Is a induction motor rotate by back emf ? If not , then how it is rotate ?

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Is a induction motor rotate by back emf ? If not , then how it is rotate ?..

Answer / chandru

Yes,back emf should be there to run it as an induction
motor.Normally what will happen is, when you give 3 phase
power to stator,rotating magnetic field(rmf) will be
created over it.Inturn,this rmf will induce an emf in rotor
side.According to lenz law,obviously this induced emf will
oppose the cause that produces it.Here, the cause is
relative motion between stator's rotating mag field and
rotor speed.Normally,we will call it as slip.So, it will
try to make that relative motion to zero.Due to this
operation, induction motor will rotate.If suppose,rotor
speed catches the stator's rmf,induction motor will
stop.Finally, the main thing to note here is that, it wont
run without slip.

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