generator

alignment can result in personal injury

and/or equipment damage.

Caution !

4.2.3 SINGLE BEARING GENERATORS

Alignment of single bearing generators is critical. If necessary

shim the generator feet to ensure alignment of the machined

surfaces.

Refer to local regulations to ensure that

the correct earthing procedure has been

followed.

Warning !

For transit and storage purposes the generator frame spigot

and rotor coupling plates have been coated with a rust

preventative.

4.4 PRE-RUNNING CHECKS

4.4.1 INSULATION CHECK

This MUST BE removed before assembly to engine.

A practical method for removal of this coating is to clean the

mating surface areas with a de-greasing agent based on a

petroleum solvent.

Before starting the generating set, both after completing

assembly and after installation of the set, test the insulation

resistance of windings. The AVR should be disconnected

during this test. A 500V Megger or similar instrument should

be used. Disconnect any earthing conductor connected

between neutral and earth and megger an output lead

terminal U, V or W to earth. The insulation resistance reading

should be in excess of 5MΩ to earth. Should the insulation

resistance be less than 5MΩ the winding must be dried out as

detailed in the Service and Maintenance section of this

Manual.

Care should be taken not to allow any

cleaning agent to come into prolonged

contact with skin.

Caution !

The sequence of assembly to the engine should generally be

as follows:

1. On the engine check the distance from the coupling

mating face on the flywheel to the flywheel housing

mating face. This should be within +/-0.5mm of nominal

dimension. This is necessary to ensure that a thrust is not

applied to the a.c. generator bearing or engine bearing.

Important ! The windings have been H.V. tested during

manufacture and further H.V. testing may

degrade the insulation with consequent

reduction in operating life. Should it be

necessary to demonstrate H.V. testing, for

customer acceptance, the tests must be

carried out at reduced voltage levels i.e.

Test Voltage= 0.8 (2 X Rated Voltage + 1000)

1. Check that the bolts securing the flexible plates to the

coupling hub are tight and locked into position. Torque

tightening is 24.9kgfm (244Nm; 180 lb ft).

2a. UCD224 Only

Torque tightening is 15.29 kgfm (150Nm; 110 lb ft).

1. Remove covers from the drive end of the generator to

gain access to coupling and adaptor bolts.

1. Check that coupling discs are concentric with adaptor

spigot. This can be adjusted by the use of tapered

wooden wedges between the fan and adaptor.

Alternatively the rotor can be suspended by means of a

rope sling through the adaptor opening.

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4.4.2 DIRECTION OF ROTATION

The generator is supplied to give a phase sequence of U V W

with the generator running clockwise looking at the drive end

(unless otherwise specified at the time of ordering). If the

generator phase rotation has to be reversed after the

generator has been despatched apply to factory for

appropriate wiring diagrams.

UCI224, UCI274, UCM224, UCM274

Machines are fitted with bi-directional fans and are suitable for

running in either direction of rotation.

UCD224, UCD274

Machines are fitted with uni-directional fans and are suitable

for running in one direction only.

4.4.3 VOLTAGE AND FREQUENCY

Check that the voltage and frequency levels required for the

generating set application are as indicated on the generator

nameplate.

4.4.4.2 TYPE AS440 AVR

The following 'jumper' connections on the AVR should be

checked to ensure they are correctly set for the generating set

application.

Three phase generators normally have a 12 ends out

reconnectable winding. If it is necessary to reconnect the

stator for the voltage required, refer to diagrams in the back of

this manual.

Refer to Fig. 2 for location of selection links.

1. Frequency selection terminals

50Hz operation

60Hz operation

LINK C-50

LINK C-60

4.4.4 AVR SETTINGS

To make AVR selections and adjustments remove the AVR

cover and refer to 4.4.4.1, 4.4.4.2, 4.4.4.3, 4.4.4.4 or 4.4.4.5

depending upon type of AVR fitted. Reference to the

generator nameplate will indicate AVR type (SX460, SX440,

SX421, MX341 or MX321).

2. Stability selection terminals

Frame UC22

LINK A-C

LINK B-C

Frame UC27

3. Sensing selection terminals

LINK 2-3

LINK 4-5

LINK 6-7

Most of the AVR adjustments are factory set in positions

which will give satisfactory performance during initial running

tests. Subsequent adjustment may be required to achieve

optimum performance of the set under operating conditions.

Refer to 'Load Testing' section for details.

4. Excitation Interruption Link

LINK K1-K2

4.4.4.1 TYPE SX460 AVR

The following 'jumper' connections on the AVR should be

checked to ensure they are correctly set for the generating set

application. Refer to Fig. 1 for location of selection links.

1. Frequency selection

50Hz operation

60Hz operation

LINK C-50

LINK C-60

2. External hand trimmer selection

No external hand trimmer LINK 1-2

External hand trimmer required -

REMOVE LINK 1-2 and

connect trimmer across

terminals 1 and 2.

3. AVR Input Selection

High voltage

Low voltage

(220/240V) Input NO LINK

(110/120V) Input LINK 3-4

Refer to diagram in the back of this manual to determine

wiring.

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4.4.4.5 TYPE MX321 AVR

The following 'jumper' connections on the AVR should be

checked to ensure they are correctly set for the generating set

application.

4.4.4.4 TYPE MX341 AVR

The following 'jumper' connections on the AVR should be

checked to ensure they are correctly set for the generating set

application.

Refer to Fig. 5 for location of setting links.

Refer to Fig. 4 for location of setting links.

Fig. 5

1. Frequency selection terminals

50Hz operation LINK 2-3

1. Frequency selection terminals

60Hz operation LINK 1-3

50Hz operation

60Hz operation

LINK 2-3

LINK 1-3

2. Stability selection terminals

Frame UC22 LINK A-C

2. Stability selection terminals

Frame UC22

Frame UC27 LINK B-C

LINK A-C

LINK B-C

Frame UC27

3. Sensing selection terminals *

LINK 2-3

LINK 4-5

LINK 6-7

3. Terminals K1 - K2

Excitation circuit breaker closed.

If this option not fitted, K1 - K2 linked at auxiliary terminal

block.

4. Excitation Interruption Link

LINK K1-K2

Fig. 4

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voltage is reached. Refer to Fig. 6a, 6b, 6c, 6d or 6e for

control potentiometer location.

4.4.5 TRANSFORMER CONTROLLED EXCITATION

SYSTEM (Series 5)

Important ! Do not increase the voltage above the rated

generator voltage shown on the generator

nameplate.

This control system is identified with the digit 5 as the last digit

of the frame size quoted on the nameplate.

The excitation control is factory set for the specific voltage

shown on the nameplate and requires no adjustment.

The STABILITY control potentiometer will have been pre-set

and should normally not require adjustment, but should this

be required, usually identified by oscillation of the voltmeter,

refer to Fig. 6a, 6b, 6c, 6d or 6e for control potentiometer

location and proceed as follows :-

4.5 GENERATOR SET TESTING

During testing it may be necessary to

remove covers to adjust controls exposing

'live' terminals or components. Only

personnel qualified to perform electrical

service should carry out testing and/or

1. Run the generating set on no-load and check that speed

is correct and stable

2. Turn the STABILITY control potentiometer clockwise,

then turn slowly anti-clockwise until the generator voltage

starts to become unstable.

adjustments.

Warning !

4.5.1 TEST METERING/CABLING

The correct setting is slightly clockwise from this position (i.e.

where the machine volts are stable but close to the unstable

region).

Connect any instrument wiring and cabling required for initial

test purposes with permanent or spring-clip type connectors.

Minimum instrumentation for testing should be line - line or

line to neutral voltmeter, Hz meter, load current metering and

kW meter. If reactive load is used a power factor meter is

desirable.

Important ! When fitting power cables for load testing

purposes, ensure cable voltage rating is at

least equal to the genrator rated voltage.

The load cable termination should be placed

on top of the winding lead termination and

clamped with the nut provided.

Check that all wiring terminations for

internal or external wiring are secure, and

fit all terminal box covers and guards.

Failure to secure wiring and/or covers may

result in personal injury and/or equipment

failure.

Caution !

4.6 INITIAL START-UP

During testing it may be necessary to

remove covers to adjust controls exposing

'live' terminals or components. Only

personnel qualified to perform electrical

service should carry out testing and/or

adjustments. Refit all access covers after

adjustments are completed.

Warning !

On completion of generating set assembly and before starting

the generating set ensure that all engine manufacturer's

prerunning procedures have been completed, and that

adjustment of the engine governor is such that the generator

will not be subjected to speeds in excess of 125% of the rated

speed.

Important ! Overspeeding of the generator during initial

setting of the speed governor can result in

damage

the

generator

rotating

components.

In addition remove the AVR access cover (on AVR controlled

generators) and turn VOLTS control fully anti-clockwise. Start

the generating set and run on no-load at nominal frequency.

Slowly turn VOLTS control potentiometer clockwise until rated

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4.7 LOAD TESTING

During testing it may be necessary to

remove covers to adjust controls

exposing 'live' terminals or components.

Only personnel qualified to perform

electrical service should carry out testing

and/or adjustments. Refit all access

covers after adjustments are completed.

Warning !

