Printed in U.S.A. 928Ć0502B 1Ć99
GGFB
GGFC
GGHB
GGHC
GGHD
Models
Detector/Sentinel Controls
GENERATOR SETS
i
Table of Contents
SECTION TITLE PAGE
SAFETY PRECAUTIONS iii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 INTRODUCTION
About This Manual 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test Equipment 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How To Obtain Service 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 AC CONTROL
General 2-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC Control Panel Components (Detector Control) 2-1 . . . . . . . . . . . . . . . . . . .
AC Control Panel Components (Sentinel Control) 2-2 . . . . . . . . . . . . . . . . . . . .
Automatic Voltage Regulator (AVR) Adjustments 2-3 . . . . . . . . . . . . . . . . . . . . .
Principle Of Generator Operation 2-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 ENGINE CONTROL (DETECTOR CONTROL)
General 3-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Panel Components 3-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Box Interior 3-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Control Monitor (A11) 3-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Sensors 3-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auxiliary Control Components 3-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sequence Of Operation 3-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 ENGINE CONTROL (SENTINEL CONTROL)
General 4-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Panel Components 4-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Box Interior 4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Relays 4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Terminal Block TB1 4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dry Contact Module 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Sensors/Gauges 4-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auxiliary Control Components 4-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sequence Of Operation 4-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The engine exhaust from this product
contains chemicals known to the State
of California to cause cancer, birth
defects or other reproductive harm.
! !
ii
SECTION TITLE PAGE
5 TROUBLESHOOTING (DETECTOR CONTROL)
The Engine Does Not Crank In Run Mode 5-1 . . . . . . . . . . . . . . . . . . . . . . . . . .
The Engine Does Not Crank In Remote Mode 5-3 . . . . . . . . . . . . . . . . . . . . . .
The Engine Cranks But Does Not Start 5-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Engine Runs Until Fault Shutdown 5-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Engine Lacks Power Or Is Unstable 5-7 . . . . . . . . . . . . . . . . . . . . . . . . . . .
An Amber Warning Lamp Is On 5-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Green Run Lamp Stays Off But The Set Runs Normally 5-10 . . . . . . . . .
No Output Voltage 5-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Voltage Is Too High Or Too Low 5-14 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Voltage Is Unstable 5-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Field Circuit Breaker Keeps Tripping 5-16 . . . . . . . . . . . . . . . . . . . . . . . . . .
The Phase Currents Are Unbalanced 5-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 TROUBLESHOOTING (SENTINEL CONTROL)
The Engine Does Not Crank In Run Mode 6-1 . . . . . . . . . . . . . . . . . . . . . . . . . .
The Engine Does Not Crank In Remote Mode 6-3 . . . . . . . . . . . . . . . . . . . . . .
The Engine Cranks But Does Not Start 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Engine Runs Until Fault Shutdown 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Engine Lacks Power Or Is Unstable 6-7 . . . . . . . . . . . . . . . . . . . . . . . . . . .
No Output Voltage 6-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Voltage Is Too High Or Too Low 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Voltage Is Unstable 6-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Field Circuit Breaker Keeps Tripping 6-13 . . . . . . . . . . . . . . . . . . . . . . . . . .
The Phase Currents Are Unbalanced 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 SERVICING THE GENERATOR
Testing The Generator 7-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removing And Disassembling The Generator 7-9 . . . . . . . . . . . . . . . . . . . . . . .
Reassembling The Generator 7-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Servicing The PMG 7-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 GOVERNORS AND FUEL SYSTEMS
Electric Governor Adjustment 8-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Linkage Adjustment 8-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Magnetic Speed Pickup Unit Adjustment 8-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel System 8-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition Timing 8-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 WIRING DIAGRAMS 9-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MS-1
iii
Safety Precautions
Before operating the generator set (genset), read the
Operator’s Manual and become familiar with it and the
equipment. Safe and efficient operation can be
achieved only if the equipment is properly operated
and maintained. Many accidents are caused by failure
to follow fundamental rules and precautions.
The following symbols, found throughout this manual,
alert you to potentially dangerous conditions to the oper-
ator, service personnel, or the equipment.
This symbol warns of immediate
hazards 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 person-
al injury or death.
CAUTION
This symbol refers to a hazard or un-
safe practice which can result in personal injury
or product or property damage.
