HARMONIC TORQUES IN CAGE INDUCTION MOTORS

Abstract

In the present work an attempt has been made to develop the general harmonic equivalent circuit with and without rotor skewed . Expressions for the parasitic synchronous torque and parasitic asynchronous torque have been derived. A comparision of the parameters of the equivalent circuit is pro• vided with and without skew of the rotor. It has been shown that by proper choice of the rotor slots and by proper skewing of the rot-or bar the harmonic torque can be avoided in the electrical machine ,desi•gn. A eomparisio'n of the results calculated for synchronous parasitic torques and asynchronous parasitic torque shows that the skewing of rotor bars decreases the magnitude of the harmonic torques