4.7.1 AVR CONTROLLED GENERATORS – AVR

ADJUSTMENTS

Refer to Fig. 6a, 6b, 6c, 6d or 6e for control potentiometer

locations.

Having adjusted VOLTS and STABILITY during the initial

startup procedure, other AVR control functions should not

normally need adjustment.

If however, poor voltage regulation on-load or voltage

collapse is experienced, refer to the following paragraphs on

each function to a) check that the symptoms observed do

indicate adjustment is necessary, and b) to make the

adjustment correctly.

4.7.1.1 UFRO (Under Frequency Roll Off) (AVR

Types SX460, SX440, SX421, MX341 and MX321)

The AVR incorporates an underspeed protection circuit which

gives a voltage/speed (Hz) characteristic as shown :

Fig. 7

The UFRO control potentiometer sets the "knee point".

Symptoms of incorrect setting are a) the light emitting diode

(LED) indicator, just above the UFRO Control potentiometer,

being permanently lit when the generator is on load, and b)

poor voltage regulation on load, i.e. operation on the sloping

part of the characteristic.

Clockwise adjustment lowers the frequency (speed) setting of

the "knee point" and extinguishes the LED. For Optimum

setting the LED should illuminate as the frequency falls just

below nominal frequency, i.e. 47Hz on a 50Hz generator or

57Hz on a 60Hz generator.

Important ! With AVR Types MX341 and MX321. If the

LED is illuminated and no output voltage is

present, refer to EXC TRIP and/or OVER/V

sections below.

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4.7.1.2 EXC TRIP (Excitation Trip)

AVR Types MX341 and MX321

DIP

AVR Types SX421, MX341 and MX321

An AVR supplied from a permanent magnet generator

inherently delivers maximum excitation power on a line to line

or line to neutral short circuit or large overload. In order to

protect the generator windings the AVR incorporates an over

excitation circuit which detects high excitation and removes it

after a pre-determined time, i.e. 8-10 seconds.

AVR Types SX421, MX341 and MX321

The dip function control potentiometer adjusts the slope of the

voltage/speed (Hz) characteristic below the knee point as

shown below :

Symptoms of incorrect setting are the generator output

collapses on load or small overload, and the LED is

permanently illuminated.

The correct setting is 70 volts +/-5% between terminals X and

XX.

4.7.1.3 OVER/V (Over Voltage)

AVR Type SX421, MX321

Over voltage protection circuitry is included in the AVR to

remove generator excitation in the event of loss of AVR

sensing input.

The MX321 has both internal electronic de-excitation and

provision of a signal to operate an external circuit breaker.

Fig. 8

The SX421 only provides a signal to operate an external

breaker, which MUST be fitted if over voltage protection is

required.

DWELL

AVR Type MX321

Incorrect setting would cause the generator output voltage to

collapse at no-load or on removal of load, and the LED to be

illuminated.

The dwell function introduces a time delay between the

recovery of voltage and recovery of speed.

The purpose of the time delay is to reduce the generator kW

below the available engine kW during the recovery period,

thus allowing an improved speed recovery.

The correct setting is 300 volts +/-5% across terminals E1,

E0. Clockwise adjustment of the OVER/V control

potentiometer will increase the voltage at which the circuit

operates.

Again this control is only functional below the "knee point", i.e.

if the speed stays above the knee point during load switching

there is no effect from the DWELL function setting.

4.7.1.4 TRANSIENT LOAD SWITCHING

ADJUSTMENTS

AVR Types SX421, MX341 and MX321

Clockwise adjustment gives increased recovery time.

The additional function controls of DIP and DWELL are

provided to enable the load acceptance capability of the

generating set to be optimised. The overall generating set

performance depends upon the engine capability and

governor response, in conjunction with the generator

characteristics.

It is not possible to adjust the level of voltage dip or recovery

independently from the engine performance, and there will

always be a 'trade off' between frequency dip and voltage dip.

The graphs shown above are representations only, since it is

impossible to show the combined effects of voltage regulator

and engine governor performance.

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4.7.1.5 RAMP

AVR Type MX321

The RAMP potentiometer enables adjustment of the time

taken for the generator's initial build up to normal rated

voltage during each start and run up to speed. The

potentiometer is factory set to give a ramp time of three

seconds, which is considered to be suitable for most

applications. This time can be reduced to one second by

turning the pot. fully counter clockwise, and increased to eight

seconds by turning the pot. fully clockwise.

4.7.2

TRANSFORMER

CONTROLLED

GENERATORS - TRANSFORMER ADJUSTMENT

Normally no adjustment is required but should the no-load

voltage and/or on-load voltage be unacceptable, adjustment

of the transformer air gap can be made as follows.

Stop the generator. Remove transformer cover box. (Normally

left hand side of the terminal box when viewed from the non

drive end).

Slacken the three transformer mounting bolts along the top of

the transformer.

Start the set with a voltmeter connected across the main

output terminals.

Adjust the air gap between the transformer top lamination

section and the transformer limbs to obtain required voltage

on no-load. Slightly tighten the three mounting bolts. Switch

load 'on' and 'off' two or three times. Application of load will

normally raise the voltage setting slightly. With the load 'off'

recheck the no-load voltage.

Readjust air gap and finally tighten mounting bolts.

Refit the access cover.

Failure to refit covers can result in

operator personal injury or death.

Warning !

4.8 ACCESSORIES

Refer to the "ACCESSORIES" - Section 6 of this Manual for

setting up procedures related to generator mounted

accessories.

If there are accessories for control panel mounting supplied

with the generator refer to the specific accessory fitting

procedures inserted inside the back cover of this book.

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SECTION 5

INSTALLATION - PART 2

Reference to local electricity regulations

or safety rules should be made to ensure

correct earthing procedures have been

followed.

5.1 GENERAL

Caution !

The extent of site installation will depend upon the generating

set build, e.g. if the generator is installed in a canopied set

with integral switchboards and circuit breaker, on site

installation will be limited to connecting up the site load to the

generating set output terminals . In this case reference should

be made to the generating set manufacturer's instruction book

and any pertinent local regulations. If the generator has been

installed on a set without switchboard or circuit breaker the

following points relating to connecting up the generator should

be noted.

5.4 PROTECTION

It is the responsibility of the end user and his

contractors/subcontractors to ensure that the overall system

protection meets the needs of any inspectorate, local

electricity authority or safety rules, pertaining to the site

location.

To enable the system designer to achieve the necessary

protection and/or discrimination, fault current curves are

available on request from the factory, together with generator

reactance values to enable fault current calculations to be

made.

5.2 GLANDING

The terminal box is most conveniently glanded on either the

right or left hand side. Both panels are removable for

drilling/punching to suit glands/or glanding boxes. If single

core cables are taken through the terminal box side panel an

insulated or non-magnetic gland plate should be fitted.

Incorrect installation and/or protective

systems can result in personal injury

and/or equipment damage. Installers must

Incoming cables should be supported from either below or

above the box level and at a sufficient distance from the

centre line of the generating set so as to avoid a tight radius

at the point of entry into the terminal box panel, and allow

movement of the generator set on its anti-vibration mountings

without excessive stress on the cable.

qualified

perform

electrical

installation work.

Warning !

5.5 COMMISSIONING

Ensure that all external cabling is correct and that all the

generating set manufacturer's pre-running checks have been

carried out before starting the set.

Before making final connections, test the insulation resistance

of the windings. The AVR should be disconnected during this

test.

The generator AVR controls will have been adjusted during

the generating set manufacturer's tests and should normally

not require further adjustment.

A 500V Megger or similar instrument should be used. Should

the insulation resistance be less than 5MΩ the windings must

be dried out as detailed in the Service and Maintenance

section of this manual.

Should malfunction occur during commissioning refer to

Service and Maintenance section 'Fault Finding' procedure

(subsection 7.4).

When making connections to the terminals the incoming cable

termination should be placed on top of the winding lead

termination(s) and clamped with the nut provided.

Important ! To avoid the possibility of swarf entering

any electrical components in the terminal

box, panels must be removed for drilling.

5.3 EARTHING

The neutral of the generator is not bonded to the generator

frame as supplied from the factory. An earth terminal is

provided inside the terminal box adjacent to the main

terminals. Should it be required to operate with the neutral

earthed a substantial earth conductor (normally equivalent to

one half of the section of the line conductors) must be

connected between the neutral and the earth terminal inside

the terminal box. Additional earth terminals are provided on

the generator feet. These should be already bonded to the

generating set bedplate by the generating set builder, but will

normally be required to be connected to the site earth system.

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SECTION 6

ACCESSORIES

Generator control accessories may be fitted, as an option, in

It is important to recognise that :

the generator terminal box. If fitted at the time of supply, the

wiring diagram(s) in the back of this book shows the

connections. When the options are supplied separately, fitting

instructions are provided with the accessory.

1. True kW are derived from the engine, and speed

governor characteristics determine the kW sharing

between sets

The following matrix indicates availability of accessories with

the differing AVRs.

and

2. kVAr are derived from the generator, and excitation

control characteristics determine the kVAr sharing.

Reference should be made to the generating set

manufacturer's instructions for setting the governor

controls.

Note the SX460 is not suitable for operation with accessories.