FUEL AND FUMES ARE FLAMMABLE
Fire, explosion, and personal injury or death can result
from 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 potential
fire hazard.
• DO NOT permit any flame, cigarette, pilot light,
spark, arcing equipment, or other ignition source
near the generator set or fuel tank.
• Fuel lines must be adequately secured and free of
leaks. Fuel connection at the engine should be
made with an approved flexible line. Do not use
copper piping on flexible lines as copper will be-
come brittle if continuously vibrated or repeatedly
bent.
• Natural gas is lighter than air, and will tend to gather
under hoods. Propane is heavier than air, and will
tend to gather in sumps or low areas. NFPA code re-
quires all persons handling propane to be trained
and qualified.
• Be sure all fuel supplies have a positive shutoff
valve.
• Be sure battery area has been well-ventilated prior
to servicing near it. Lead-acid batteries emit a highly
explosive 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 or
sheltered areas and areas where individuals are
likely to congregate. Visually and audibly inspect
the exhaust daily for leaks per the maintenance
schedule. Make sure that exhaust manifolds are se-
cured and not warped. Do not use exhaust gases to
heat 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 SEVERE
PERSONAL 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 are
secure. Tighten supports and clamps, keep guards
in position over fans, drive belts, etc.
• Do not wear loose clothing or jewelry in the vicinity of
moving parts, or while working on electrical equip-
ment. Loose clothing and jewelry can become
caught 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.
iv
ELECTRICAL SHOCK CAN CAUSE
SEVERE PERSONAL INJURY OR DEATH
• Remove electric power before removing protective
shields or touching electrical equipment. Use rub-
ber insulative mats placed on dry wood platforms
over floors that are metal or concrete when around
electrical equipment. Do not wear damp clothing
(particularly wet shoes) or allow skin surface to be
damp when handling electrical equipment.
• Use extreme caution when working on electrical
components. High voltages can cause injury or
death. DO NOT tamper with interlocks.
• Follow all applicable state and local electrical
codes. Have all electrical installations performed by
a qualified licensed electrician. Tag and lock open
switches to avoid accidental closure.
• DO NOT CONNECT GENERATOR SET DIRECT-
LY TO ANY BUILDING ELECTRICAL SYSTEM.
Hazardous voltages can flow from the generator set
into the utility line. This creates a potential for elec-
trocution or property damage. Connect only
through 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 system
pressure first.
• Benzene and lead, found in some gasoline, have
been identified by some state and federal agencies
as causing cancer or reproductive toxicity. When
checking, draining or adding gasoline, take care not
to ingest, breathe the fumes, or contact gasoline.
• Used engine oils have been identified by some state
or 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 install
them in convenient locations. Consult the local fire
department for the correct type of extinguisher to
use. 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 the
unit. 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 area
clean 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 or
physically fatigued, or after consuming any alcohol
or drug that makes the operation of equipment un-
safe.
• Substances in exhaust gases have been identified
by some state or federal agencies as causing can-
cer or reproductive toxicity. Take care not to breath
or ingest or come into contact with exhaust gases.
KEEP THIS MANUAL NEAR THE GENSET FOR EASY REFERENCE
1-1
1. Introduction
ABOUT THIS MANUAL
This service manual is for the GG Series generator
sets (gensets) listed on the front cover. It includes
engine and generator troubleshooting guides. En-
gine service instructions are in the applicable en-
gine service manual. Operating and maintenance
instructions are in the applicable Operator’s Manu-
al.
This manual does not have instructions for servic-
ing printed circuit board assemblies. Always re-
place a faulty printed circuit board assembly.
Attempts to repair a printed circuit board can lead to
costly damage to the equipment.
This manual contains basic (generic) wiring
diagrams and schematics that are included to help
in troubleshooting. Service personnel must use the
actual wiring diagram and schematic shipped with
each unit. The wiring diagrams and schematics that
are maintained with the unit should be updated
when modifications are made to the unit.
Read Safety Precautions and carefully observe all
instructions and precautions in this manual.
TEST EQUIPMENT
Most of the tests in this manual can be done with an
AC-DC multimeter, frequency meter, Wheatstone
bridge (0.001 ohm precision is necessary for mea-
suring stator winding resistance) and load test pan-
el.
