Terex GenPac T15 Guide

Operator/Service & Parts Manual
First Edition
Rev A1
Part No. 833006
T15/T25 GenPac
after serial number GGG-19214

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OPERATOR’S MANUAL
To the Operator ................................................................................................. 4
Safety Alert Symbols ......................................................................................... 5
General Safety ............................................................................................... 6-9
Receipt of Delivery Checklist........................................................................... 10
Transport & Towing ..........................................................................................11
Set-Up ........................................................................................................ 12-13
Operating Instructions ................................................................................ 14-16
Maintenance............................................................................................... 17-18
Troubleshooting.......................................................................................... 19-21
Wiring Diagram - Kubota Gen-Pac Control Panel........................................... 22
Wiring Diagram - Isuzu Gen-Pac Control Panel.............................................. 23
Wiring Diagram - T25G Single Phase Distribution .......................................... 24
Wiring Diagram - T15G Single Phase Distribution .......................................... 25
Wiring Diagram - T15G & T25G Generator..................................................... 26
Dimensions ..................................................................................................... 27
Torque Specifications ...................................................................................... 28
PARTS MANUAL
Parts Ordering Information.............................................................................. 29
General Information ........................................................................................ 31
Cabinet Assembly ........................................................................................... 34
Trailer Frame/ Tongue/ Fuel Tank.................................................................... 36
Axle Assembly................................................................................................ 38
Electrical Enclosure......................................................................................... 40
Control Panel Assembly .................................................................................. 42
Distribution Panel Assembly........................................................................... 44
Engine T25G ................................................................................................... 46
Engine T15G ................................................................................................... 48
Generator T15G & T25G................................................................................. 50
Hitches ............................................................................................................ 51
Tail Lights ........................................................................................................ 52

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Operator’s
Manual

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To The Operator
An operator should never use drugs, alcohol or any other substance which can change his alertness or
coordination.
Do not work on this equipment when mentally or physically fatigued.
This manual is compiled from information available and current at time of approval for printing. Terex reserves
the right to improve its products without giving prior notice or incurring any obligation.
If this manual becomes lost, order a new one from Terex so future operation and maintenance personnel may
read these instructions.
DO NOT ATTEMPT TO SETUP, OPERATE, OR WORK ON THE TEREX GEN-PAC GENERATORS UNLESS
YOU HAVE READ AND UNDERSTAND THIS MANUAL AND THE ENGINE AND GENERATOR MANUALS
CAREFULLY. READING THESE MANUALS WILL TEACH YOU HOW TO SAFELY SETUP, OPERATE,
AND PROPERLY MAINTAIN THE GENERATOR SET AND ITS COMPONENTS.
REMEMBER THAT YOU ARE THE KEY TO SAFETY. GOOD SAFETY PRACTICES NOT ONLY PROTECT
YOU, BUT ALSO THOSE WORKING AROUND YOU. MAKE THIS MANUAL A WORKING PART OF YOUR
SAFETY PROGRAM.
THIS EQUIPMENT USES HIGH VOLTAGE CIRCUITS CAPABLE OF CAUSING
SERIOUS INJURY OR DEATH.

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Safety Alert Symbols
MEANS:
ATTENTION! BE ALERT!
YOUR SAFETY IS INVOLVED
THIS SAFETY SYMBOL IS USED FOR IMPORTANT SAFETY MESSAGES. WHEN YOU
SEE THIS SYMBOL, FOLLOW THE SAFETY MESSAGE TO AVOID PERSONAL INJURY
OR PROPERTY DAMAGE.
Understanding Signal Words
Asignal word - DANGER, WARNING or CAUTION is used with the safety alert symbol.
DANGER Identifies the hazard or unsafe practice that will
result in severe injury or death.
WARNING Identifies the hazard or unsafe practice that
could result in severe injury or death.
CAUTION Identifies the hazard or unsafe practice that
could result in minor injury or property damage.
NOTICE Identifies important installation, operation or
maintenance information.

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General Safety
DO NOT SETUP OR OPERATE THE TEREX GEN-PAC GENERATORS WITH-
OUT READING THIS OPERATOR’S MANUAL.
SAFETY ALERT SYMBOL
Stop and take time to readALL Safety alert messages.
Follow the safety messages to avoid personal injury or
propertydamage.
ACCIDENT PREVENTION
Use protective clothing and safety equipment. Always
wear approved safety equipment such as gloves,
safety boots, safety hard hat, goggles, ear protection,
and dust masks when necessary. Wear protective
clothing that is snug and belted where required.
UNAUTHORIZED WELDING
DO NOT weld on any structural member.
Any unauthorized welding or repair procedure will void
thewarranty.
DO NOT WORK ON OR OPERATE THE TEREX GEN-PAC GENERATORS WHILE UNDER THE INFLU-
ENCE OF PERFORMANCE IMPAIRING DRUGS OR ALCOHOL.
UNAUTHORIZED WELDING
CAN CAUSE STRUCTURAL
FAILURE OR PERSONAL
INJURY.

