Section 5.Troubleshooting

DC Electric Motor

Unsatisfactory Condition-Streaky Film With Commutator Wear

Unsatisfactory Condition-Double Pole Pitch

Unsatisfactory Condition-Brush Contact Mark

Model 6210 Maintenance Manual

This is a further development of the third example. Earlier corrective action should have been taken. Continued use may result in failure and damage to other systems. The motor should be replaced or re-cut at a qualified repair facility. Consider more frequent scheduled maintenance intervals.

Darkening of commutator in sequences two pole pitches apart. This condition may result from an armature fault or some other fault. Continued use may result in failure and damage to other systems. The motor should be replaced or re-cut at a qualified repair facility.

This condition may result from storage of the machine for long periods with brushes in position. It may also result from operation in prolonged stall conditions. Storage marks are easily removed with a polishing stone, see “Polishing the Commutator” on page7-61. Stall marks should be cleaned and inspected for damage or shorts. The motor should be replaced if damage has occurred.

Unsatisfactory Condition-Bar Edge Burning-Cause High Mica

This condition is caused by high mica in every slot and can be caused by incorrect or excessive stoning. The same effect can occur on one bar only. Chattering or loud operation may also be noticed. Continued operation will result in increased brush wear and may result in commutator damage. The motor should be replaced or re-cut at a qualified repair facility.

Unsatisfactory Condition-Small Bright Spots

This condition is due to sparking under the brush. This is caused by overloaded machines or low brush pressure. Check the brush spring tension, see “Motor Brush Spring Tension” on page7-60. If not corrected, this condition will result in damage to the commutator. This condition may be repaired with a polishing stone if caught early and no scoring has occurred, see “Polishing the Commutator” on page7-61. If damaged, the motor should be replaced or re-cut at a qualified repair facility.

Publication: 1146947, Revised: 12 Jan 2017