Onan detector.pdf

9600515 72000

DFBJDFCFDFCG

Models

Detector ControlGENERATOR SETS

iTable of Contents

SECTION TITLE PAGESAFETY PRECAUTIONS iii, iv. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 INTRODUCTIONAbout this Manual 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test Equipment 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How To Obtain Service 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control and Generator Overview 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 AC CONTROL 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Standard Control Panel Components 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optional Control Panel Components 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Principle Of Generator Operation 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automatic Voltage Regulator (AVR) Adjustments 2-2. . . . . . . . . . . . . . . . . . . . . Optional Circuit Breaker 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 ENGINE CONTROL 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Standard Control Panel Components 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optional Control Panel Components 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control Box Interior 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Engine Control Monitor (A11) 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Engine Sensors 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Auxiliary Control Components 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sequence Of Operation 3-17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 TROUBLESHOOTINGThe Engine Does Not Crank In Run Mode 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . The Engine Does Not Crank In Remote Mode 4-3. . . . . . . . . . . . . . . . . . . . . . . The Engine Cranks But Does Not Start 4-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . The Engine Runs Until Fault Shutdown 4-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . The Engine Lacks Power Or Stable Speed 4-6. . . . . . . . . . . . . . . . . . . . . . . . . Engine Condition Warnings 4-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . There Is No Output Voltage (Engine Speed Is Stable) 4-9. . . . . . . . . . . . . . . . Output Voltage Is Too High Or Too Low 4-12. . . . . . . . . . . . . . . . . . . . . . . . . . . Output Voltage Is Unstable 4-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Field Circuit Breaker Keeps Tripping 4-14. . . . . . . . . . . . . . . . . . . . . . . . . . The Phase Currents Are Unbalanced 4-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ii

SECTION TITLE PAGE5 SERVICING THE GENERATOR

Testing the Generator 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exciter Stator 5-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exciter Rectifier Bridge (Rotating Rectifier Assembly) 5-3. . . . . . . . . . . . . . . . Exciter Rotor 5-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Main Rotor (Generator Field) 5-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Main Stator 5-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing the PMG 5-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Generator Disassembly 5-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Generator Assembly 5-17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 GOVERNORElectronic Governor 6-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7 OPTIONSTesting Optional AC Load Circuit Breaker 7-1. . . . . . . . . . . . . . . . . . . . . . . . . . . Day Tank Fuel Transfer Pump and Control 7-3. . . . . . . . . . . . . . . . . . . . . . . . . .

8 WIRING DIAGRAMSGeneral 8-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LS-12ciii

Safety Precautions

Before operating the generator set (genset), read theOperators Manual and become familiar with it and theequipment. Safe and efficient operation can beachieved only if the equipment is properly operatedand maintained. Many accidents are caused by failureto follow fundamental rules and precautions.

The following symbols, found throughout this manual,alert you to potentially dangerous conditions to the op-erator, service personnel, or the equipment.

This symbol warns of immediatehazards which will result in severe personal in-jury or death.

WARNING This symbol refers to a hazard or un-safe practice which can result in severe per-sonal injury or death.

CAUTION This symbol refers to a hazard or un-safe practice which can result in personal injuryor product or property damage.

FUEL AND FUMES ARE FLAMMABLE

Fire, explosion, and personal injury or death can resultfrom improper practices.

DO NOT fill fuel tanks while engine is running, un-less tanks are outside the engine compartment.Fuel contact with hot engine or exhaust is a potentialfire hazard.

DO NOT permit any flame, cigarette, pilot light,spark, arcing equipment, or other ignition sourcenear the generator set or fuel tank.

Fuel lines must be adequately secured and free ofleaks. Fuel connection at the engine should bemade with an approved flexible line. Do not use zinccoated or copper fuel lines with diesel fuel.

Be sure all fuel supplies have a positive shutoffvalve.

Be sure battery area has been well-ventilated priorto servicing near it. Lead-acid batteries emit a highlyexplosive hydrogen gas that can be ignited by arc-ing, sparking, smoking, etc.

EXHAUST GASES ARE DEADLY Provide an adequate exhaust system to properly

expel discharged gases away from enclosed orsheltered areas and areas where individuals arelikely to congregate. Visually and audibly inspectthe exhaust daily for leaks per the maintenanceschedule. Make sure that exhaust manifolds are se-cured and not warped. Do not use exhaust gases toheat a compartment.

Be sure the unit is well ventilated. Engine exhaust and some of its constituents are

known to the state of California to cause cancer,birth defects, and other reproductive harm.

MOVING PARTS CAN CAUSE SEVEREPERSONAL INJURY OR DEATH Keep your hands, clothing, and jewelry away from

moving parts. Before starting work on the generator set, discon-

nect battery charger from its AC source, then dis-connect starting batteries, negative (-) cable first.This will prevent accidental starting.

Make sure that fasteners on the generator set aresecure. Tighten supports and clamps, keep guardsin position over fans, drive belts, etc.

Do not wear loose clothing or jewelry in the vicinity ofmoving parts, or while working on electrical equip-ment. Loose clothing and jewelry can becomecaught in moving parts. Jewelry can short out elec-trical contacts and cause shock or burning.

If adjustment must be made while the unit is run-ning, use extreme caution around hot manifolds,moving parts, etc.

DO NOT OPERATE IN FLAMMABLE ANDEXPLOSIVE ENVIRONMENTSFlammable vapor can cause an engine to overspeed andbecome difficult to stop, resulting in possible fire, explo-sion, severe personal injury and death. Do not operate agenset where a flammable vapor environment can becreated by fuel spill, leak, etc., unless the genset isequipped with an automatic safety device to block the airintake and stop the engine. The owners and operators ofthe genset are solely responsible for operating the gen-set safely. Contact your authorized Onan/Cummins deal-er or distributor for more information.

iv

ELECTRICAL SHOCK CAN CAUSESEVERE PERSONAL INJURY OR DEATH Remove electric power before removing protective

shields or touching electrical equipment. Use rub-ber insulative mats placed on dry wood platformsover floors that are metal or concrete when aroundelectrical equipment. Do not wear damp clothing(particularly wet shoes) or allow skin surface to bedamp when handling electrical equipment.

Use extreme caution when working on electricalcomponents. High voltages can cause injury ordeath. DO NOT tamper with interlocks.

Follow all applicable state and local electricalcodes. Have all electrical installations performed bya qualified licensed electrician. Tag and lock openswitches to avoid accidental closure.

DO NOT CONNECT GENERATOR SET DI-RECTLY TO ANY BUILDING ELECTRICAL SYS-TEM. Hazardous voltages can flow from the gen-erator set into the utility line. This creates a potentialfor electrocution or property damage. Connect onlythrough an approved isolation switch or an ap-proved paralleling device.

GENERAL SAFETY PRECAUTIONS Coolants under pressure have a higher boiling point

than water. DO NOT open a radiator or heat ex-changer pressure cap while the engine is running.

Allow the generator set to cool and bleed the systempressure first.

Used engine oils have been identified by some stateor federal agencies as causing cancer or reproduc-tive toxicity. When checking or changing engine oil,take care not to ingest, breathe the fumes, or con-tact used oil.

Provide appropriate fire extinguishers and installthem in convenient locations. Consult the local firedepartment for the correct type of extinguisher touse. Do not use foam on electrical fires. Use extin-guishers rated ABC by NFPA.

Make sure that rags are not left on or near the en-gine.

Remove all unnecessary grease and oil from theunit. Accumulated grease and oil can cause over-heating and engine damage which present a poten-tial fire hazard.

Keep the generator set and the surrounding areaclean and free from obstructions. Remove any de-bris from the set and keep the floor clean and dry.

Do not work on this equipment when mentally orphysically fatigued, or after consuming any alcoholor drug that makes the operation of equipment un-safe.

Substances in exhaust gases have been identifiedby some state or federal agencies as causing can-cer or reproductive toxicity. Take care not to breathor ingest or come into contact with exhaust gases.

KEEP THIS MANUAL NEAR THE GENSET FOR EASY REFERENCE

1-1

1. Introduction

ABOUT THIS MANUALThis manual provides troubleshooting and repairinformation for the controls and generators used onthe generator sets listed in Table 1-1.Engine service instructions are in the applicableengine service manual. Operation and mainte-nance instructions are in the applicable OperatorsManual.This manual does not have instructions forservicing printed circuit board assemblies. Afterdetermining that a printed circuit board assembly isfaulty, replace it. Do not attempt to repair a printedcircuit board, this can result in costly damage to theequipment.This manual contains basic (generic) wiring dia-grams and schematics that are included to help introubleshooting. Service personnel must use theactual wiring diagram and schematic shippedwith each unit. The wiring diagrams and schemat-ics that are maintained with the unit should be up-dated when modifications are made to the unit.Read the Safety Precautions section on pages iiiand iv and carefully follow all of the instructions andprecautions in this manual.

TEST EQUIPMENTMost of the test procedures in this manual can beperformed with an AC-DC multimeter such as a

Fluke model 87. Additional instruments required toservice the genset are: Battery Hydrometer Tachometer or Frequency Meter Jumper Leads Wheatstone Bridge or Digital Ohmmeter Variac Load Test Panel Megger or Insulation Resistance Meter

HOW TO OBTAIN SERVICEAlways give the complete model, specification, andserial number of the generator set as shown on thenameplate when seeking additional service in-formation or replacement parts. The nameplate islocated on the side of the generator output box.For replacement parts identification, refer to theParts Manual supplied with the generator set.

WARNING Incorrect service or replacement ofparts can result in severe personal injury ordeath, and/or equipment damage. Service per-sonnel must be qualified to perform electricaland mechanical service. Read and follow SafetyPrecautions, on pages iii and iv.