HOW TO OBTAIN SERVICE
Always give the complete Model, Specification and
Serial number of the generator set as shown on the
nameplate when seeking additional service
information or replacement parts. The nameplate is
located on the side of the generator output box.
WARNING
Incorrect service or replacement of
parts can result in severe personal injury or
death, and/or equipment damage. Service per-
sonnel must be qualified to perform electrical
and mechanical service. Read and follow Safety
Precautions, on pages iii and iv.
There are separate Engine Control and Trouble-
shooting sections for gensets using the Sentinel
control or the Detector control (Figure 1-1). Refer to
the Table of Contents for specific information relat-
ing to your genset. The remaining sections apply to
both versions.
Detector 12 Control Sentinel Control
FIGURE 1-1. CONTROL PANEL CONFIGURATIONS
1-2
2-1
2. AC Control
GENERAL
The control box is mounted on top of the generator,
facing the rear. Figure 2-1 (Detector Control) and
Figure 2-2 (Sentinel Control) point out the compo-
nents on the AC control panel. Refer to Section 9 for
the AC control wiring diagrams.
AC CONTROL PANEL COMPONENTS
(DETECTOR CONTROL)
Field Circuit Breaker (CB21) The field circuit
breaker protects the generator from over-excita-
tion.
AC Voltmeter (M21) The voltmeter indicates output
voltage for the phase selected.
AC Ammeter (M22) The ammeter indicates output
amperage for the phase selected. Input to the am-
meter is from current transformers CT21, CT22,
and CT23.
Phase Selector Switch (S21) The selector switch
is used to select the phase for voltage and amper-
age readings.
Scale Indicator Lamps (DS21 and DS22) The
scale indicator lamps indicate whether to read the
upper or lower scales of the voltmeter and ammeter.
Frequency Meter (M23) The frequency meter indi-
cates output frequency in Hertz (Hz) and engine
speed in RPM.
Output Voltage Trimmer (R21) The output voltage
trimmer can be used to adjust output voltage plus or
minus five percent of nominal voltage.
UPPER AND LOWER
SCALE INDICATOR
VOLTAGE
ADJUST
EXCITATION
FIELD BREAKER
PHASE
SELECTOR
SWITCH
FREQUENCY/
RPM METER
AC AMMETER
AC VOLTMETER
A-C AMPERES
A-C VOLTS
HERTZ
RPM
FIGURE 2-1. AC CONTROL PANEL (DETECTOR CONTROL)
2-2
AC CONTROL PANEL COMPONENTS
(SENTINEL CONTROL)
AC Voltmeter (M21) The voltmeter indicates output
voltage for the phase selected.
AC Ammeter (M22) The ammeter indicates output
amperage for the phase selected. Input to the am-
meter is from current transformers CT21, CT22,
and CT23.
Frequency/RPM Meter (M23) The frequency me-
ter indicates output frequency in Hertz (Hz) and en-
gine speed in RPM.
Phase Selector Switch (S21) The selector switch
is used to select the phase for voltage and amper-
age readings.
Output Voltage Trimmer (R21) The output voltage
trimmer can be used to adjust output voltage plus or
minus five percent of nominal voltage.
Field Circuit Breaker (CB21) The field circuit
breaker protects the generator from over-excita-
tion.
VOLTAGE
ADJUST
EXCITATION
FIELD BREAKER
PHASE
SELECTOR
SWITCH
FREQUENCY/
RPM METER
AC AMMETER
AC VOLTMETER
FIGURE 2-2. AC CONTROL PANEL (SENTINEL CONTROL)
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Cummins Onan GGFB GGFC GGHB GGHC GGHD Generator Sets Complete Workshop Service Repair Manual
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Description
This complete workshop service repair manual for Cummins Onan GGFB GGFC GGHB GGHC GGHD Generator Sets is an essential resource for both professional mechanics and DIY enthusiasts. It covers every service and repair procedure with easy-to-follow step-by-step instructions and pictures, making any job easy to do. You can save a significant amount of money by performing your own repairs using this comprehensive manual.
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All models, engines, trim, and transmission types are covered in this manual, ensuring that it caters to a wide range of needs. It includes high-quality content that comprehensively covers all repair procedures from A to Z, making it a valuable asset for anyone working on Cummins Onan GGFB GGFC GGHB GGHC GGHD Generator Sets.
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