Hobart 140GT17P Operation And Maintenance Manual With Illustrated Parts List page 78

OM-2029
(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 (38, Fig. 1) in REGULATED position.
(b) Place test-bank switch (36) in AIRCRAFT position.
(c) Meter switch (5) may be in any position except pointing straight down.
(d) If the adjustment of the voltage regulator rheostat has been disturbed, position the knob to
mid-range position. (See TM-759 or OM-2020 in Chapter 6, depending on which regulator is
used, the mag-amp or solid state).
(6) Bring the engine up to governed speed and also energize the generator by holding the engine-gen-
erator control switch (23) 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 appears on the voltmeter (8), the
electric governor and excitationdeenergization relay circuits are functioning.
(7) Observe frequency meter (9). If engine speed is properly adjusted, frequency will be exactly 400
Hz. If not, adjust engine governed speed. See Fig. 6.
(8) Observe voltmeter (8). Use rheostat to adjust voltage to 115 V AC.
(9) Measure governor magnetic pickup signal. See Para. 3, E, (4).
(10) Check speed limiting governor
Set engine speed-limiting governor to 1714 +/- 25 RPM. See John Deere Diesel Handbook in
Chapter 6 for instructions on how to set the governor.
(11) Check adjustable voltage range in automatic operating mode.
(a) Observe voltmeter a nd turn rheostat CLOCKWISE to full clockwise position. Maximum volt-
age should be at least 134 V AC, or higher.
NOTE: If voltage should decrease when the knob is turned clockwise, it indicates that internal wiring of
the voltage regulator is incorrect. Replace the complete regulator tray assembly.
(b) Observe voltmeter and turn rheostat knob to full COUNTERCLOCKWISE position. Minimum
voltage should be 108 V AC, or lower.
(12) Observe voltmeter and adjust rheostat to obtain 115-V AC voltmeter reading.
(13) Position load bank switches, etc., to apply a light load to the generator.
(14) Place the load contactor "on-off" switch (18, Fig. 1) in the top, spring loaded, CLOSE position.
Hold in this position momentarily. Hold in this position momentarily. The No. 1 indicating light (17)
should glow GREEN and an amperage value should appear on the AC ammeter (7).
(15) Release the switch (18) and allow it to return to the center ON position. The No. 1 load contactor
should open immediately, and the No. 1 generator "on" indicating light should go OFF. This is be-
cause the plug interlock relay (Ref. 1-1; 8, Fig. 8) is not receiving power from an outside source of 28
V DC. It indicates that the plug interlock contacts are OPEN as they should be when the interlock coil
is not receiving 28-V DC power.
(16) Place the test bank switch (36, Fig. 1) in TEST BANK position.
(17) Again place No. 1 load contactor switch (18) in the top, CLOSE position. Light (17) should glow
GREEN and remain ON when switch is released and allowed to return to center ON position. This in-
dicates that test bank switch (36) is functioning to by-pass the No. 1 plug interlock relay.
(18) Return the test bank switch to AIRCRAFT position. The load contactor should open at once and
the green indicating light (17) should go off.
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July 27/90 Revised