Electrical Machines
The rotor speed of an induction motor is given by

None of these
  Nr = 120f / p × (1-s).
  Ns = 120f /p × ( 1 - r).
  Ns = 120f / p × ( 1 - s ).

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Electrical Machines
The mmf produced by rotor currents of a 3 - Φ induction motor

  rotates at synchronous speed with respect to rotor.
  is at standstill with respect to stator mmf.
  rotates at slip speed with respect to stator mmf.
  rotates at the speed of rotor in the air gap.

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Electrical Machines
Cogging in induction motor occurs when

 number of stator teeth - number of rotor teeth = even number.
 number of stator teeth - number of rotor teeth = negative number.
 number of stator teeth - number of rotor teeth = 0.
 number of stator teeth - number of rotor teeth = odd number.

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Electrical Machines
Two synchronous generators operating in parallel 200 MW and 400 MW respectively. The drooping characteristics of their governors are identical as 4% from no load to full load. Consider the governors operating at 50Hz on no load. How will the machine share, if the load is 600 MW?

 generator 1 gets over load
 generator 2 gets over load
 230.7 MW and 369.23 MW respectively
 200 MW and 400MW respectively

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