Like other motors, a three phase induction AC motor consists of a stator and a rotor. There are two types of three phase induction AC motors, namely the squirrel cage induction motor and the phase wound induction motor (slip-ring induction motor). These types have similar constructed rotor, but they differ in the rotor’s construction.
Most of the induction motors belong to the squirrel cage type. Owing to this kind of type has simple and indestructible construction, they are widely used in the factory.
Phase wound rotor is wound with three phase, double layer, distributed winding. The number of poles of rotor are kept same to the number of poles of the stator. The rotor is always wound three phase even if the stator is wound two phase.
A three phase induction AC motor is based on the three phase ac supply. Owing to they have simple and almost unbreakable construction, reliable operating system, lower cost and high efficiency and good power factor and minimum maintenance required. The three phase induction motor is extensively used for various industrial applications.
However, they have some disadvantages. Such as with the increasing of the load, the speed will decreases. If the speed is to be varied, it will have effect on its efficiency.
As one of the most important power equipment, three phase induction AC motors are the leading products of small motors. It convert electrical energy into mechanical energy, thus driving different kinds of machinery and equipment. They are mass products with wide range of electronic products which play an important role in the national economy, energy conservation as well as environmental protection. They also play an indispensable and irreplaceable role in improving people’s life. Therefore, three phase AC induction motor are widely applied in many fields. Such as the textile, construction, agricultural industry and other light industries.