Home / ECE / Power Electronics :: Section 5

ECE :: Power Electronics

  1. Multiphase choppers are used in

  2. A.
    low power circuits
    B.
    high power circuit
    C.
    both low and high power circuits
    D.
    medium power circuits

    View Answer

    Workspace

    Discuss Discuss in Forum


  3. In a single phase converter using a centre tapped transformer and with a highly inductive load, the firing angles is a. Each thyristor conducts for a period

  4. A.
    p
    B.
    a
    C.
    p - a
    D.

    View Answer

    Workspace

    Discuss Discuss in Forum


  5. In a parallel inverter

  6. A.
    each thyristor is turned on twice during each cycle
    B.
    each thyristor is turned on once during each cycle
    C.
    each thyristor is turned on either once or twice in each load cycle
    D.
    each thyristor may be turned on upto four times in each load cycle

    View Answer

    Workspace

    Discuss Discuss in Forum


  7. A step up chopper can give an output voltage

  8. A.
    higher than input voltage
    B.
    lower than input voltage
    C.
    both higher and lower input voltage
    D.
    all of the above

    View Answer

    Workspace

    Discuss Discuss in Forum


  9. The specified maximum junction temperature of thyristors is about

  10. A.
    50°C
    B.
    80°C
    C.
    120°C
    D.
    200°C

    View Answer

    Workspace

    Discuss Discuss in Forum


  11. A bridge type single phase cycloconverter changes the frequency f to f/3. Then one half wave of output contains

  12. A.
    3 full waves of input
    B.
    3 half waves of input
    C.
    6 full waves of input
    D.
    6 half waves of input

    View Answer

    Workspace

    Discuss Discuss in Forum


  13. A half bridge inverter

  14. A.
    needs a 3 wire dc supply
    B.
    may use a two wire or 3 wire dc supply
    C.
    has higher output voltage if fed from 3 wire dc supply
    D.
    has higher efficiency if fed from 3 wire dc supply

    View Answer

    Workspace

    Discuss Discuss in Forum


  15. A 3 phase series inverter has

  16. A.
    12 thyristors
    B.
    6 thyristors
    C.
    3 thyristors
    D.
    3 or 6 thyristors

    View Answer

    Workspace

    Discuss Discuss in Forum


  17. In figure, thyristor Th is in off state. When thyristor is turned on, the peak thyristor current can be

  18. A.
    5 A
    B.
    10 A
    C.
    15 A
    D.
    20 A

    View Answer

    Workspace

    Discuss Discuss in Forum


  19. HVDC systems are preferable for only long distances.

  20. A.
    True
    B.
    False

    View Answer

    Workspace

    Discuss Discuss in Forum