Figure 5-5. Armature Open Test
Brushes and Brush Holder
1. Remove armature and brush holder from field coil. See
5.2 STARTER, Field Coil Assembly.
2. Measure the brush length. If any one of four brushes is
less than 0.433 in. (11 mm), replace the field coil and
brush holder assembly. No further testing is necessary.
3. See Figure 5-6. Check for a GROUNDED FIELD COIL
WINDING with an ohmmeter or continuity tester.
a. Touch one probe to the field coil housing (frame).
b. Touch the other probe to each of two brushes
attached to the field coil winding.
c. There should be no continuity (infinite ohms). If there
is continuity at either brush, then the field coil winding
is grounded. Replace the field coil/brush holder
assembly if grounded.
4. See Figure 5-7. Check for an OPEN FIELD COIL
WINDING with an ohmmeter or continuity tester.
a. Touch one probe to the field wire.
b. Touch the other probe to each of the two brushes
attached to the field coil winding(s).
c. There should be continuity (0 ohms). If there is no
continuity at either brush, then the field coil winding(s)
are open. Replace the field coil/brush holder assembly
if open.
5. See Figure 5-8. Test the BRUSH HOLDER INSULATION
with an ohmmeter or continuity tester.
a. Touch one probe to the holder plate.
b. Touch the other probe to each of the positive (insu-
lated) brush holders.
c. There should be no continuity (infinite ohms). If there
is continuity at either brush holder, replace the field
coil/brush holder assembly.
d. Touch one probe to the non-insulated brush holders
and the other probe to the holder plate. If any resist-
ance is measured, replace the field coil/brush holder
assembly.
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