Determination of interbar current effects in the detection of broken rotor bars in squirrel cage induction motors

In present monitoring techniques for the detection of broken rotor bars in squirrel cage induction motors, the assumption is made that a broken bar conducts no current. This causes a magnetic imbalance, which can then be detected to indicate a broken bar. In certain motors, however, large currents are still able to flow in the broken bar by means of interbar currents. This paper deals with the effects these currents have on broken bar monitoring. The work shows theoretically and experimentally that interbar currents reduce any magnetic imbalance brought about by the broken bar. >