Distribution transformers are generally designed for maximum efficiency around________________?

Related Mcqs:

1. Power transformers are generally designed to have maximum efficiency around__________?

   A. no-load
   B. half-load
   C. near full-load
   D. 10% overload

2. Power transformers are designed to have maximum efficiency at___________?

   A. nearly full load
   B. 70% full load
   C. 50% full load
   D. no load

3. Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in____________?

   A. short-circuiting of the secondaries
   B. power factor of one of the transformers is leading while that of the other lagging
   C. transformers having higher copper losses will have negligible core losses
   D. loading of the transformers not in proportion to their kVA ratings

4. The efficiency of two identical transformers under load conditions can be determined by_______________?

   A. short-circuit test
   B. back-to-back test
   C. open circuit test
   D. any of the above

5. Which of the following protection is normally not provided on small distribution transformers ?

   A. Overfluxing protection
   B. Buchholz relay
   C. Overcurrent protection
   D. All of the above

6. N atural air coo ling is generally restricted for transformers up to__________?

   A. 1.5 MVA
   B. 5 MVA
   C. 15 MVA
   D. 50 MVA

7. The maximum efficiency of a distribution transformer is____________?

   A. at no load
   B. at 50% full load
   C. at 80% full load
   D. at full load

8. Sumpner’s test is conducted on transformers to determine_____________?

   A. temperature
   B. stray losses
   C. all-day efficiency
   D. none of the above

9. If the percentage impedances of the two transformers working in parallel are different, then______________________?

   A. transformers will be overheated
   B. power factors of both the transformers will be same
   C. parallel operation will be not possible
   D. parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load

10. Which of the following is not a routine test on transformers ?

    A. Core insulation voltage test
    B. Impedance test
    C. Radio interference test
    D. Polarity test