Synchronous Generator MCQs Part 15

Electrical Engineering MCQs on Sync Gen – Synchronous Generator MCQs Part 15

The stator of an alternator is wound for ____________ on the rotor

The stator of an alternator is wound for ____________ on the rotor:

1. The same number of poles as
2. More number of poles than
3. Less number of poles than
4. None of the above

Correct answer: 1. The same number of poles as

Keeping the same rating, the size of low-speed alternator is __________ that of high-speed alternator

Keeping the same rating, the size of low-speed alternator is __________ that of high-speed alternator:

1. More than
2. Less than
3. About the same as
4. None of the above

Correct answer: 1. More than

The DC armature resistance of delta-connected alternator measured across its two terminals is 2 Ω. The per phase resistance is

The DC armature resistance of delta-connected alternator measured across its two terminals is 2 Ω. The per phase resistance is:

1. 1 Ω
2. 2 Ω
3. 3 Ω
4. 4 Ω

Correct answer: 3. 3 Ω

Explanation:

The DC resistance measured across any two terminals of delta connected alterantor is equal to resistance of one phase in parallel with two other phases in series. Therefore the per phase DC armature resistance is half of measured value. In current case can be calculated as

= 2 + 2 || 2 = 3 Ω

The rating of the prime-mover driving an alternator is determined entirely on the basis of its

The rating of the prime-mover driving an alternator is determined entirely on the basis of its

1. Voltage rating
2. Current rating
3. Speed rating
4. Kw output rating

Correct answer: 4. Kw output rating

The armature reaction effect in a synchronous generator depends on which of following

The armature reaction effect in a synchronous generator depends on which of following:

1. Speed
2. load current
3. PF of load
4. Both 2 & 3

Correct answer: 4. Both 2 & 3