GATE EE concept:single-phase-transformer PYQs & Answers

Questions 1–4 of 4. Imported answers require independent review unless marked reviewed.

A 220V/12V single-phase transformer is designed for use in India and rated 100 VA at 50 Hz. Later, this unit is shipped to the USA where it is used as a 110V/6V transformer at 60 Hz.

Which of the following statements is/are correct?

Your answerSelect all correct options. You can choose more than one.

No-load current drawn would be smaller for operation in the USA compared to that in India

For the same load current, the losses would be higher in the USA compared to that in India

The peak magnetic flux density in the core would be higher while operating in the USA compared to that in India

The eddy current losses in the core would be approximately 44% higher while operating in the USA compared to that in India

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In a single-phase transformer, the total iron loss is 2500 W at nominal voltage of 440 V and frequency 50 Hz. The total iron loss is 850 W at 220 V and 25 Hz. Then, at nominal voltage and frequency, the hysteresis loss and eddy current loss respectively are

Your answerChoose one option.

1600 W and 900 W

900 W and 1600 W

250 W and 600 W

600 W and 250 W

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A 5 kVA, 50

V/100 V, single-phase transformer has a secondary terminal voltage of 95 V when loaded. The regulation of the transformer is

Your answerChoose one option.

4.5%

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A single-phase transformer of rating 25 kVA, supplies a 12 kW load at power factor of 0.6 lagging. The additional load at unity power factor in kW (round off to two decimal places) that may be added before this transformer exceeds its rated kVA is ____________.

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GATE EE concept:single-phase-transformer PYQs

How to practice concept:single-phase-transformer

Question 31

Question 33

Question 8

Question 45