Electrical Machines
High inrush of current during a starting of DC motor can efficiently be restricted to a safer value by increasing the _________________ resistance.

 none of above
 both A and B
 shunt field
 armature circuit

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Electrical Machines
What is/are the necessary conditions for voltage build up in self excited generator?

All of these
 Poles should contain residual flux.
 Field winding resistance should be less than critical resistance.
 Field winding should be properly connected to armature winding.

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Electrical Machines
For satisfactory parallel operation of two transformers which of the following conditions is most essential,

 voltage ratio of all transformers must be same.
 MVA rating of all transformer inversely proportional to impedance.
  polarities of all transformers must be same.
 percentage impedance of all transformers must be same.

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Electrical Machines
In large sized DC machines the compensating windings are provided to

  neutralize voltage induced in coil due to fluctuation of l
 compensate for the decrease in speed due to increase of load.
 reduce eddy current losses by providing local short circuits.
None of these

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