☑ Induction Motor Not Self Starting

For an induction motor to be self starting the stator needs to have a rotating magnetic field. A 3 phase supply given to the armature of induction motor produces a rotating magnetic field.

Why Capacitor Is Used In Single Phase Induction Motor Full

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Why Single Phase Motor Are Not Self Start Why We Connect

Hence single phase induction motor is not self starting.

Induction motor not self starting. In a three phase induction motor the rotating magnetic field is created by the fluxes of the three phase windings which are displaced by 120 degrees. When the supply is connected to the stator of a three phase induction motor a rotating magnetic field is produced and the rotor starts rotating and the induction motor starts. For this purpose the stator of the single phase induction motor is provided with an extra winding known as starting or auxillary winding in addition to the main or running winding.

To overcome this problem and to make the motor self starting it is temporarily converted into two phase motor during starting. It is not synchronously revolving or rotating flux as in case of 3 phase stator winding the fed cannot produce rotation. Let us consider a 3 phase induction motor first and see how it rotates.

But the synchronous motor is not self startingso a question arises that why three phase induction motor self starting but synchronous motor not. So simply we can say in order to make a single phase induction motor self starting we have to temporarily convert it into a two phase motor during its starting period. Starting of an induction motor a three phase induction motor is self starting.

The page includes the construction working principle of single phase induction motor. Three phase induction motor does not need any starter for starting or in other words three phase induction motor is self startingthree phase synchronous motor has almost the same in construction as three phase induction motor. At the time of starting the motor slip is unity and the starting current is very large.

Single phase induction motor is not self starting because when the main winding is excited from a single phase supply it produces an alternating magnetic field instead of rotating magnetic field. Why 3 phase induction motors are self starting but 3 phase synchronous motors not. This page is about single phase induction motor.

The page also answers why single phase induction motor is not self starting and also tells methods for making it as a self starting motor.