1-2

CONTROL AND GENERATOR OVERVIEWGeneralRead through this manual to identify the controloptions, and generator type. The control andgenerator are described in more detail in the controland generator sections.Periodically review this manual and the OperatorsManual to become familiar with the generator setoperation and troubleshooting procedures.Control PanelThe control panel is located inside the front portion

of the generator output box. The control panel ismounted to the genset with vibration isolators. Thecontrol assembly is separated into a DC panel formonitoring the engine and an AC panel for monitor-ing the generator. See Figures 2-1 and 3-1.

GeneratorThe generator sets covered in this manual use aPermanent Magnet Generator (PMG).The generators are controlled by an Automatic Volt-age Regulator (AVR). The AVR is mounted on theinside, back wall of the control panel. See Figure2-3.

VOLTAGE REGULATOR(LOCATED INSIDECONTROL PANEL)

CONTROL PANEL

PMGHOUSINGCOVER PLATE (FOR

ACCESS TO ROTATINGRECTIFIER ASSEMBLY)

OTHER GENERATOR CONTROLCOMPONENTS (OVER/UNDER

VOLTAGE AND FREQUENCY MODULES,ETC.) ARE LOCATED INSIDE CONDUIT

BOX

AC METERING CURRENTTRANSFORMERS (LOCATED INSIDE

CONDUIT BOX)

PMG VOLTAGE REGULATOR

FIGURE 1-1. TYPICAL PMG GENERATOR AND CONTROLS

2-1

2. AC Control

GENERALThe control box is mounted above the generator.The AC section of the control panel is used to moni-tor the generator (if equipped with meter options).Figure 2-1 shows the components on the AC controlpanel. Section 8 shows the wiring connections.

STANDARD CONTROL PANELCOMPONENTS

Field Circuit Breaker (CB21) The field circuitbreaker protects the generator from over-excitation.

OPTIONAL CONTROL PANELCOMPONENTS

AC Voltmeter (M21) The voltmeter indicates outputvoltage for the phase selected.AC Ammeter (M22) The ammeter indicates outputamperage for the phase selected. Input to the am-meter is from current transformers CT21, CT22 andCT23.

Phase Selector Switch (S21) The selector switchis used to select the phase for voltage and amper-age readings.

Scale Indicator Lamps (DS21 and DS22) Thescale indicator lamps indicate whether to read theupper or lower scales of the voltmeter and ammeter.

Frequency Meter (M23) The frequency meter indi-cates output frequency in Hertz (Hz) and enginespeed in RPM.

Wattmeter (M24) The wattmeter indicates outputpower in kilowatts (kW).

Powerfactor Meter (M25) The power factor meterindicates load power factor as a percentage of unitypower factor.

Output Voltage Trimmer (R21) The output voltagetrimmer can be used to adjust output voltage plus orminus five percent of nominal voltage.

SCALEINDICATOR

LAMPS

FIELDCIRCUIT

BREAKER

ACVOLTMETER

ACAMMETER

PHASESELECTOR

SWITCHFREQUENCY

METER

WATTMETER

POWERFACTORMETER

OUTPUTVOLTAGETRIMMER

FIGURE 2-1. AC CONTROL PANEL

2-2

AVR

MAIN ROTOREXCITERROTOR

ANDSTATOR

PMGROTOR

ANDSTATOR

MAIN STATOR

ROTATINGMECHANICALPOWERINPUT

ELECTRICAL POWER OUTPUT

FIGURE 2-2. DIAGRAM OF PMG EXCITED GENERATOR OPERATION

PRINCIPLE OF GENERATOR OPERATION

Refer to Figure 2-2 during the generator operationdescription.1. The Permanent Magnet Generator (PMG) pro-

vides power for excitation of the exciter field.Output from the PMG is supplied via the auto-matic voltage regulator (AVR) to the exciter.The PMG consists of a stator and a permanentmagnet rotor mounted on the end of the mainrotor shaft.

2. The AVR senses a signal from the main stator,compares it with a reference value, and re-sponds by supplying a controlled excitationcurrent to the exciter stator.

3. The exciter field (stator) induces current in theexciter rotor windings. A full wave rectifierbridge (rotating rectifiers), mounted on theexciter rotor, converts exciter output (3-phaseAC) to DC. DC output from the rotating rectifi-ers is supplied to the main rotor.

4. Generator field strength is proportional to thefield current supplied by the exciter. Generatoroutput current is proportional to field strength,which is varied to match the load. Output volt-age and frequency are held constant by thevoltage regulator and engine governor, respec-tively.

VOLTAGE REGULATOR ADJUSTMENTS

Generator output voltage is adjusted by the optionalvoltage trimmer rheostat (R21) located on thecontrol front panel and by the voltage regulatorlocated inside the control panel (see Figure 2-3).

Two, similar PMG voltage regulators have been usedin permanent magnet exciter generator sets. One is afour position mount, and the newer of the two has sixmounting holes (only four are used). Adjustmentprocedures are the same for both, even though thepotentiometers are located differently. Refer to Fig-ure 2-3 to identify which AVR the genset uses.

The generator voltage may be adjusted within 5percent of the rated nameplate voltage via theoptional control-panel mounted voltage trimmerrheostat (R21). If the adjustment cannot be madewith R21, or if R21 is not installed, adjust the voltageregulator as described under Voltage and VoltageStability Adjustments in this section.

These measurements and adjustments are donewhile the set is running and require access to unin-sulated high voltage parts in the control and poweroutput boxes.

2-3

7 8 1 2

VOLTAGE REGULATOR(VR21)

VOLTAGE REGULATOR (VR21) PRIOR TO JANUARY 1990

VOLTAGE REGULATOR (VR21) BEGINNING JANUARY 1990

3 2 1

C B A S1 S2 A1 A2S1 S2S1 S2E0 E1 B0 B1

K1 K2 P2 P3 P4 XX X 6

NO LINK 6P - 506P - 604P - 504P - 60

U V W

E0 E1 B0 B1

K1 K2 P2 P3 P4 XX X 6 7 8 1 2

S1 S2

U V W

S1 S2 S1 S2 A1 A2

A TO C UNDER 90 KW

A TO B OVER 550 KWB TO C 90 550 KW

OPTIMUMRESPONSESELECTION

DWELL STABILITY

OVER/V DROOP V/TRIM

UNDER FREQUENCY

DIP RMS

FREQUENCYSELECTION

VOLTS

I/LIMIT

VOLTS I/LIMITUNDER FREQUENCY

DIPLARGE

CAPACITOR

RMS

OVER/V

EXCTRIP

EXCTRIP

STABILITY 1

STABILITY 2

DROOP V/TRIM

FIGURE 2-3. VOLTAGE REGULATOR ADJUSTMENT POTS AND SELECTION JUMPERS

2-4

HIGH VOLTAGE. Touching uninsu-lated high voltage parts inside the control andpower output boxes will result in severe per-sonal injury or death. Measurements and ad-justments must be done with care to avoidtouching high voltage parts.

Stand on a dry wooden platform or rubber insu-lating mat, make sure your clothing and shoesare dry, remove jewelry and wear elbow lengthinsulating gloves.

Jumper Reconnections

Jumpers provide for reconnections to adapt thevoltage regulator to the application. See Figure 2-3.Reconnect the response jumper, if necessary, sothat terminal B connects to terminal C if generatoroutput is greater than 90 kW but less than 550 kWand A to B if output is greater than 550kW. Recon-nect the frequency jumper, if necessary, to corre-spond to the application frequency. (ReplacementAVRs are preset for 50 Hz operation.)

Voltage and Voltage Stability AdjustmentsUse the control panel mounted voltage trimmer, ifprovided, for small voltage adjustments. Measuregenerator output voltage while the set is runningwithout load at the nominal frequency. If the trimmerdoes not provide enough adjustment, lock it at itsmidpoint. Then turn the VOLTS pot fully counter-clockwise and the STABILITY pot to its midpoint. Ifthe red LED (light emitting diode) on the boardlights, refer to Jumper Reconnections and to UFROAdjustments. Then turn the VOLTS pot clockwiseuntil rated voltage is obtained. If voltage becomesunstable when a large load is connected, turn theSTABILITY pot clockwise until voltage is stable.Check and readjust the VOLTS pot, if necessary,each time the STABILITY pot is readjusted.

UFRO AdjustmentsThe voltage regulator has an under-frequency pro-tection circuit having a threshold frequency that canbe preset (typically at 59 Hz for 60 Hz applicationsand 49 Hz for 50 Hz applications). The red LED onthe board lights when frequency dips below thethreshold. The threshold frequency is preset byturning the UFRO (under frequency roll off) potclockwise to raise it and counterclockwise to lowerit. Use an insulated handle screw driver to preventelectrical shock. Set UFRO as follows:

1. Make a note of the no-load frequency.2. Determine the roll-off frequency by turning the

governor speed pot (to lower frequency) untilthe LED lights. If roll-off frequency is okay, go tostep 5. If roll-off frequency is incorrect, go tostep 3.

3. Adjust the governor speed pot to the properroll-off frequency.

4. Turn the UFRO pot until LED goes off, thenslowly turn it back until the LED just goes on.

5. Adjust the governor speed pot back to the initialfrequency setting.

Note that Dip and Dwell adjustments, below, arerelated.

Dip AdjustmentsThe DIP pot adjusts the voltage vs. frequency slopeof the generator for frequencies below the thresholdpreset by the UFRO pot. Turning the DIP pot clock-wise increases the slope (for greater voltage roll offas frequency drops), making it easier for the engineto pick up a large load, but also increasing the volt-age dip. The generator voltage vs. frequency slopeis the same above and below the threshold fre-quency when the pot is turned fully counterclock-wise.

Dwell AdjustmentsThe DWELL pot times voltage recovery when fre-quency dips below the preset threshold. Clockwiseadjustment increases dwell time. Full counterclock-wise adjustment eliminates dwell, in which case,voltage recovery follows engine speed recovery.

