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?

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

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Electrical Machines
With the increase in speed of a DC motor

 both back emf as well as line current increase.
 back emf increases but line current falls.
 back emf falls and line current increases.
 both back emf as well as line current fall.

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Electrical Machines
An alternator is feeding an infinite busbar. Its prime mover is suddenly shutdown. The alternator will

 continue to work as alternator but the direction of rotation will reverse.
 come to stand still.
 continue to work as synchronous motor with same direction of rotation.
 start working as induction motor.

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