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General Safety
FUELING
ALWAYS handle fuel with care. It is highly flammable.
ALWAYS stop engine before refueling. Fill fuel tank
outdoors.
DO NOT replace fuel lines with materials different from
those supplied as original equipment.
Prevent fires by keeping the generator and its sur-
rounding area clean.
DO NOT refuel while smoking or when near open
flame or sparks.
DO NOT refuel the engine when it is hot. Allow to cool
for several minutes before refueling.
DO NOT spill fuel inside the engine compartment.
If fuel has leaked, wipe it up and have leak repaired
before next use.
Have a fire extinguisher nearby. Be sure the extin-
guisher is properly maintained and be familiar with its
use. Extinguishers ratedABC by the NFPA are appro-
priate for all applications.
FIRES CAN CAUSE
SEVERE PERSONAL
INJURY OR MACHINE
DAMAGE.

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BATTERY HAZARDS
Lead acid batteries can be dangerous. The sulfuric acid in the battery can cause severe skin and eye burns.
The hydrogen gas emitted during charging can explode if an arc or flame is present.
DO NOT smoke while servicing the battery.
DO NOT allow tools to touch battery terminals and create an arc.
Disconnect the negative terminal of the battery when working on the engine or other parts to prevent accidental
arcing. Disconnect the negative cable at the end away from the battery.
DO NOT remove the vent caps when charging the battery.
Always wear eye protection when servicing the battery.
If acid gets on skin or eyes, immediately flush under running water and obtain medical attention.
ELECTRICAL SAFETY
This equipment uses high voltage circuits capable of causing serious injury or death. Exercise ex-
treme caution around any electrical component while operating this unit.
Always ground the unit when possible.
A grounding lug has been added to the trailer frame for your convenience.
Beware of cut or damaged power cords. Have a qualified electrician replace any damaged cords
immediately.
General Safety
EXHAUST GASES ARE TOXIC. DO NOT USE IN-
DOORS UNLESS PROPERLY VENTILATED OR AN
EXHAUST SCRUBBER IS USED.
Check exhaust system regularly for leaks and ensure that the exhaust manifolds are secure and not
warped.
Make sure the unit is well ventilated.
DO NOT TOUCH HOT PARTS
The exhaust manifold and tail pipe are very hot. Parts of the engine are also hot. Use protective
gloves when handling hot parts.

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General Safety
KEEP ALL BODY PARTS AND CLOTHING AWAY
FROM MOVING PARTS
Loose jackets, shirts, sleeves, and especially neckties should not be worn while working on or running
the unit.
Only remove guards or protective devices from unit temporarily to gain access for maintenance.
Always replace guards immediately after servicing. Never remove guards while unit is operating.
Keep your hands away from moving parts, particularly clear of the radiator fan and alternator belts
when the engine is running.
BEWARE OF TRAFFIC HAZARDS
Stand clear of traffic when starting or checking the unit along the road.
Check the fuel tank, oil pan, and fuel and oil lines for leaks that would spill fuel or oil on the road.
Check fasteners and mounting brackets periodically to insure all are tight and nothing is in danger of
falling off during transit.
Be careful when lifting. Never suspend any other
equipment from the shipping tie downs.
Use the lifting eye for lifting the trailer (with cabinet).
Make sure any tie-downs at the bottom of the trailer are released prior to lifting.
NEVER CLIMB ON TOP OF THE CABINET.

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Receipt of Delivery Checklist
The generator will be serviced, tested and ready for operation upon delivery. Terex recommends the following
checks:
Insure there is no freight handling damage which should be charged against the carrier.
Check the front jack for security and proper operation.
Check that the tires are not damaged, under inflated or that any lugs are loose.
Check the engine/generator for obvious damage, loose connections, or leaks.
Check the control panel for damage or loose connections.
Check the exhaust system for damage.
Check all fluid levels; battery, radiator, and engine oils.
Insure manuals are in the pocket provided inside the unit.

