Explore topic-wise MCQs in Transformers.

This section includes 6 Mcqs, each offering curated multiple-choice questions to sharpen your Transformers knowledge and support exam preparation. Choose a topic below to get started.

1.

A 600-kVA, single-phase transformer with 0.012 pu resistance and 0.06 pu reactance is connected in parallel with a 300-kVA transformer with 0.014 pu resistance and 0.045 pu reactance to share a load of 800 kVA at 0.8 pf lagging. Find how they share the load (a) when both the secondary voltages are 440 V.

A. S<sub>1</sub>= 377+j305.2
B. S<sub>2</sub>= 377-j305.2
C. S<sub>1</sub>= 264+ j171.6
D. S<sub>1</sub>= 377-j305.2
Answer» E.
Discussion
2.

Which is the correct formula of current flowing through one of the transformers having unequal ratios?

A. I<sub>2</sub>= E<sub>2</sub>Z<sub>1</sub>-(E<sub>1</sub>-E<sub>2</sub>) Z<sub>L</sub> / (Z<sub>1</sub>Z<sub>2</sub> + ZL(Z<sub>1</sub>+Z<sub>2</sub>))
B. I<sub>1</sub>= E<sub>2</sub>Z<sub>1</sub>+(E<sub>1</sub>+E<sub>2</sub>) Z<sub>L</sub> / (Z<sub>1</sub>Z<sub>2</sub> + ZL(Z<sub>1</sub>+Z<sub>2</sub>))
C. I<sub>1</sub>= E<sub>2</sub>Z<sub>1</sub>-(E<sub>1</sub>-E<sub>2</sub>) Z<sub>L</sub> / (Z<sub>1</sub>Z<sub>2</sub> ZL(Z<sub>1</sub>-Z<sub>2</sub>))
D. I<sub>2</sub>= E<sub>2</sub>Z<sub>1</sub>+(E<sub>1</sub>-E<sub>2</sub>) Z<sub>L</sub> / (Z<sub>1</sub>Z<sub>2</sub> + ZL(Z<sub>1</sub>+Z<sub>2</sub>))
Answer» B. I<sub>1</sub>= E<sub>2</sub>Z<sub>1</sub>+(E<sub>1</sub>+E<sub>2</sub>) Z<sub>L</sub> / (Z<sub>1</sub>Z<sub>2</sub> + ZL(Z<sub>1</sub>+Z<sub>2</sub>))
Discussion
3.

Maximum load kVA is _____________________

A. greater than addition of individual rated kVAs
B. lesser than addition of individual rated kVAs
C. equal to addition of individual rated kVAs
D. depends on the loading condition
Answer» C. equal to addition of individual rated kVAs
Discussion
4.

Which is the correct formula for current flowing through the transformer 1, when they re having equal voltage ratio?

A. I<sub>1</sub>= Z<sub>2</sub>/(Z<sub>1</sub>+Z<sub>2</sub>) *I<sub>L</sub>
B. I<sub>2</sub>= Z<sub>2</sub>/(Z<sub>1</sub>+Z<sub>2</sub>) *I<sub>L</sub>
C. I<sub>1</sub>= Z<sub>1</sub>/(Z<sub>1</sub>+Z<sub>2</sub>) *I<sub>L</sub>
D. I<sub>1</sub>= Z<sub>2</sub>/(Z<sub>1</sub>-Z<sub>2</sub>) *I<sub>L</sub>
Answer» B. I<sub>2</sub>= Z<sub>2</sub>/(Z<sub>1</sub>+Z<sub>2</sub>) *I<sub>L</sub>
Discussion
5.

If two transformers secondaries are connected to each other with unequal primary voltage ratio then, __________

A. no circulating current will flow
B. very high short circuit current will flow
C. small circulating current will flow
D. insufficient information
Answer» D. insufficient information
Discussion
6.

If the primary voltages at two transformers V1 and V2 are not equal then on load, we ll get ____________

A. V<sub>1</sub>-V<sub>2</sub> at secondary
B. E<sub>1</sub>-E<sub>2</sub> at secondary
C. V<sub>1</sub>+V<sub>2</sub> at secondary
D. E<sub>1</sub>+E<sub>2</sub> at secondary
Answer» C. V<sub>1</sub>+V<sub>2</sub> at secondary
Discussion