Kohler 11.5EFOZ, Service Manual

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TP-6071 3/00 29 Section 7 Generator Troubleshooting
Section 7 Generator Troubleshooting
7.1 General
Before beginning the troubleshooting procedures, read
all the safety precautions at the beginning of this
manual. The following tests include additional safety
precautions; OBSERVE THESE PRECAUTIONS!
Hazardous voltage.
Can cause severe injury or death.
Operate the generator set only when
all guards and electrical enclosures
are in place.
Moving rotor.
WARNING
Grounding electrical equipment. Hazardous voltage can
cause severe injury or death.
Electrocution is possible
whenever electricity is present. Open the main circuit
breakers of all power sources before servicing the equipment.
Configure the installation to electrically ground the generator
set, transfer switch, and related equipment and electrical
circuits to comply with applicable codes and standards. Never
contact electrical leads or appliances when standing in water
or on wet ground because these conditions increase the risk of
electrocution.
Short circuits. Hazardous voltage/current can cause
severe injury or death. Short circuits can cause bodily injury
and/or equipment damage . Do not contact electrical
connections with tools or jewelry while making adjustments or
repairs.
Remove wristwatch, rings, and jewelry before
servicing the equipment.
7.2 Generator Troubleshooting
To determine the cause of no- or low-AC output, check
the condition of the voltage regulator 8-amp fuse. If the
fuse is functional, separately excite the generator. See
Section 7.3. The separate excitation test duplicates the
role of the voltage regulator in providing excitation
current to the rotor.
Refer to the troubleshooting flow chart (Figure 7-1).
Generator has no or
low output
Separately
excite the generator
Test the rotor
Test the voltage
regulator & wiring
Generator has no or
low output
Generator has
output
Test the stator
TP-5983-7
Test the exciter circuit
& rectifier module
Figure 7-1 General Troubleshooting
7.3 Separate Excitation
By separately exciting the generator to determine the
presence of a faulty generator component, it is possible
to determine if a running fault exists in the rotor and/or
stator. A generator component that appears functional
while static (stationary) may exhibit a running open or
short circuit while dynamic (moving). Short circuits can
be caused by centrifugal forces acting on the windings
during rotation or insulation breakdown as temperatures
increase.
Separate Excitation Procedure:
1. Disconnect all the leads from the voltage regulator.
2. Disconnect the P6 (F1, F2) connector.