Electrical Machines
A separately excited DC motor has an armature resistance of 0.5 Ohm. The supply voltage is 250V. Armature current is 20A and the speed of rotation is 1500 rpm. Find the torque developed?

 Zero
 15.28 Nm
 16.55 Nm
 15.6 Nm

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Electrical Machines
The synchronous motor can be started by

  coupling it with a DC compound motor.
  coupling it with a small AC induction motor called the pony motor.
  providing damper winding in its rotor circuit.
  any of the above methods.

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Electrical Machines
The mmf produced by rotor currents of a 3 - Φ induction motor

  is at standstill with respect to stator mmf.
  rotates at synchronous speed with respect to rotor.
  rotates at the speed of rotor in the air gap.
  rotates at slip speed with respect to stator mmf.

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