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ALWAYS USE THE PROPER TRAILER HITCH AND SAFETY
CHAINS. OBEY ALL LOCAL OR STATE D.O.T. LAWS WHEN TOW-
ING A GENERATOR.
Transport and Towing
All trailer-mounted Terex Gen-Pac generators are designed for highway and off-road towing capability. Please
consult state and local transportation codes before transporting the generator set.Additionally, all state and
local traffic laws take precedence over the following instructions whenever differences arise between them.
1. Make sure the towing vehicle is of adequate size to both tow and stop the unit.
2. Disconnect all wiring and cabling (including the ground wire) from the generator set.
3. Close and latch or lock all access doors.
4. Using the front leveling jack, raise the trailer hitch to an adequate height so that the generator can be se
curely attached to the transporting vehicle.
5. Insure that the coupler is properly secured to the towing vehicle and attach the safety chains.Attach the
“breakaway” chain on the surge brake and the electrical coupler if these options are included on the unit.
6. Retract and rotate the front leveling jack into its stowed position.
7. Check the tires for proper inflation and verify the lug nuts are tight.
8. Remove tire chocks.
9. Observe posted speed limits for trailers. Generally, do not exceed 45 mph on paved roads and 10 mph on
unpaved roads.
FAILURE TO PROPERLY SECURE THE TRAILER TO THE TOW-
ING VEHICLE MAY RESULT IN SERIOUS INJURY OR DEATH.
Exceeding these recommended speeds can cause severe
damage to the unit. Damage caused by these unsafe practices
will void the manufacturer’s warranty.

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Setup
Move the generator set to the desired location keeping the following in mind:
1. The spot where the generator set is positioned should be relatively level.
2. The location selected should be centrally located to equipment requiring the loads
to minimize voltage drop in the power cord.
3. Locate so power cords can be routed without crossing roads and access routes.
4. Locate where the engine will get good ventilation. Do not locate where fumes will
enter a building.
5. Do not place beside a building wall that would reflect and intensify noise.
Unhitch from the towing vehicle as follows:
1. Locate the generator set in the desired location.
2. If the axle is sloped downhill, turn the generator set so that the axle is level.
3. Chock wheels if generator set is not on level ground.
4. Unhook hitch, safety chains and running lights.
5. Rotate the tongue jack into position (90 degrees), release the hitch pin and raise
the tongue off the towing vehicle.
THE WHEELS MUST BE PROPERLY CHOCKED IF THE
GENERATOR IS ON UNLEVEL GROUND.DO NOT OPERATE
THE GENERATOR SET UNTIL IT HAS BEEN PROPERLY
SECURED.

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Never remove the radiator cap while the engine is running
or while the engine is hot.
2. Check the oil level in the engine crankcase, and add as required.
Check engine manufacturer’s recommendations for motor
oil types and weights.
3. If the battery is not a maintenance free battery, check the electrolyte level in the battery and add distilled
water if necessary.
4. Check fuel/water separator for water in the fuel system. Drain water from separator if necessary.
5. Check fuel level in the fuel tank and add as required. Check to insure the fuel tank vent is “open” and not
clogged.
Use #2 diesel fuel only.
6. Verify that the generator main circuit breaker is in the “OFF” position.
7. Make sure the generator set is properly grounded. This is accomplished by connecting the grounding lug
provided at the rear of the generator set enclosure to a mechanical earth-ground with a minimum 2/0 size
electrical cable. If this differs from your local code, always follow the local code for grounding.
8. Check all electrical connections to insure they are in the proper configuration and all connections are tight.
When preparing to start the generator set, follow the sequence listed below:
1. Check the coolant level in the radiator, and add as necessary. If adding coolant, use only a 50/50 mixture
of antifreeze and water.
Setup
THIS GENERATOR SET PRODUCES VOLTAGES THAT CAN
CAUSE SEVERE SHOCK OR DEATH! ONLY QUALIFIED
ELECTRICIANS SHOULD PERFORM ELECTRICAL WORK.

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STARTING THE ENGINE/GENERATOR SET
Operating Instructions
Once setup procedures are completed, the generator set is ready to be started. Start the unit according to the
following steps:
1. Turn the ENGINE ON/OFF SWITCH clockwise to the ‘run’ position until the glow plug indicator LED illumi-
nates. The unit will preheat for 15-20 seconds.
Never attempt to start the generator set with the main circuit
breaker “ON”. This breaker is located on the distribution
panel. Starting with the breaker “ON” can cause damage to the
generator.
Never preheat for more than 30 seconds, damage may be
done to the heating elements.
2. Turn the ENGINE ON/OFF SWITCH to the extreme clockwise or ‘start’ position until the engine “fires”,
then release it.
To avoid starter damage, never operate the starter for
more than 30 seconds at a time.
3. Now that the generator set is running, allow five minutes for warm-up time.
4. Listen for any unusual sounds or excess vibrations that could signal problems and require immediate
shutdown of the unit. Should unusual sounds be detected, shut the unit down, and contact theTerex
Service Department at 1-800-433-3026.
5. Once the engine has been started and running smoothly, the following gauges should be monitored:
-AC Voltmeter- This gauge should read 240 VAC in the standard factory set
configuration.
-AC Frequency Meter- This gauge should read 60-62 Hz. This indicates a proper
engine speed of about 1800 rpm.
-ACAmmeter- The reading on this gauge should be zero since the main breaker is
in the “OFF” position. Once a load is applied to the generator, the
ammeter will produce an appropriate reading.

