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?

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

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Electrical Machines
Which of the following is done in speed control of DC motor by field flux control?

 Inserting an additional resistance in the field circuit.
 Inserting an additional resistance in the armature circuit.
 Any of above.
 Inserting resistance to armature circuit and field circuit.

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