Electrical Machines
Flashing of DC generator means

  increasing flux density by providing extra ampere-turns in field.
  creation of residual magnetism by a DC source.
None of these
 neutralization of residual magnetism.

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

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