Three‐Phase Induction Machine

This chapter is dedicated to the fundamental concepts associated with the operation and characteristics of a three‐phase induction motor. A three‐phase induction machine has two parts; stationary called stator and the rotating, called rotor. The principle of operation of a three‐phase induction motor depends upon Faraday’s law of electromagnetic induction. The analysis of the induction motor is done by obtaining its per‐phase equivalent circuit. A simple relationship can be derived between air‐gap power, rotor copper loss and mechanical power developed. The chapter presents the machine equivalent circuit which is then used for further analysis of the machine characteristics. It provides the testing procedure that helps in determining the machine parameters. Analysis of the exact equivalent circuit is quite cumbersome and hence for simple analysis of the equivalent circuit, Thevenin’s theorem is applied which states that the whole circuit can be represented by Thevenin’s equivalent voltage and Thevenin’s equivalent impedance.