Hobart 140GT17P Operation And Maintenance Manual With Illustrated Parts List page 79

(19) Connect a source of 24-V DC power (two twelve-volt batteries connected in series) to terminals
"N" and "F" (or "E") at the output terminal panel. Connection polarity should be: MINUS to terminal N
and PLUS to terminal E or F.
(20) With test-bank switch in AIRCRAFT position, hold the No. 1 contactor operating switch (18) in
top, CLOSE position momentarily. The generator "on" indicating light (17) should glow GREEN and re-
main on when the switch is released and allowed to return to the center ON position. This indicates
that the load contactor is closed and the plug interlock relay is functioning properly.
(21) Check operation of the No. 2 output contactor switch (20), the No. 2 plug interlock relay, and the
No. 2 contactor indicating light (19) by following the same procedures as used in steps 15-21 to check
the No. 2 contactor switch, plug interlock relay, and indicating light.
(22) Close both load contactors and apply 1/3 to 1/2 load at the load bank and allow the unit to run for
15 to 30 minutes. Observe operation of all monitoring instruments.
(23) Increase load bank resistance to apply a full load.
(24) Check operation of the governor by observing the frequency meter (9, Fig. 1) when generator is
switched from no-load to full-load and vice versa. Use the contactor control switch es (18 and 20) to
apply and remove load several times. Frequency drop should be no more than 1 Hz. Adjust governor
if necessary (see Para. 3, E, (3)).
(25) Follow instructions in voltage regulator manual TM-759 or OM-2020 to set voltage regulator line
drop compensation potentiometers. Set knob pointer on cable size potentiometer (33) to size (2/0,
4/0, etc.) of cable being used. Set knob pointer on cable length potentiometer (31) to length (20 feet,
40 feet, etc.) of cable being used. See instruction plate (mounted below knobs).
(26) Check voltage regulator, at intervals, from no-load to full load, and on up to 125% load. Observe
and note voltage at various loads. Voltages should vary no more than plus or minus 1% from 115 V.
(27) Check accuracy of voltmeter.
(a) Open generator control panel door.
(b) Connect a master voltmeter of known accuracy to terminals of the voltmeter (8).
(c) Compare unit voltmeter reading with master meter. Error must not exceed 2% of full scale.
(28) Check accuracy of AC ammeter.
(a) Connect a master ammeter of known accuracy to the AC ammeter (7) terminals.
(b) Compare unit ammeter reading with master meter under various loads. Error must not exceed
4% of full scale.
(29) Check operation of meter selector switch (5). A voltage value should be shown in each switch po-
sition.
(30) Check operation of the line switch (6). A normal voltage of 115 V AC should be indicated when
the switch is in LINE-TO-NEUTRAL position. A voltage of approximately 200 V AC should be indi-
cated when the switch is placed in LINE-TO-LINE position.
(31) Check accuracy of frequency meter.
(a) Connect a master frequency meter of known accuracy to the frequency meter (9) terminals.
(b) Compare meter readings. Error must not exceed 1% of full scale.
(32) Operate the unit not less than 10 minutes under full load. The overload device (Ref. 1-1; 19, Fig.
8) MUST NOT trip.
September 30/89 Revised
OM-2029
2-3
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