Paralleling

Droop or

Astatic

Manual

Voltage

Regulator

Var/PF

Control

Current

Limit

AVR Model

SX460

AS440

MX341

MX321

6.2.1 DROOP

The most commonly used method of kVAr sharing is to create

a generator voltage characteristic which falls with decreasing

power factor (increasing kVAr). This is achieved with a current

transformer (C.T.) which provides a signal dependent on

current phase angle (i.e. power factor) to the AVR.

6.1 REMOTE VOLTAGE ADJUST (ALL AVR TYPES)

A remote voltage adjust (hand trimmer) can be fitted.

The current transformer has a burden resistor on the AVR

board, and a percentage of the burden resistor voltage is

summed into the AVR circuit. Increasing droop is obtained by

turning the DROOP control potentiometer clockwise.

SX460

Remove link 1-2 on the AVR and

connect adjuster to terminals 1 and 2.

AS440

Remove link 1-2 at the auxiliary

terminals

and connect adjuster to terminals 1

and 2.

The diagrams below indicate the effect of droop in a simple

two generator system : -

MX341 and MX321

6.2 PARALLEL OPERATION

Understanding of the following notes on parallel operation is

useful before attempting the fitting or setting of the droop kit

accessory. When operating in parallel with other generators or

the mains, it is essential that the phase sequence of the

incoming generator matches that of the busbar and also that

all of the following conditions are met before the circuit

breaker of the incoming generator is closed on to the busbar

(or operational generator).

1. Frequency must match within close limits.

2. Voltages must match within close limits.

3. Phase angle of voltages must match within close limits.

variety of techniques, varying from simple

synchronising lamps to fully automatic synchronisers, can

be used to ensure these conditions are met.

Important ! Failure to meet conditions 1, 2, and 3 when

closing the cricuit breaker, will generate

excessive

mechanical

and

electrical

stresses, resulting in equipment damage.

Once connected in parallel a minimum instrumentation level

per generator of voltmeter, ammeter, wattmeter (measuring

total power per generator), and frequency meter is required in

order to adjust the engine and generator controls to share kW

in relation to engine ratings and kVAr in relation to generator

ratings.

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Generally 5% droop at full load current zero p.f. is sufficient to

ensure kVAr sharing.

Should the generator be required to be converted from

standard droop to 'astatic' control, diagrams are available on

request.

If the droop accessory has been supplied with the generator it

will have been tested to ensure correct polarity and set to a

nominal level of droop. The final level of droop will be set

during generating set commissioning.

The setting procedure is exactly the same as for DROOP.

(Subsection 6.2.1.1)

Important ! When using this connection arrangement a

shorting switch is required across each C.T.

burden (terminals S1 and S2.)The switch

must be closed a) when a generating set is

not running and b) when a generating set is

selected for single running.

The following setting procedure will be found to be helpful.

6.2.1.1 SETTING PROCEDURE

Depending upon available load the following settings should

be used - all are based on rated current level.

6.3 MANUAL VOLTAGE REGULATOR (MVR) -

MX341 and MX321 AVR

0.8 P.F. LOAD (at full load current)

Zero P.F. LOAD (at full load current) SET DROOP TO 5%

SET DROOP TO 3%

This accessory is provided as an 'emergency' excitation

system, in the event of an AVR failure.

Setting the droop with low power factor load is the most

accurate. Run each generator as a single unit at rated

frequency or rated frequency + 4% depending upon type of

governor and nominal voltage. Apply available load to rated

current of the generator. Adjust 'DROOP' control

potentiometer to give droop in line with above table.

Clockwise rotation increases amount of droop. Refer to Fig

9a, 9b, 9c or 9d for potentiometer locations.

Powered from the PMG output the unit is manually set, but

automatically controls the excitation current, independent of

generator voltage or frequency.

The unit is provided with 'MANUAL', 'OFF', 'AUTO' switching

facility.

Note 1)

'MANUAL'

- position connects the exciter field to the MVR output.

Generator output is then controlled by the operator adjusting

the excitation current.

Reverse polarity of the C.T. will raise the generator voltage

with load. The polarities S1-S2 shown on the wiring diagrams

are correct for clockwise rotation of the generator looking at

the drive end. Reversed rotation requires S1-S2 to be

reversed.

'OFF'

- disconnects the exciter field from both MVR and the normal

AVR.

Note 2)

'AUTO'

The most important aspect is to set all generators equal. The

precise level of droop is less critical.

- connects the exciter field to the normal AVR and the

generator output is controlled at the pre-set voltage under

AVR control.

Note 3)

A generator operated as a single unit with a droop circuit set

at rated load 0.8 power factor is unable to maintain the usual

+/-0.5% regulation. A shorting switch can be connected

across S1-S2 to restore regulation for single running.

switching mode of operation should be carried out with the

generator set stationary to avoid voltage surges on the

connected load, although neither the MVR nor AVR will be

damaged should the switching be carried out with the set

running.

Important ! LOSS OF FUEL to an engine can cause its

generator to motor with consequent damage

to the generator windings. Reverse power

relays should be fitted to trip main circuit

breaker.

6.4 OVERVOLTAGE DE-EXCITATION BREAKER

MX321 AVR

This accessory provides positive interruption of the excitation

power in the event of overvoltage due to loss of sensing or

internal AVR faults including the output power device.

LOSS OF EXCITATION to the generator can

result in large current oscillations with

consequent damage to generator windings.

Excitation loss detection equipment should

be fitted on trip main circuit breaker.

With the MX321 AVR this accessory is supplied loose for

fitting in the control panel.

6.2.2 ASTATIC CONTROL

Important ! When the circuit breaker is supplied loose,

the AVR is fitted with a link on terminals K1-

K2 to enable operation of the AVR. When

connecting the circuit breaker this link must

be removed.

The 'droop' current transformer can be used in a connection

arrangement which enables the normal regulation of the

generator to be maintained when operating in parallel. This

feature is only supplied from the factory as a fitted droop kit,

however, if requested at the time of order, the diagrams inside

the back cover of this book will give the necessary site

connections. The end user is required to provide a shorting

switch for the droop current transformer secondary.

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6.4.1 RESETTING THE BREAKER

In the event of operation of the circuit breaker, indicated by

loss of generator output voltage, manual resetting is required.

When in the "tripped" state the circuit breaker switch lever

shows "OFF". To reset move the switch lever to the position

showing "ON".

When fitted in the generator, access to the breaker is gained

by removal of the AVR access cover.

Terminals which are LIVE with the

generating set running are exposed when

the AVR access cover is removed.

Resetting of the circuit breaker MUST be

carried out with the generating set

Danger !

stationary, and engine starting circuits

disabled.

The circuit breaker is mounted on the AVR mounting bracket

either to the left or to the right of the AVR depending upon

AVR position. After resetting the circuit breaker replace the

AVR access cover before restarting the generating set.

Should resetting of the circuit breaker not restore the

generator to normal operation, refer to subsection 7.5.

6.5 CURRENT LIMIT - MX321 AVR

These accessories work in conjunction with the AVR circuits

to provide an adjustment to the level of current delivered into

a fault. One current transformer (CT) per phase is fitted to

provide current limiting on any line to line or line to neutral

fault.

Note: The W phase CT can also provide "DROOP". Refer to

6.2.1.1 for setting droop independent of current limit.

Adjustment means is provided with the "I/LIMIT" control

potentiometer on the AVR. Refer to Fig. 9d for location. If

current limit transformers are supplied with the generator the

limit will be set in accordance with the level specified at the

time of order, and no further adjustment will be necessary.

However, should the level need to be adjusted, refer to the

setting procedure given in 6.5.1.

6.5.1 SETTING PROCEDURE

Run the generating set on no-load and check that engine

governor is set to control nominal speed.

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Stop the generating set. Remove the link between terminals

K1-K2 at the auxiliary terminal block and connect a 5A switch

across the terminals K1-K2.

Turn the "I/LIMIT" control potentiometer fully anticlockwise.

Short circuit the stator winding with a bolted 3 phase short at

the main terminals. An AC current clip-on ammeter is required

to measure the winding lead current.

With the switch across K1-K2 open start the generating set.

Close the switch across K1-K2 and turn the "I/LIMIT" control

potentiometer clockwise until required current level is

observed on the clip-on ammeter. As soon as correct setting

is achieved open the K1-K2 switch.

Should the current collapse during the setting procedure, the

internal protective circuits of the AVR will have operated. In

this event shut down the set and open the K1-K2 switch.

Restart the set and run for 10 minutes with K1-K2 switch

open, to cool the generator windings, before attempting to

resume the setting procedure.

Important ! Failure to carry out the correct COOLING

procedure, may cause overheating and

consequent damage to the generator

windings.

6.6 POWER FACTOR CONTROLLER (PFC3)

This accessory is primarily designed for those generator

applications where operation in parallel with the mains supply

is required.

Protection against loss of mains voltage or generator

excitation is not included in the unit and the system designer

must incorporate suitable protection.

The electronic control unit requires both droop and kVAr

current transformers. When supplied with the generator,

wiring diagrams inside the back cover of this manual show the

connections and the additional instruction leaflet provided

gives details of setting procedures for the power factor

controller (PFC3).

The unit monitors the power factor of the generator current

and adjusts excitation to maintain the power factor constant.

