Transformers MCQs

1.Identify the incorrect statement about an ideal single-phase transformer with a turns ratio of 1:2, which draws 10 A from a 200 V AC source.

The current on the secondary side is 5 A.The voltage on the secondary side is 400 V.The transformer's power rating is 2 kVA.The secondary current measures 20 A.This device functions as a step-up transformer.

2.In a transformer operating at a fixed voltage, which losses stay constant regardless of variations in load?

Hysteresis and eddy current lossesFriction and windage lossesCopper lossesNone of the above

3.Which type of losses are present in rotating electrical machines but are absent in transformers?

Losses due to friction and air resistanceLosses caused by magnetic effectsLosses from hysteresis and eddy currentsLosses occurring in copper windings

4.How does the eddy current loss change when the frequency of a fixed applied voltage is increased?

The eddy current loss will reduceThe eddy current loss will riseThe eddy current loss will stay the sameNone of these options

5.Why are approximately 10% of the end turns in a power or distribution transformer heavily insulated?

To endure the high voltage stress caused by line surges generated from the shunting capacitance of the end turnsTo absorb surge voltages and protect the transformer winding from harmTo reflect surge voltages and prevent damage to the transformer windingNone of the above

6.Which type of transformer core construction results in reduced core losses and enhanced permeability?

A core assembled from laminations of cold-rolled grain-oriented steelA core made from laminations of hot-rolled steel sheetsEither of the above core typesNone of the above options

7.What is the common term for the sound generated by a transformer?

8.Which component of a transformer can be seen externally?

9.Among the following insulating materials, which one can endure the highest temperature without damage?

10.How can the efficiency of two identical transformers be evaluated when operating under load?

Performing a short-circuit testConducting a back-to-back testUsing an open-circuit testAny of the mentioned tests

11.Which device is used to safeguard electrical systems from voltage spikes caused by lightning and switching operations?

Horn gapsThermal overload relaysBreatherConservator

12.What does good voltage regulation in a transformer signify?

The output voltage changes minimally when going from no load to full loadThe output voltage varies the least with changes in power factorThe voltage difference between primary and secondary windings is minimalThe voltage difference between primary and secondary windings is at its highest

Transformers MCQs

About this subject

1.Identify the incorrect statement about an ideal single-phase transformer with a turns ratio of 1:2, which draws 10 A from a 200 V AC source.

2.In a transformer operating at a fixed voltage, which losses stay constant regardless of variations in load?

3.Which type of losses are present in rotating electrical machines but are absent in transformers?

4.How does the eddy current loss change when the frequency of a fixed applied voltage is increased?

5.Why are approximately 10% of the end turns in a power or distribution transformer heavily insulated?

6.Which type of transformer core construction results in reduced core losses and enhanced permeability?

7.What is the common term for the sound generated by a transformer?

8.Which component of a transformer can be seen externally?

9.Among the following insulating materials, which one can endure the highest temperature without damage?

10.How can the efficiency of two identical transformers be evaluated when operating under load?

11.Which device is used to safeguard electrical systems from voltage spikes caused by lightning and switching operations?

12.What does good voltage regulation in a transformer signify?

13.Which type of protection is typically absent in small distribution transformers?

14.At a steady load current, at which power factor does a transformer achieve its highest efficiency?

15.What does a transformer primarily change in an electrical circuit?

16.Under which condition does a transformer exhibit voltage regulation closest to zero?

17.What should the resistance value be between the primary and secondary windings of a transformer?

18.Why is the secondary winding of a current transformer kept short-circuited during normal operation?

19.What characteristic is associated with a shell-type transformer?

20.Natural air cooling for transformers is typically limited to transformers with a rating of up to what capacity?

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