The GM High-Performance Induction Motor Drive System

The recent advances in the power handling capacity of semiconductor devices make it possible to replace dc and ac commutator machines for variable-speed applications by high-speed, lightweight, squirrel-cage induction motors. This paper describes a controlled slip-frequency system which eliminates the low-starting torque, low-power factor, and the low efficiency at lower speeds, normally associated with induction motors. The development program at the General Motors Research Laboratories that resulted in fabrication of the experimental electric vehicles, GM Electrovair and Electrovan (exhibited in October 1966), is described chronologically.