The gate-turn-off thyristor-a breakthrough for the retrofit of existing induction motors from fixed to adjustable speed

A description is given of a breakthrough in the design of an induction motor drive utilizing gate-turn-off thyristors that greatly simplify commutation, making retrofits more feasible with less complicated inverters. One of the major advantages of gate-turn-off technology is a nearly sinusoidal output waveform for the motor. Since this product is directed for use with existing induction motors, down time and expense for conversion to adjustable speed can be greatly reduced. Less investment is needed, and payout time is shortened. The authors look at application considerations and novel inverter design features and provide an example of drive economics.<>