Open & Short Circuit Tests in Single-Phase Transformer - MCQs with Answers

Open & Short Circuit Tests in Single-Phase Transformer - MCQs with Answers

Q1. While performing a circuit test on transformer at 30v, 30 Hz it gives Φ₁ as lagging power factor. If the same test is performed at 30V, 50Hz, then

a. Φ₁ > Φ₂
b. Φ₁ < Φ₂
c. Φ₁ = Φ₂
d. None of these

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Q2. If the magnitude of leakage reactance is equal to the resistance of both primary and secondary of a single phase transformer. Then the input power factor is

a. 1 / √2
b. 1
c. √2
d. zero

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Q3. Open circuit test is to be performed on transformer to find

a. Constant losses
b. Copper losses
c. Both constant losses and copper losses
d. None of these

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Q4. If the transformer is step-up transformer then for performing short circuit test meter is connected to the

a. H.V. side
c. L.V. side
c. Any side
d. Test cannot be performed on step up t / f

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Q5. If short circuit test is performed on the transformer with constant rated voltage and increased frequency, then the short circuit current and power factor

a. Both will increase
b. Both will decrease
c. Increase, decrease
d. Decrease, remains constant

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