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Operating Instructions
LOADING INSTRUCTIONS:
If all readings are correct, an electrical hookup can be made to the generator set. To make the electrical
hookup to the generator set, observe the following set of procedures:
SHUT DOWN THE GENERATOR SET BY TURNING THE
ENGINE ON/OFF SWITCH TO THE “OFF” POSITION BE-
FORE MAKING ANY ELECTRICAL CONNECTIONS.
1. Shut down the generator set, verify the main breaker is in the “OFF” position.
2. Connect the desired electrical equipment/apparatus to the generator set, while making sure no other
power source is connected to the same equipment/apparatus.
3. After the connections have been completed, close the cover over the 3 phase distribution lugs.
Failure to close the cover over the 3 phase lugs will cause the
main breaker to shunt trip when the unit is started.
4. Restart the engine and monitor the critical functions as outlined in the Operating Instructions section.
5. Switch the main generator circuit breaker to the “ON” position.
6. Monitor theAC Ammeter- If the needle deflects severely to the right and stays there, immediately turn the
main generator circuit breaker to the “OFF” position.
Severe deflection of the ammeter indicates a wiring
problem or an overload problem. Continued operation
under this condition will cause damage to the generator
and/or connected apparatus.
The needle on the ammeter will deflect to the right temporarily and then return to a normal reading if the unit is
operatingproperly.

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Operating Instructions
SHUTDOWN PROCEDURES:
1. Switch the main generator breaker to the “off” position.
2. Allow the engine to run for 5 minutes under no load as a cool down cycle.
3. Stop the engine by turning the Engine On/Off Switch to the “OFF” position.
NEVER SHUT THE UNIT DOWN WHILE UNDER LOAD. THIS
COULD CAUSE SERIOUS INJURIES TO THE PERSON OPER-
ATING THE MACHINE OR DAMAGE TO THE GENERATOR.
Never shut the unit down with the main generator circuit
breaker in the “ON” position. This can cause damage to the
generator and/or the connected apparatus.

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Maintenance
MINIMUM MAINTENANCE PROCEDURES:
The following maintenance intervals are only suggested by Terex. You should always check your engine
owner’s manual for specific information. Should you find any discrepancies between the Terex Manual and the
Engine Manufacturer’s Manual always follow the Engine Manufacturer’s Manual.
Every 8 Hours of Operation:
-Check the crankcase oil and fill as required.
-Check the fuel tank level and fill as required.
NEVER ADD FUEL TO THE UNIT WHILE IT IS RUNNING.
THIS CONSTITUTES A SEVERE FIRE HAZARD THAT CAN
CAUSE DAMAGE TO THE UNIT AND INJURY TO THE
OPERATOR.
Daily: -Check the engine and generator for any loose bolts, connections, and fittings.
-Check the coolant levels and fill as required.
-Check the fuel/water separator for the presence of water contamination. Drain as
required.
Water contaminated fuel will cause severe damage to the
injection and fuel pumps.
-Check battery electrolyte level and replenish if necessary.
NEVER REMOVE THE RADIATOR CAP OR CHECK
ELECTOLYTE LEVELS ON A HOT UNIT. THIS COULD
RESULT IN SEVERE BURN TO THE OPERATOR.
Note: Use a 50% solution of water and antifreeze for the engine coolant.
Weekly:
-Check the air cleaner and clean as required.
-Inspect the radiator fins for damage or clogging and clean as required.
Bi-weekly:
-Check the engine oil quality and change as required.
Bi-Monthly or every 250 hours:
-Change the engine crankcase oil.
-Check cooling fan belt tension and adjust if necessary.

