Transformer MCQs Part 24

Transformer MCQs Part 24

The steel used for transformer core has

The steel used for transformer core has:

1. Low hysteresis losses
2. High permeability
3. High silicon content
4. All of these

Correct answer: 4. All of these

The all-day efficiency of transformer is also known as its

The all-day efficiency of transformer is also known as its:

1. Power efficiency
2. Energy efficiency
3. Current efficiency
4. None of these

Correct answer: 2. Energy efficiency

Open-circuit test on transformer is done on

Open-circuit test on transformer is done on:

1. Low voltage winding
2. High voltage winding
3. Any of above
4. None of above

Correct answer: 1. Low voltage winding

Explanation: Open circuit test on transformer is carried out on low voltage winding (High voltage winding is left open). Although the iron losses on either of the windings will be same, but open circuit test is carried out on low voltage winding since, measurement on high voltage winding will have very small no-load current and very high voltage.

Leakage flux in a transformer results in

Leakage flux in a transformer results in:

1. Voltage drop in windings
2. Increased copper losses
3. Decreased copper losses
4. None of above

Correct answer: 1. Voltage drop in windings

Usually, transformers with rating less than 5 kVA are

Usually, transformers with rating less than 5 kVA are:

1. Natural air cooled
2. Oil cooled
3. Water cooled
4. None of these

Correct answer: 1. Natural air cooled