Answer / ankush miglani 09718151073

in induction motor power is not fed to rotor but it is
induced in the rotor through electromagnetic induction.
its various starting methods are:
1. dol direct on line starting
2. star delta starter
3. through variable frequency drives
4. restance starter
5. auto transformer starter
6. series reactor starter

Answer / virendra joshi

Yes, as armine said that there is a diffrent method for
starting both the motores in single phase more it can be
driven as capacitor start, capccitor run ,also capacitor
start capacitor run motor.

Considering a three phase motor when three phase supply is
given to the startor winding rotating magnatic field is
developed which rotaes with syschronous speed ( NS =
120F/P ). now this magnatic field is connected to rotar bar
& as the rotar winding is shot ( in case of Squrell cage
rotor through copper ring & in case of sleepring rotor
through resistence ) so the current flows in rotor bar .
now as this in magnatic field . the force is applied on the
rotor . rotor start moving & as the magnatic field is
rotating rotor keep moving but is legs behind a bit then a
synchronous speed & this phenomina called a Slip.

please revert if any querry exists.

Answer / armine george

please specify whether its a single or three phase motor.
becoz both of them hav different starting methods

Answer / amjad ali soomro

The stator Like A primary and Rotor Acts as a secondary ,
When stator is powered by the primary the squirrel cage rotor .The substantial iron cores, with a very small air gap between stator core and rotor core, efficiently conveys the magnetic fields produced by the stator currents to the rotor conductors. A stator (primary) sine wave voltage will induce a sine wave voltage in the rotor (secondary), the same as any transformer. But the rotor will have no overall force acting on it to cause rotation. If its is 3-Phase than it will Automatically starts Revolving field developed by three phases
and if it is single phase than it will require external rotation...

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