Transformers MCQ Questions Part 3

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Transformer MCQ Questions Part 3.

A transformer transfers energy from primary to secondary with a change in

A transformer transfers energy from primary to secondary with a change in:

  1. Voltage
  2. Frequency
  3. Power
  4. Time period

Correct answer: 1. Voltage

A 3300/1100 ideal transformer has 50 turns on secondary. What is the number of turns on primary

A 3300/1100 ideal transformer has 50 turns on secondary. What is the number of turns on primary:

  1. 16
  2. 150
  3. 350
  4. 1100

Correct answer: 2. 150

Solution:

From formula

Vp/Vs = Np/Ns

3300/1100 = Np/50

Np = 3 * 50 = 150 turns

Leakage flux in transformer occurs due to which reason

Leakage flux in transformer occurs because of which reason:

  1. The applied voltage is sinusoidal
  2. Employing Iron core in the design
  3. Air is not a good magnetic insulator
  4. All of the above

Correct answer: 3. Air is not a good magnetic insulator

Leakage flux in the transformer occurs because air is not a good magnetic insulator.

The iron loss of a transformer is 500 W at full load. What is iron loss at half load

The iron loss of a transformer is 500 W at full load. What is iron loss at half load:

  1. 50 W
  2. 250 W
  3. 336.85 W
  4. None of the above

Correct answer: 4. None of the above.

The iron loss in a transformer is independent of load. Rather it depends on voltage and frequency of the supply. Therefore iron loss will be 500 W and from above options 4. None of the above is correct.

Transformers rated under 5 kVA are recommended to be cooled

Transformers rated under 5 kVA are recommended to be cooled:

  1. Air cooled
  2. Natural air cooled
  3. Water cooled
  4. None of above

Correct answer: 2. Natural air cooled

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