Electrical Machines
Hunting in a synchronous motor takes place

  when power factor is unity.
  when supply voltage fluctuates.
  when load varies.
  motor is under loaded.

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Electrical Machines
A dc shunt generator, when commissioned after a major repair of the field system, failed to build Up voltage. It was because

 there was a break in the armature circuit
 field resistance was higher than critical resistance
 field system lost residual magnetism
 field winding was wrongly connected

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Electrical Machines
In a dc generator operating on load with its brushes on the geometrical neutral axis (GNA), the magnetic neutral axis (MNA) is shifted in the direction of rotation. Now, if the brushes are given a lead of 90° (electrical), then the MNA will

 coincide with the GNA
 shift forward by more than 90°
 shift forward by less than 90°
 shift forward by 90°

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