TP-5353 8/947-12 Generator Troubleshooting
Automatic Voltage Regulator (AVR)
Operation and Adjustment
The AVR monitors output voltage magnitude and
frequency to supply current to the stationary LED board.
The AVR circuit board includes volts/Hz and stability
adjustment pots. The volts/Hz adjustment is factory set
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 pots according to the procedure
following. See Figure 7-8.
C-255670-B
1
2
3
1. 60 Hz Voltage Adjustment
2. 50 Hz Voltage Adjustment
3. Stability Adjustment
Figure 7-8. AVR Adjustment
Stability Pot. Fine tunes voltage regulator to reduce
light flicker.
Volt/Hz. Pot. This adjustment determines engine
speed (Hz) at which generator output voltage will begin
to drop.
1. Turn generator master switch to OFF/RESET.
2. Set stability pot to far counterclockwise position.
3. Connect a 100-watt light bulb across terminals V0
and V7 on controller terminal strip or across
terminals on controller frequency meter.
4. Start generator set. With generator running at no
load, observe light bulb flicker. Excessive light bulb
flicker indicates poor stability.
5. Adjust stability pot until minimum flicker is
obtained.
6. Use controller voltage adjustment pot (or remote
voltage adjustment pot) to make adjustments to
generator while running under normal load (if
required).
7. Adjust engine speed to 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
frequency meter. See Section 7—Governor for
more information on engine adjustment.
8. Rotate Volts/Hz adjustment pot clockwise until
voltage level begins to drop (as measured on
voltmeter). When set to these specifications, the
generator will attempt to maintain normal output
until engine speed drops below the frequency set in
the previous step (as load is applied).
9. Adjust engine speed to obtain a full load engine
speed of 1800 rpm (60 Hz) or 1500 rpm (50 Hz).
10. Use controller voltage adjustment pot (or remote
voltage adjustment pot) to make final adjustments
to generator while running under normal load.
11. Readjust stability pot (if necessary).
To determine whether the AVR is functioning properly,
reduce engine speed (Hz) and watch for a
corresponding drop in AC voltage. At 60 Hz operation,
the voltage will remain constant until engine speed
drops below 58 Hz (approximately). If AC frequency
drops below 58 Hz, AC voltage will decline. At 50 Hz
operation, AC voltage remains constant until engine
speed is reduced to 48 Hz (approximately). If the AVR is
not functioning properly, refer to the following test to
determine cause of malfunction.
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