1. If two alternators are running in proper synchronism and the voltage of one machine is suddenly increased ?

both machines will stop

one machine will stop

synchronising torque will be produced to restore further synchronism

none of the above

Answer: synchronising torque will be produced to restore further synchronism

Explanation:


2. ln an alternator field the effect of cross magnetisation is to make the output ?

non-sinusoidal

true sinusoidal

free from harmonics

none of the above

Answer: non-sinusoidal

Explanation:


3. An alternator is capable of delivering power at a particular efficiency. The frequency can be increased by ?

reversing the armature rotation

reversing the field polarity

increasing the current supplied to the field electromagnets

increasing the armature speed

Answer: increasing the armature speed

Explanation:


4. Zero power factor method for an alternator is generally used to determine ?

synchronous impedance of alternator

efficiency of alternator

voltage regulation of the alternator

none of the above

Answer: voltage regulation of the alternator

Explanation:


5. If an alternator is operating at leading power factor, then it can be concluded that ?

the alternator is under-excited

the alternator is over-excited

the torque angle of the alternator has negative value

the residual magnetism of the poles is zero

Answer: the alternator is over-excited

Explanation:


6. The power factor of an alternator is determined by its ?

primemover

excitation

speed

load

Answer: load

Explanation:


7. Voltage regulation of an alternator is usually ?

equal to that of power transformer

much lower than that of a power transformer

much higher than that of a power transformer

none

Answer: much higher than that of a power transformer

Explanation:


8. Dirt accumulation in generators can cause ?

flashovers

overheating

poor voltage regulation

all of the above

Answer: all of the above

Explanation:


9. The fictitious part of synchronous reactance takes care of ?

inductive reactance

armature reaction

voltage regulation

none of the above

Answer: armature reaction

Explanation:


10. Overheating of generator's winding ?

reduces life of the machine

does not have any significant effect

reduces generated voltage

reduces power factor

Answer: reduces life of the machine

Explanation: