Automatic Voltage Regulator (Avr) Operation And Adjustment - Kohler 40COZ/33CFOZ Service Manual

7.5 Automatic Voltage Regulator
(AVR) Operation and
Adjustment
The AVR monitors output voltage amplitude and
frequency to supply current to the stationary LED board.
The AVR circuit board includes volts/Hz and stability
adjustment potentiometers. The factory sets the
volts/Hz adjustment and normally requires no further
adjustment. If replacement of the controller circuit board
or operation of the generator under extreme loads
results in voltage instability, adjust the potentiometers
according to the procedure following. See Figure 7-10.
1
2
3
1. 60 Hz voltage adjustment
2. 50 Hz voltage adjustment
3. Stability adjustment
Figure 7-10 AVR Adjustment
Stability Potentiometer.
regulator to reduce light flicker.
Volt/Hz Potentiometer. This adjustment determines
engine speed (Hz) at which the generator output voltage
begins to drop.
Voltage Regulator Adjustment
1. Place the generator set master switch in the
OFF/RESET position.
2. Set the stability potentiometer to the far
counterclockwise position.
3. Connect a 100-watt light bulb across terminals V0
and V7 on the controller terminal strip or across the
terminals on the controller frequency meter.
66 Section 7 Component Testing and Adjustment
C-255670-D
Fine tunes the voltage
4. Start the generator set. With the generator running
at no load, observe light bulb flicker. Excessive light
bulb flicker indicates poor stability.
5. Adjust the stability potentiometer until minimum
flicker is obtained.
6. Use the controller
potentiometer (or remote voltage adjustment
potentiometer) to make adjustments to the
generator while running under normal load, if
required.
7. Adjust the engine speed to the desired cut-in
frequency. Factory setting is 57.5--58.0 Hz for
60 Hz models or 47.5--48.0 Hz for 50 Hz models as
measured on the frequency meter. See Section
7.14, Governor Adjustment, for more information
on engine adjustment.
8. Rotate the Volts/Hz adjustment potentiometer
counterclockwise until the voltage level begins to
drop (as measured on the voltmeter). When set to
these specifications, the generator attempts to
maintain normal output until the engine speed
drops below the frequency set in the previous step
(as load is applied).
9. Adjust the engine speed to the appropriate
operating point. See Section 7.14.
10. Use the controller
potentiometer (or remote voltage adjustment
potentiometer) to make final adjustments to the
generator while running under normal load.
11. Readjust the stability potentiometer, if necessary.
12. Check the AVR's function by reducing the engine
speed (Hz) and watching for a corresponding drop
in AC voltage.
At 60 Hz operation, AC voltage remains constant
until the engine speed drops below 58 Hz
(approximately). If AC frequency drops below
58 Hz, AC voltage declines.
At 50 Hz operation, AC voltage remains constant
until the engine speed drops to 48 Hz
(approximately). If AC frequency drops below 48
Hz, AC voltage declines.
If the AVR does not function as described above,
refer to the following test for the cause of the
malfunction.
voltage adjustment
voltage adjustment
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