Guardian Technologies 4758 User Manual
Page 44
SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
generally proportional to AC frequency. A low or high governor
speed will result in a correspondingly low or high AC frequency
and voltage output. The governed speed must be adjusted
before any attempt to adjust the voltage regulator is made.
PROCEDURE (7KW UNITS):
1. Loosen the governor clamp bolt (Figure 9).
2. Hold the governor lever at its wide open throttle position,
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 an AC frequency meter across the generators
AC output leads.
5. Turn the speed adjust nut to obtain a frequency reading
of 62 Hz.
6. When frequency is correct at no load, check the AC
voltage reading. If voltage is incorrect, the voltage
regulator may require adjustment.
Figure 9. Engine Governor Adjustment Single
Cylinder Engines
Figure 10. Engine Governor Adjustment
V-twin Engines
PROCEDURE (12/15 KW UNITS):
1. Loosen governor clamp bolt (See Figure 10).
2. Completely remove the idle spring.
3. With governor arm at wide open throttle position, rotate
governor shaft fully clockwise. Tighten clamp bolt to 84
inch-pounds.
4. Start unit and apply full load. Use full load speed adjust
screw (Figure 11) to adjust frequency to 58 Hz.
5. Remove load, stop engine, loosen the idle adjust screw
and reconnect the idle spring.
6. Using your hand, push the governor arm to the closed
throttle position. Make sure the idle spring does not
stretch at all.
7. Restart the unit.
8. Slowly turn the idle adjust screw to adjust the no-load
idle speed to 62.5 Hz.
9. The governor is now set.
Figure 11. Full Load Speed Adjust
ScrewV-twin Engines
RESULTS:
1. If, after adjusting the engine governor, frequency and
voltage are good, tests may be discontinued.
2. If frequency is now good, but voltage is high or low, go
to Test 13.
3. If engine was overspeeding, check linkage and throttle
for binding. If no governor response is indicated refer to
engine service manual.
4. If engine appears to run rough and results in low
frequency, proceed tp Problem 11, Page 4.3-3.
PART 2
Page 2.4-9