Likely cause: Suspect a burr on the commutator. What to do: Remove burr from commutator using a commutator stone.

Likely cause: Incorrect wiring What to do: Interchange the two motor leads.

Likely cause: Motor controller not properly set. What to do: Adjust the acceleration trim pot of the controller. Likely cause: Brushes are worn. What to do: Verify brush length. Likely cause: Bearings may be defective. What to do: Inspect bearings. Noisy or rough bearings should be replaced.

Likely cause: Load had increased. What to do: Ensure that the load has not changed. Measure the amp draw of the motor against the full load amp rating of the motor. If the amp draw is higher than the rated one, the motor is undersized for the application. Likely cause: Motor controller not properly set. What to do: Check controller manual for adjustments. The torque and/or IR compensat...

Likely cause: Fuse or circuit breaker is tripped. What to do: Replace the fuse or reset the breaker. Likely cause: Armature is shorted. Motor may make a humming noise and the circuit breaker or fuse will trip. What to do: Disassemble motor and inspect the armature for a burnt coil. Inspect the commutator for burnt bars. If this condition exists, the motor needs to be replaced. Li...

Likely cause: Motor is incorrectly wired What to do: Verify that the motor is wired correctly. Likely cause: No output power from controller. What to do: Measure voltage coming from the controller. Likely cause: Motor is damaged and the armature is rubbing against the magnets. What to do: Disassemble motor and see if the armature can be realigned by reassembly. Motor may hav...