A synchronous and synchronous motors are the two main categories of ac motors. The induction motor is a common form of asynchronous motor and is basically an ac transformer with a rotating secondary.

This document written by Steve Bowling, Application Segments Engineer at Microchip Technology, discusses how motor works and describes the AC induction motor, variable-speed ACIM control, and FOC.

From tiny hysteresis motors that drive electric clocks to huge synchronous motors that develop more than 50,000 hp, the alternating current (AC) motor has become an indispensable part of everyday life ...