Three Phase Induction Motors
A three phase induction rotor consists a stators and a motor stator has balanced three phase winding. These windings are distributed in the stator slots. These are displaced by 1200in space with respect to each other. According to their rotor three phase induction motors are classified into followings types:
a.Squirrel cage induction motor
b.Slip ring induction motor
In SCIM the rotor windings consists of uninsulated conductors in the form of copper or aluminium bars embedded in the semi closed. These solid bars are short circuited at both ends by end ring of the same material. Without the rotor core the rotor bars and end ring look like the cage of a squirrel hence the name squirrel cage induction motor. The rotor bars form a uniformly distributed winding in the rotor slots
A 3- phase induction motor receives electrical energy from on alternating voltage source therefore it is a simply excited machine. The stator carries the field winding and armature winding (in which the working emf is induced by the working flux) is on the rotor. This motor has come to be called as induction motor because stator delivers energy to rotor by means of induction.