Why is an induction motor called a rotating transfer motor?

An induction motor is called a "rotating transformer" due to its fundamental operating principle, which closely resembles that of a conventional transformer. Both induction motors and transformers rely on electromagnetic induction to transfer energy between their components, but they differ in the physical arrangement and application.

• Principle of Operation: In an induction motor, the stator windings create a rotating magnetic field. This field, when it interacts with the rotor windings, induces an electromotive force (EMF) in the rotor, causing it to rotate.

• Similarity to Transformers: The key similarity between an induction motor and a transformer lies in the fact that both devices use magnetic fields to transfer energy without direct electrical contact between the primary and secondary components. In a transformer, the primary winding is energized by an AC supply, creating a magnetic field that induces a voltage in the secondary winding, also through electromagnetic induction.

• Rotating Magnetic Field and Energy Transfer: The rotating magnetic field in an induction motor is analogous to the stationary magnetic field in a transformer. The energy transfer in both cases occurs through the interaction of magnetic fields, with the main difference being that the transformer transfers energy between stationary parts, while the induction motor transfers energy to a rotating part (the rotor).

• Summary: In summary, an induction motor is called a "rotating transformer" because its operation involves the induction of EMF in a rotor due to a rotating magnetic field, much like how a transformer transfers energy through the interaction of magnetic fields without direct electrical connection between primary and secondary components.

This shared principle of electromagnetic induction is what gives the induction motor its distinctive name within the realm of electrical engineering.