This mode can also be used to control the power factor of the

mains if the point of current monitoring is moved to the mains

cables. Refer to the factory for appropriate details.

It is also possible to operate the unit to control kVAr of the

generator if required. Refer to the factory for appropriate

details.

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SECTION 7

SERVICE AND MAINTENANCE

As part of routine maintenance procedures, periodic attention

Any temporarily reduction in IR values can be restored to

expected values by following one of the drying out

procedures.

to winding condition (particularly when generators have been

idle for a long period) and bearings is recommended. (Refer

to subsections 7.1 and 7.2 respectively).

7.1.1 WINDING CONDITION ASSESSMENT

The AVR should be disconnected and the

When generators are fitted with air filters regular inspection

and filter maintenance is required. (Refer to subsection 7.3).

Caution !

Resistance Temperature Detector (R.T.D.)

leads grounded during this test.

7.1 WINDING CONDITION

Service and fault finding procedures

present hazards which can result in severe

personal injury or death. Only personnel

qualified to perform electrical and

mechanical service should carry out these

procedures. Ensure engine starting

The condition of the windings can be assessed by

measurement of insulation resistance [IR] between phase to

phase, and phase to earth.

Measurement of winding insulation should be carried out : -

1. As part of a periodic maintenance plan.

circuits are disabled before commencing

Warning !

service or maintenance procedures.

Isolate any anti-condensation heater

supply.

2. After prolonged periods of shutdown.

3. When low insulation is suspected, e.g. damp or wet

windings.

Guidance of Typical Insulation Resistance [IR]

Values

Care should be taken when dealing with windings that are

suspected of being excessively damp or dirty. The initial

measurement of the [IR] Insulation Resistance should be

The following is offered as general information about IR

values and is aimed at providing guidance about the typical IR

values for generators from new through to the point of

refurbishment.

established using

low voltage (500V) megger type

instrument. If manually powered the handle should initially be

turned slowly so that the full test voltage will not be applied,

and only applied for long enough to very quickly assess the

situation if low values are suspected or immediately indicated.

New Machines

The generators Insulation Resistance, along with many other

critical factors, will have been measured during the alternator

manufacturing process. The generator will have been

transported with an appropriate packaging suitable for the

method of delivery to the Generating Set assemblers works.

Where we expect it to be stored in a suitable location

protected from adverse environmental conditions.

Full megger tests or any other form of high voltage test should

not be applied until the windings have been dried out and if

necessary cleaned.

Procedure for Insulation Testing

Disconnect all electronic components, AVR, electronic

protection equipment etc. Ground the [RTD's] Resistance

Temperature Detection devices if fitted. Short out the diodes

on the rotating diode assembly. Be aware of all components

connected to the system under test that could cause false

readings or be damaged by the test voltage.

However, absolute assurance that the generator will arrive at

the Gen-set production line with IR values still at the factory

test levels of above 100 MΩ cannot be guaranteed.

At Generating Set Manufacturers Works

Carry out the insulation test in accordance with the ‘operating

instructions for the test equipment.

The generator should have been transported and stored such

that it will be delivered to the assembly area in a clean dry

condition. If held in appropriate storage conditions the

generator IR value should typically be 25 MΩ.

The measured value of insulation resistance for all windings

to earth and phase to phase should be compared with the

guidance given above for the various 'life stages' of a

generator. The minimum acceptable value must be greater

than 1.0 MΩ.

If the unused/new generators IR values fall below 10 MΩ then

a drying out procedure should be implemented by one of the

processes outlined below before being despatched to the end

customer’s site. Some investigation should be undertaken into

the storage conditions of the generator while on site.

If low winding insulation is confirmed use one or more of

the methods, given below, for drying the winding should

be carried out.

Generators in Service

1. METHODS OF DRYING OUT GENERATORS

Whilst It is known that a generator will give reliable service

with an IR value of just 1.0 MΩ. For a relatively new generator

to be so low it must have been subjected to inappropriate

operating or storage conditions.

Cold Run

Consider a good condition generator that has not been run for

some time, and has been standing in damp, humid conditions.

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It is possible that simply running the gen set unexcited – AVR

terminals K1 K2 open circuit - for a period of say 10 minutes

will sufficiently dry the surface of the windings and raise the IR

sufficiently, to greater than 1.0 MΩ , and so allow the unit to

be put into service.

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Rebuild the genset, replace all covers and re-commission as

appropriate.

Blown Air Drying

Remove the covers from all apertures to allow the escape of

the water-laden air. During drying, air must be able to flow

freely through the generator in order to carry off the moisture.

If the set is not to be run immediately ensure that the

anticondensation heaters are energised, and retest the

generator prior to running.

Direct hot air from two electrical fan heaters of around 1 – 3

kW into the generator air inlet apertures. Ensure the heat

source is at least 300mm away from the windings to avoid

over heating and damage to the insulation.

TYPICAL DRYING OUT CURVE

Whichever method is used to dry out the generator the

resistance should be measured every half-hour and a curve

plotted as shown. (fig 6.)

Apply the heat and plot the insulation value at half hourly

intervals. The process is complete when the parameters

covered in the section entitled, ‘Typical Drying Out Curve’, are

met.

Remove the heaters, replace all covers and re-commission as

appropriate.

If the set is not to be run immediately ensure that the

anticondensation heaters are energised, and retest prior to

running.

Short Circuit Method

NOTE: This process should only be performed by

competent engineer familiar with safe operating practices

within and around generator sets of the type in question.

The illustration shows a typical curve for a machine that has

absorbed a considerable amount of moisture. The curve

indicates a temporary increase in resistance, a fall and then a

gradual rise to a steady state. Point ‘A’, the steady state, must

be greater than 1.0 MΩ. (If the windings are only slightly

damp the dotted portion of the curve may not appear).

Ensure the generator is safe to work on, initiate all mechanical

and electrical safety procedures pertaining to the genset and

the site.

For general guidance expect that the typical time to reach

point 'A' will be :

Bolt a short circuit of adequate current carrying capacity,

across the main terminals of the generator. The shorting link

should be capable of taking full load current.

1 hour for a BC16/18,

2 hours for a UC22/27

3 hours for an HC4,5,6&7

Drying should be continued after point “A” has been reached

for at least one hour.

Disconnect the cables from terminals “X” and “XX” of the

AVR.

Connect a variable dc supply to the “X” (positive) and “XX”

(negative) field cables. The dc supply must be able to provide

a current up to 2.0 Amp at 0 - 24 Volts.

It should be noted that as winding temperature increases,

values of insulation resistance may significantly reduce.

Therefore, the reference values for insulation resistance can

only be established with windings at a temperature of

approximately 20°C.

Position a suitable ac ammeter to measure the shorting link

current.

Set the dc supply voltage to zero and start the generating set.

Slowly increase the dc voltage to pass current through the

exciter field winding. As the excitation current increases, so

the stator current in the shorting link will increase. This stator

output current level must be monitored, and not allowed to

exceed 80% of the generators rated output current.

If the IR value remains below 1.0 MΩ, even after the above

drying methods have been properly conducted, then a

Polarisation Index test [PI] should be carried out.

If the minimum value of 1.0 MΩ for all components cannot be

achieved rewinding or refurbishment of the generator will be

necessary.

After every 30 minutes of this exercise:

The generator must not be put into service until the

minimum values can be achieved.

Stop the generator and switch off the separate excitation

supply, and measure and record the stator winding IR values,

and plot the results. The resulting graph should be compared

with the classic shaped graph. This drying out procedure is

complete when the parameters covered in the section entitled

'Typical Drying Out Curve' are met.

Important ! The short circuit must not be applied with

the AVR connected in circuit. Current in

excess of the rated generator current will

cause damage to the windings.

Once the Insulation Resistance is raised to an acceptable

level - minimum value 1.0 MΩ − the dc supply may be

removed and the exciter field leads “X” and “XX” re-connected

to their terminals on the AVR.

After drying out, the insulation resistances should be

rechecked to verify minimum resistances quoted above are

achieved.

On re-testing it is recommended that the main stator

insulation resistance is checked as follows :-

Separate the neutral leads

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Ground V and W phase and megger U phase to ground

Ground U and W phase and megger V phase to ground

Ground U and V phase and megger W phase to ground

If the minimum value of 1.0MΩ is not obtained, drying out

must be continued and the test repeated.7.2 BEARINGS

7.4 FAULT FINDING

Important ! Before commencing any fault finding

procedure examine all wiring for broken or

loose connections.

All bearings are supplied sealed for life and are, therefore, not

regreasable.

Important ! The life of a bearing in service is subject to

Four types of excitation control system, involving four types of

AVR, can be fitted to the range of generators covered by this

manual. The systems can be identified by a combination of

AVR type, where applicable, and the last digit of the generator

frame size designation. Refer to the generator nameplate then

proceed to the appropriate subsection as indicated below :-

the

working

conditions

and

the

environment.

Important ! Long stationary periods in an environment

where there is vibration can cause false

brinnelling which puts flats on the ball and

grooves on the races. Very humid

atmospheres or wet conditions can emulsify

the grease and cause corrosion.

DIGIT

EXCITATION CONTROL

SX460 AVR

SUBSECTION

7.4.1

AS440 AVR

7.4.2

7.4.3

Important ! High axial vibration from the engine or

misalignment of the set will stress the

bearing.

