Home / EEE / Transformers :: General Questions 1

EEE :: Transformers

  1. The use of higher flux density in the transformer design

  2. A.

     reduces weight per kVA

    B.

     reduces iron losses

    C.

     reduces copper losses

    D.

     increases part load efficiency


  3. A transformer has a 1:6 turns ratio and a secondary coil load resistance of 470 Ω. The load resistance as seen by the source is

  4. A.

     1.3 Ω

    B.

     7.8 Ω

    C.

     78 Ω

    D.

     13 Ω


  5. In a transformer the tappings are generally provided on

  6. A.

     primary side

    B.

     secondary side

    C.

     low voltage side

    D.

     high voltage side


  7. No-load current in a transformer

  8. A.

     lags behind the voltage by about 75°

    B.

     leads the voltage by about 75°

    C.

     lags behind the voltage by about 15°

    D.

     leads the voltage by about 15°


  9. The purpose of providing iron core in a step-up transformer is

  10. A.

     To provide coupling between primary and secondary

    B.

     To increase the magnitude of mutual flux

    C.

     To decrease the magnitude of magnetizing current

    D.

     To provide all above features


  11. Which of the following is not the standard voltage for power supply in India?

  12. A.

     llkV

    B.

     33kV

    C.

     66 kV

    D.

     122 kV


  13. When the equivalent circuit diagram of doouble squirrelcage induction motor is constructed the two cages can be considered

  14. A.

     in series

    B.

     in parallel

    C.

     in series-parallel

    D.

     in parallel with stator


  15. An ideal transformer has infinite values of primary and secondary inductances. The statement is

  16. A.

     true

    B.

     false


  17. During open circuit test of a transformer

  18. A.

     primary is supplied rated voltage

    B.

     primary is supplied full-load current

    C.

     primary is supplied current at reduced voltage

    D.

     primary is supplied rated kVA


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

  20. A.

     Core insulation voltage test

    B.

     Impedance test

    C.

     Radio interference test

    D.

     Polarity test