Kohler 40COZ/33CFOZ Service Manual page 134

Disconnecting the electrical load. Hazardous voltage can
cause severe injury or death. Disconnect the generator set
from the load by opening 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. Do not use the safeguard
circuit breaker in place of the line circuit breaker.
safeguard circuit breaker does not disconnect the generator
set from the load.
Short circuits. Hazardous voltage/current can cause
severe injury or death. Short circuits can cause bodily injury
and/or equipment damage.
connections with tools or jewelry while making adjustments or
repairs. Remove all jewelry before servicing the equipment.
Overvoltage Shutdown Adjustment Procedure
1. Disconnect the generator set engine starting
battery, negative (--) lead first. Disconnect power to
the battery charger (if equipped).
2. With the generator set shut down, open the output
line circuit breaker to disconnect the load from the
generator set.
3. Remove the controller cover.
4. Wrap the shaft of an insulated-handle screwdriver
with electrical tape to insulate the metal shaft. Turn
the overvoltage potentiometer (R41) on the main
circuit board fully clockwise. See Figure 9-24.
5. Connect a digital AC voltmeter (or other 1%
minimum accuracy voltmeter) to terminals V0 and
V7F (or V7) on the controller terminal block. See
Figure 9-22.
6. Reconnect the battery, negative (--) lead last.
7. Start the generator set by placing the generator set
master switch in the RUN position.
8. Adjust the output voltage to 115% of the nominal
output voltage using the voltage adjustment
potentiometer. If the voltage configuration is
139/240 volts (low wye) or 277/480 volts (high
wye), 3-phase, 4-wire, 60 Hz, adjust the output
voltage to 160 volts across terminals V0 and V7F
(or V7). For all other voltages, adjust the output
voltage to 115% of the nominal output voltage
measured across terminals V0 and V7F (or V7).
Adjust the voltage using the voltage adjustment
potentiometer on the generator controller front
panel. See Figure 9-23.
9. Use the insulated screwdriver to slowly rotate the
overvoltage adjustment
counterclockwise until red LED4 lights.
120 Section 9 Wiring Diagrams
The
Do not contact electrical
potentiometer (R41)
See
Figure 9-24. The generator set should shut down
on an overvoltage
2 seconds.
R41
P2
1. Overvoltage adjustment potentiometer (R41)
2. LED4 (red)
Figure 9-24 Overvoltage Shutdown Adjustment on
Main Circuit Board
10. Turn the voltage
counterclockwise to prevent overvoltage shutdown
upon restart. Restart the generator set. Slowly
increase the voltage by turning the voltage
adjustment potentiometer clockwise. Verify the
shutdown voltage point (115% of the nominal
output voltage) by observing the voltmeter and
noting when LED4 lights. The generator set should
shut down on overvoltage fault in approximately
2 seconds. If the shutdown voltage point is not
115% of nominal voltage, repeat the calibration
procedure; otherwise, continue to step 11.
11. Turn the voltage
counterclockwise to prevent overvoltage shutdown
upon restart. Restart the generator set. Readjust
the generator set output to the nominal voltage
using the voltage adjustment potentiometer.
12. Stop the generator set by placing the generator set
master switch in the OFF/RESET position. Seal
the overvoltage adjustment potentiometer (R41)
with RTV sealant or equivalent.
controller cover.
fault in approximately
2
1
LED4
P1
A-336415-A
adjustment potentiometer
adjustment potentiometer
Replace the
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TP-5737 5/01