Electrical Machines
A 250 volt dc series motor having an armature resistance of 0.2 Ω takes a load current of 60 A. What will be the torque produced at the shaft of the motor? Consider brush drop of 1V.

 133.22 N-m
 266.20 N-m.
 can not be determined.
 234.76 N-m.

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Electrical Machines
For a given torque, reducing divertor resistance of a DC series motor

  Decrease in speed demanding less armature current.
  Increase in speed but armature currnet remains the same.
  Increase in speed demanding more armature current.
  Decrease in speed but armature current remains the same.

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Electrical Machines
Consider the following statements regarding the magnetization characteristics of a dc generator : 1. It represents the variation of field flux with field current. 2. Variation of open-circuit terminal voltage with field current is independent of speed 3. It is non-linear from zero to rated field current 4. It helps to determine the critical field resistance at a given speed 5. It always starts from the origin Which of these statements are correct ?

 1 and 4
 1, 2 and 5
 2, 3 and 4
 3 and 5

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