INTRODUCTION

Induction machines are also called asynchronous machines, that is, the machines that never run at a synchronous speed. Whenever we say induction machine we mean to say induction motor. Induction motors may be either single phase or three phase. The single-phase induction motors are usually built in small sizes (up to 3 H.P.). Three-phase induction motors are the most commonly used AC motors in the industry, because they have simple and rugged construction, low cost, high efficiency, reasonably good power factor, self-starting torque, and low maintenance. Nearly, more than 90 per cent of the mechanical power used in industry is provided by three-phase induction motors.

In this chapter, all the important aspects of a three-phase induction motor are discussed.