Single Phase Induction Motors Mcqs
This set of Electrical engineering Multiple Choice Questions & Answers (MCQs) focuses on “Single Phase Induction Motors”. These questions are chosen from a collection of most authoritative and best reference books on Electrical engineering. Our aim is to prepare an individual for competitive exams like NTS, GAT, ECAT, University and College entrance exams, Jobs and interviews. One should practice our MCQS to assimilate Single Phase Induction Motors Mcqs comprehensively.
2. If a D.C. series motor is operated on A.C. supply, it will____________?
Spark excessively
Have poor efficiency
Have poor power factor
All of the above
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3. A universal motor is one which______________?
Can be operated either on D.C. or A.C. supply at approximately the same speed and output
Can be marketed internationally
Runs at dangerously high speed on no-load
All the above
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4. In a A.C. series motor armature coils are usually connected to commutator____________?
Through resistance
Through reactances
Through capacitors
Solidly
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5. A repulsion motor is equipped with__________?
Slip rings
Commutator
Both A. and (b)
None of the above
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6. Which of the following motors has two separate windings on the motor ?
Repulsion motor
Repulsion induction motor
Repulsion start induction run motor
None of the above
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7. Which of the following statements regarding a reluctance motor is incorrect ?
It cannot be reversed, ordinarily
It requires no D.C. field excitation for its operation
It is nothing else but a single-phase, salient pole synchronous-induction motor
Its squirrel cage-rotor is of unsym-metrical magnetic construction in order to vary reluctance path between stator and rotor
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8. A shaded pole motor does not possess___________?
Centrifugal switch
Capacitor
Commutator
All of the above
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9. To reverse the direction of rotation of acapacitor start motor while it is running we should___________?
Disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding
Disconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding
Reverse the direction of connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply
Reverse the direction of connections of the auxiliary winding and immediately connect it to supply
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10. In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will_____________?
Become unstable
Draw excessive armature current and may burn out
Fall out of synchronism and come to stand still
Run as induction motor
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11. Most of the fractional horsepower motors have either___________?
Hard and annealed bearings
Ball or roller bearings
Soft and porous bearings
Plain or sleeve bearings
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12. In a universal motor, the most common cause of brush sparking is___________?
Open armature winding
Shorted armature winding
Shorted field winding”
High commutator mica
all of the above
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13. Which of the following statements regarding reluctance-start motor is incorrect ?
It is similar to reluctance motor
It is basically an induction motor and not a synchronous one
So far as its basic working principle is concerned, it is similar to shaded pole motor
The air-gap between rotor and salient poles is non- uniform
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14. If starting winding of a single-phase induction motor is left in the circuit, it will____________?
Run faster
Spark at light loads
Draw excessive current and overheat
Run slower
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15. If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open then____________?
Motor will not come up to speed
Motor will not carry the load
Current drawn by the motor will be excessively high
Electrolytic capacitor will, in all probability, suffer break down
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