Droop AdjustmentsThe DROOP pot is for adjusting the input signalfrom the droop compensating CT in parallelingapplications. DROOP is preset at the factory for fivepercent droop at full load and zero power factor.

V/Trim AdjustmentsThe V/Trim pot is for adjusting the input signal froma VAR/PF controller in utility paralleling applica-tions. Full clockwise adjustment is normal, resultingin maximum sensitivity. The auxiliary controller hasno effect when the pot is turned fully counterclock-wise.

EXC, OVER V, I/LIMIT, STAB/1and RMSThese pots are factory preset and do not requireadjustment.

2-5

TB21 K1 K2 P2 P3 P4 S2 S1 A2 A1XXXX 8 7 6 3 2 1

876

23

25

K1K2

78

XXX

22

6

7

6

8

NS

21

E1

E0

P4

P2P3

X78 6 78 6

INPUT OUTPUT

ISOLATION TRANSFORMER(NOTE 3)

MX321VOLTAGE

REGULATOR(VR21)

A2

A1

OUTPUTVOLTAGESENSINGLEADS(NOTE 2)

PMGSTATOR

PMGROTOR

EXCITERROTOR

ROTATINGRECTIFIERS

MAINROTOR

MAINSTATOR

EXCITERSTATOR

AUXILIARY TERMINAL BOARD

24

32

21

VOLTAGETRIMMER R21

(NOTE 4)

FIELD CIRCUITBREAKER

CB21

NOTES 1. Connect like numbered terminals on auxiliary

terminal board and voltage regulator.2. See the appropriate reconnection diagram for

connecting sensing leads AUX -6, -7 and -8.3. When the generator is connected for single-

phase output, voltage regulator terminal 6 is

not connected to the isolation transformer butis jumpered to voltage regulator terminal 8.

4. There must be a jumper between voltage regu-lator terminals 1 and 2 when voltage trimmerR21 is not used.

WHEN PARALLELING WITHA UTILITY, TERMINALS A1

AND A2 ARE FORCONNECTING A

VAR / POWER FACTORCONTROLLER

WHEN PARALLELING WITHA GENERATOR SET ORUTILITY, TERMINALS S1

AND S2 ARE FORCONNECTING A DROOP

COMPENSATING CTWS2WS1VS2VS1US2US1

FIGURE 2-4. TYPICAL VOLTAGE REGULATING CIRCUITS FOR PMG-EXCITED GENERATORS

2-6

OPTIONAL CIRCUIT BREAKEROptional circuit breakers are available that can bemounted in the generator AC output box.DescriptionOptional breakers are of the thermal and magnetictrip type. Depending on customer requirements, thebreaker may also include shunt trip and remotealarm connections. Review the following descrip-tions and requirements (refer to Figure 2-5).Generator set output is connected to the loadthrough the circuit breaker.When an overload or short circuit occurs on any oneconductor, a common trip bar will disconnect allthree conductors.

The thermal trip action of the breaker is accom-plished by bimetal strips. A sustained overcurrentcondition will cause a thermal reaction of thebimetal and trip the breaker. Response of thebimetal is proportional to current; high currentfastresponse, low currentslow response. This actionprovides a time delay for normal inrush current andtemporary overload conditions such as motor start-ing.The magnetic trip action of the breaker is caused byan electromagnet, which partially surrounds the in-ternal bimetal strips. If a short circuit occurs, thehigh current through the electromagnet will attractthe bimetal armature and trip the breaker. Somebreaker models provide front adjustment of themagnetic trip action. These adjustments are nor-mally set at the factory at the high position, but pro-

vide for individual conductor settings to suit cus-tomer needs.

The shunt trip mechanism (if equipped) consists ofa solenoid tripping device mounted in the breakerwith external lead connections for remote signaling.A momentary signal to the solenoid coil will causethe breaker to trip.

This feature is available in AC or DC voltages, andis normally installed at the factory to meet customerneeds. The shunt trip mechanism is most often con-nected to a common alarm.

Auxiliary contacts (if equipped) are used for local orremote annunciation of the breaker status. Theyusually have one normally-open and one normally-closed contact (1 form C contacts) to comply withthe annunciator requirement.

The trip actuator (if applicable) is for periodic exer-cise of the breaker to clean and maintain its properoperation. Rotating this actuator mechanicallysimulates over-current tripping through actuation oflinkages not operated by the On/Off handle. SeeSection 7, Options, for further information.

Operation of the circuit breaker is determined bysite-established procedures. In emergency stand-by installations, the breaker is often placed to theOn position, and is intended for safety trip actuationin the event of a fault condition. If the breaker tripsopen, investigate the cause and perform remedialsteps per the troubleshooting procedures. To closethe breaker, the handle must be placed to the Resetposition and then to On.

GENERATOROUTPUT BOX

CURRENTTRANSFORMER

L0TO LOAD SIDE VIEW - HANDLE POSITIONSSHUNT TRIP

+COMMON ALARMGROUND

AUXILIARYA

BCOMMON

ONTRIPOFF

RESET

FIGURE 2-5. TYPICAL GENERATOR-MOUNTED CIRCUIT BREAKER

3-1

3. Engine Control

GENERAL

The control box is mounted on top of the generator,facing the rear. Figure 3-1 shows the componentson the engine control panel.

STANDARD CONTROL PANELCOMPONENTS

Run/Stop/Remote Switch (S12) The switch ispushed to the Run position to start and run the gen-erator set and the Stop position to stop the set. TheRemote position allows a remote controller to auto-matically run the set. The switch must be in the Stopposition when the reset switch (described next) isused to restore generator set operation following afault shutdown.

Reset/Lamp Test/Panel Lamp Switch (S11) Theswitch is pushed to the Reset position (momentarycontact) to reset the engine control to restore opera-tion following a fault shutdown. The Run/Stop/Re-mote switch must be in the Stop position for reset tooccur. On later production controls this switch has alight that illuminates following a fault or emergencyshutdown. This light remains lit until the engine con-trol has been reset.

The Lamp Test position (momentary contact) lightsall the fault indicator lamps. Replace lamps that donot light.The Panel Lamp position lights the panel illumina-tion lamp.

Oil Pressure Gauge (M11) The oil pressure gaugeindicates engine oil pressure.

OIL PRESSUREGAUGE

COOLANTTEMPERATURE

GAUGE

DCVOLTMETER

OIL TEMPERATURE GAUGE

TACHOMETER EMERGENCY STOPBUTTON

RUN/STOP/REMOTESWITCH

HOURMETER

INDICATORLAMPS

RESET/LAMP TEST/PANEL LIGHT SWITCH

PANELLIGHT

SPEEDADJUSTINGRHEOSTAT

ENGINEEXHAUST

PYROMETER

FIGURE 3-1. ENGINE CONTROL PANEL

3-2

Coolant Temperature Gauge (M12) The coolanttemperature gauge indicates engine coolant tem-perature.DC Voltmeter (M13) The DC voltmeter indicatesvoltage across the battery terminals during opera-tion.Hour Meter (M14) The hour meter indicates the ac-cumulated number of hours the set has run. It can-not be reset.Panel Lamp (DS11) The panel lamp illuminates thecontrol panel.Fault and Status Indicator Lamps (A12) Run (Green) This lamp indicates that the gen-

erator set is running and that the starter hasbeen disconnected.

Pre Low Oil Pressure (Yellow) This lamp indi-cates that engine oil pressure is abnormally low(less than 20 psi).

Low Oil Pressure (Red) This lamp indicatesthat the engine shut down because of exces-sively low engine oil pressure (less than14 psi).

Pre High Engine Temperature (Yellow) Thislamp indicates that engine coolant tempera-ture is abnormally high (greater than 220 F).

High Engine Temperature (Red) This lampindicates that the engine shut down because ofexcessively high engine coolant temperature(greater than 230 F).

Overspeed (Red) This lamp indicates that theengine shut down because of overspeed.

Overcrank (Red) This lamp indicates that theengine shut down because it did not start dur-ing the timed cranking period (approximately75 seconds, including two rest periods).

Fault 1 (Red) This lamp indicates that the en-gine shut down because of a system fault. Thecustomer has to make connections to use thislamp. The lamp is a part of a 10 second time de-lay shutdown circuit. The customer can makereconnections for non-timed shutdown. SeeEngine Control Monitor (ECM).

ORBasin (Yellow) This (optional) lamp indicatesthat the inner fuel tank is leaking and the fuel isgathering in hte outer basin. This fault is nor-mally set for a warning while the genset is run-ning or is in the standby mode. See EngineControl Monitor.

FIGURE 3-2. FAULT/STATUS INDICATOR LAMPS

3-3

Fault 2 (Red) This lamp indicates that the en-gine shut down because of a system fault. Thecustomer has to make connections to use thislamp. The lamp is part of a non-time delay shut-down circuit. The customer can make recon-nections for 10 second time delay shutdown.See Engine Control Monitor (ECM).

Low Engine Temperature (Yellow) This lampindicates that engine temperature is less than70 F, and the possibility that the engine mightnot start.

Low Fuel (Yellow) This lamp indicates that thefuel level in the supply tank has dropped to lessthan the reserve necessary to run the set at fullload for the prescribed number of hours. Thecustomer has to make connections to use thislamp.

Switch-off (Flashing Red) This lamp indi-cates that the Run/Stop/Remote switch is inthe Stop position, which prevents remote,automatic operation.

