D.C. Generators Mcqs
This set of Electrical engineering Multiple Choice Questions & Answers (MCQs) focuses on study of “D.C. Generators Mcqs”. 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 D.C. Generators Mcqs comprehensively.
2. In a four-pole D.C. machine____________?
All the four poles are north poles
Alternate poles are north and south
All the four poles are south poles
Two north poles follow two south poles
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3. In lap winding, the number of brushes is always_____________?
Double the number of poles
Same as the number of poles
Half the number of poles
Two
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4. The bearings used to support the rotor shafts are generally______________?
Ball bearings
Bush bearings
Magnetic bearmgs
Needle bearings
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5. In D.C. generators, the cause of rapid brush wear may be___________?
Severe sparking
Rough commutator surface
Imperfect contact
Any of the above
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6. For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f___________ ?
Lap winding
Wave winding
Either of A. and B. above
Depends on other features of design
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7. Copper brushes in D.C. machine are used_____________?
Where low voltage and high currents are involved
Where high voltage and small cur-rents are involved
In both of the above cases
In none of the above cases
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8. In case of D.C. machines, mechanical losses are primary function of____________?
Current
Voltage
Speed
None of above
9. Fleming’s right-hand rule regarding direction of induced e.m.f., correlates__________?
Magnetic flux, direction of current flow and resultant force
Magnetic flux, direction of motion and the direction of e.m.f. induced
Magnetic field strength, induced voltage and current
Magnetic flux, direction of force and direction of motion of conductor
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10. In D.C. generators the pole shoes are fastened to the pole core by_____________?
Rivets
Counter sunk screws
Brazing
Welding
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11. While applying Fleming’s right-hand rule to And the direction of induced e.m.f., the thumb points towards___________?
Direction of induced e.m.f.
Direction of flux
Direction of motion of the conductor if forefinger points in the direction of generated e.m.f.
Direction of motion of conductor, if forefinger points along the lines of flux
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12. According to Fleming’s right-hand rule for finding the direction of induced e.m.f., when middle finger points in the direction of induced e.m.f., forefinger will point in the direction of____________?
Motion of conductor
Lines of force
Either of the above
None of the above
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13. In a commutator_____________?
Copper is harder than mica
Mica and copper are equally hard
Mica is harder than copper
None of the above
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14. The field coils of D.C. generator are usually made of_____________?
Mica
Copper
Cast iron
Carbon
15. The resistance of armature winding depends on
Length of conductor
Cross-sectional area of the conductor
Number of conductors
All of the above
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