Transistor-oscillator induction-motor drive

Transistor and saturable-core-transformer oscillators driving small 2-phase induction motors provide, in effect, a d-c motor without a commutator. The inductive, motor load on the oscillators requires that the transistors carry current in both directions and this is aided by shunting the transistors with rectifiers. Simple interconnection of two oscillators provides the 2-phase system. Operation of an experimental drive in the range from 125 to 500 cycles per second resembles behavior of a separately excited d-c motor except that motor shaft rotation is not reversed by reversing the d-c source. The harmonics in the square-wave motor voltages usually have negligible effect.