TRIPLE-POLE BRAKING OF CAGE INDUCTION MOTORS IN AC DRIVES

Abstract

The presented triple-pole braking method is based on operating the 3-phase cage induction motor from a l-phase supply and utilizing the third-harmonic air-gap mmf wave produced by reconnection of the stator phases in series or in parallel. This results in a braking motor torque in the range from the fundamental syncronous speed to one-third of this speed, where mechanical brake is to applied to stop to motor. This presented method competes successfully with the methods in present industrial use in respect of electrical energy consumption during the braking process, simplicity of switching, and saving in space and cost.