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Stator I2R loss: Considerations for rewinds and redesigns

Publication date: 
March 2013
Mike Howell, EASA Technical Support Specialist
Type of media: 

Aside from managing his family's brewery in England, J.P. Joule did some pretty amazing work in physics during the mid-nineteenth century. Joule discovered that the rate at which heat is produced by a steady current in any part of an electric circuit is proportional to the resistance and the square of the current. So, the I2R loss of a conductor is not creatively named. How does this apply to motor stator windings? The stator I2R loss is typically the largest contributing factor to the stator winding temperature rise and the largest detractor of efficiency. Topics discussed include:

  • Rewinding a stator for the same rating
  • Reducing the mean length of turn
  • Inceasing the stator copper cross section
  • Rewinding the stator for increased output rating
  • Additional winding losses
AC motors