Electrical Machines
For a DC machine having P no of pole pairs, Z no of conductors having length L of resistivity ρ and cross section S are arranged. what is the armature resistance for simple wave-winding ?

 PZL/4Sp²
 PZL/ 4Sa
 PZL/4Sa²
 PZL/4S

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Electrical Machines
A compound dc generator is delivering full load current at a terminal voltage of 230 V. Its series-field winding gets short circuited. If its terminal voltage 1. becomes more than 230 V, it is overcompounded generator 2. becomes more than 230 V, it is differentially compounded generator 3. becomes less than 230 V, it is overcompounded generator 4. becomes less than 230 V, it is differentially compounded generator 5. becomes less than 230 V, it is level compounded generator From these, the correct answer is

 1, 4, 5
 2, 3, 5
 2,3
 1, 4

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

  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.
  Decrease in speed demanding less armature current.

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