Rotor Bar Failures in Induction Motors

  • By Ken Keith
  • 12 months ago
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As a general rule, motors below 200 HP are limited by stator design
and above 200 HP by rotor design. That is to say if a motor smaller
than 200 HP is stalled the stator will fail before than the rotor.
Designers will often build larger motors with a copper bars, however
due to the added manufacturing cost aluminum bars are becoming
more common in larger motors. In this situation, one must rely on
motor protection to preserve the rotor.