Sunday, 29 December 2019

How AC MOTOR Works? Its Construction, Types, Applications


  • An AC motor is an electric motor driven by an alternating current (AC).
  • The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field 
  • An inside rotor attached to the output shaft producing a second rotating magnetic field.

Construction of AC Motor

It consists of a Frame or Yoke, stator, rotor, bearings, fan, shaft, and slip rings. The parts of an AC machine is explained below.


  • Yoke is outer part of body which is made up of cast steel or iron.
  • It provides mechanical strength to the inner parts of body


  • The rotor in an electric motor is the moving part, and the main function of this is to rotate the shaft for generating the mechanical power. 
  • Generally, the rotor includes conductors which are laid to carry currents, and communicate with the magnetic field in the stator.


  • The bearings provide proper friction for the rotor to run smoothly. 
  • A fan is employed to remove the unwanted heat that gained during the running of the rotor. 
  • It is expelled out through the ventilation that is provided behind the machine. 


  • A shaft is provided to deliver the mechanical output as the rotor rotates. 

Slip rings 

  • The slips rings are employed for a normal Ac machine where rotating armature stationary field winding is employed. 
  • In this situation, the slip rings allow the input alternating current to change continuously in the coils.

Construction of AC Motor
Construction of AC Motor

Working principle

whenever a current-carrying conductor is placed in the magnetic field it exhibits some force in it. When alternating current supply is fed to the coil of the rotor, it experiences some force due to the law of the Lorentz force equation. Due to this force, torque will be developed in the clockwise direction that enables the rotor to rotate.

Types of AC Motors

  • Synchronous motor 
  • Asynchronous motor - 1) Single phase induction motor                                      2) Three phase induction motor

Applications of AC Motors

  • It is used in mixer grinders, pumps, and household appliances.
  • Used in industries.


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