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.
 1130 r.p.m.
 4575.4 r.p.m.
 1037.5 r.p.m.

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Electrical Machines
In a DC shunt generator working on load, the brushes are moved forward in the direction of rotation, as a result of this, commutation will

  worsen and terminal voltage will rise.
  improve and terminal voltage will rise .
  worsen and terminal voltage will fall
 improve but terminal voltage will fall.

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

 decrease in speed demanding less armature current.
 increase in speed demanding more armature current.
 decrease in speed but armature current remains the same.
 increase in speed but armature currnet remains the same.

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