Electrical Machines
The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that

 Eb is zero, but Td is unchanged
 both Eb and Td are unchanged
 both Eb and Td are zero
 Eb is unchanged, but Td is zero

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Electrical Machines
In a star - delta starting of an IM

  resistance is inserted in the rotor.
  reduced voltage is applied to the stator.
  applied voltage per stator phase is 57.7 % of a line volt
  line voltage is 57.7 % of stator voltage.

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

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

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