Electrical Machines
A DC motor with armature resistance of 0.5 ohms connected directly to a 220 Volt supply. If the armature is stationary then the current flowing through the armature is

 570 A.
 340 A.
 250 A.
 440 A.

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Electrical Machines
Which of the following represents the commutator pitch?

 Number of conductors spanned by one coil at the back end of the armature.
 Number of conductors spanned by one coil at the front end of the armature.
 The distance between the staring of first coil and its next successive coil
 Number of commutator segments between two successive coils.

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Electrical Machines
Armature reaction in a DC machine

 is in direct opposition to the main poles.
  makes an angle of 90° with the main pole axis.
 is in the same direction as the main poles.
 makes an angle with the main pole axis which is load dependent.

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