OPTIONAL CONTROL PANELCOMPONENTS

Oil Temperature Gauge (M15) The oil temperaturegauge indicates engine oil temperature.Tachometer (M16) The tachometer indicates en-gine speed in RPM.Speed Adjusting Rheostat (R11) The speed ad-justing rheostat is used to adjust engine speed fromthe control panel (an option with the optional electricgovernor).Engine Exhaust Pyrometer (M26) The pyrometerindicates engine exhaust gas temperature. On dualexhaust systems, a switch is used to select the sen-sor to be monitored.Emergency Stop Button (S14) The emergencystop button is a red, push-in switch used to stop theengine. The button lights up when it is pushed in.The button has to be pulled out and the engine con-trol reset to restore operation.

3-4

A13 A14ARM RELAY MODULES

TERMINAL BOARD TB21

AUTOMATICVOLTAGE

REGULATORVR21

ENGINECONTROL

MONITOR A11

RUN RELAYS K11 (MOUNTED ON A BRACKET

IN FRONT OF A11)

TIME DELAYSTART/STOP MODULE A15

OVERSPEED MODULE

FIGURE 3-3. LOCATION OF COMPONENTS INSIDE CONTROL BOX

CONTROL BOX INTERIOR

Figure 3-3 shows the arrangement of componentsinside the control box, including the engine controlmonitor and some of the auxiliary components un-der following headings.

ENGINE CONTROL MONITOR (A11)The heart of the engine control system is the enginecontrol monitor (ECM) (Figure 3-4). It is a printedcircuit board assembly mounted on the back wall ofthe control box. It starts and stops the engine in re-sponse to the control panel switches, engine sen-sors and remote control signals.

Terminals and Connectors

See Section 8 for the appropriate connection andschematic drawings for the DC control system. Alsorefer to Section 8 for typical customer connectionsat terminal boards TB1 and TB2 on the ECM and forinformation on the auxiliary relay board (ifequipped).

FusesThe ECM has five replaceable fuses to protect itfrom overloads and groundfaults. They are:F1 Starter solenoid circuit, 20 ampsF2 Fuel solenoid (switched B+) circuits, 20 ampsF3 Continuous B+ out to remote circuits, 15 ampsF4 ECM circuits, 5 ampsF5 Engine gauge circuits, 5 ampsFunction Selection JumpersECM boards have six selection jumpers that can berepositioned to provide the following timed ornon-timed warnings or timed or non-timedshutdowns with warnings:W1 (12 light only) Jumper Position (jumper W8

must be in the B position):A Non-timed warning under FLT 2

conditions.B Non-timed shutdown under FLT 2

conditions.C Timed warning under FLT 2 conditions.D Timed shutdown under FLT 2 conditions.

3-5

W2 (12 light only) Jumper Position (jumper W9must be in the B position):

A Non-timed warning under FLT 1conditions.

B Non-timed shutdown and under FLT 1conditions.

C Timed warning under FLT 1 conditions.D Timed shutdown under FLT 1 conditions.

W6 Jumper Position:A Warning under Pre-High Engine

Temperature conditions.B Shutdown under Pre-High Engine

Temperature conditions.

W7 Jumper Position:A Warning under Pre-Low Oil Pressure

conditions.B Shutdown under Pre-Low Oil Pressure

conditions.W8 (12 light only) Jumper Position:

A Warning while running or during standbyunder FLT 2 conditions.

B Allows selection of functions with W1jumper.

W9 (12 light only) Jumper Position:A Warning while running or during standby

under FLT 1 conditions.B Allows selection of functions with W2

jumper.

8 7 6 5 4 3 2 1 6 5 4 3 2 1

FIGURE 3-4. ENGINE CONTROL MONITOR FUSES AND FUNCTION SELECTION JUMPERS

3-6

ENGINE SENSORS

Figure 3-5 shows the locations of the gauge send-ers and the coolant temperature and oil pressure

sensing switches that the ECM monitors. Theswitches function by closing the fault or warningcircuit to the engine chassis ground (batterynegative []).

HIGH ENGINETEMP SWITCH

500-2594

COOLANT TEMPGAUGE SENDER

PRE-HIGH ENGINETEMP SWITCH LOW ENGINE

TEMP SWITCH

LOW OIL PRESSURESWITCH (FAR SIDE)

OIL PRESSURE GAUGESENDER (FAR SIDE)

PRE-LOW OIL PRESSURESWITCH (FAR SIDE)

FIGURE 3-5. ELECTRONIC OVERSPEED MODULE

3-7

Low Coolant Level Cutout SwitchWhen coolant level in the radiator top tank falls be-low the switch sensor, the switch closes the circuit toground. This switch may be connected in parallelwith the high engine temperature cutout switch toshut down the engine and light the High EngineTemperature lamp or in parallel with the pre-highengine temperature switch to light the Pre High En-gine Temperature light only.

SWITCH TERMINALS

SCHEMATICS

LOWCOOLANT

LEVELSWITCH (S7)

RADIATORTANK TOP

WARNINGONLY

SHUTDOWN

ENGINEGROUND

SWITCHS2 OR S6

SWITCHEDB+ (T26)

FIGURE 3-6. LOW COOLANT LEVEL SWITCH

3-8

AUXILIARY CONTROL COMPONENTSThe set might be equipped with one or more of thefollowing components.

Electronic Overspeed ModulePMG-excited generators are equipped with an elec-tronic overspeed module in the control box. The

module senses PMG output frequency to determinegenerator speed (frequency). Adjust the overspeedpot (HIGH) to cut out at 1800 to 1900 RPM for 50 Hzsets and 2100 to 2200 RPM for 60 Hz sets.For non-PMG generator sets, speed sensing is partof the engine ignition system and is not adjustable.50 and 60 Hz sets are both set at 2100 to 2200RPM.

VR21-P2

A11TB1-1Not Used

Not Used

A11TB1-5

VR21-P3

A11TB1-10

OVERSPEEDADJUSTMENT

POT

FIGURE 3-7. ELECTRONIC OVERSPEED MODULE

3-9

Auxiliary Relay Board (ARB) (Optional)The following describes the design/functional crite-ria for the auxiliary relay board (ARB) (Figure 3-8).The board is mounted directly on top of the ECM us-ing standoffs and has access holes for the fuses lo-cated on the ECM. Page 8-10 is a detailed connec-tion diagram for the ARB.

Terminal BlocksTB1 ARB TB1 and ECM TB1 are identically num-bered and provide the same remote control connec-tion points. Note that additional terminals are pro-vided for terminals 5, 7, and 10 of ARB TB1.TB2 through TB5 Connection points for relaysK1 through K3. TB2 provides the N/O and N/C con-nections (three form C contacts for each relay).TB3 through TB5 provide the common connectionpoints (TB3 for K1, TB4 for K2 and TB5 for K3).TB6 and TB7 Connection points for fault relaysK4 through K15. Three terminals are provided foreach relay, which are labeled COM, N/C, N/O.

Plug-In Relays (K1, K2, K3)The ARB can be equipped with one to three 3-pole,double-throw relays. These relays (K1, K2, K3) arefield changeable plug-in relays for easy field addi-tion and replacement.The relay contact ratings are: 10 amps at 28 VDC or 120 VAC, 80% PF 6 amps at 240 VAC, 80% PF 3 amps at 480 VAC, 80% PF

Each relay can be operated as a RUN, COMMONALARM, or ISOLATED COIL with the changing of ajumper.Jumper Positions for Plug-In RelaysJumpers W1, W2, and W3 perform the same func-tions for their respective relays, W1 for relay K1, W2for relay K2, and W3 for relay K3. They can be lo-cated in any of 3 positions (A, B, C) independently ofeach other.

Jumper Position A (Run): The relay operatesas a Run relay, energizing when SW B+ is ap-plied from the ECM.Jumper Position B (Common Alarm): Therelay operates as a Common Alarm relay. Therelay energizes any time there is an engineshutdown. This signal is provided from theECM.Jumper Position C (Isolated): The relay op-erates as an Isolated relay. The relay coil is en-ergized by a customer applied B+ signalthrough the terminal block; TB3-1 for relay K1,TB4-1 for relay K2, and TB5-1 for relay K3.

Jumpers W11, W12, and W13 perform the samefunctions for their respective relays; W11 for relayK1, W12 for relay K2, and W13 for relay K3. Theycan be located in two different positions (A, B) inde-pendently of one another.

Jumper Position A: The relay operates iso-lated from the board. The customer providesthe circuit completion through terminal block;TB3 for relay K1, TB4-5 for relay K2, and TB5-5for relay K3. The customer can operate the re-lay with switched ground logic or use this relayin the middle of more complex logic circuits ifneeded.Jumper Position B: The relays operate withthe coils connected to ground through theboard connections. The coil will require a B+signal to energize with the jumper in this posi-tion.

Fault Relays (K4 through K15)These relay modules are used to operate a remotealarm annunciator that has an independent powersource. This allows the use of either AC or DC foralarm drives. The relays are energized through thelatching relays on the ECM and provided N/O andN/C contacts for each external alarm connection.

The 12 relays with form C contacts are rated: 10 Amp, 120 VAC 10 Amp. 30 VDC

3-10

K1 K2 K3

RUN RELAYMODULE(S)

JUMPERS

J1, J2 WIREHARNESS PLUGCONNECTIONS

FROM ECM

JUMPERS

FIGURE 3-8. AUXILIARY RELAY BOARD

3-11

Time Delay Start / Stop Module (Optional)The set can be equipped with a module to delaystarting and stopping when the start and stop sig-nals are received from the remote controller. It is ad-justable to delay starts from 1 to 15 seconds to pre-

vent nuisance starts in installations where momen-tary power interruptions are frequent. It is adjust-able to delay stops 1 to 30 minutes to allow theprime source of power time to stabilize and the gen-erator set to cool down.

