Rotor (Field) Winding Internal Short Circuit Test; Stator Windings-Short Circuit To Ground Test - Jeep 1987 Wrangler Workshop Manual

ELECTRICAL
CHARGING SYSTEM - DELCO
Rotor (Field) Winding Internal Short
Circuit Test
Test Procedure
To perform this test, remove the rotor and front
housing from the stator and rear housing
assembly. Refer to A l t e r n a t o r O v e r h a u l
Section for the procedure. This test is per-
formed with a 12-volt battery and an ammeter.
Connect the battery and ammeter in series with
the slip rings (1). The field current with 12 volts
applied at 27°C (80°F) should be between 4.0
and 5.0 amps. In both cases replace the rotor.
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Test Results
Current flow exceeding 5.0 amps indicates
internally shorted windings. Replace rotor.
NOTE: The winding resistance and ammeter
indication will vary slightly with winding temper-
ature changes.
Stator Windings-Short Circuit to Ground Test
Test Procedure
To perform this test, separate the rear housing
and stator from the rotor and front housing
assembly.
Disconnect the stator winding terminals from the
bridge rectifier (and diode trio) terminal studs.
Refer to Alternator Overhaul Section for the
procedure.
NOTE: The test is performed with an ohmmeter
set for the x1000 scale or with a 110-volt test
lamp.
Touch one test lead probe to the bare metal
surface of the stator core and the other test
lead probe to the end of one stator winding.
Because all three stator winding terminals are
soldered together, it is not necessary to test
each winding. The ohmmeter should indicate
infinite resistance (no pointer movement) or the
test lamp should not light.
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