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CS-144 GENERATOR 6P2-7
ELECTRICAL TESTS
Except as stated, make the following tests with an
ohmmeter on the low range scale.
ROTOR FIELD WINDING CHECKS
The rotor may be checked electrically with a 110-volt
test lamp or art ohmmeter (figure 12).
Open Winding
To check for opens, connect the test-lamp or ohmme
ter to each slip ring. If the lamp fails to light, or the
ohmmeter reading is high (infinite), the winding is open.
Grounded Winding
Connect a test lamp or ohmmeter from one slip ring
to the shaft. If the lamp lights, or the reading is low, the
rotor winding is grounded.
Short Circuit or Resistance Check
The winding is checked for short circuits or excessive
resistance by connecting a battery and ammeter in
series with the edge of the two slip rings. Note the
ammeter reading and refer to “Specifications” later in
this section.
An ammeter reading above the specified value indi
cates shorted windings. An alternate method is to check
the resistance of the field by connecting an ohmmeter
to the two slip rings. If the resistance reading is above
the specified value the winding has excessive resis
tance; if below the specified value the winding is short
ed. The specified resistance value can be determined
by dividing the Voltage by the current.
A. CHECK FOR G ROUNDS
B. CHECK FOR OPENS
22. FRAME, DRIVE END
4 1 . !OHMMETER
‘ V3051
F i g u r e 1 2 —
C h e c k i n g t h e R o t o r F i e l d W
i n d i n g s
Remember that the winding resistance and ammeter
readings will vary slightly with winding temperature
changes. If the rotor is not defective, but the generator
fails to supply rated output, the problem is in the rectifi
er bridge, stator, or regulator.
If the rotor fails any of the above checks, replace it.
STATOR CHECKS
The stator may be checked with a 110-volt test lamp
or ohmmeter (figure 13). If the ohmmeter reads low or if
the lamp lights when connected from any stator lead to
bare metal on the stator frame, the stator is grounded.
An ohmmeter cannot be used to test the delta stator
for shorts or opens. Noticeable discoloration at any
place on the assembly usually indicates a problem in
the stator windings.
RECTIFIER BRIDGE CHECK
To check the rectifier bridge, connect the ohmmeter to
the grounded heat sink and one of the three terminals,
pressing down firmly on the flat metal clip (figure 14).
Observe the ohmmeter reading and reverse the lead
connectors to the grounded heat sink and the same
metal clip. A good rectifier bridge will give one high and
F i g u r e 1 3 —
C h e c k i n g t h e S t a t o r
Summary of Contents for C Series 1993
Page 1: ......
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Page 44: ...3B1A 2 POWER STEERING GEAR UNIT REPAIR Figure 1 710 Power Steering Gear ...
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Page 147: ...5J 10 AIR COMPRESSOR AND GOVERNOR 286 F9051 Figure 18 Bendix BX 2150 Compressor Components i ...
Page 204: ...MODEL 295 TBI UNIT 6C1 3 F7973 Figure 3 Model 295 TBL Unit ...
Page 251: ...6D4 6 37 MT STARTER MOTORS V3022 Figure 8 37 MT Components ...