Electrical Machines
The direction of rotation of a 3 - Φ induction motor is clockwise when it is supplied with 3 - Φ sinusoidal voltage having phase sequence A - B - C. For counterclockwise rotation of motor, the phase sequence of the supply should be

 B - C - A or C - A - B.
 C - A - B.
  A - C - B.
 B - C - A.

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Electrical Machines
Commutation in a DC machine may be explained as a process

 how alternate flux affects the main field flux.
  in which magnetic field is set up.
 by virtue of which emf is induced in the armature conductors.
  by which electric current in a coil is reversed.

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Electrical Machines
In large sized DC machines the compensating windings are provided to

 compensate for the decrease in speed due to increase of load.
None of these
  neutralize voltage induced in coil due to fluctuation of l
 reduce eddy current losses by providing local short circuits.

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