A three-phase induction motor is analogous to

A three-phase induction motor is analogous to

Right Answer is:

Rotating transformer


Analysis of transformer model is very easy to visualize then induction motor so, the induction motor is generalized as transformer because of following reasons :

  1. Operations of both induction motor and transformer are somewhat same that is “both operate on the same principle of induction”.
  2.  Both have two windings
    • Transformer: primary and secondary
    • Induction motor: Stator and rotor
    • Rotor windings are short-circuited at the end to produce torque for the rotation.
  3. Voltage ratios of two windings in both cases are of a similar kind
    • Transformer: 1:n where ‘n’ is voltage transfer ratio
    • Induction motor: 1:s where ‘s’ is slip(also voltage ratio)
  4. Both have the core in between two windings :
    • Transformer: Ferromagnetic material
    • Induction Motor: Air gap
  5. In fact, the AC induction motor was patented as Rotating Transformer by Nikola Tesla. The reason behind that is the stator(stationary part) is essentially the primary side of the transformer and the rotor Rotating part is the secondary side of the transformer.

Because of the above reasons Induction motor is called a two windings transformer with secondary short-circuited.

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