TM 5-3805-291-23-1
ELECTRICAL SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
0013 00
STARTING MOTOR TEST - CONTINUED
The following information provides some results of a no-load test and possible problems.
1.
A rated current draw at a no-load speed indicates a normal starting motor.
2.
A low free speed and a high current draw indicates:
a.
An increase in friction could be caused by tight bearings, dirty bearing, or worn bearings. A bent armature or loose
field pole shoes that would allow armature to drag are possible causes of increased friction.
b.
A shorted armature could cause a high current draw.
c.
A grounded armature or a grounded field winding could cause a high current draw.
3.
Failure to operate with a high current draw indicates:
a.
A direct ground in terminal or field windings.
b.
The bearings cease to operate properly. This can be seen by turning armature by hand.
4.
Failure to operate with no current draw indicates:
a.
An open field circuit will cause a failure.
b.
An open armature will cause a failure.
c.
Broken bush springs, worn brushes, or high insulation between commutator bars could prevent good contact
between brushes and commutator.
5.
A low no-load speed and a low current draw indicates:
An internal resistance that is high is possibly caused by poor connections, leads that are faulty, a commutator that is
dirty, and/or causes that are listed in step 4.
6.
A high free speed and a high current draw indicates:
A shorted field circuit will cause a failure.
Starting Motor Solenoid Test
N OT E
A basic four terminal starting motor sole-
noid circuit is shown. The two windings
that are found in solenoid are the hold-in
winding and the pull-in winding. Wind-
ings can be checked by using procedures
that follow.
427-C1983
0013 00-76