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Maintenance
Six months or every 500 hours:
-Replace the oil filter.
-Check valve clearances (consult Manufacturer’s Manual)
-Check electrical components and clean as required.
-Check electrical wiring for chafing, wear and replace as needed.
Yearly or every 1,000 hours:
-Clean or replace the fuel filter.
-Clean or replace the fuel pump strainer, if equipped.
-Check the head and manifold bolts for tightness.
-Replace air cleaner element.
CLEANING:
The Terex GenPac generators employ various electronic controls that may be damaged by liquid spray wash-
ing or high pressure washing. Follow these procedures to prevent any damage to these components.
DO NOT SPRAY WATER INTO THE UNIT WHILE IT IS RUNNING.
THIS MAY RESULT IN INJURY OR DEATH BY ELECTRIC SHOCK.
Exterior Cleaning:
1. The exterior housing may be washed by most conventional cleaners and methods.
2. The exterior housing may be waxed using any conventional automotive wax.
Interior Cleaning:
1. Using a damp cloth covered with a mild soap, carefully clean around any electric controls, generator, and
thermostats.
2. The base and housing foam may be cleaned with a damp cloth covered with mild soap.

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Trouble Shooting Guide
The engine/generator set is factory installed. These units are tested and set at the factory for proper operation
in the field. These units should never require additional adjustments in the field.Adjustments should only be
made by a qualified service technician, otherwise the manufacturer’s warranty may become void.
TROUBLE POSSIBLE CAUSE REMEDY
1. No generator output voltage. a. Circuit breaker is tripped a. Reset circuit breaker
b. Voltage regulator power lead loose b. Check voltage regulator wiring
c. Defective voltage regulator c. Replace voltage regulator
d. Defective generator d. Refer to generator manual
2. Low generator output voltage a. Voltage adjustment potentiometer a. Reset voltage adjustment
set too low
b. Low engine speed b. Reset engine speed to 61.5 Hz
(1845 rpm) under no load
c. Loose wire on voltage selector c. Check wiring
switch
d. Fluctuating or surging engine d. Check engine fuel, oil, and oil
speed filters
e. Loose wire on voltage selector e. Check wiring
sensing circuit
f. Defective voltage regulator f. Replace voltage regulator
3.High generator output voltage a. Voltage adjustment potentiometer a. Reset voltage adjustment
set too high
b. High engine speed b. Reset engine speed to 61.5 Hz
(1845 rpm) under no load
c. Loose wire on voltage adjustment c. Check wiring
potentiometer
d. Defective automatic voltage d. Replace voltage regulator
regulator
4.Fluctuating generator output a. An "ON/OFF" type load may be a. Redistribute load if possible
voltage the cause
b. Fluctuating or surging engine b. Check: Engine fuel system, air
speed leaks, plugged filters, clogged pick-up
tube in fuel tank
c. Automatic voltage regulator setting c. Check stability adjustment and
may be wrong check engine governor for stability
d. Loose wire on automatic voltage d. Check wiring
regulator sensing lead

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Trouble Shooting Guide
5.Low engine speed a. Engine speed adjustment has a. Reset engine speed to 61.5 Hz
slipped (1845 rpm) under no load
b. Clogged fuel system b. Check for air leaks, clogged fuel
line, or clogged fuel pick-up tube
c. Blocked air intake c. Check air filter
d. Blocked exhaust system d. Check engine exhaust system,
remove obstructions
e. Contaminated fuel e. Check fuel/water separator and
fuel tank for contamination. Replace
fuel if needed
f. Defective governor on engine f. Have governor checked by a
qualified technician
g. Defective injectors on engine g. Have injectors checked by a
qualified technician
h. "Surging" engine speed h. Reset engine speed to 61.5 Hz
(1845 rpm) under no load
6. Engine turns over (cranks), but a. Unit out of fuel a. Check fuel level in tank, fill as
will not run needed
b. Loose or bad DC FUSE in engine b. Check and replace with 25 amp
control circuit SLOBLO type fuse if needed
c. Loose or broken wire in control c. Check wiring to verify 12v DC is
circuit to fuel injection pump solenoid being supplied to the pump
d. Clogged fuel system d. Check fuel system
e. Air in fuel system e. "Bleed" fuel system
f. Defective fuel pump f. Check and replace if needed
g. Clogged air intake g. Check air cleaner
h. Clogged exhaust h. Check exhaust system
I. Contaminated fuel I. Check fuel/water separator and
fuel tank for contamination. Replace
fuel if needed
j. Defective injectors on engine j. Have injectors checked by a
qualified technician
k. Loss of engine compression k. Have compression checked by a
qualified technician
7. Engine will not crank a. Loose battery cable or discharged a. Check cables and battery
battery electrolyte level and recharge if
needed
b. Engine "ON/OFF" switch set in b. Check switch position
"ON"
c. Blown fuse in DC control circuit c. Replace fuse
d. Defective starter solenoid d. Replace solenoid
e. Defective starter e. Replace starter
f. Seized engine f. Have engined checked by a
qualified technician