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Reclosure: How it Happens and What To Do About It

Publication date: 
February 2015
Jim Bryan, EASA Technical Support Specialist
Type of media: 
Webinar recording
Recording duration: 
45 minutes

Reclosure occurs when power to a motor is briefly interrupted and restored before the magnetic field has fully collapsed in the motor’s winding. If this occurs while the applied power is out of phase with the collapsing field, significant damage can result. This webinar will address how this can happen and what measures can mitigate damage potential.

Topics covered include:

  • Reclosing a switch or breaker before the magnetic field collapses
  • Utilities’ automatic reclosure
  • Contactor “chatter”
  • Determining the time constraint
  • Remedies: Time delay; Zero crossing
AC motors
Troubleshooting & failure analysis