TB1

TIME DELAY STOPPOTENTIOMETER

TIME DELAY STARTPOTENTIOMETER

A11-TB1-2(PRIMARY START DISCONNECT)

A11-TB1-3(SECONDARY START DISCONNECT)

A11-TB1-7(B+)

REMOTECONTROL

A11-TB1-6(REMOTE START)

A11-TB1-7(B+)

A11-TB1-5(B)

FIGURE 3-9. TIME DELAY START / STOP MODULE (A15)

3-12

Over/Under Voltage Module (A17)The set can be equipped with an adjustable volt-age-sensitive relay usually connected into the Fault1 circuit. The module will shut down the set whenthe output voltage is over or under nominal voltageby the preselected percentage (typically 10 percentover and under).This module has an adjustable time delay relay(K17), used on early production gensets to allow anover/under voltage condition during startup (laterproduction gensets use the engine control monitordelay). An adjustment of 25 percent is equivalent toabout 2.5 seconds delay.Recalibrate the module as follows before installingit on 139/240 VAC or 277/480 VAC sets.

WARNING Contact with high voltage can causesevere personal injury or death. Do not touchany exposed wiring or components with anybody part, clothing, tool or jewelry. Stand on aninsulating mat or dry wood platform when per-forming these steps.1. Remove the two screws that secure the top to

the case of the module and withdraw the topassembly.

2. Adjust the SET pot for the UNDER setpoint onthe face of the top assembly to 75 percent.

3. Apply single-phase, 60 Hertz, 104.25 VACacross terminals L and N.

4. Adjust pot R25 on the PC board until the relaytrips (de-energizes).

5. Adjust the SET pot for the OVER setpoint onthe face of the top assembly to 125 percent.

6. Apply single-phase, 60 Hertz, 173.75 VACacross terminals L and N.

7. Adjust pot R26 on the PC board until the relaytrips (energizes).

8. Repeat the above steps until no adjustmentsare necessary.

9. Reassemble the module.10. On the module nameplate mark out the factory

calibration value for monitored voltage (120 V)and write in 139 V.

* CONNECTED TO TB11-45 WHEN GENERA-TOR IS PARALLELED.

** CONNECTED TO GENERATOR LEAD LOWHEN THE GENERATOR IS CONNECTEDFOR SINGLE PHASE.

**

**

FIGURE 3-10. OVER/UNDER VOLTAGEMODULE

3-13

Over/Under Frequency Module (A19)The set can be equipped with an adjustable fre-quency-sensitive relay to shut down the set whenthe output frequency (Hz) is over or under nominalfrequency by the preselected amount (Figure 3-11).It is usually connected into the Fault 2 circuit if theover / under voltage module is also provided. Setpoints are typically 5 Hertz over and under nominalfrequency (50 or 60 Hertz) and reset points 3 Hertzover and under.

FIGURE 3-11. OVER/UNDER FREQUENCYMODULE

3-14

Ground Fault Relay (Optional)The optional Ground Fault Relay is typically locatedbehind the lower control housing grille. The groundfault relay continuously monitors the neutral toground connection and activates a fault alarm whenthe connection is broken. During genset operation,the relay continuously monitors the line to neutraland activates a fault alarm when a ground fault issensed.

The relay alarm contacts are typically connected tothe genset control (terminal 14 to control groundand terminal 15 to A11 TB2-1) to provide a Ground

Fault Alarm indication. The auto reset link is set atthe factory so the fault condition is cleared at thegenset control by pushing the Run/Stop (Reset)/Remote switch to Reset.

Terminals 9 (+) and 10 () can used for percent fullscale metering output (01 mA full scale).The relay has a time delay setting of 0 to onesecond.

The relay has one set of form C contacts rated: 1100VA at 250V 250 VAC, 5A continuous, 3A breaking

GENERATORFRAME GROUND

GENERATOR

POWERSUPPLY

L1

L2

L3

N

()

(+)24VDC

ALARMCONTACTS

RESET BUTTON(NOT USED,

FACTORY SET TOAUTO RESET)

TIME DELAY CONTROL(1 SECOND)FAULT INDICATORS

> I (OVER CURRENT)

NG(OPEN CIRCUIT)

LINK(NOT USED ON 3

PHASE/4 WIRE WITH 3POLE TRANSFER

SWITCH)

BONDING JUMPER(NOT USED ON 3

PHASE/4 WIRE WITH3 POLE TRANSFER

SWITCH)

TESTBUTTON

ONINDICATOR

CURRENT CONTROL(9=1200)

AUTORESET

LINK

FIGURE 3-12. GROUND FAULT ALARM RELAY (OPTIONAL)

3-15

RTD Relay (Optional)The optional RTD relay is rail mounted inside theaccessory box. This relay is used to monitor six sep-arate temperature zones in the generator windingsusing resistive temperature detectors (RTDs). Therelay determines the sensed temperature and actsto isolate, alarm, or initiate corrective action.

The RTD relay compares the six inputs to the prede-termined setpoint (temperature setpoint is factoryadjusted). If one or more of the inputs exceed thesetpoint, the output relay is energized. LEDs indi-

cate the state of the output relay (green for normal,red for tripped). Additional red LEDs are used to in-dicate which inputs exceed the setpoint.The relay terminals 11, 12 and 14 are for customerconnection. These terminals can be attached to ei-ther of the two Customer Fault inputs on TB1 to pro-vide a warning/shutdown condition or to other cus-tomer warning devices.The contacts are rated: 240 VAC, 5 amps non-inductive 24 VDC, 25 amps resistive

OUTPUT RELAY(CUSTOMER USE) 24 VDC

TO RTD TERMINALBLOCK

TEMPERATURE RELAY CONNECTIONS

TO RTD TERMINALBLOCK

()(+)

A11TB1-10(SWITCHED B+)

CONTROLGROUND

FIGURE 3-13. RTD RELAY (OPTIONAL)

3-16

Thermistor Relay (Optional)

The optional thermistor relays are rail mounted in-side the accessory box. Each relay monitors threethermistors (one per phase) that are connected inseries inside the generator. One series or chain ofthermistors are rated at 140 C and the other at 160C. The 140 C relay is commonly used in a pre-alarm circuit and the 160 C relay in a shut-down cir-

cuit. The relay will energize (trip) when the thermis-tor chain resistance reaches 3000 500 ohms.The relay terminals 1, 2 and 3 are for customer con-nection and are normally connected to a breakershunt trip or a load shed circuit.The contacts are rated: 3 amps at 250 VAC 1 amp at 480 VAC

A40-TB1-4(GROUND)

WHITE/REDTHERMISTORS A B C

A40-TB1-2(SWITCHED B+)

BLUE

FAULT CHANNELS(CUSTOMER

CONNECTIONS)

RELAY CONTACTS

FIGURE 3-14. THERMISTOR RELAY (OPTIONAL)

3-17

SEQUENCE OF OPERATIONThe sequence of operation is as follows. Refer tothe schematic on Page 8-3 or 8-9, as appropriate.1. The ECM is powered by cranking battery volt-

age (24 VDC). Terminal TB1-9 is connected tobattery positive (+) and connector P1-6 to bat-tery negative (-).

2. The starting cycle begins when relay K7 ispowered, either manually by pushing the panelRun switch, or automatically by a remote con-troller connected at terminal TB1-6. (The panelswitch must be in the Remote position for re-mote, automatic operation.)

3. Relay K7 powers relays K2 and K3.4. Relay K2 powers the engine gauges and termi-

nal TB1-10, to which the fuel solenoid, ignitionmodule and electronic governor are con-nected.

5. Relay K3 powers terminal TB1-8 to whichstarter relay K4 is connected. Engine crankingbegins.

6. The engine starts and runs up to governedspeed in a matter of seconds.

7. The starter is disconnected when enginespeed gets to about 600 RPM. This is done byrelay K10 or K14, whichever acts first to openthe circuit powering relay K3.

8. Relay K10 is powered by the generator outputvoltage (120 VAC) through plug-in connectorsP1-1 and P1-2. The remote Run indicator lampshould light (connected through terminalTB1-3).

9. Relay K14 is powered by the engine-drivenbattery charging alternator (24 VDC) throughplug-in connector P1-3. The panel Run indica-tor lamp should light. Relays K10 and K14 areredundant.

10. Relays K2 and K3 are deenergized (by latchingfault relay K6) causing shutdown to occur if theengine does not start within 75 seconds. TheOvercrank indicator lamp lights and commonalarm terminal TB1-4 is powered.The ECM has a cycle crank feature whereby theengine is cranked for three 15 second periodsalternated with two 15 second rest periods.

11. Relay K2 is deenergized (by latching fault relayK6) causing shutdown to occur during opera-tion when a low oil pressure, high engine tem-perature or engine overspeed condition issensed or the optional emergency stop buttonis pressed. The appropriate fault indicator lamplights and common alarm terminal TB1-4 ispowered. (There is no fault lamp for emergencystop.)An oil pressure time delay (12 seconds) pre-vents the ECM from sensing low oil pressureand high engine coolant temperature until 12seconds after either start disconnect signal isapplied to the ECM.

12. To restore operation after a shutdown fault hasbeen serviced, reset latching relay K6 by push-ing the panel Stop switch and then the Resetswitch. The set should run or be ready to runwhen the panel switch is pushed to Run or toRemote.

If the emergency stop switch has been used, thecontrol will have to be reset to restore operation.First pull the emergency stop switch button andthen push the panel Stop and Reset switches.

13. The set is stopped manually by pressing thepanel Stop switch or automatically by a remotecontroller. (The panel switch must be in the Re-mote position for remote, automatic opera-tion.)

3-18

THIS PAGE LEFT INTENTIONALLY BLANK

4-1

4. Troubleshooting

These troubleshooting charts are designed to helpyou diagnose generator set problems. To save timetroubleshooting, read the entire manual ahead oftime to understand the generator set. Go over theoptions and modifications and review what was

done during the last service call. Look the generatorset over for any obvious problems. The problemcould be as simple as an empty fuel tank, closedfuel shutoff valve, loose wire, blown fuse or trippedcircuit breaker.

