Motor Maintenance: Caring for Commutators and Brushes

Sinotech    September 8, 2014

Commutators and BrushesTo prevent costly motor problems and unnecessary downtime, don’t overlook the commutators and brushes when performing motor maintenance. Use the following tips to help ensure the longevity of these essential parts.

  • Observe commutators and brushes as the motor runs: When the pressure on a commutator is correct, the brushes will not spark or make a lot of noise.
  • Brush observations: When the motor is stopped, the brushes should have similar tension and move freely in their holder. A brush that’s seated well will appear to have a polished surface.
  • Brush replacement: If there is doubt about a brush working well until the next inspection, replace it.
  • Commutator observations: A commutator that’s in good shape is smooth, clean and has a burnished appearance.
  • Commutator and brush cleaning: Clean grit, dirt, oil and other debris that you find in the bush holders, posts and commutator bars. When applicable, trim frayed or unevenly worn brushes so they’re square.
  • Lubrication: Use mineral oil on commutators.
  • Prevent short circuits: Inspect the insulation between a commutator’s segments and remove burrs, filings and metallic dust. If the insulation has too much oil in it, you may need to replace the insulation.
  • Red flags: Indications of a potentially serious problem with a DC motor include:
    • Grooves around the commutator’s circumference.
    • Brushes that spark, chatter, leave imprints, show signs of arcing, or have excessive or uneven wear.
    • Worn or dirty commutators.

When maintaining your motor or building a new one, keep in mind that Sinotech offers a wide range of commutator styles and a full line of brushes ground to your exact specifications. Call Sinotech to learn about its competitive pricing and manufacturing services.

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