| 1. | The speed of a salient pole machine is nearly ? | |
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500 r.p.m.
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1000 r.p.rn.
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1500 r.p.m.
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3000 r.p.m.
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Report Question| 2. | The power factor of an alternator is determined by its ? | |
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excitation
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speed
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prime mover
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load
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| 3. | Turbo-alternators usually have ? | |
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12 poles
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8 poles
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4 poles
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2 poles
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| 4. | The number of poles in turbo alternators is usually ? | |
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2
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4
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12
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50
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| 5. | In an alternator, the armature reaction will be completely magnetizing in case the load power factor is ? | |
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zero lagging
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zero leading
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0.866
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unity
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| 6. | Turbo-rotor is made up of ? | |
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solid steel forging having milled slots for field winding
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large spider to which laminated pole shoes are secured
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laminations
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none of the above
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| 7. | Turbo-alternators are generally used to run at ? | |
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1500 r.p.m.
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3000 r.p.m.
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5000 r.p.m.
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15000 r.p.m.
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| 8. | Which of the following prime mover is least efficient ? | |
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Gas turbine
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Petrol engine
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Diesel engine
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Steam engine
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| 9. | Which of the following conditions does not have to be met by alternators working in parallel ? | |
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Alternators must· operate at the same frequency
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Machines must have the same phase rotation
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The terminal voltage of each machine must be the same
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The machines must have equal kVA ratings
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| 10. | The speed of an alternator is changed from 3000 r.p.m. to 1500 r.p.m. The generated e.m.f./phase will become ? | |
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one fourth
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half
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double
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unchanged
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