TABLE IV. TROUBLE SHOOTING
Trouble
Probable Cause
Remedy
Motor fails to start
Open circuit
Inspect power circuit for
blown fuses or defective
wiring. Repair as necessary.
Check for continuity to motor
terminal and through motor.
Motor does not come up to
Motor overloaded
Check accessory mounted on
rated speed or draws
motor for excessive torque.
excessive current
Low voltage at motor
Check voltage at motor
terminal
terminal. Check for under-
size cables.
Worn Brushes
Replace brushes.
Defective bearings
Replace bearings.
Shorts or grounds in
Replace part or parts.
armature or field coils
Commutator dirty
Clean commutator using a
strip of rough cloth. Wipe with
a cloth dampened with
unleaded gasoline.
Brushes sticking in
Clean brushes by rubbing on
brush holders
rough cloth. Clean brush
holders with a small brush and
blow out with compressed air
at moderate pressure.
Brushes arcing
Rough commutator
Resurface commutator, refer
to Repair and Replacement.
Mica insulation too high
Refer to Repair and
between commutator
Replacement.
segments
Noisy motor
Insulation rubbing
Check clearance of insulation.
Bearing faulty
Replace bearing or bearings.
Armature not concentric
Replace armature.
A-9
