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.
Contents
Auto-transformer is recommended for the transformation ratio
Auto-transformer is recommended for the transformation ratio:
- 1
- 5
- 1.1
- 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:
- Remain constant
- Increase upto 25% of orginal losses
- Decrease by 13% of original losses
- 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:
- Frequency
- Flux density
- Thickness
- 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:
- Three-phase to two-phase transformation is required
- Single-phase to two-phase transformation is required
- Three-phase to two and three-phase transformation is required
- 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:
- Unity
- Leading
- Lagging
- 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:
- Low viscosity and Low volatility
- Low viscosity and High volatility
- High viscosity and Low volatility
- 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:
- 5 kVA, 1000 Hz
- 5 kVA, 2000 Hz
- 5 kVA, 3000 Hz
- 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:
- CT
- PT
- Tesla coil
- 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:
- A powered inductor
- A powered capacitor
- Both of these
- None of these
Correct answer: a. A powered inductor
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