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PM and PdM for electric motors: Build the right balance of predictive and preventive tactics to extend long-term operating service life

Publication: 
Plant Services
Publication date: 
May 2015
Author: 
Tom Bishop, P.E., EASA Senior Technical Support Specialist

We often hear the terms preventive maintenance (PM) and predictive maintenance (PdM) of electric motors, but far less often do we give consideration to the tasks associated with these methods of maintaining motor operation and extending operating service life. This article addresses some of the more common activities associated with PM and PdM, with the focus on three-phase squirrel cage motors.

Preventive maintenance:

  • Insulation resistance (IR) test
  • Polarization index (PI) test
  • Motor current signature analysis (MCSA)
  • Mechanical activities such as lubrication, lubricant level checks, and lubricant analysis
  • Visual inspection
  • Thermal scanning
  • Ultrasonic testing
  • Cleaning
  • Belt tensioning
  • Bolt tightness checks

Predictive maintenance activities:

  • Trending and assessing most activities associated with preventive maintenance
  • Vibration analysis
  • Checking and adjusting alignment