Transformer MCQ’s

Electrical Engineering XYZ provides transformer MCQ’s part 1 which are very important for competitive tests. Prepare these MCQ before appearing in interviews, job tests, university exams and develop your basic concepts on transformers.

Auto-transformer is recommended for the transformation ratio

Auto-transformer is recommended for the transformation ratio:

  1. 1
  2. 5
  3. 1.1
  4. 5

Correct answer: 3. 1.1 is the right answer.
Explanation: An autotransformer is used for smaller transformation ration. e.g 21 kV to 21.5 kV stepping is required.

From no load to full load condition, the Iron losses in real transformer

From no load to full load condition, the Iron losses in real transformer:

  1. Remain constant
  2. Increase upto 25% of orginal losses
  3. Decrease by 13% of original losses
  4. None of these

Correct answer: 1. Remain constant
Explanation: The iron losses depend on the core flux which remains constant from no load to full load.

The Eddy losses in a transformer depends on

The Eddy losses depends on:

  1. Frequency
  2. Flux density
  3. Thickness
  4. All of these

Correct answer: 4. All of these
Explanation: The formula of Eddy current losses is: P = kef2Bmax2τ2

Scott connection in transformers are used when

Scott connection in transformers are used when:

  1. Three-phase to two-phase transformation is required
  2. Single-phase to two-phase transformation is required
  3. Three-phase to two and three-phase transformation is required
  4. For all of these

Correct answer: 2. Three-phase to two and three-phase transformation is required

The PF of the transformer

The PF of the transformer:

  1. Unity
  2. Leading
  3. Lagging
  4. Depends on load

Correct answer: 4. Depends on load
Explanation: The PF depends on PF of the connected load

The transformer oil should have

The transformer oil should have:

  1. Low viscosity and Low volatility
  2. Low viscosity and High volatility
  3. High viscosity and Low volatility
  4. High viscosity and High volatility

Correct answer: 1. Low viscosity and Low volatility
Explanation: Viscosity is the resistance against friction, whereas volatility is the tendency to vaporize a good oil should have low viscosity as well as low volatility.

Which of following will be the smallest transformer

Figure the smallest transformer:

  1. 5 kVA, 1000 Hz
  2. 5 kVA, 2000 Hz
  3. 5 kVA, 3000 Hz
  4. 5 kVA, 4000 Hz

Correct answer: d. 5 kVA, 4000 Hz
Explanation: Size of transformer is inversely proportional to the frequency.

Which one of following is a step-up transformer dealing with high frequency

Which one of following is a step-up transformer dealing with high frequency:

  1. CT
  2. PT
  3. Tesla coil
  4. None of these

Correct answer: c. Tesla coil is the right answer

The primary winding of a transformer can be considered as

The primary winding of a transformer can be considered as:

  1. A powered inductor
  2. A powered capacitor
  3. Both of these
  4. None of these

Correct answer: a. A powered inductor

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