Electrical Machines
In a DC generator the emf generated by the armature is maximum when

 shaft rotation is high.
 induced voltage is high.
  rate of change of flux is maximum.
 rate of change of flux is minimum.

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Electrical Machines
In a DC machine

 emf in armature conductors and at the terminals is alternating.
 current and emf in armature are unidirectional
 current and emf in armature are alternating.
 current and emf at the terminals are alternating.

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

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