Kohler EKOZD Series Service page 187

Section 11 Alternator Component Testing and Adjustment
(35- 40 kW Generator Sets Equipped with 4PX/4QX Alternators)
Note: See Section 10 for 11- 32 kW generator sets
equipped with 4D/4E alternators.
11.1 Introduction
This section provides information on troubleshooting
the alternator and testing components of the generator
set.
To troubleshoot the alternator assembly components,
the following equipment is needed for many of the tests:
Multimeter (Voltmeter/Ohmmeter)
D
Megohmmeter
D
WARNING
Accidental starting.
Can cause severe injury or death.
Disconnect the battery cables before
working on
Remove the negative (- ) lead first
when disconnecting the battery.
Reconnect the negative (- ) lead last
when reconnecting the battery.
Disabling the generator set.
cause severe injury or death.
generator set or equipment connected to the set, disable the
generator set as follows: (1) Press the generator set off/reset
button to shut down the generator set. (2) Disconnect the
power to the battery charger, if equipped. (3) Remove the
battery cables, negative (- ) lead first. Reconnect the negative
(- ) lead last when reconnecting the battery. Follow these
precautions to prevent the starting of the generator set by the
remote start/stop switch.
WARNING
Hazardous voltage.
Can cause severe injury or death.
Operate the generator set only when
all guards and electrical enclosures
are in place.
TP-6953 7/19
the generator set.
Accidental starting can
Before working on the
Moving parts.
Disconnecting the electrical load. Hazardous voltage can
cause severe injury or death. Disconnect the generator set
from the load by turning off the line circuit breaker or by
disconnecting the generator set output leads from the transfer
switch and heavily taping the ends of the leads. High voltage
transferred to the load during testing may cause personal
injury and equipment damage.
High voltage test. Hazardous voltage can cause severe
injury or death. Follow the instructions of the test equipment
manufacturer when performing high-voltage tests on the rotor
or stator. An improper test procedure can damage equipment
or lead to generator set failure.
Grounding electrical equipment. Hazardous voltage can
cause severe injury or death. Electrocution is possible
whenever electricity is present. Ensure you comply with all
applicable codes and standards.
generator set, transfer switch, and related equipment and
electrical circuits. Turn off the main circuit breakers of all
power sources before servicing the equipment. Never contact
electrical leads or appliances when standing in water or on wet
ground because these conditions increase the risk of
electrocution.
Testing live electrical circuits.
current can cause severe injury or death. Have trained and
qualified personnel take diagnostic measurements of live
circuits. Use adequately rated test equipment with electrically
insulated probes and follow the instructions of the test
equipment manufacturer when performing voltage tests.
Observe the following precautions when performing voltage
tests: (1) Remove all jewelry. (2) Stand on a dry, approved
electrically insulated mat. (3) Do not touch the enclosure or
components inside the enclosure. (4) Be prepared for the
system to operate automatically.
(600 volts and under)
11.2 Alternator Troubleshooting
Follow all safety precautions listed in the front of this
manual and the additional precautions within the text.
Refer to Figure 11-1, AC Voltage Control, for assistance
in troubleshooting. Figure 11-2 lists various alternator
output conditions and component tests.
Use the following flowcharts to troubleshoot the
generator set when voltage problems are detected. The
remaining parts of this section give additional and more
detailed information about the individual checks/tests
mentioned in the flowcharts. Use the flowcharts to
initially isolate the possible problem.
This section covers alternator testing for the following
conditions:
No voltage output on any phase (Section 11.2.1)
D
Overvoltage (Section 11.2.2)
D
Fluctuating voltage (Section 11.2.3)
D
Section 11 Alternator Component Testing and Adjustment
Electrically ground the
Hazardous voltage or
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