THE ENGINE DOES NOT CRANK IN RUN MODE

There are hazards present in troubleshooting that can cause equipment damage,severe personal injury or death. Troubleshooting must be performed by qualified persons whoknow about the hazards of fuel, electricity and machinery. Read the safety precautions on pagesiii and iv and observe all instructions and precautions in this manual.

WARNING

Possible Cause Corrective Action

1. The Emergency Stop switchhas been used. (The switch but-ton is lit.)

Pull the Emergency Switch button. To reset the engine con-trol, push the Run-Stop-Remote switch to Stop and the Re-set switch to Reset. Then push the Run-Stop-Remoteswitch to Run.

2. A Fault Shutdown is being indi-cated by one of the red lights onthe control panel.

Service the set as necessary. To reset the engine control,push the Run-Stop-Remote switch to Stop and the Resetswitch to Reset. Then push the Run-Stop-Remote switch toRun.

3. A LO Shutdown is being indi-cated on the day tank pump con-trol panel.

Determine the cause and service as necessary (See Section7). To reset the engine control, push the Run-Stop-Remoteswitch to Stop and the Reset switch to Reset. Then push theRun-Stop-Remote switch to Run or Remote. Note that theengine control will shut down unless the day tank control hasbeen reset first.

4. Cranking voltage is too low tocrank the engine.

a. Clean and tighten or replace the positive (+) and negative ()battery cable connectors and cables at the battery and theset.

b. Recharge or replace the battery. Specific gravity for a fullycharged battery is approximately 1.260 at 80 F (27 C).

c. If the set is in standby service, install a battery charger.d. Replace the engine-driven battery charging alternator if nor-

mal battery charging voltage (24 to 28 VDC)is not obtained.

5. Fuse F1 (see Figure 3-4) on en-gine monitor board A11 hasblown (no voltage [B+] atA11-TB1-8).

The wire between A11-TB1-8 and starter terminal S may beloose and shorting to ground. Repair as necessary and re-place the fuse with one of the same type and amp rating (20A). If fuse continues to blow repair the solenoid or starter asnecessary.

4-2

THE ENGINE DOES NOT CRANK IN RUN MODE

There are hazards present in troubleshooting that can cause equipment damage,severe personal injury or death. Troubleshooting must be performed by qualified persons whoknow about the hazards of fuel, electricity and machinery. Read the safety precautions on pagesiii and iv and observe all instructions and precautions in this manual.

WARNING


6. The wire between ECM terminalTB1-9 and starter terminal BATis loose damaged or missing.

Check for battery voltage (24 VDC) between ECM terminalTB1-9 (B+) and the grounding stud () on the floor of the con-trol cabinet. Check, clean and tighten the connectors at bothends and replace the wire if it is damaged.

7. The grounding strap between thecontrol box and the battery nega-tive () terminal is loose, dam-aged or missing.

Check for continuity (zero ohms) between the groundingstud on the bottom of the control box and the battery negative() terminal. If there is no continuity or or the grounding strapis loose or damaged, repair as necessary.

8. The Run-Stop-Remote switch(S12) or wiring is faulty.

Disconnect pin connector J4 from engine monitor board A11and check for electrical continuity (zero ohms) betweenswitch terminals 2 and 3 when the switch is in the Run posi-tion and between terminals 1 and 2 when it is in the Remoteposition. Replace the switch if either set of contacts is faulty.

9. Engine monitor board A11 isfaulty. (Check fuses F1 and F4and for B+ at A11-TB1-9 again.)

Push the Run-Stop-Remote switch to Run and check forbattery voltage (24 VDC) at terminal A11-TB1-8. Replaceengine monitor board A11 if there is no voltage at A11-TB1-8but 24 VDC at A11-TB1-9.

10. The wire between ECM terminalTB1-8 and starter solenoid termi-nal SW is loose, damaged ormissing.

Push the Run-Stop-Remote switch to Run and check forbattery voltage (24 VDC) at starter solenoid terminal SW. Ifthere is no voltage repair the wiring as necessary.

11. The starter motor or solenoid ismalfunctioning.

Push the Run-Stop-Remote switch to Run and check forbattery voltage (B+) at starter solenoid terminal SW. Replacethe starter motor if there is voltage but the motor does notfunction.

12. The Time Delay Start/StopModule (A15) is malfunctioning.

Check for constant B+ at A15 terminal TB1-4. Check for runsignal at A15 TB1-5. Voltage at A15 TB1-6 should be at B+at the end of the start delay period. Check wiring and connec-tions from A15 TB1-6 to A11 TB1-6.

13. The starter motor or solenoid ismalfunctioning.

Push the Run-Stop-Remote switch to Run and check forbattery voltage (B+) at starter solenoid terminal SW. Replacethe starter motor if there is voltage but the motor does notfunction.

4-3

THE ENGINE DOES NOT CRANK IN REMOTE MODE

There are hazards present in troubleshooting that can cause equipment damage, se-vere personal injury or death. Troubleshooting must be performed by qualified persons whoknow about the hazards of fuel, electricity and machinery. Read the safety precautions on pagesiii and iv and observe all instructions and precautions in this manual.

WARNING


1. The Run-Stop-Remote switch isat Stop. (The Switch-Off lightwill be flashing, if provided.)

Push the Run-Stop-Remote switch to Remote.

2. The Emergency Stop switchhas been used. (The switch but-ton is lit.)

Pull the Emergency Switch button. To reset the engine con-trol, push the Run-Stop-Remote switch to Stop and the Re-set switch to Reset. Then push the Run-Stop-Remoteswitch to Remote.

3. A Fault Shutdown is being indi-cated by one of the red lights onthe control panel.

Service the set as necessary. To reset the engine control,push the Run-Stop-Remote switch to Stop and the Resetswitch to Reset. Then push the Run-Stop-Remote switch toRemote.

4. There is no remote circuit signal(24 VDC at auxiliary relay boardA28-TB1-6) because fuse F3 onengine monitor board A11 hasblown.

a. Replace the fuse with one of the same type and amp rat-ing (15 A).

b. If fuse F3 blows again, find and repair the fault in the remotecontrol circuit, such as a loose wire that may be shorting toground or a shorted relay coil or other component. See Sec-tion 8 for remote connections.

5. There is no remote circuit signal(24 VDC at auxiliary relay boardA28-TB1-6) because the remotecircuit is not functioning properly.

Apply 24 VDC to A28-TB1-6. If the engine cranks, find andrepair the fault in the remote control circuit. See Section 8 forremote connections.

6. Auxiliary relay board A28 is notfunctioning properly.

Check for misconnections (see Section 8) or loose connec-tions and replace auxiliary relay board A28 if there is 24 VDCat terminal A28-TB1-6 but not at A28-J2-6.

7. Same as Steps 3 through 11 inthe RUN mode.

See steps 3 through 11 in the preceding RUN mode.

4-4

THE ENGINE CRANKS BUT DOES NOT START


WARNING


1. The engine is not getting fuel. Open any closed shutoff valve. Fill the main fuel supply tank.

2. Fuse F2 on the engine monitorboard A11 has blown.

Replace fuse with one of the same type and amp rating.If fuse F2 blows again, the wire between A11 TB1-10 and en-gine block terminal T26, or the wire between T26 and fuel so-lenoid K1 may be loose or shorting to ground.

3. Fuel solenoid K1 does not ener-gize.

a. Fuel solenoid not energized by ECM A11. Check for B+ atTB1-10 when cranking. If no voltage present and fuse F2 isgood replace ECM.

b Connect B+ to fuel solenoid (K1) terminal BAT. Replace thefuel solenoid if does not click when energized. If fuel sole-noid is working, check for blocked fuel line or fuel filter.

4. Low engine temperature is caus-ing too low a cranking speed forstarting.

a. Plug in, repair or install engine coolant and engine oil heat-ers.

b. Replace the engine oil if it is not of the recommended viscos-ity for the ambient temperature.

5. Cranking voltage is too low toreach required cranking speed.

a. While cranking the engine, measure voltage directly acrossthe battery terminals and then immediately across the startermotor terminal and the grounding bolt on the block. Cable,terminal or relay contact resistance is too high if the differ-ence is more than 2 volts. Service as necessary.

b. Recharge or replace the battery. Specific gravity for a fullycharged battery is approximately 1.260 at 80 F (27 C).

c. Replace the engine-driven battery charging alternator if nor-mal battery charging voltage is not between 24 and 28 volts.

6. The air cleaner is blocked. Service as necessary.

7. Ignition system, fuel system orother engine malfunction.

Service according to the engine service manual.

4-5

THE ENGINE RUNS UNTIL FAULT SHUTDOWN


WARNING


1. The OVERSPEED lamp comeson when the engine shuts down.

a. Reset engine monitor board A11 by pushing the Run-Stop-Remote switch to Stop and the Reset switch to Reset andrestart the set, monitoring engine speed and adjust the Elec-tronic Overspeed Module (Section 3).

b. Check the governor for binding, repair and adjust the gover-nor as necessary (see Section 6).

2. The LO OIL PRES lamp comeson when the engine shuts down.

a. Check the engine oil level, repair any oil leaks and fill to theproper level. Then reset engine monitor board A11 by push-ing the Run-Stop-Remote switch to Stop and the Resetswitch to Reset.

b. If the set still shuts down due to low oil pressure, restart theset and observe oil pressure while cranking the engine. Serv-ice the lubricating oil system according to the engine servicemanual if oil pressure is less than 10 psi. Replace the low oilpressure cutout switch if oil pressure is greater than 10 psi.See Section 8 to locate the switch.

