Transformer MCQ Questions Part 1

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Transformer MCQ Questions Part 1 by ElectricalEngineeringMCQ

Under: Electrical Transformer MCQ

Connecting 1000 KVA transformers in parallel

If two transformers of 1000 kVA are operated in parallel, the first one having a 6% impedance, and the other one having a 3% impedance, each having the same turns ratio are connected to a 1700 kVA common load. What is the correct statement about loading:

  1. First one will be loaded by 56%
  2. Both will be equally loaded
  3. Second one will be loaded by 13%
  4. Both will be underloaded

Correct answer: 1. First will be loaded by 56%

Solution Formulas:

No-load Power Factor of transformer MCQ

No-load power factor of transformer is low because:

  1. Magnetizing component of Io is small
  2. Magnetizing component of Io is large

Correct answer: 2. Magnetizing component of Io is large

Which transformer connection will give the highest secondary voltage

Which of the following transformer connection will give highest secondary voltage:

  1. Delta primary, Delta secondary
  2. Delta primary, Star secondary
  3. Star primary, Delta secondary
  4. Star primary, Star secondary

Correct answer: 2. Delta primary, Star secondary

The delta primary, star secondary connection will provide the highest secondary voltage

What is the approximate value of efficiency in large transformers

What is approximate value of efficiency in large transformers:

  1. 50%
  2. 74%
  3. 89.93%
  4. 95%

Correct answer: 4. 95%

The approximate value of efficiency in large transformers is 95%

What is the turns ratio of isolation transformer

What is the turns ratio of isolation transformer:

  1. 0:1
  2. 1:0
  3. 1:1
  4. None of these

Correct answer: 3. 1:1

The turns ratio of isolation transformer is 1:1

The sole purpose of isolation transformer is to electrically isolate the power source connected to primary from the circuit connected to secondary

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