Transformer control

MX341 AVR

7.4.4

7.4.5

MX321 AVR

7.4.6

The bearing, in service, is affected by a variety of factors that

together will determine the bearing life. We recommend that

the health of the bearings be monitored, using ‘spike energy’

vibration monitoring equipment. This will allow the timely

replacement of bearings, that exhibit a deteriorating trend,

during a major engine overhaul.

7.4.1 SX460 AVR - FAULT FINDING

1. Check speed

2. Check residual voltage. Refer to

subsection 7.4.7.

3. Follow Separate Excitation Test

Procedure to check generator and

AVR.

No voltage

build-up when

starting set

If excessive heat, noise or vibration is detected, change the

bearing as soon as practicable. Failure to do so could result in

bearing failure.

Unstable voltage

1. Check speed stability.

either on no-load 2. Check stability setting. Refer to

In the event that ‘spike energy’ vibration monitoring equipment

is not available, it is strongly recommend that consideration

be given to changing the bearing during each ‘major engine

overhaul’.

or with load

subsection 4.6.

High voltage

1. Check speed.

either on no-load 2. Check that generator load is not

or with load

capacitive (leading power factor).

1. Check speed.

Low voltage

no-load

Belt driven application will impose an additional load on

bearings. The bearing life will therefore be significantly

affected. It is important that the side load limits given in

SECTION 3 are not exceeded and the health of the bearing is

monitored more closely.

2. Check link 1-2 or external hand

trimmer leads for continuity.

1. Check speed.

2. Check UFRO setting. Refer to

subsection 4.7.1.1.

Low voltage

on-load

3. Follow

Separate

Excitation

7.3 AIR FILTERS

Procedure to check generator and

AVR. Refer to subsection 7.5.

The frequency of filter maintenance will depend upon the

severity of the site conditions. Regular inspection of the

elements will be required to establish when cleaning is

necessary.

7.3.1 CLEANING PROCEDURE

Removal of filter elements enables access

to LIVE parts. Only remove elements with

the generator out of service.

Danger !

Remove the filter elements from the filter frames. Immerse or

flush the element with a suitable detergent until the element is

clean. Dry elements thoroughly before refitting.

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7.4.2 SX440 AVR - FAULT FINDING

1. Check link K1-K2 on auxiliary

7.4.4 TRANSFORMER CONTROL - FAULT FINDING

terminals.

2. Check speed

3. Check residual voltage. Refer to

subsection 7.4.7.

No voltage

build-up when

starting set

1. Check transformers rectifiers.

2. Check transformer secondary

winding for open circuit.

1. Check speed.

No voltage

build-up when

starting set

4. Follow Separate Excitation Test

Procedure to check generator and

AVR. Refer to subsection 7.5.

Low voltage

2. Check transformer air gap setting.

Refer to subsection 4.7.2.

1. Check speed.

2. Check transformer air gap setting.

Refer to subsection 4.7.2.

Unstable voltage

either on no-load 2. Check stability setting. Refer to

1. Check speed stability.

High voltage

3. Check

transformer

secondary

or with load

subsection 4.6.

winding for open circuit.

1. Check speed drop on-load.

2. Check transformers rectifiers.

3. Check transformer air gap setting.

Refer to subsection 4.7.2.

High voltage

1. Check speed.

Excessive

voltage/speed

dip on load

switching

either on no-load 2. Check that generator load is not

or with load

capacitive (leading power factor).

1. Check speed.

2. Check link 1-2 or external hand

trimmer leads for continuity.

1. Check speed.

Low voltage

no-load

2. Check UFRO setting. Refer to

subsection 4.7.1.1.

Low voltage

on-load

3. Follow

Separate

Excitation

Procedure to check generator and

AVR. Refer to subsection 7.5.

7.4.3 SX421 AVR - FAULT FINDING

1. Check circuit breaker ON. Refer to

subsection 6.4.1.

2. Check speed

3. Check residual voltage. Refer to

subsection 7.4.7.

4. Follow Separate Excitation Test

Procedure to check generator and

AVR. Refer to subsection 7.5.

1. Check speed stability.

No voltage

build-up when

starting set

Unstable voltage

either on no-load 2. Check stability setting. Refer to

or with load

subsection 4.6.

1. Check speed.

2. Check link 1-2 or external hand

trimmers leads for continuity. Check

continuity of leads 7-8 and P3-P2 for

continuity.

High voltage

either on no-load

or with load

3. Check that generator load is not

capacitive (leading power factor).

1. Check speed.

2. Check link 1-2 or external hand

trimmer leads for continuity.

1. Check speed.

Low voltage

no-load

2. Check UFRO setting. Refer to

subsection 4.7.1.1.

Low voltage

on-load

3. Follow

Separate

Excitation

Procedure to check generator and

AVR. Refer to subsection 7.5.

Excessive

voltage/speed

dip on load

switching

1. Check governor response.

2. Refer to generating set manual.

Check ‘DIP’ setting. Refer to

subsection 4.7.1.4.

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7.4.5 MX341 AVR - FAULT FINDING

7.4.6 MX321 AVR - FAULT FINDING

1. Check link K1-K2 on auxiliary

terminals

2. Follow Separate Excitation Test

Procedure to check machine and

AVR. Refer to subsection 7.5.

1. Check link K1-K2 on auxiliary

No voltage

build-up when

starting set

No voltage

build-up when

starting set

terminals. Follow Separate Excitation

Test Procedure to check machine

and AVR. Refer to subsection 7.5.

Voltage very slow 1. Check setting of ramp potentiometer.

1. First stop and restart set. If no

voltage or voltage collapses after

short time, follow Separate Excitation

Test Procedure. Refer to subsection

7.5.

to build up

Refer to 4.7.1.5.

1. First stop and restart set. If no

voltage or voltage collapses after

short time, follow Separate Excitation

Test Procedure. Refer to subsection

7.5.

Loss of voltage

when set runninig

Loss of voltage

when set running

Generator

voltage high

followed by

collapse

1. Check sensing leads to AVR.

2. Refer to Separate Excitation Test

Procedure. Refer to subsection 7.5.

Generator

voltage high

followed by

collapse

1. Check sensing leads to AVR.

2. Refer to Separate Excitation Test

Procedure. Refer to subsection 7.5.

1. Check speed stability.

Voltage unstable,

either on no-load

or with load

2. Check “STAB” setting. Refer to Load

Testing section for procedure. Refer

to subsection 4.6.

1. Check speed.

2. If correct check “UFRO” setting.

Refer to subsection 4.7.1.1.

1. Check speed stability.

Voltage unstable,

either on no-load

or with load

2. Check “STAB” setting. Refer to Load

Testing section for procedure. Refer

to subsection 4.6.

1. Check speed.

2. If correct check “UFRO” setting.

Refer to subsection 4.7.1.1.

1. Check governor response. Refer to

generating set manual. Check “DIP”

setting. Refer to subsection 4.7.1.4.

1. Check governor response. Refer to

generating set manual. Check

“DWELL” setting. Refer to Load

Testing section 4.7.1.4.

Low voltage

on-load

Low voltage

on-load

Excessive

voltage/speed

dip on load

switching

Sluggish

recovery on load

switching

1. Check governor response. Refer to

generating set manual. Check “DIP”

setting. Refer to subsection 4.7.1.4.

Excessive

voltage/speed dip

on load switching

1. Check governor response. Refer to

generating set manual.

Sluggish

recovery on load

switching

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7.4.7 RESIDUAL VOLTAGE CHECK

7.5.1 GENERATOR WINDINGS, ROTATING DIODES

and PERMANENT MAGNET GENERATOR (PMG)

This procedure is applicable to generators with either SX460

or SX440 or SX421 AVR.

Important ! The resistances quoted apply to a standard

winding. For generators having windings or

voltages other than those specified refer to

factory for details. Ensure all disconnected

leads are isolated and free from earth.

With the generator set stationary remove AVR access cover

and leads X and XX from the AVR.

Start the set and measure voltage across AVR terminals 7-8

on SX460 AVR or P2-P3 on SX440 or SX421 AVR.

Important ! Incorrect

speed

setting

will

give

proportional error in voltage output.

Stop the set, and replace leads X and XX on the AVR

terminals. If the measured voltage was above 5V the

generator should operate normally.

CHECKING PMG

Start the set and run at rated speed. Measure the voltages at

the AVR terminals P2, P3 and P4. These should be balanced

and within the following ranges :-

If the measured voltage was under 5V follow the procedure

below.

Using a 12 volt d. c. battery as a supply clip leads from battery

negative to AVR terminal XX, and from battery positive

through a diode to AVR terminal X. See Fig. 10.

50Hz generators - 170-180 volts

60Hz generators - 200-216 volts

Should the voltages be unbalanced stop the set, remove the

PMG sheet metal cover from the non drive endbracket and

disconnect the multipin plug in the PMG output leads. Check

leads P2, P3, P4 for continuity. Check the PMG stator

resistances between output leads. These should be balanced

and within +/-10% of 2.3 ohms. If resistances are unbalanced

and/or incorrect the PMG stator must be replaced. If the

voltages are balanced but low and the PMG stator winding

resistances are correct - the PMG rotor must be replaced.