3. The HI ENG TEMP lamp comeson when the engine shuts down.

a. Check the engine coolant level, repair any coolant leaks andrefill as necessary. Then reset engine monitor board A11 bypushing the Run-Stop-Remote switch to Stop and the Re-set switch to Reset.

b. If the set still shuts down due to high engine temperature,start the engine and observe coolant temperature as the sys-tem heats up. If shutdown occurs before the coolant reaches200 F (93 C), replace the high engine temperature cutoutswitch. If coolant temperature exceeds 200 F (93C), cleanand service the entire cooling system as required to restorefull cooling capacity. See Section 8 to locate the switch.

4. The FAULT 1 or FAULT 2 lampcomes on when the engine shutsdown.

Service as required. (The customer has supplied the systemfault indication switches. Either fault can be chosen to dis-play the warning only. See Section 3.)If the shutdown was due to low frequency, the set probablyran out of fuel or the governor is out of adjustment.If the shutdown was due to over/under voltage, the voltageregulator may be out of adjustment.

4-6

THE ENGINE LACKS POWER OR IS UNSTABLE


WARNING


1. Fuel delivery to the genset isinadequate.

a. Check for clogged fuel lines and filters.b. Check for air in the fuel lines and repair all air leaks.c. Measure the vertical distance between the fuel lift pump on

the engine and bottom of the dip tube in the supply tank. Thelift must not exceed 6 feet (1.8 meters).

2. The fuel is contaminated. Connect the set to a supply of good quality fuel and run theset under various loads. Replace the contents of the fuel sup-ply tank if there is a noticeable improvement in performance.

3. The engine air filter element isdirty.

Replace the air filter element.

4. The governor settings or linkageadjustment is incorrect.

a. Make governor settings and adjustments according to Sec-tion 6, Governor.

b. Check the magnetic speed pick-up unit (MPU) clearancewith flywheel. Replace the MPU if output voltage at crankingspeed is less than 2.5 VDC measured at terminals 10() and11 (+) on the governor controller.

5. The engine fuel system (liftpump, injection pump, injectors,timing) is faulty.

Service the fuel system according to the engine servicemanual.

6. The engine is worn. Service the engine according to the engine service manual.

4-7

AN AMBER WARNING LAMP IS ON


WARNING


1. The PRE LO OIL PRES lampcomes on while the engine is run-ning.

Shut down the set if possible or disconnect non-criticalloads.(Oil pressure will be less than 20 psi but greater than14 psi.) Service the engine lubricating system according tothe engine service manual.

2. The PRE HI ENG TEMP lampcomes on while the engine is run-ning.

Shut down the set if possible or disconnect non-critical loads.(Engine temperature will be greater than 220F but less than230 F.) Service the engine cooling system to restore fullcooling capacity.

3. The LOW ENGINE TEMPERA-TURE lamp comes on while theset is in standby.

a. Plug in, repair or install engine coolant and engine oil heat-ers.

b. If the engine coolant gauge indicates more than 70 F (21C), replace the gauge board. See Figure 3-4.

4. The LO FUEL lamp comes on. Fill the main fuel supply tank with the appropriate grade offuel. (The customer has supplied the fuel level switch tomake use of this warning.)

5. The FAULT 1 or FAULT 2 lamp(may be a specifically labeledamber lamp) comes on.

Service as required. (The customer has supplied the systemfault indicating switches. By means of selection jumpers,either fault may be chosen to shut down the engine. See Sec-tion 3, Engine Control.)

4-8

THE GREEN RUN LAMP STAYS OFF BUT THE SET RUNS NORMALLY


WARNING


1. The set mounted RUN lamp doesnot light, although the starter hasdisconnected normally and theengine is running. The remoteRUN lamp does light (AC startdisconnect is okay).

a. Press the panel Lamp Test switch and replace the run lampbulb if it does not light.

b. If the lamp is good and the set has an older ECM board (onewith cartridge-type fuses), this indicates that the DC discon-nect circuit (K14 relay on ECM) is not working. Check the DCvoltmeter and if there is not at least 24 VDC, Check for looseor missing wiring between the battery charging alternator ter-minal TB1-2 and pin connector P1-3 on the ECM. See theconnection diagram in Section 8. If the connections are goodreplace the battery charging alternator.

c. If the RUN lamp, wiring connections and battery charging al-ternator are all good and the RUN lamp does not light, re-place the engine monitor board A11.

2. Both the remote and set mountedRUN lamps do not light, althoughthe starter has disconnectednormally and the engine is run-ning.

a. Press the panel Lamp Test switch and replace the run lampbulb if it does not light. Test the remote RUN lamp by suitablemeans and replace it if it does not light.

b. If both lamps are good, this indicates that the AC disconnectcircuit is not working. Check the AC voltmeter to determinewhether or not there is generator output voltage and serviceas necessary. See There Is No Output Voltage in Trouble-shooting.

c. If there is generator output voltage, check for 120 VACacross pin connectors P1-1 and P1-2 on engine monitorboard A11. If there is no voltage, check for loose or missingleads between the connectors and TB21-21 and TB21-32 in-side the control box and service as necessary.

d. Replace engine monitor board A11 if there is 120 VACacross pin connectors P1-1 and P1-2 but neither RUN lamplights during normal operation.

4-9

NO OUTPUT VOLTAGE


WARNING


1. The line circuit breaker is OFF. Find out why the circuit breaker was turned OFF, make sureit is safe to reconnect power, and then throw the circuitbreaker ON.

2. The line circuit breaker hasTRIPPED.

Shut down the set and service as necessary to clear the shortcircuit or ground fault that caused tripping, and then RESETthe circuit breaker and start the set.

3. The line circuit breaker is faulty. Shut down the set, make sure the power output lines from theset have been disconnected from all other sources of power,attempt to RESET the circuit breaker and throw it ON andcheck for electrical continuity across each line contact. Re-place the circuit breaker if there is measurable resistanceacross any contact.

4. Field circuit breaker CB21 hasTRIPPED.

RESET the circuit breaker. If it keeps tripping, troubleshootaccording to the chart, Field Circuit Breaker Keeps Tripping.

5. Field circuit breaker CB21 isfaulty.

Shut down the set, attempt to RESET the circuit breaker anddisconnect either lead. Replace the circuit breaker if there ismeasurable resistance across the terminals.

4-10

NO OUTPUT VOLTAGE (CONT.)


WARNING


Determine if the problem is in the voltage regulating or generator circuits as follows:a. Throw the line circuit breaker OFF and shut down the set.

This test involves unregulated excitation of the generator. To prevent damage tothe generator due to overcurrent, make sure that all loads have been disconnected and that allfaults have been cleared from the power output terminals of the generator.

b. Open the control panel and disconnect the field leads X (F1) and XX (F2) from the voltage regulator.See Figure 2-4. Perform the exciter stator winding resistance test (Section 5). The exciter statorresistance must test okay before proceeding.

c. Prepare to measure output voltage across the generator terminals while the set is running.d. Bring two jumpers from a 12 volt battery for connection to the X (F1) and XX (F2) leads inside the

control box. Connect the jumper from the positive (+) post of the battery to the F1 (X) lead. Be preparedto connect the jumper from the negative () post of the battery to the XX (F2) lead. If one of the 12 voltcranking batteries is used, bring the jumpers from the battery connection on the grounded side of thesystem to avoid inadvertently imposing 24 volts on the system.

e. Check polarity again. Polarity must be correct or this test will be inconclusive because the induced andresidual magnetic polarities in the exciter stator will be opposed.

HIGH VOLTAGE. Touching uninsulated high voltage parts inside the control boxcan result in severe personal injury or death. Measurements and adjustments must be donewith care to avoid touching high voltage parts. For your protection, stand on a dry wooden plat-form or rubber insulating mat, make sure your clothing and shoes are dry, remove jewelry fromyour hands and wear elbow length insulating gloves.

f. Start the set and connect the jumper wire from the battery negative () terminal to the XX (F2) lead.g. The generator is probably okay if rated output voltage or higher is obtained and the voltages for all

phases are balanced when the exciter is powered by the 12 volt battery. Refer to the Voltage Regulatorfault chart (step 6) for troubleshooting. (Normal excitation voltage ranges approximately from10 VDCat no-load to 40 VDC at full-load.)

h. Use the Generator fault chart If the output voltages are not balanced, or are less than ninety percentof rated output voltage; the problem is probably in the generator. If the voltages are unbalanced, firsttroubleshoot the main statorStep 11, If the voltages are uniformly low, first troubleshoot the exciterand field circuitsSteps 7, 8, 9 and 10.

CAUTION

4-11

NO OUTPUT VOLTAGE (CONT.)


WARNING


6. Voltage Regulator VR21 is faulty. a. Follow the PMG test described in Section 5 to determine ifit is okay.

b. Check all connections against the applicable reconnectiondiagram (Section 8) and rewire as necessary. Replace thevoltage regulator if the PMG checks okay, the wiring iscorrect and there is no output voltage.

Replacing the voltage regulator beforeservicing other faults can lead to damage to the newvoltage regulator.

CAUTION

7. The exciter field winding is open. Shut down the set and check exciter field winding resistanceaccording to Section 5. Replace the exciter field assembly ifwinding resistance does not meet specifications.

8. The rotating rectifier assembly(diodes CR1 through CR6) isfaulty.

Shut down the set and check each diode according toSection 5. Service as necessary.

9. The exciter rotor windings areopen.

Shut down the set and check exciter winding resistances ac-cording to Section 5. Replace the generator rotor assemblyif exciter rotor winding resistances do not meet specifica-tions.

10. The main rotor winding is open. Shut down the set and check main rotor winding resistanceaccording to Section 5. Replace the generator rotor assem-bly if main rotor winding resistance does not meet specifica-tions.

11. The stator windings are open. Shut down the set and check stator winding resistances ac-cording to Section 5. Replace the generator stator assemblyif stator winding resistances do not meet specifications.

