| 1. | In a lap wound D.C. generator having p as number of poles and Z as number of conductors, the maximum number of equilizer rings will be ? | |
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Z
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p
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2Z/p
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2p/Z
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Report Question| 2. | The e.m.f. generated in a D.e. generator is directly proportional to ? | |
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flux/pole
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speed of armature
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number of poles
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all of the above
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| 3. | Following energized winding of a D.C. machine should not be opened as it would produce high inductive voltage which may be dangerous to personnel and may cause its own insulation failure ? | |
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Series field
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Compensating field
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Inter pole field
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Shunt field
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| 4. | Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.f are 270 V and 265 V, their bus bar voltage will be ? | |
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270 V
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267.5 V
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265 V
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257.4 V
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| 5. | If a self excited DC generator after being installed, fails to build up on its first trial run, the first thing to do is to ? | |
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reverse the field connections
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increase the field resistance
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increase the speed of prime mover
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check armature insulation resistance
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| 6. | Copper brushes in D.C. machine are used ? | |
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where low voltage and high currents are involved
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where high voltage and small currents are involved
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in both of the above cases
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in none of the above cases
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| 7. | While applying Fleming's right-hand rule to find the direction of induced e.m.f., the thumb points towards ? | |
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direction of induced e.m.f.
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direction of flux
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direction of motion of the conductor if forefinger points in the direction of generated e.m.f.
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direction of motion of conductor, if forefinger points along the lines of flux
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| 8. | Which of the following could be lamina-proximately the thickness of laminations of a D.C. machine ? | |
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0.005 mm
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0.06mm
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0.6.m
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5 m
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| 9. | The field coils of D.C. generator are usually made of ? | |
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mica
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cast iron
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copper
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carbon
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| 10. | The armature of D.C. generator is laminated to ? | |
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reduce the bulk
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provide the bulk
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insulate the core
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reduce eddy current loss
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