Important ! A diode must be used as shown below to

ensure the AVR is not damaged.

CHECKING GENERATOR WINDINGS AND

ROTATING DIODES

This procedure is carried out with leads

and XX

disconnected at the AVR or transformer control rectifier bridge

and using a 12 volt d.c. supply to leads X and XX.

Start the set and run at rated speed.

Measure the voltages at the main output terminals U, V and

W. If voltages are balanced and within +/-10% of the

generator nominal voltage, refer to 7.5.1.1.

Important ! If the generating set battery is used for field

flashing the generator main stator neutral

must be disconnected from earth.

Check voltages at AVR terminals 6, 7 and 8. These should be

balanced and between 170-250 volts.

Restart the set and note output voltage from main stator,

which should be approximately nominal voltage, or voltage at

AVR terminals 7 and 8 on SX460, P2-P3 on SX440 or SX421

which should be between 170 and 250 volts.

If voltages at main terminals are balanced but voltage at 6, 7

and 8 are unbalanced, check continuity of leads 6, 7 and 8.

Where an isolating transformer is fitted (MX321 AVR) check

transformer windings. If faulty the transformer unit must be

replaced.

Stop the set and unclip battery supply from terminals X and

XX. Restart the set. The generator should now operate

normally. If no voltage build-up is obtained it can be assumed

a fault exists in either the generator or the AVR circuits.

Follow the SEPARATE EXCITATION TEST PROCEDURE to

check generator windings, rotating diodes and AVR. Refer to

subsection 7.5.

If voltages are unbalanced, refer to 7.5.1.2.

7.5.1.1 BALANCED MAIN TERMINAL VOLTAGES

If all voltages are balanced within 1% at the main terminals, it

can be assumed that all exciter windings, main windings and

main rotating diodes are in good order, and the fault is in the

AVR or transformer control. Refer to subsection 7.5.2 for test

procedure.

7.5 SEPARATE EXCITATION TEST PROCEDURE

The generator windings, diode assembly and AVR can be

checked using the appropriate following section.

7.5.1 GENERATOR WINDINGS, ROTATING DIODES and

PERMANENT MAGNET GENERATOR (PMG)

If voltages are balanced but low, there is a fault in the main

excitation windings or rotating diode assembly. Proceed as

follows

identify

7.5.2 EXCITATION CONTROL TEST.

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UCD27J

UCD27K

2.08

0.182

Rectifier Diodes

* Used with 1 phase transformer controlled 3 phase or 1

phase generators.

** Used with 3 phase transformer controlled 3 phase

generators.

The diodes on the main rectifier assembly can be checked

with a multimeter. The flexible leads connected to each diode

should be disconnected at the terminal end, and the forward

and reverse resistance checked. A healthy diode will indicate

a very high resistance (infinity) in the reverse direction, and a

low resistance in the forward direction. A faulty diode will give

a full deflection reading in both directions with the test meter

on the 10,000 ohms scale, or an infinity reading in both

directions.

7.5.1.2 UNBALANCED MAIN TERMINAL VOLTAGES

If voltages are unbalanced, this indicates a fault on the main

stator winding or main cables to the circuit breaker.

NOTE : Faults on the stator winding or cables may also cause

noticeable load increase on the engine when excitation is

applied. Disconnect the main cables and separate the winding

leads U1-U2, U5-U6, V1-V2, V5-V6, W1-W2, W5-W6 to

isolate each winding section. (U1-L1, U2-L4 on single phase

generators).

On an electronic digital meter a healthy diode will give a low

reading in one direction, and a high reading in the other.

Replacement of Faulty Diodes

The rectifier assembly is split into two plates, the positive and

negative, and the main rotor is connected across these plates.

Each plate carries 3 diodes, the negative plate carrying

negative biased diodes and the positive plate carrying positive

biased diodes. Care must be taken to ensure that the correct

polarity diodes are fitted to each respective plate. When fitting

the diodes to the plates they must be tight enough to ensure a

good mechanical and electrical contact, but should not be

overtightened. The recommended torque tightening is 4.06 -

4.74Nm (36-42lb in).

Measure each section resistance - values should be balanced

and within +/-10% of the value given below:-

AVR CONTROLLED GENERATORS

SECTION RESISTANCES

FRAME

SIZE

WINDING

311

WINDING

UC22C

UC22D

UC22E

UC22F

UC22G

0.09

0.065

0.05

0.033

0.028

0.14

0.1

0.075

0.051

0.043

0.045

0.033

0.028

0.018

0.014

0.03

0.025

0.02

0.012

0.01

Surge Suppressor

UC27C

UC27D

UC27E

UC27F

UC27G

UC27H

UCD27J

UCD27K

0.03

0.019

0.016

0.012

0.01

0.008

0.006

0.044

0.026

0.025

0.019

0.013

0.014

0.009

0.016

0.01

0.009

0.007

0.006

0.004

0.011

0.007

0.008

0.005

0.004

The surge suppressor is a metal-oxide varistor connected

across the two rectifier plates to prevent high transient

reverse voltages in the field winding from damaging the

diodes. This device is not polarised and will show a virtually

infinite reading in both directions with an ordinary resistance

meter. If defective this will be visible by inspection, since it will

normally fail to short circuit and show signs of disintegration.

Replace if faulty.

Main Excitation Windings

TRANSFORMER CONTROLLED GENERATOR

SECTION RESISTANCES, 3 PHASE WINDINGS

If after establishing and correcting any fault on the rectifier

assembly the output is still low when separately excited, then

the main rotor, exciter stator and exciter rotor winding

resistances should be checked (see Resistance Charts), as

the fault must be in one of these windings. The exciter stator

resistance is measured across leads X and XX. The exciter

rotor is connected to six studs which also carry the diode lead

terminals. The main rotor winding is connected across the two

rectifier plates. The respective leads must be disconnected

before taking the readings.

FRAME

SIZE

380V

50Hz

0.059

0.054

0.041

0.031

0.022

400V

50Hz

0.078

0.056

0.05

415V

50Hz

0.082

0.057

0.053

0.033

0.028

416V

60Hz

0.055

0.049

0.038

0.025

0.021

460V

60Hz

0.059

0.054

0.041

0.031

0.022

UC22C

UC22D

UC22E

UC22F

UC22G

0.032

0.026

Measure insulation resistance between sections and each

section to earth.

Resistance values should be within +/-10% of the values

given in the table below :-

Unbalanced or incorrect winding resistances and/or low

insulation resistances to earth indicate rewinding of the stator

will be necessary. Refer to removal and replacement of

component assemblies subsection 7.5.3.

FRAME

SIZE

Main

Rotor

0.59

0.64

0.69

0.83

0.94

Exciter Stator

Type 1 Type 2* Type 3**

Exciter

Rotor

0.142

0.156

UC22C

UC22D

UC22E

UC22F

UC22G

138

155

7.5.2 EXCITATION CONTROL TEST

7.5.2.1 AVR FUNCTION TEST

All types of AVR's can be tested with this procedure :

UC27C

UC27D

UC27E

UC27F

UC27G

UC27H

1.12

1.26

1.34

1.52

0.69

0.82

0.156

0.182

1. Remove exciter field leads X & XX (F1 & F2) from the

AVR terminals X & XX (F1 & F2).

2. Connect a 60W 240V household lamp to AVR terminals

X & XX (F1 & F2).

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3. Set the AVR VOLTS control potentiometer fully

clockwise.

Low insulation resistance, unbalanced primary or secondary

winding resistances, open or short circuited winding sections

indicates the transformer unit should be replaced.

4. Connect a 12V, 1.0A DC supply to the exciter field leads

X & XX (F1 & F2) with X (F1) to the positive.

Rectifier units - Three phase and single phase

5. Start the generating set and run at rated speed.

With the leads 10-11-12-X and XX removed from the rectifier

unit (lead 12 is not fitted on single phase transformer rectifier

units), check forward and reverse resistances between

terminals 10-X, 11-X, 12-X, 10-XX, 11-XX and 12-XX with a

multimeter.

6. Check that the generator output voltage is within +/-10%

of rated voltage.

Voltages at AVR terminals 7-8 on SX460 AVR or P2-P3 on

SX440 or SX421 AVR should be between 170 and 250 volts.

If the generator output voltage is correct but the voltage on 7-

8 (or P2- P3) is low, check auxiliary leads and connections to

main terminals.

A low forward resistance and high reverse resistance should

be read between each pair of terminals. If this is not the case

the unit is faulty and should be replaced.

7.5.3 REMOVAL AND REPLACEMENT OF

COMPONENT ASSEMBLIES

Voltages at P2, P3, P4 terminals on MX341 and MX321 hould

be as given in 7.5.1.

METRIC THREADS ARE USED THROUGHOUT

The lamp connected across X-XX should glow. In the case of

the SX460, SX440 and SX421 AVRs the lamp should glow

continuously. In the case of the MX341 and MX321 AVRs the

lamp should glow for approximately 8 secs. and then turn off.

Failure to turn off indicates faulty protection circuit and the

AVR should be replaced. Turning the "VOLTS" control

potentiometer fully anti-clockwise should turn off the lamp with

all AVR types.

