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Selection and use of a VFD for service center testing

Publication date: 
January 2016
Art Godfrey (retired), Birclar Electric & Electronics
Type of media: 

With the growing popularity of variable frequency drives (VFDs), it is likely almost every EASA service center has repaired motors powered by one in a customer’s installation. For these motors, it is best that after repair they are tested using a VFD, typically at no-load. This will provide operation mimicking the actual customer application, at varying speeds, and will help ensure proper mechanical operation throughout the speed range. This will include detecting vibration problems, identifying any resonant speeds within the operating range, and more. Also, if the motor is used above utility line frequency (i.e., 50 Hz or 60 Hz), it should be operated up to top speed for vibration measurement and a good break-in of the bearings.

Topics covered include:

  • Selection challenges
  • Voltage, power rating and frequency
  • New or used VFDs for testing?
  • Operating parameters
AC motors
Service center equipment
Motor testing