D.C. Generators

1. A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be

1. zero
2. about 2 V
3. about 50 V
4. 220 V

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2. A cumulatively compounded long shunt generator when operating as a motor would be

1. cumulatively compounded long shunt
2. differentially compounded long shunt
3. cumulatively compounded short shunt
4. differentially compounded short shunt

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3. A D.C. generator can be considered as

1. rectifier
2. primemover
3. rotating amplifier
4. power pump

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4. A D.C. generator works on the principle of

1. Lenz's law
2. Ohm's law
3. Faraday's law of electromagnetic induction
4. none of the above

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5. A D.C. welding generator has

1. lap winding
2. wave moving
3. duplex winding
4. any of the above

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6. A separately excited generator as compared to a self-excited generator

1. is amenable to better voltage control
2. is more stable
3. has exciting current independent of load current
4. has all above features

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7. A series generator can self-excite

1. only if the load current is zero
2. only if the load current is not zero
3. irrespective of the value of load current
4. none of the above

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8. A shunt generator can self-excite

1. only if the resistance of the field circuit is less than critical value
2. only if the resistance of the field circuit is greater than critical value
3. irrespective of the value of the resistance in the field circuit
4. none

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9. A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly

1. 150 V
2. 175 V
3. 240 V
4. 290 V

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10. A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave

1. will be zero
2. will be of 5 Hz
3. will be of 5 xiVHz
4. will be of v Hz 5

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