Frequency Adjustment - Kohler 8.5RES Service Manual

6. After adjusting the air gap, check the voltage again
as described in step 4. If the voltage does not
measure 1.75 VAC minimum, replace the magnetic
pickup.
7. To test the controller's governing function,
disconnect the magnetic pickup leads and open
the generator set circuit breaker.
8. Manually move the throttle shaft/governor stepper
motor fully counterclockwise (closed throttle).
9. Start the generator set. The stepper motor should
step clockwise to the wide open throttle position.
The stepper motor should remain in the clockwise
(throttle fully open) position. If the stepper motor
does not operate as described here, proceed to the
next steps to check the governor and stepper
motor.
10. Place the generator set master switch in the STOP
position. Check the stepper motor connections to
the controller: Leads 1A, 1B, 2A, and 2B to pins
P1-4, P1-5, P1-6 and P1-7. Check the pins and
connections at plugs J6 and P6. See the wiring
diagrams in Section 7.
11. Check the stepper motor coil resistance across
pins 2 and 3 and across pins 1 and 4. Only two
stepper motor leads of each coil group are used
(BLK-YEL and RED-WHT). See Figure 5-16. The
resistance per half coil is 38.5 ohms. If one of the
coils has a significantly higher resistance or is
shorted, replace the stepper motor.
12. If there is power and a good ground connection to
the ADC 2100 and the stepper motor coil
resistances are good, but the stepper motor does
not operate as described in step 9, the problem is
with the ADC controller.
connections, fuses, wiring, and settings. Refer to
the troubleshooting procedures in Section 3.
PIN 3, BLK
PIN 2, YEL
PIN 5, GRN
(not used)
Figure 5-16 Actuator Coil Group
50 Section 5 Component Testing and Adjustment
Check controller
PIN 4, PIN 1, PIN 6, BLUE
RED WHT (not used)
5.8.5

Frequency Adjustment

The engine speed determines the generator output
frequency; 60 Hz units operate at 3600 rpm and 50 Hz
units run at 3000 rpm. Adjust the engine governor to
change the output frequency using the following
procedure.
Note: Engine governor speed (frequency) and gain
adjustments are made using the ADC controller.
See Section 4.5.3 for instructions.
Frequency Adjustment Procedure
1. Open the generator set line circuit breaker.
2. Attach a frequency meter to the AC output leads.
3. Start and run the generator set until it reaches
normal operating temperature (at least 10 minutes).
4. Use the ADC controller to adjust the electronic
governor speed (parameter 4P) to obtain a
frequency reading of 60 Hz (or 50 Hz on 50 Hz
models).
Note: Often hunting/surging problems thought to
be caused by the governor are actually
caused by engine or carburetor problems. If
the generator set speed is unstable, hunts,
or surges, check for the cause using the
procedure
proceeding.
5. Check stability with the generator set running and
with no load applied. If the generator set speed is
unstable, hunts, or surges, use the ADC controller
to decrease the gain (parameter 5P) until the
generator set becomes stable with no hunting or
surging. Observe the frequency reading.
6. Repeat steps 4 and 5 to obtain the rated frequency
and stable operation.
7. Save the settings.
instructions.
Note: The controller will revert to the previous
settings at the next startup if the changes
are not saved within one minute after the last
change.
8. Apply rated load to the generator set and observe
the frequency reading. The no load and full load
SB555
frequencies should be within 0.4 Hz of the rated
generator frequency; if not, check that the
in Section 5.8.3 before
Refer to Section 4.5 for
TP-6196 5/04