Generator Testing; No Output On Any Phase - Kohler TP-5353 Service Manual

This section covers generator testing for the following
generator conditions:
D No output on any phase
D Overvoltage
D Fluctuating voltage
Accidental starting can cause severe injury or
death. Turn generator set master switch to OFF
position, disconnect power to battery charger, and
remove battery cables (remove negative lead first and
reconnect it last) to disable generator set before working
on any equipment connected to generator set. The
generator set can be started by automatic transfer
switch or remote start/stop switch unless these
precautions are followed.
WARNING
Hazardous voltage.
Can cause severe injury or death.
Do not operate generator set without all guards and
electrical enclosures in place.
Hazardous voltage can cause severe injury or
death. Disconnect generator set from load by opening
line circuit breaker or by disconnecting generator set
output leads from transfer switch and heavily taping
ends of leads. If high voltage is transferred to load
during test, personal injury and equipment damage may
result. Do not use the safeguard circuit breaker in place
of the line circuit breaker.
7-4 Generator Troubleshooting

Generator Testing

Moving rotor.
Follow all safety precautions in front of this manual and
the additional precautions within the text. Figure 7-1
lists the various generator output conditions and
component tests. Refer to Figure 7-2, AC Voltage
Control for assistance in troubleshooting.

No Output On Any Phase

1. Check the safeguard breaker (if equipped). If
safeguard breaker is open, close breaker and, with
set running, check AC voltmeter for proper output
voltage.
2. If proper output does not show, then:
a. Check wire 1B from safeguard breaker and wire
7N (ground) to voltage regulator.
b. Check for voltage to safeguard breaker (if
equipped).
3. If all items in step 2 are okay, proceed to the LED
circuit board flashlight test and Automatic Voltage
Regulator (AVR) test as described later in this
section.
4. If tests indicate LED and AVR are functioning
correctly, visually inspect photo transistor board for
damage (open foil pattern or heat discoloration).
5. If the photo transistor board test appears good,
proceed to the exciter armature test as described
later in this section.
6. If the exciter armature test indicates the armature is
functioning correctly, proceed to the generator field
test as described later in this section.
7. If the generator field test indicates the field is
functioning correctly, replace the SCR assembly or
the photo transistor board as described later in this
section.
TP-5353 8/94