Synchronous Motors PART 1
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Attempt Free Synchronous Motors PART 1 Here. Read The Important Electrical MCQ From Below.
1. Synchronous motor can operate at
(A) Lagging power factor only
(B) Leading power factor only
(C) Unity power factor only
(D) Lagging, leading and unity power factor only.Get Answer
2. An unexcited single phase synchronous motor is
(A) reluctance motor
(B) repulsion motor
(C) universal motor
(D) AC series motor.
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Synchronous Motors PART 1
3. The maximum power developed in the synchronous motor will depend on
(A) rotor excitation only
(B) maximum value of coupling angle
(C) supply voltage only
(D) rotor excitation supply voltage and maximum value of coupling angle.
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Synchronous Motors PART 1
4. In case the field of a synchronous motor is under excited, the power factor will be
(A) leading
(B) lagging
(C) zero
(D) unity.
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5. A synchronous motor is switched on to supply with its field windings shorted on themselves. It will
(A) not start
(B) start and continue to run as an induction motor
(C) start as an induction motor and then run as synchronous motor
(D) bum immediately.
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6. When the excitation of an unloaded salient pole synchronous motor gets disconnected
(A) the motor will bum
(B) the motor will stop
(C) the motor will ran as a reluctance motor at the same speed
(D) the motor will run as a reluctance motor at a lower speed.
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7. The damping winding in a synchronous motor is generally used
(A) to provide starting torque only
(B) to reduce noise level
(C) to reduce eddy currents
(D) to prevent hunting and provide the starting torque.
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Synchronous Motors PART 1
8. The back emf set up in the stator of a synchronous motor will depend on
(A) rotor speed only
(B) rotor excitation only
(C) rotor excitation and rotor speed
(D) coupling angle, rotor speed and excitation.
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9. A synchronous motor is a useful industrial machine on account of which of the following reasons ?
I. It improves the power factor of the complete installation
II. Its speed is constant at all loads, provided mains frequency remains constant
III. It can always be adjusted to operate at unity power factor for optimum efficiency and economy.
(A) I only
(B) II only
(C) III only
(D) I, II and III.
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10. Which of the following is an unexcited single phase synchronous motor ?
(A) A.C. series motor
(B) Universal motor
(C) Reluctance motor
(D) Repulsion motor.
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11. An over excited synchronous motor draws current at
(A) lagging power factor
(B) leading power factor
(C) unity power factor
(D) depends on the nature of load.
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12. With the increase in the excitation current of synchronous motor the power factor of the motor will
(A) improve
(B) decrease
(C) remain constant
(D) depend on other factors.
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Synchronous Motors PART 1
13. The armature current of a synchronous motor has large values for
(A) low excitation only
(B) high excitation only
(C) both low and high excitation
(D) depends on other factors.
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14. A synchronous motor is switched on to supply with its field windings shorted on themselves. It will
(A) not start
(B) start and continue to run as an induction motor
(C) start as induction motor and then run as a synchronous motor.
Get Answer
15. If the field of a synchronous motor is under excited, the power factor will be
(A) lagging
(B) leading
(C) unity.
Get Answer
Synchronous Motors PART 1
