Electrical Machines
In a DC machine, for the same value of φ, Z and N; which one of the following statements is correct?

 Armature emf is less with wave winding than with lap winding.
 Armature emf depends on weather the machine is running as a motor or generator.
  Armature emf is more with wave winding than with lap winding.
 Armature emf is same as long as the flux density in the air gap remains the same.

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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.
 Would be equal to If1/2.
 Would be equal to If1.
 Woud be equal to 2If1.

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