Transformers(Engineering > Electrical Engineering ) Questions and Answers

Question 1. The efficiencies of transformers compared with that of electric motors of the same power are
  1.    about the same
  2.    much smaller
  3.    much higher
  4.    somewhat smaller
Explanation:-
Answer: Option C. -> much higher
Question 2. The noise resulting from vibrations of laminations set by magnetic forces, is termed as
  1.    Magnetostriction
  2.    Boo
  3.    Hum
  4.    Zoom
Explanation:-
Answer: Option C. -> Hum
Question 3. The power transformer is a constant
  1.    voltage device
  2.    current device
  3.    power device
  4.    main flux device
Explanation:-
Answer: Option D. -> main flux device
Question 4. Sumpner's test is conducted on transformers to determine
  1.    temperature
  2.    stray losses
  3.    all-day efficiency
  4.    none of the above
Explanation:-
Answer: Option A. -> temperature
Question 5. For the parallel operation of single phase transformers it is necessary that they should have
  1.    same efficiency
  2.    same polarity
  3.    same kVA rating
  4.    same number of turns on the secondary side.
Explanation:-
Answer: Option B. -> same polarity
Question 6. In a transformer routine efficiency depends upon
  1.    supply frequency
  2.    load current
  3.    power factor of load
  4.    both (B) and (C)
Explanation:-
Answer: Option D. -> both (B) and (C)
Question 7. No-load on a transformer is carried out to determine
  1.    copper loss
  2.    magnetising current
  3.    magnetising current and loss
  4.    efficiency of the transformer
Explanation:-
Answer: Option C. -> magnetising current and loss
Question 8. The dielectric strength of transformer oil is expected to be
  1.    lkV
  2.    33 kV
  3.    100 kV
  4.    330 kV
Explanation:-
Answer: Option B. -> 33 kV
Question 9. A transformer oil must be free from
  1.    sludge
  2.    odour
  3.    gases
  4.    moisture
Explanation:-
Answer: Option D. -> moisture
Question 10. Losses which occur in rotating electric machines and do not occur in trans formers are
  1.    friction and windage losses
  2.    magnetic losses
  3.    hysteresis and eddy current losses
  4.    copper losses
Explanation:-
Answer: Option A. -> friction and windage losses
© Lakshya_Education.com, All Right Reserved.
Contact Us services