Induction Motors and EMF

No.

The rotors magnetic field is not fixed. Any back emf will be absorbed by different current paths within the rotor.

For a complex explanation see

http://scholarsmine.umr.edu/post_prints/pdf/01620539_09007dcc8030d9da.pdf

In the working principle of FCMA starters it is said that the compensating winding of FCMA is excited by counter emf of Induction motor.How can it be made possible? i would like to know the electrical connection

That is BS or in other words, rhyming off big words to sell a product

In an AC cct, A coil in series works like a resistor. (current limiter)

The FCMA is only a name given to series impedance type soft starter.The manufacturer is fooling everybody by tall claims as if he is next to Einstein.

The claims are Bogus. No such theory exists in the world

The AC current in the Stator produces a rotating magnetic field. Due to this an induced magnetic field is produced in the rotor, which is also rotating but at a particular angle to the Stator produced magnetic field. This magnetic field produces in turn the counter EMF in the Stator coils.

The angle between the magnetic fields increases as the load increases and decreases as the load decreases. Since in theory, in ideal conditions, the resistance of the Stator coils is considered negligible the counter EMF will be only slightly less than the Stator EMF. The difference between the two EMF's divided by the resistance of the Stator coils equals the current. Since both the difference in EMF's and resistance are small, the current is significant.

That is correct.

Techno's (comment #1) is WRONG. (and not very professional)

The counter EMF is what limits the current to the motor.

Thanx 4 that description.In FCMA starters for Induction motors, it is said that it is connected in stator side.it has 2 windings on a core.main winding is in series with motor. the second one,the compensating winding(wound in opposition to main winding) is excited by counter emf of the motor.how is it excited by counter emf?what can be the electrical connection to the compensating winding?

kasharma is correct in his description of how counter EMF exists in the motor. That pdf file is almost completely irrelevant.

As to the FCMA starter issue, it is an outgrowth of a very old technology called a Magnetic Amplifier that was abandoned 30+ years ago for motor control as being too expensive and inefficient. If you do a google search on a "Mag-Amp" you will get some more detailed descriptions of the theory of operation. The only people making that FCMA starter are in India and are claiming to have improved it somewhat, but the world is not beating a path to their door, so it's overall value is still suspect.