Synchronous Generator MCQs Part 5

Synchronous Generator MCQs Part 5

In an alternator, the salient-pole construction for field structure is generally used for machine having

In an alternator, the salient-pole construction for field structure is generally used for machine having:

1. 2-poles
2. 4-poles
3. 8-poles
4. none of above

Correct answer: 3. 8-poles

The EMF generated in an 8-pole alternator running at 900 RPM has frequency of

The EMF generated in an 8-pole alternator running at 900 RPM has frequency of:

1. 50 Hz
2. 60 Hz
3. 120 Hz
4. none of these

Correct answer: 2. 60 Hz

Solution: f = NP/120 = (900*8)/120 = 60 Hz

The voltage of the bus-bar to whom several alternators are paralleled may be raised by simultaneously

The voltage of the bus-bar to whom several alternators are paralleled may be raised by simultaneously:

1. Increasing input to prime movers of all generators
2. Decreasing input to prime movers of all generators
3. Increasing field excitation of all generators
4. Decreasing field excitation of all generators

Correct answer: 3. Increasing field excitation of all generators

A pole-pitch in an electrical machine equals

A pole-pitch in an electrical machine equals:

1. 90 electrical degrees
2. 120 electrical degrees
3. 180 electrical degrees
4. 360 electrical degrees

Correct answer: 3. 180 electrical degrees

The magnitude of the resultant flux due to 3-phase balanced supply is how many times the value of the maximum flux due to current in each phase

The magnitude of the resultant flux due to 3-phase balanced supply is how many times the value of the maximum flux due to current in each phase:

1. Half
2. Equal to
3. 1.5 times of
4. 3 times of

Correct answer: 3. 1.5 times of