When lifting single bearing generators,

care is needed to ensure the generator

frame is kept in the horizontal plane. The

rotor is free to move in the frame and can

Caution !

slide out if not correctly lifted. Incorrect

lifting can cause serious personal injury.

7.5.3.1 REMOVAL OF PERMANENT MAGNET

GENERATOR (PMG)

Should the lamp fail to light the AVR is faulty and should be

replaced.

1. Remove 4 screws holding the sheet metal cylindrical

cover at the non-drive end and remove the cover.

Important ! After this test turn VOLTS control

potentiometer fully anti-clockwise.

2. Disconnect the in line connector from the PMG stator (3

wires go to this connector). It may be necessary to cut off

the nylon cable tie first.

7.5.2.2 TRANSFORMER CONTROL

The transformer rectifier unit can only be checked by

continuity, resistance checks and insulation resistance

measurement.

3. Remove the 4 threaded pillars and clamps holding the

PMG stator onto the end bracket.

Two phase transformer

4. Tap the stator out of the 4 spigots and withdraw. The

highly magnetic rotor will attract the stator. Take care to

avoid contact which may damage the windings.

Separate primary leads T1-T2-T3-T4 and secondary leads 10-

11. Examine windings for damage. Measure resistances

across T1-T3 and T2-T4. These will be a low value but should

be balanced. Check that there is resistance in the order of 8

ohms between leads 10 and 11. Check insulation resistance

of each winding section to earth and to other winding

sections.

5. Remove the bolt in the centre from the rotor shaft and

pull off the rotor. It may be necessary to gently tap the

rotor away. Take care to tap gently and evenly - the rotor

has ceramicmagnets which are easily broken by shock.

Low insulation resistance, unbalanced primary resistance,

open or short circuited winding sections, indicates the

transformer unit should be replaced.

Important ! The rotor assembly must not be dismantled.

Replacement is a reversal of the above procedure.

Three phase transformer

7.5.3.2 REMOVAL OF BEARINGS

Separate primary leads T1-T2-T3 and secondary leads 6-7-8

and 10-11-12.

Important ! Position the main rotor so that a full pole

face of the main rotor core is at the bottom

of the stator bore.

Examine windings for damage. Measure resistances across

T1-T2, T2-T3, T3-T1. These will be low but should be

balanced.

NOTE: Removal of the bearings may be effected either after

the rotor assembly has been removed OR more simply by

removal of endbracket(s). Refer to 7.5.3.3. and 7.5.3.4.

Check that resistances are balanced across 6-10, 7-11 and

8-12 and in the order of 18 ohms. Check insulation resistance

of each winding section to earth and to other winding

sections.

The bearings are pre-packed with grease and sealed for life.

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The bearing(s) are a press fit and can be removed from the

shaft with 3 leg or 2 leg manual or hydraulic bearing pullers.

4. Remove the screens and louvres (if fitted) at each side

on the drive end.

SINGLE BEARING ONLY : Before trying to pull off the

bearing remove the small circlip retaining it.

Now ensure that the rotor is positioned with a full pole face at

the bottom centre line. This is to avoid damage to the bearing

exciter, or rotor winding, by limiting the possible rotor

downward movement to the air gap length.

When fitting new bearings use a bearing heater to expand the

bearing before fitting to the shaft. Tap the bearing into place

ensuring that it contacts the shoulder on the shaft.

5. Remove 6 bolts holding drive endbracket onto adaptor

ring DE. The boltheads face towards the non-drive end.

The top bolt passes through the centre of the lifting lug.

Refit the retaining circlip on single bearing generators.

6. Tap the drive endbracket away from the adaptor ring DE

and withdraw the endbracket.

7.5.3.3 REMOVAL OF ENDBRACKET AND EXCITER

STATOR

7. Ensure the rotor is supported at the drive end on a sling.

1. Remove exciter leads X+, XX- at the AVR.

8. Tap the rotor from the non-drive end to push the bearing

clear of the endbracket and its position within an 'O' ring.

2. Slacken 4 bolts (2 each side) situated on horizontal

centre line holding the terminal box.

9. Continue to push the rotor out of the stator bore,

gradually working the sling along the rotor as it is

withdrawn, to ensure that it is fully supported all the

time.

3. Remove 2 bolts holding lifting lug, at the non-drive end,

and remove lug.

4. Remove sheet metal cylindrical cover (4 screws) over

PMG (if fitted) or Remove shallow sheet metal cover (4

screws) at the nondrive end.

SINGLE BEARING GENERATORS

1. Remove the screws, screens and louvres (if fitted) at

each side on drive end adaptor.

5. Ease up the terminal box and support clear of the

nondrive endbracket.

2. UCI224, UCI274, UCM224, UCM274, UCD274 Only

Remove 6 bolts holding the adaptor at the drive end. It

may be preferred to sling the adaptor on a hoist. The bolt

heads face towards the non-drive end. The top bolt

passes through the centre of the lifting lug.

6. Remove 6 bolts holding the non-drive endbracket to the

stator bar assembly. The endbracket is now ready for

removal.

7. Replace the lifting lug onto the endbracket and sling the

endbracket on a hoist to facilitate lifting.

2a. UCD224 Only Remove 6 bolts holding the adaptor at the

drive end. It may be preferred to sling the adaptor on a hoist.

8. Tap the endbracket around its perimeter to release from

the generator. The endbracket and exciter stator will

come away as a single assembly.

3. UCI224, UCI274, UCM224, UCM274, UCD274 Only Tap

the adaptor away from stator bar adaptor ring.

9. Remove the 4 screws holding the exciter stator to the

endbracket and gently tap the exciter stator to release it.

Replacement is a reversal of the above procedure.

3a. UCD224 Only Tap the adaptor away from stator bar

assembly.

ALL SINGLE BEARING GENERATORS

7.5.3.4 REMOVAL OF THE ROTOR ASSEMBLY

4. Ensure the rotor is supported at drive end on a sling.

Remove the permanent magnet generator. Refer to 7.5.3.1

Remove the four screws holding the sheet metal cover at the

non drive end and remove cover.

5. Tap the rotor from the non-drive end to push the bearing

clear of the endbracket and its position within an 'O' ring.

6. Continue to push the rotor out of the stator bore,

gradually working the sling along the rotor as it is

withdrawn, to ensure that it is fully supported at all times.

With the PMG rotor removed single

bearing generator rotors are free to move

in the frame. Ensure frame is kept in the

horizontal plane when lifting.

Caution !

Replacement of rotor assemblies is a reversal of the

procedures above.

TWO BEARING GENERATORS

Before commencing re-assembly, components should be

checked for damage and bearing(s) examined for loss of

grease.

1. Remove 2 screws holding the sheet metal cover around

the adaptor at the drive end and remove the cover.

2. Remove the bolts holding the adaptor to the endbracket

at the drive end.

Fitting of new bearing(s) is recommended during major

overhaul.

3. Tap off the adaptor. It may be preferred to sling the

adaptor first depending on its size and weight.

Before replacement of a single bearing rotor assembly, check

that the drive discs are not damaged, cracked or showing

other signs of fatigue. Also check that the holes in the discs

for drive fixing screws are not elongated.

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Damaged or worn components must be replaced.

When major components have been

replaced, ensure that all covers and

guards are securely fitted, before the

Caution !

generator is put into service.

7.6 RETURNING TO SERVICE

After rectification of any faults found, remove all test

connections and reconnect all control system leads. Restart

the set and adjust VOLTS control potentiometer on AVR

controlled generators by slowly turning clockwise until rated

voltage is obtained. Refit all terminal box covers/access

covers and reconnect heater supply.

Failure to refit all guards, access covers

and terminal box covers can result in

Caution !

personal injury of death.

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SECTION 8

SPARES AND AFTER SALES SERVICE

8.1 RECOMMENDED SPARES

Service parts are conveniently packaged for easy

identification. Genuine parts may be recognised by the Nupart

name.

We recommend the following for Service and Maintenance. In

critical applications a set of these service spares should be

held with the generator.

AVR Controlled Generators

1. Diode Set (6 diodes with surge suppressor) RSK 2001

2. AVR SX440

AVR SX460

E000 24030

E000 24602

E000 24210

E000 23212

E000 23410

AVR SX421

AVR MX321

AVR MX341

3. Non drive end Bearing

UC22 051

01032

01049

01044

01050

UC27 051

UC22 051

UC27 051

4. Drive end Bearing

Transformer Controlled Generators (UC22 Only)

1. Diode Set (6 diodes with surge suppressor) RSK 2001

2. Diode Assembly

E000 22006

3. Non drive end Bearing

4. Drive end Bearing

UC22 051

01032

01044

When ordering parts the machine serial number or machine

identity number and type should be quoted, together with the

part description. For location of these numbers see paragraph

1.3.

Orders and enquiries for parts should be addressed to:

STAMFORD & AvK Parts Department

Barnack Road

STAMFORD

Lincolnshire

PE9 2NB

ENGLAND

Telephone: 44 (0) 1780 484000

Fax: 44 (0) 1780 766074

Or any of our subsidiary companies listed on the back cover.

8.2 AFTER SALES SERVICE

A full technical advice and on-site service facility is available

from our Service Department at Stamford or through our

Subsidiary Companies. A repair facility is also available at our

Stamford Works.

