4C-16 - CHARGING SYSTEM 90-823225--1 1096
STATOR
IMPORTANT: Stator leads MUST BE discon-
nected from rectifier for this test.
1. Test stator for grounds (Test 1), using an ohmme-
ter (set on R x1 scale) as follows:
a. Connect one lead of ohmmeter to one of the
stator leads and the other lead to stator
frame. Be sure that lead makes good contact
with frame.
b. Meter should indicate no continuity (meter
should not move). If continuity does exist, sta-
tor is grounded and must be replaced.
2. Test for opens in stator (Test 2), using an ohmme-
ter (set on R x1 scale) as follows:
a. Connect ohmmeter between each pair of sta-
tor windings (three different ways).
b. Continuity should be present in all three
cases (meter should move). If it does not, one
or more of the windings are open and stator
must be replaced.
72833
TEST 1 TEST 2 TEST 2
TEST 2
Testing Stator
3. A short in the stator is difficult to detect without
special equipment, because of the low windings
resistance. If all other electrical components test
out good, and alternator fails to produce rated
output, stator probably is shorted and should be
replaced. Also, examine stator for heat discolor-
ation, as this usually is a sure sign of a short.
RECTIFIER AND DIODE ASSEMBLY
NOTE: Failure of any component in tests following
will require replacement of entire rectifier assembly.
NEGATIVE (–) RECTIFIER
IMPORTANT: Rectifier MUST BE disconnected
from stator for this test.
!
CAUTION
DO NOT use a test instrument with more than a
12 volt source (in the following test), as rectifier
may be damaged.
1. Connect one lead of an ohmmeter (set on R x1
scale) to negative (–) rectifier heat sink and the
other lead to one of the rectifier terminals. Note
the reading.
2. Reverse leads and again note reading.
3. Meter should indicate a high or infinite resistance
(no meter movement) when connected one way
and a low reading when connected the other. If
both readings are high or infinite, rectifier is open.
If both readings are low, rectifier is shorted.
4. Repeat Steps 1 through 3 for two other rectifiers
in heat sink.
5. Replace assembly if any of the rectifiers is
shorted or open.
72147
b
a
c
a - Heat Sink
b - Rectifier Terminal
c - Test These Two Rectifiers In The Same Manner
To Next Page
Loading...
