ELECTRICAL SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
STARTING MOTOR TEST - CONTINUED
The following information provides some results of a no-load test and possible problems.
A rated current draw at a no-load speed indicates a normal starting motor.
A low free speed and a high current draw indicates:
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.
A shorted armature could cause a high current draw.
A grounded armature or a grounded field winding could cause a high current draw.
Failure to operate with a high current draw indicates:
A direct ground in terminal or field windings.
The bearings cease to operate properly. This can be seen by turning armature by hand.
Failure to operate with no current draw indicates:
An open field circuit will cause a failure.
An open armature will cause a failure.
Broken bush springs, worn brushes, or high insulation between commutator bars could prevent good contact
between brushes and commutator.
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.
A high free speed and a high current draw indicates:
A shorted field circuit will cause a failure.
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