Electrical Machines
For a DC Shunt Motor having armature resistance of 0.5 Ω and 2 A armature current at no-load, when the armature current is changed to 20 A at loaded condition the speed is 1000 r.p.m. What is the speed at no-load?

 none of above.
 4575.4 r.p.m.
 1130 r.p.m.
 1037.5 r.p.m.

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Electrical Machines
If the frequency of input voltage of a transformer is increased keeping the magnitude of voltage unchanged, then

 Ph will increase but Pe will decrease
 Pe will increase but Ph will decrease
 Ph will decrease but Pe will remain same
 both hysteresis loss(Ph) and eddy current loss(Pe) will increase

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

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

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