Transformer MCQs Part 31

Electrical Engineering MCQs on Transformer Part 31 – Transformers Multiple Choice Questions

The transformer insulation material that is best compared to Kraft paper

The transformer insulation material that is best compared to Kraft paper:

  1. Asbestos
  2. Cotton
  3. Low grade pressboard
  4. Oil

Correct answer: 4. Oil

Insulation of HVDC transformers should be

Insulation of HVDC transformers should be:

  1. Dry always
  2. Wet always
  3. Any of above
  4. HVDC transformers have no insulation

Correct answer: 1. Dry always

Transformer oil must be free from

Transformer oil must be free from:

  1. Odour
  2. Gases
  3. Moisture
  4. Sulphur

Correct answer: 3. Moisture

Generally, a transformer transfers electrical energy from primary to secondary with a change in

Generally, a transformer transfers electrical energy from primary to secondary with a change in:

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

Correct answer: 2. Voltage

A 200 kVA transformer has full-load Cu loss of 2000 W. It will have maximum efficiency for load having value

A 200 kVA transformer has full-load Cu loss of 2000 W. It will have maximum efficiency for load having value:

  1. 25 kVA
  2. 50 kVA
  3. 100 KVA
  4. 200 kVA

Correct answer: 3. 100 KVA

Explanation:

Solution:

Load for maximum efficiency = Full load kVA * (Iron loss/ Full load Cu loa4. ^1/2

= 200 * (500/2000)

= 100 kVA

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