Marine Electrotechnology. Test 4

It is possible to operate two similar generators in parallel at equal power (kW) but at different power factors. The generator with lower power factor will cause it to run:

Hotter due to increased current
Cooler due to increased speed
Slower due to increased current
Faster due to increased voltage

After successful synchronising the kW and kVar loading are respectively transferred by the following controls:

Voltage regulator and synchroscope
Speed governor and load power factor
Speed governor and voltage regulator
Current regulator and voltage regulator

When 3 phase alternators are operating in parallel, it is very important that the reactive load is evenly shared so that the total alternator loads are evenly shared. If the total alternator load is the vector sum of active and reactive loads, which side of the vector diagram shown represents the reactive load?

(Y)
None of the mentioned alternatives
Either (X) or (Y)
(X)

Will it matter to the accuracy of the measurement how you are installing a resistance element in a thermo-well

Wrong installation will result in a major deviation in measurement
Will only result in mechanical problems
No influence at all
Will have a minor influence on the measurement

What is the purpose of the alternator reverse power trip?

To prevent parallel operation if the excitation field voltage is reversed
To give automatic disconnection of the circuit breaker when you are taking the alternator off the switchboard
To prevent the alternator from 'motoring' by being supplied power from other parallel alternator
To prevent the alternator from being paralleled if it is out of phase with the main switchboard

A three phase alternator is connected singularly to the main switchboard. The switchboard instruments show 440 Volts/950 amperes. With a power factor of 0.8 what will be the kW load?

579.2 kW
905 kW
522.5 kW
334.4 kW

If you alter the field excitation voltage of one alternator operating in parallel, this will cause change in that alternators:

None of the mentioned alternatives
Active load (kW)
Frequency
Reactive load (kVAR)

Review Answers

Marine Electrotechnology. Test 4

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