Electrical Machines
For a 3 - Φ, 4 pole, 50 Hz IM rotating at full load speed of 1440 rpm, calculate speed of rotor field with respect to rotor structure and stator structure respectively?

 1440, 1500.
  60, 1500.
 60, 1440.
 50, 1500.

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Electrical Machines
In DC machines, the interpoles are provided

  both (B) and (C).
 to counteract the reactance voltage and the cross-magnetizi
  to make commutation spark less.
 to counteract demagnetizing effect of armature mmf in commutating zone.

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Electrical Machines
Ward-Leonard system for controlling the speed of a DC motor is used where

 All of above.
 The accuracy in speed control is required.
 The speed in both the direction is required.
 Very fine speed control over the whole range from zero to normal speed is required.

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