4-12

OUTPUT VOLTAGE IS TOO HIGH OR TOO LOW


WARNING


1. Engine speed is unstable. Troubleshoot according to the chart, The Engine LacksPower or is Unstable.

2. The voltage has been adjustedimproperly.

Adjust output voltage according to Section 2, AC Control.

3. Improper connections have beenmade at the generator output ter-minals.

Shut down the set and reconnect according to the appropri-ate reconnection diagram. See Section 8.


Shut down the set and check each diode according to Sec-tion 5, Servicing the Generator. Service as necessary.

5. Voltage Regulator VR21 is faulty. Replace the voltage regulator.Replacing the voltage regulator before

servicing other faults can lead to damage to the newvoltage regulator.

CAUTION

4-13

OUTPUT VOLTAGE IS UNSTABLE


WARNING


1. The voltage has been adjustedimproperly.

Adjust output voltage according to Section 2, AC Control.

2. The voltage adjusting rheostaton the control panel is faulty (ifprovided).

Unlock the voltage adjusting screw on the front of the controlpanel and disconnect either lead from the rheostat. Measureresistance between terminals 1 and 2 while turning the ad-justing screw fully one way and then the other. Replace therheostat if it is open at any point, or if resistance does not varysmoothly from zero to approximately 2,500 ohms.



CAUTION

4-14

THE FIELD CIRCUIT BREAKER KEEPS TRIPPING


WARNING



Shut down the set and check each diode according to Sec-tion 5, Servicing the Generator. Service as necessary.

2. The exciter field winding isshorted.

Shut down the set and check exciter field winding resistanceaccording to Section 5, Servicing the Generator. Replace theexciter field assembly if winding resistance does not meetspecifications.

3. The exciter rotor windings areshorted.

Shut down the set and check exciter winding resistances ac-cording to Section 5, Servicing the Generator. Replace thegenerator rotor assembly if exciter rotor winding resistancesdo not meet specifications.

4. The main rotor winding isshorted.

Shut down the set and check main rotor winding resistanceaccording to Section 5, Servicing the Generator. Replace thegenerator rotor assembly if main rotor winding resistancedoes not meet specifications.

5. The stator windings are shorted. Shut down the set and check stator winding resistances ac-cording to Section 5, Servicing the Generator. Replace thegenerator stator assembly if stator winding resistances donot meet specifications.



CAUTION

4-15

THE PHASE CURRENTS ARE UNBALANCED


WARNING


1. The connected loads are distrib-uted unevenly among thephases.

Shut down the set and redistribute the loads as evenly aspossible.

2. Improper connections have beenmade at the generator outputterminals.

Shut down the set and reconnect according to the appropri-ate reconnection diagram. See Section 8.

3. The stator windings are faulty(open or shorted).

Shut down the set and check stator winding resistances ac-cording to Section 5, Servicing the Generator. Replace thegenerator stator assembly if stator winding resistances donot meet specifications.

4. A load has a ground fault or shortcircuit.

Service the faulty equipment as necessary.

4-16

THIS PAGE LEFT INTENTIONALLY BLANK

5-1

5. Servicing the GeneratorTESTING THE GENERATOR

These tests can be performed without removing thegenerator. Before starting tests, disconnect the bat-tery charger from its AC source. Then disconnectthe starting battery cables (negative [] first) tomake sure the engine will not start while performingthese tests.

CAUTION Always disconnect battery charger

from its AC source before disconnecting thebattery cables. Otherwise disconnecting thecables can result in voltage spikes high enoughto damage the DC control circuits of the set.

WARNING Accidental starting of the genset

while working on it can cause severe personalinjury or death. Prevent accidental starting bydisconnecting the starting battery cables (neg-ative [] first).

Make certain battery area has been well-venti-lated before servicing battery. Arcing can igniteexplosive hydrogen gas given off by batteries,causing severe personal injury. Arcing can oc-cur when cable is removed or re-attached, orwhen negative () battery cable is connectedand a tool used to connect or disconnect posi-tive (+) battery cable touches frame or othergrounded metal part of the set. Always removenegative () cable first, and reconnect it last.Make certain hydrogen gas from the battery, en-gine fuel, and other explosive fumes are fullydissipated. This is especially important if thebattery has been connected to a battery char-ger.

RECONNECTIONTERMINALS

STATOR

BLOWER

COUPLING

DRIVEDISCS

ROTORSHAFT

AIR DISCHARGECOVERS

FRAME

ROTATINGRECTIFIERASSEMBLY

PMGSTATOR

EXCITERROTOR

END BRACKET

PMGROTOR

EXCITERSTATOR

END BRACKET/ENGINEADAPTOR

ROTOR

ENDBEARING

G1185

PRESSUREPLATE

FIGURE 5-1. GENERATOR

5-2

EXCITER STATORTesting Winding Resistance: Measure windingresistance with a Wheatstone bridge or digital ohm-meter. Replace the stator if winding resistance isnot as specified in the generator Installation, Ser-vice & Maintenance Manual.

Testing Winding Insulation Resistance: Discon-nect exciter stator leads X (F1) and XX (F2) fromtheir connectors in the AC generator wiring harnessand isolate them from ground.Connect the megger between one of the leads andground and conduct the test. Refer to Table 5-1 formegger voltage selection and required resistancevalues.

MEASURE WINDING IN-SULATION RESISTANCE BE-TWEEN EITHER LEAD ANDTHE STATOR LAMINATIONS

MEASURE WINDING RESISTANCEBETWEEN THE TWO STATOR

LEADS, X (F1) AND XX (F2)

FIGURE 5-2. TESTING THE EXCITER STATOR

TABLE 5-1. GENERATOR INSULATION RESISTANCE

GENERATOR MEGGER VDCMINIMUM RESISTANCE (MEGOHMS)

GENERATORVOLTAGE

MEGGER VDCSETTING MAIN STATOR MAIN ROTOR EXCITOR STATOR/

ROTOR600 VAC or less 500 5.0 1.0 5.0 1.0 5.0 1.0

5-3

EXCITER RECTIFIER BRIDGE (ROTATINGRECTIFIER ASSEMBLY)

The exciter rectifier bridge is mounted on the exciterrotor, inboard, facing the main rotor. It consists of apositive plate and a negative plate, split diametrical-ly. Each carries three diodes, three terminal postsfor connecting exciter rotor leads to the diode pig-tails and a terminal for the main rotor (generatorfield) lead. A surge suppresser is connected acrossthe two plates to prevent transient voltages thatcould damage the diodes.

Testing Diodes: Disconnect the diode pigtails fromthe terminal posts. Using an ohmmeter, measureelectrical resistance between each diode pigtail andthe plate on which the diode is mounted. Reversethe meter test probes and repeat the tests. Theelectrical resistance across each diode should behigh in one direction and low in the other. If the re-sistance is high or low in both directions, replace thediode.

Replacing Diodes: Make sure the replacementdiode is of the correct polarity. Disconnect the pigtailfrom the terminal post and unscrew the old diode.Apply heat-sink compound under the head of thediode. Make sure the compound does not get on thethreads. Torque the diodes to 36 to 42 in-lbs (4 to 4.7Nm) and the pigtail terminals to 24 in-lbs (2.7 Nm)when reassembling.

Surge Suppresser Testing and Replacement:Remove the suppresser. Replace the suppresser ifit appears to have overheated or if ohmmeter read-ings indicate less than infinite resistance (end ofscale) in both directions. Torque the terminals to 24in-lbs (2.7 Nm) when reassembling.

CAUTION Layers of dust can cause diodes to

overheat and fail. Brush dust off regularly.

TERMINAL(ONE OF SIX)

DIODE (ONE OF SIX)DISCONNECT THE DIODE PIG-

TAIL FROM THE TERMINALAND MEASURE ELECTRICALRESISTANCE BETWEEN THE

PIGTAIL AND THE METALPLATE UNDER THE DIODE

SURGE SUPPRESSERREMOVE TO TEST

DIODE PLATES(TWO)

FIGURE 5-3. TESTING THE ROTATING RECTIFIER ASSEMBLY

5-4

EXCITER ROTORTesting Winding Resistance: Disconnect the sixrotor winding leads from the terminal posts on therectifier assembly. With a Wheatstone bridge, mea-sure electrical resistance across each pair of rotorwindings: U (CR1 or CR4) and V (CR2 or CR5), V(CR2 or CR5) and W (CR3 or CR6), W (CR3 orCR6) and U (CR1 or CR4). See the winding sche-matic. Replace the whole rotor shaft assembly if theresistance of any winding is not as specified in thegenerator Installation, Service & MaintenanceManual.

Testing Winding Insulation Resistance: Discon-nect all six exciter rotor leads from diode terminalsCR1 through CR6 and isolate them from ground.

Connect the megger between one of the leads andground and conduct the test. Refer to Table 5-1 formegger voltage selection and required resistancevalues.

WINDING SCHEMATIC

MEASURE WINDING INSULATIONRESISTANCE BETWEEN ANY LEADOR THE TERMINAL TO WHICH IT IS

CONNECTED AND THE ROTORLAMINATIONS

DISCONNECT THE SIX ROTOR WINDINGLEADS FROM THEIR TERMINALS ANDMEASURE ELECTRICAL RESISTANCE

ACROSS EACH PAIR OF WINDINGS: U-V,V-W, W-U

MAIN ROTORLEADS

FIGURE 5-4. TESTING THE EXCITER ROTOR

5-5

MAIN ROTOR (GENERATOR FIELD)Testing Winding Resistance: Disconnect the twoleads of the main rotor from the terminals on the ro-tating rectifier assembly. See Figure 5-5. Measureelectrical resistance between the two leads with aWheatstone bridge or digital ohmmeter. Replacethe rotor if the resistance is not as specified in thegenerator Installation, Service & MaintenanceManual. Connect the rotor leads a

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