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Motor bearings: Electrical damage simplified

Publication date: 
December 2017
Joe Junion, L&S Electric, Inc.
Type of media: 

Electrical bearing damage has become a very common issue in electric motors. This is not a new problem, but awareness has put the spotlight on this important reliability factor and industry has stepped up to deal with it.

Let’s keep it simple though. Voltage is induced on the rotating member of an electric motor. If the voltage level gets high enough, it will discharge across the thin lubrication film of a bearing and cause damage.

Topics covered in this article include:

  • Effects of arcing
  • Detecting shaft voltage
  • Preventing damage
  • Shaft grounding products
  • Identifying and assessing damage
AC motors
Troubleshooting & failure analysis