Induction Motor

Why transformer does not rotate like induction motor. Inspite both having same principle?

Questions by ravi.dcrust

Showing Answers 1 - 14 of 14 Answers

In induction motor the 3 phase windings are distributed windings where as in a transformer the windings are concentrated windings , a 3 phase distributed winding produces rotating magnetic field where as 3 phase concentrated windind can't. So Rotating magnetic field of induction motor interacts with rotor currents rotates the rotor.

Many above mentioned answer insists "Since there is no rotor in transformer, so it won't rotate"

If we see the analogy of IM and Transformer, will find rotor of IM is analogous to Secondary of Transformer. So, According to them, Secondary of transformer should always feel a torque which tries to rotate it but wont, because its not free to rotate. Is this true????? No way....

He answered bit right as He told " Since no rotating magnetic field generated in Transformer as was in IM, so, transformer can't rotate". BUT distributed winding is not the right answer for developing rotating field.
Sometimes we also use concentrated winding in IM. But generally concentrated winding is not practiced because it need more conductor and distorted waveform due to harmonics..


SPATIAL position of winding in stator of IM is 120 degree(angular displacement of winding is 120). This causes magnetic field to rotate with constant speed. While primary winding of transformer is not spaced with 120 degree angular displacement. So, magnetic field of transformer is not rotating and it won't let primary winding to run ....... that's ur answer.

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  • Nov 10th, 2011

THE induction motor and transformer works on the same principle which is "induction principle".but the induction motor have a rotor so its rotate.where as in transformer all the part is stationary so it does not rotates nearest to me this is reasons.

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amit pandey (svpoly bhopal)

  • Nov 17th, 2011

transformer is not rotate because it does not carry mechanical load while induction motor carry mechanical load

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  • Dec 3rd, 2011

Both transformer and Induction motor works on the principle of mutual induction ( Electromagnetic Induction). where as in motor it produce a rotating magnetic field which rotates at synchronous speed. in the air gap between stator coils and short circuited rotor. which makes the rotor to rotate. where as in Transformer there is a mutual induced Emf which is linked throu core of transformer.where there is no rotating field

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  • Dec 26th, 2011

In transformer the flux is constant where as in IM the flux is varying so the rotator will rotate.

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  • Dec 27th, 2011

How did you say flux is constant in transformer and rotating in IM as we are giving same supply (3-phase AC) to both?

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  • Dec 30th, 2011

The net flux in the core of the transformer is constant because the windings are laid on commn core. Where as in the IM the stator flux and the rotor flux is not same because This rotor current will create a flux which will interact with the revolving flux. There will be a force exerted upon this flux from the rotor. The current in the rotor will flow in such a direction so that it can decrease the rate of change of flux from which it is created. As a result the rotor will try to revolve in the direction of the revolving flux to reduce the rate of change of flux cut.

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I am very surprised to hear all these rubbish answers like "IT DOES NOT HAVE ROTATING PARTS", etc etc etc...

Have you all gone mad....??? Dont you understand the principles of Electrical Engineering.

It is true that both Transformer and Motors work on the same principle. But the major requirement is that the secondary winding should be a closed circuit and most importantly movable.

For example, take a slip ring induction motor, It wont rotate unless the rotor windings are shorted together.

This is what happens in Squirrel Cage induction motor, the rotor bars are shorted.

Whereas in transformer we pull out the secondary leads and take the output of induced EMF...!!!

That is all what happens...!!

Avishek Pal

  • Jan 21st, 2012

Transformer winding is made of concentric winding but the stator winding of induction motor is made of distributed winding over inner periphery. Hence flux in transformer is pulsating in nature and static. But flux in induction motor is rotating at synchronous speed depending upon the supply frequency.

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  • Feb 3rd, 2012

Actually in 3 phase induction motor the windings are displaced with angle of 120 degree in space that is why a rotating magnetic field is produced while in transformer the windings are concentric rather than displaced

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