Hobart 60PL20 Operation And Maintenance Manual page 60

OM-2053
(2) Check operation of engine instruments: DC ammeter (14, Fig. 1) , coolant temperature indicator
(18) , oil pressure gage (20) , and hourmeter (16) .
(3) Check engine idle speed. Should be 825 to 875 RPM. Adjust, if necessary, in accordance with in-
structions in Engine Operator's Manual.
NOTE: A stroboscope is required for this check.
(4) Again check for oil, fuel, and coolant leaks and correct any leaking condition.
(5) Position switches and controls for automatic voltage regulation and power delivery as follows:
(a) Place regulated-diagnostic switch (25, Fig. 1) in REGULATED position.
(b) Place test-bank switch (26) in AIRCRAFT position.
(c) Meter switch (4) may be in any position other than the directly downward (OFF) position.
(d) If the adjustment of the voltage regulator rheostat potentiometer (27) has been disturbed, posi-
tion the knob to mid-range position.
(6) Bring the engine up to governed speed and also energize the generator by holding the engine-gen-
erator control switch (15) in BUILD-UP-VOLTS position momentarily. Release switch and allow it to
position in "center" RUN position. If the engine "comes-up" to governed speed and a voltage value ap-
pears on the voltmeter (2) , the electric governor and excitationdeenergization relay circuits are func-
tioning.
(7) Observe frequency meter (1) . If engine speed is properly adjusted, frequency will be exactly 400
Hz. If not, adjust engine governed speed in accordance with Para. 3, E, (3) (d).
(8) Observe voltmeter (2). Use rheostat (27) to adjust voltage to 115 V AC.
(9) Measure governor actuator input signal. See Para. 3, E, (4), (a).
(10) Measure governor magnetic pickup signal. See Para. 3, E, (4), (b).
(11) Check speed limiting governor
Set engine speed-limiting governor to 2300 +/-25 RPM. See Perkins Diesel Handbook in Chapter
6 for instructions on how to set the governor.
(12) Check adjustable voltage range
(a) With regulated/diagnostic switch (25) in REGULATED position, observe voltmeter (2, Fig. 1)
and turn voltage regulator potentiometer (27) CLOCKWISE to full clockwise position. Maximum
voltage should be at least 134 V AC, or higher.
NOTE: If voltage should decrease when the potentiometer is turned clockwise, it indicates that
the voltage regulator PC board is defective. Replace the regulator PC board.
(b) Observe voltmeter and turn rheostat knob to full COUNTERCLOCKWISE position. Minimum
voltage should be 108 V AC, or lower.
(13) Observe voltmeter and adjust rheostat to obtain 115-V AC voltmeter reading.
(14) Position load bank switches, etc., to apply a light load to the generator.
(15) Place the load contactor "on-off" switch (17, Fig. 1) in the top, spring loaded, CLOSE position.
Hold in this position momentarily. Hold in this position momentarily. The indicating light (19) should
glow GREEN and an amperage value should appear on the AC ammeter (3) .
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December 31/91 Revised