Why an induction motor is also known as rotating transformer?

An induction motor is sometimes called a rotating transformer because the stator (stationary part) is essentially the primary side of the transformer and the rotor (rotating part) is the secondary side.

Is induction motor and transformer same?

A transformer transfers electrical power from one circuit to another without changing the supply frequency, i.e. it only step-up or step-down the level of voltage and current, whereas induction motor converts electrical power into mechanical power.

Is it possible to have transformer emf in any rotating machine?

So to answer the question, motors have special spatial arrangement of armature windings which produces rotating magnetic field. This type of spatial arrangement is absent in transformers as they can transform voltages without any rotation.

Why the transformer rating is in KVA?

Transformers are rated in kVA because the losses occurring in the transformers are independent of power factor. KVA is the unit of apparent power. It is a combination of real power and reactive power. Transformers are manufactured without considering the load being connected.

In what ways induction motor and transformer are similar?

The rotor of the induction motor is short-circuited and the secondary of the transformer is open circuited. The working principle of the induction motor and transformer is similar. The secondary of the transformer is kept open circuited, the external load is connected to it.

Why secondary voltage of a transformer has the same frequency as primary?

Transformers use magnetic fields to change an AC voltage. This fluctuating magnetic field induces current in the secondary coil. The AC in the secondary will have the same frequency as the AC sent into the primary, but the voltage will be different, depending on which coil has more windings (loops of wire).

Why does a DC motor rotate?

When the motor is powered by DC current, a magnetic field is created within the stator, attracting and repelling the magnets on the rotor. This causes the rotor to start rotating. To keep the rotor rotating, the motor has a commutator. This way the rotor can keep spinning.