Working Principle And Types Of Induction Motor

Working Principle And Types Of Induction Motor

Instigation Motors are the most usually utilized motors as a part of numerous applications. These are likewise called as Asynchronous Motors, in light of the fact that an incitement motor dependably keeps running at a pace lower than synchronous velocity. Synchronous velocity implies the pace of thepivoting attractive field in the stator.

There essentially 2 sorts of instigation motor contingent on the kind of info supply – (i) Single stage actuation motor and (ii) Three stage incitement motor.

Or they can be divided according to type of rotor – (i) Squirrel cage motor and (ii) Slip ring motor or wound type

Basic Working Principle Of Induction Motor:

In a DC motor, supply is should have been be given for the stator twisting and the rotor winding. In any case, in an incitement motor just the stator winding is encouraged with an AC supply.

1. Rotating flux is created around the stator twisting because of AC supply. This rotating flux spins with synchronous pace. The spinning flux is called as “Turning Magnetic Field” (RMF).
2. The relative pace between stator RMF and rotor conductors causes a prompted emf in the rotor conductors, as indicated by the Faraday’s law of electromagnetic instigation. The rotor conductors are shortcircuited, and consequently rotor current is delivered because of affected emf. That is the reason such motors are called as prompting motors.(This activity is same as that happens in transformers, henceforth incitement motors can be called as pivoting transformers.)
3. Presently, incited current in rotor will likewise create exchanging flux around it. This rotor flux lingers behind the stator flux. The course of incited rotor present, as indicated by Lenz’s law, is such that it will have a tendency to contradict the reason for its generation.
4. As the reason for creation of rotor current is the relative speed between pivoting stator flux and the rotor, the rotor will attempt to get up to speed with the stator RMF. In this manner the rotor pivots in the same course as that of stator flux to minimize the relative speed. On the other hand, the rotor never succeeds in getting up to speed the synchronous velocity. This is the fundamental working rule of impelling motor of either sort, single period of 3 stage.

Synchronous Speed:

 The rotational speed of the rotating magnetic field is called as synchronous speed.

Rotor tries to get up to speed the synchronous pace of the stator field, and subsequently it pivots. In any case, by and by, rotor never succeeds in making up for lost time. In the event that rotor gets up to speed the stator speed, there wont be any relative rate between the stator flux and the rotor, subsequently no impelled rotor current and no torque creation to keep up the turn. Be that as it may, this won’t stop the motor, the rotor will back off because of lost of torque, the torque will again be applied because of relative pace. That is the reason the rotor turns at rate which is constantly less the synchronous rate.

The difference between the synchronous speed (Ns) and actual speed  (N) of the rotor is called as slip.