Introduction to induction motor - Electrical Engineering Gate

Online Electrical Engineering Study Site

Friday, March 4, 2016

Introduction to induction motor

Introduction to induction motor
           An induction or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor therefore does not require mechanical commutation, separate-excitation or self-excitation for all or part of the energy transferred from stator to rotor, as in universal, DC and
large synchronous motors
An induction motor's rotor can be either
      Wound type 
      Squirrel-cage type
Three-phase squirrel-cage induction motors are widely used in industrial drives because they are rugged, reliable and economical. Single-phase induction motors are used extensively for smaller loads, such as household appliances like fans. Although traditionally used in fixed-speed service, induction motors are increasingly being used with variable-frequency drives (VFDs) in variable-speed service
Its characteristic features are-
o    Simple and rugged construction
o    Low cost and minimum maintenance
o    High reliability and sufficiently high efficiency
o    Needs no extra starting motor and need not be synchronized

Induction machines are by far the most common type of motor used in industrial, commercial or residential settings.