Frequency Adjustment - Kohler Power Systems 8RESV Service Manual

5.11 Frequency Adjustment

WARNING
Hazardous voltage.
Can cause severe injury or death.
Operate the generator set only when
all guards and electrical enclosures
are in place.
Servicing the generator set when it is operating. Exposed
moving parts can cause severe injury or death. Keep
hands, feet, hair, clothing, and test leads away from the belts
and pulleys when the generator set is running. Replace
guards, screens, and covers before operating the generator
set.
The engine speed determines the generator output
frequency; 60 Hz units operate at 3600 RPM.
system frequency setting on the controller is changed,
the engine run speed will automatically update.
Set the system frequency to 60 Hz before adjusting the
engine speed. The system frequency can be adjusted
using the controller keypad on the RDC2 controller or
using a personal computer running Kohlerr SiteTecht
software. The DC2 controller must be adjusted using
SiteTecht software.
Frequency Adjustment Procedure
1. Use the RDC2 controller's Genset System menu
or use SiteTech to set the system frequency to 60
Hz.
Note: Although the RDC2 System Frequency
menu scrolls through numbers from 51-59,
the only available settings are 50 and 60 Hz.
2. Open the generator set line circuit breaker.
3. Attach a frequency meter to the AC output leads.
4. Start and run the generator set. Verify that the
output frequency matches the desired system
frequency.
5. Check stability with the generator set running and
with no load applied. If the generator set speed is
unstable, hunts, or surges, use SiteTech to verify
that the engine speed control parameters are set to
the default settings (Engine Speed Governor
settings in SiteTech).
90 Section 5 Component Testing and Adjustment
Moving parts.
When the
Note: Hunting/surging problems thought to be
caused by the governor are more likely to be
caused by fuel supply, engine or carburetor
problems. If the generator set speed is
unstable, hunts, or surges, check for the
cause using the procedure in Section 5.10.3
before proceeding.
6. Apply rated load to the generator set and observe
the frequency reading. The no load and full load
frequency should not vary more than 0.4 Hz from
the rated generator frequency.
a. If the frequency varies significantly more than
0.4 Hz from the system frequency, check that
the carburetor throttle plate opens completely
without sticking and check the carburetor
adjustment.
b. If the frequency is steady but running below
rated frequency, verify that the throttle is
completely open. If so, reduce the load on the
engine until the frequency recovers.
7. Check for hunting and surging at full load. If the
generator speed is unstable, hunts, or surges, the
governor gain may require adjustment. See
Section 5.11.1, Engine Speed Gain adjustment, for
instructions to change the governor gain.
8. Remove the load and observe the frequency. The
frequency should return to the rated level within a
few seconds. If the speed does not recover or the
generator controller shuts down for over frequency
or overspeed, it may be necessary to adjust the
governor gain. See Section 5.11.1.
TP-6881 7/15