Question

Explain the working principle of three-phase induction motor with its advantages.

Hint:

Three-phase induction motors are reliable and efficient, working on electromagnetic induction without brushes or commutators.

Answer 1

Working Principle: A three-phase induction motor works on the principle of electromagnetic induction:
When a three-phase AC supply is given to the stator winding, it produces a rotating magnetic field (RMF).
The RMF rotates at synchronous speed and cuts the rotor conductors.
This induces an electromotive force (EMF) in the rotor conductors according to Faraday’s law.
The induced current in rotor conductors produces its own magnetic field.
The interaction of the rotor magnetic field with the stator RMF produces torque, causing the rotor to rotate.
The rotor speed is slightly less than synchronous speed (called slip), which is necessary for induction. Advantages of Three-Phase Induction Motor:
Simple and rugged construction, making it durable.
Requires low maintenance.
Self-starting motor, no need for external starting mechanisms.
High efficiency and good power factor.
Cost-effective and widely available.
Suitable for a wide range of industrial applications.