Electrical Machines
In DC generators, the brushes remain in contact with conductors which

 lie under south pole.
 lie in the inter polar gaps.
 there is no hard and fast rule for this.
 lie under north pole.

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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

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

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Electrical Machines
The speed of a DC series motor is

 Proportional to the armature current.
 Inversely proportional to the armature current.
 Proportional to field current.
 Proportional to the square of the armature current.

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