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AC GENERATORS
Procedure
1.
Connect an accurate AC frequency meter across the Blue
and Black Wire terminals of the generator main line circuit
breaker (see Figure 19).
2.
Start the engine, let it stabilize and warm up at no-load.
3.
When engine has stabilized, read the frequency meter. The
no-load frequency should be about 61-63 Hertz.
Results
1.
Refer back to flow chart.
2.
If frequency and voltage are both good, tests may be
discontinued.
TEST 13 – ADJUST ENGINE GOVERNOR
If both AC frequency and voltage are correspondingly high or
low, adjust the engine governor as follows:
The engine must be OFF to perform steps 1 and 2.
1.
Loosen the governor clamp bolt (13mm). See Figure 23.
2.
Hold the governor lever at its wide open throttle position
(clockwise), and rotate the governor shaft clockwise as
far as it will go. Then, tighten the governor lever clamp
bolt to 70 inch-pounds (8 N-m).
3.
Start the generator; let it stabilize and warm up at no-load.
4.
Connect a frequency meter across the generators AC
output leads.
5.
Turn the adjust nut to obtain a frequency reading of 62.5
Hz.
Figure 23. Engine Governor Adjustment Points
PART 2
TEST 14 – ADJUST VOLTAGE REGULATOR
Procedure
1.
Remove two screws holding down the voltage regulator
(AVR).
2.
Leave the C1 connector and the brush connections
connected.
3.
Set VOM (Volt-Ohm-Meter) to measure AC voltage.
4.
Connect meter test leads across the main breaker.
240
Figure 24. VOM Test Leads Connected to the main breaker.
6.
Ensure all material is clear of the alternator before
proceeding.
7.
Set the AUTO-OFF-MANUAL switch to the MANUAL
position.
8.
Refer to Figure 25 for location of adjustment screw.
9.
Adjusting screw clockwise will increase voltage, adjusting
counterclockwise will lower the voltage.
Results
1.
If no change in voltage while adjusting refer back to flow
chart.
2.
If voltage is correct, stop testing.
Figure 25. Voltage Regulator Adjustment Screw
Section 2.4
Diagnostic Tests
Page 35
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Troubleshooting
