Generator And Exciter Stator Test - Hobart 9OC24S Operation Manual

OPERATION, MAINTENANCE, AND OVERHAUL MANUAL, TM-240A
SELF-PROPELLED GENERATOR SET, SPEC. NO, 5381A
NOTE: Make certain the battery is in good condition and the pointer is
adjusted to zero when the test lead points are shorted together.
Set the scale selector to RXl.
(3) Hold one ohmmeter lead point on the threaded end of the diode. Hold the other
lead point on the wire terminal end.
Observe and note the indicated resistance.
Now reverse the lead connections on the diode. Again observe and note the
ohmmeter indicated resistance. Generally speaking, if an infinite or very high
resistance was indicated with the leads connected one way and a low, readable
resistance was indicated with the leads connected the opposite way, the diode
may be considered good.
D. Generator and Exciter Test
The generator fields may be tested with a "Kelvin" bridge. This is a double-bridge
type instrument required for the very low resistances encountered in this test. It is
understood that 0 resistance indicates a SHORT CIRCUITED condition. An infinite
resistance reading indicates an OPEN CIRCUITED condition. See Fig. 4 below for
resistance values.
NOTE: The equipment should be COLD or at normal ambient temperature when
tests are made.
(1) Disconnect generator stator leads at the power module panel.
(2) Disconnect exciter leads at terminals E-l and E-2, Fig. 3. Positive lead (E-l) is
RED. Negative (E -2) is YE LLOW-BLACK.
(3) Compare resistance values to those in Fig. 4.
TEST CONNECTION NOMINAL RESISTANCE IN OHMS
GENERATOR STATOR
Phase A to N 0.00438
Phase B to N 0.00427
Phase C to N
0.00432
NOTE: The two leads of a phase must be connected when test is made.
EXCITER
2-3
Page 14
Fie Id (RED to YE LLOW BLACK) 28.28
Generator and Exciter Stator Test
- -Values--(70°- F Ambient Temperature) ~~-~ -~---~ .~~. -- -~- ~~ ~-
Figure 4
act 30/73
..__..... - . . . _-.- ~--~ . . . -_ .._.._