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EEE :: Transformers

  1. What will happen if the transformers working in parallel are not connected with regard to polarity?

  2. A.

     The power factor of the two transformers will be different from the power factor of common load

    B.

     Incorrect polarity will result in dead short circuit

    C.

     The transformers will not share load in proportion to their kVA ratings

    D.

     none of the above


  3. Transformer breaths in when

  4. A.

     load on it increases

    B.

     load on it decreases

    C.

     load remains constant

    D.

     none of the above


  5. Material used for construction of transformer core is usually

  6. A.

     wood

    B.

     copper

    C.

     aluminium

    D.

     silicon steel


  7. Natural oil cooling is used for transformers up to a rating of

  8. A.

     3000 kVA

    B.

     1000 kVA

    C.

     500 kVA

    D.

     250 kVA


  9. The maximum load that a power transformer can carry is limited by its

  10. A.

     temperature rise

    B.

     dielectric strength of oil

    C.

     voltage ratio

    D.

     copper loss


  11. Which of the following is the most likely source of harmonics in a transformer?

  12. A.

     poor insulation

    B.

     Overload

    C.

     loose connections

    D.

     Core saturation


  13. The leakage flux in a transformer depends upon

  14. A.

     load current

    B.

     load current and voltage

    C.

     load current, voltage and frequency

    D.

     load current, voltage, frequency and power factor


  15. The noise produced by a transformer is termed as

  16. A.

     zoom

    B.

     hum

    C.

     ringing

    D.

     buzz


  17. A no-load test is performed on a transformer to determine

  18. A.

     core loss

    B.

     copper loss

    C.

     efficiency

    D.

     magnetising current

    E.

     magnetising current and loss


  19. Which of the following parts of a transformer is visible from outside?

  20. A.

     Bushings

    B.

     Core

    C.

     Primary winding

    D.

     Secondary winding