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PARTS LIST

TYPICAL SINGLE BEARING GENERATOR

Plate Ref.

Description

Stator

Rotor

Exciter Rotor

Exciter Stator

N.D.E. Bracket

Cover N.D.E.

Bearing ‘O’ Ring N.D.E.

Bearing N.D.E.

Bearing Circlip N.D.E.

D.E. Bracket/Engine Adaptor

D.E. Screen

Coupling Disc

Couplimg Bolt

Foot

Frame Cover Bottom

Frame Cover Top

Air Inlet Cover

Terminal Box Lid

Endpanel D.E.

N.D.E.

D.E.

P.M.G.

A.V.R.

Non Driven End

Driven End

Permanent Magnet Generator

Automatic Voltage Regulator

Endpanel N.D.E.

AVR

Side Panel

AVR Mounting Bracket

Main Rectifier Assembly - Forward

Main Rectifier Assembly - Reverse

Varistor

Diode - Forward Polarity

Diode - Reverse Polarity

Lifting Lug - D.E.

Lifting Lug - N.D.E.

Frame to Endbracket Adaptor Ring

Main Terminal Panel

Terminal Link

Edging Strip

Fan

Foot Mounting Spacer

Cap Screw

AVR Access Cover

AVR Anti-Vibration Mounting Assembly

Auxiliary Terminal Assembly

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Fig. 11.

TYPICAL SINGLE BEARING GENERATOR

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PARTS LIST

TYPICAL TWO BEARING GENERATOR

Plate Ref.

Description

Stator

Rotor

Exciter Rotor

Exciter Stator

N.D.E. Bracket

Cover N.D.E.

Bearing ‘O’ Ring N.D.E.

Bearing N.D.E.

Bearing Wave Washer.D.E.

D.E. Bracket

D.E. Screen

Bearing D.E.

Foot

Frame Cover Bottom

Frame Cover Top

Air Inlet Cover

Terminal Box Lid

Endpanel D.E.

Endpanel N.D.E.

AVR

Side Panel

AVR Mounting Bracket

Main Rectifier Assembly - Forward

Main Rectifier Assembly - Reverse

Varistor

Diode - Forward Polarity

Diode - Reverse Polarity

Lifting Lug - D.E.

Lifting Lug - N.D.E.

Frame to Endbracket Adaptor Ring

Main Terminal Panel

Terminal Link

N.D.E.

D.E.

P.M.G.

A.V.R.

Non Driven End

Driven End

Permanent Magnet Generator

Automatic Voltage Regulator

Edging Strip

Fan

Foot Mounting Spacer

Cap Screw

AVR Access Cover

AVR Anti-Vibration Mounting Assembly

Auxiliary Terminal Assembly

PMG Exciter Rotor

PMG Exciter Stator

PMG Bolt

PMG Pillar

PMG Clamp

PMG Dowel

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Fig. 12.

TYPICAL TWO BEARING GENERATOR

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PARTS LIST

TYPICAL TWO BEARING (SERIES 5) GENERATOR

Plate Ref.

Description

Stator

Rotor

Exciter Rotor

Exciter Stator

N.D.E. Bracket

Cover N.D.E.

Bearing ‘O’ Ring N.D.E.

Bearing N.D.E.

Bearing Wave Washer N.D.E.

D.E. Bracket

D.E. Screen

Bearing D.E.

Foot

N.D.E.

D.E.

Non Driven End

Driven End

Frame Cover Bottom

Frame Cover Top

Air Inlet Cover

Terminal Box Lid

Endpanel D.E.

Endpanel N.D.E.

Series 5 Control Gear

Side Panel

Main Rectifier Assembly - Forward

Main Rectifier Assembly - Reverse

Varistor

Diode - Forward Polarity

Diode - Reverse Polarity

Lifting Lug - D.E.

Lifting Lug - N.D.E.

Frame to Endbracket Adaptor Ring

Main Terminal Panel

Terminal Link

Edging Strip

Fan

Foot Mounting Spacer

Cap Screw

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Fig. 13.

TYPICAL TWO BEARING (SERIES 5) GENERATOR

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Fig. 14.

ROTATING RECTIFIER ASSEMBLY

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A.C. GENERATOR WARRANTY

WARRANTY PERIOD

A.C. Generators

In respect of a.c. generators the Warranty Period is eighteen months from the

date when the goods have been notified as ready for despatch by N.I. or twelve

months from the date of first commissioning (whichever is the shorter period).

DEFECTS AFTER DELIVERY

We will make good by repair or, at our option, by the supply of a replacement,

any fault which under proper use appears in the goods within the period

specified on Clause 12, and is found on examination by us to be solely due to

defective material and workmanship; provided that the defective part is promptly

returned, carriage paid, with all identification numbers and marks intact, or our

works or, if appropriate to the Dealer who supplied the goods.

Any part repaired or replaced, under warranty, will be returned by N.I. free of

harge (via sea freight if outside the UK).

We shall not be liable for any expenses which may be incurred in removing or

replacing any part sent to us for inspection or in fitting any replacement supplied

by us. We shall be under no liability for defects in any goods which have not

been properly installed in accordance with N.I. recommended installation

practices as detailed in the publications 'N.I. Installation, Service and

Maintenance Manual' and 'N.I. Application Guidelines', or which have been

improperly stored or which have been repaired, adjusted or altered by any

person except ourselves or our authorised agents, or in any second-hand

goods, proprietary articles or goods not of our own manufacture although

supplied by us, such articles and goods being covered by the warranty (if any)

given by the separate manufacturers.

Any claim under this clause must contain fully particulars of the alleged defect,

the description of the goods, the date of purchase, and the name and address

of the Vendor, the Serial Number (as shown on the manufacturers identification

plate) or for Spares the order reference under which the goods were supplied.

Our judgement in all cases of claims shall be final and conclusive and the

claimant shall accept our decision on all questions as to defects and the

exchange of a part or parts.

Our liability shall be fully discharged by either repair or replacement as above,

and in any event shall not exceed the current list price of the defective goods.

Our liability under this clause shall be in lieu of any warranty or condition implied

by law as to the quality or fitness for any particular purpose of the goods, and

save as expressly provided in this clause we shall not be under any liability,

whether in contract, tort or otherwise, in respect of defects in goods delivered or

for any injury, damages or loss resulting from such defects or from any work

undone in connection therewith.

MACHINE SERIAL NUMBER

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REGISTERED OFFICE AND ADDRESS:

BARNACK ROAD

STAMFORD

LINCOLNSHIRE

PE9 2NB ENGLAND

Telephone: 44 (0) 1780 484000

Fax: 44 (0) 1780 484100

SUBSIDIARY COMPANIES

7. NORWAY:

NEWAGE NORGE A/S

1. AUSTRALIA : NEWAGE ENGINEERS PTY. LIMITED

PO Box 6027, Baulkham Hills Business Centre,

Baulkham Hills NSW 2153.

Økern Naeringspark, Kabeigt. 5

Postboks 28, Økern, 0508 Oslo

Telephone: Oslo (47) 22 97 44 44

Fax: (47) 22 97 44 45

Telephone: Sydney (61) 2 9680 2299

Fax: (61) 2 9680 1545

8. SINGAPORE:

NEWAGE ASIA PACIFIC PTE LIMITED

10 Toh Guan Road #05-03

TT International Tradepark

Singapore 608838

Telephone: Singapore (65) 794 3730

Fax: (65) 898 9065

2. CHINA:

WUXI NEWAGE ALTERNATORS LIMITED

Plot 49-A, Xiang Jiang Road

Wuxi High - Technical Industrial Dev. Zone

Wuxi, Jiangsu 214028

PR of China

Tel: (86) 51 027 63313

Telex: RS 33404 NEWAGE

Fax: (86) 51 052 17673

9. SPAIN:

STAMFORD IBERICA S.A.

3. GERMANY: NEWAGE ENGINEERS G.m.b.H.

Rotenbrückenweg 14, D-22113 Hamburg.

Telephone: Hamburg (49) 40 714 8750

Fax: (49) 40 714 87520

Ctra. Fuenlabrada-Humanes, km.2

Poligono Industrial "Los Linares"

C/Pico de Almanzor, 2

E-28970 HUMANES DE MADRID (Madrid)

Telephone: Madrid (34) 91 604 8987/8928

Fax: (34) 91 604 81 66

4. INDIA:

5. ITALY:

6. JAPAN:

C.G. NEWAGE ELECTRICAL LIMITED

C33 Midc, Ahmednagar 414111, Maharashtra.

Telephone: (91) 241 778224

10. U.S.A.:

NEWAGE LIMITED

4700 Main St, N.E.

Fridley

Minnesota 55421

Telephone: (1) 800 367 2764

Fax: (1) 800 863 9243

Fax: (91) 241 777494

NEWAGE ITALIA S.r.I.

Via Triboniano, 20156 Milan.

Telephone: Milan (39) 02 380 00714

Fax: (39) 02 380 03664

NEWAGE INTERNATIONAL JAPAN

8 - 5 - 302 Kashima

Hachioji-shi

Tokyo, 192-03

Telephone: (81) 426 77 2881

Fax: (81) 426 77 2884

TD_UC MAN GB_10.06_

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