An induction motor can be treated as a transformer with ______.

Transformer as an induction motor

• In a transformer, electrical energy is transferred from the primary to the secondary winding through electromagnetic induction, where both the primary and secondary windings are stationary.
• In an induction motor, the stator winding acts like the primary winding of a transformer, and the rotor winding acts like the secondary winding.
• In an induction motor, the rotor winding (acting as the secondary winding) is not connected to any external circuit; instead, it is short-circuited internally due to the nature of the induction process.
• This is similar to a transformer where the secondary winding is short-circuited, allowing current to flow freely and creating the necessary magnetic interaction.

Working of Induction Motor as a Transformer

• When the AC voltage is applied to the stator winding, it produces a time-varying magnetic field that rotates in the air gap at synchronous speed, known as a rotating magnetic field. Similar to the transformer, where AC voltage is given to the primary winding produces a time-varying magnetic field in the magnetic core, although it is stationary, unlike an induction motor.
• In the case of a transformer, due to the magnetic core, the magnetizing current (current required to set up the magnetic field) requirement is less as compared to an induction motor. Thus, an induction motor works at a low lagging power factor.
• The rotating magnetic flux produced by the stator links the both stator winding and rotor winding, and induces emf in both the windings.
• Similar to the transformer, where the flux produced by the primary winding links with both primary as well as second winding and induces emf in both primary and secondary.