Electrical Machines
Use of fractional pitch winding

All of these
  make it stiffer.
  results in reduced leakage reactance.
  results in reduced axial length of the machine.

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Electrical Machines
In a synchronous motor when the rotor speed exceeds the synchronous speed during hunting

  the damper bars develop synchronous motor torque.
  the damper bars develop induction generator torque.
  the damper bars develop induction motor torque.
  negative sequence currents are generated.

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Electrical Machines
A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current

  Cannot be predicted due to insufficient data.
 Woud be equal to 2If1.
 Would be equal to If1/2.
 Would be equal to If1.

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