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EEE :: Rectifiers and Converters

  1. In a glass bulb mercury arc rectifier the maximum current rating is restricted to

  2. A.

     2000 A

    B.

     1500 A

    C.

     1000 A

    D.

     500 A


  3. A rotary converter in general construction and design, is more or less like

  4. A.

     a transformer

    B.

     an induction motor

    C.

     an alternator

    D.

     any 'C. machine


  5. The applications of selenium rectifiers are usually limited to potential of

  6. A.

     10 V

    B.

     30 V

    C.

     60 V

    D.

     100 V

    E.

     200 V


  7. The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?

  8. A.

     They are mechanically strong

    B.

     They do not require any voltage for filament heating

    C.

     Both (A) and (B)

    D.

     None of the above


  9. In a mercury arc rectifier characteristic blue luminosity is due to

  10. A.

     colour of mercury

    B.

     ionization

    C.

     high temperature

    D.

     electron streams


  11. Copper oxide rectifier is usually designed not to operate above

  12. A.

     10°C

    B.

     20°C

    C.

     30°C

    D.

     45°C


  13. In mercury arc rectifiers having grid, the arc can be struck between anode and cathode only when the grid attains a certain potential, this potential being known as

  14. A.

     maximum grid voltage

    B.

     critical grid voltage

    C.

     any of the above

    D.

     none of the above


  15. Which of the following are the applications of D.C. system?

  16. A.

     Battery charging work

    B.

     Arc welding

    C.

     Electrolytic and electro-chemical processes

    D.

     Arc lamps for search lights

    E.

     All of the above


  17. Glass rectifiers are usually made into units capable of D.C. output (maximum continuous rating) of

  18. A.

     100 A at 100 V

    B.

     200 A at 200 V

    C.

     300 A at 300 V

    D.

     400 A at 400 V

    E.

     500 A at 500 V


  19. Which of the following AC. motors is usually used in large motor-generator sets?

  20. A.

     Synchronous motor

    B.

     Squirrel cage induction motor

    C.

     Slip ring induction motor

    D.

     Any of the above