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EEE :: Electrical Machine Design

  1. Commercial available medium size machines have a speed range of ______ .

  2. A.

     200 to 400 r.p.m.

    B.

     600 to 1000 r.p.m.

    C.

     1000 to 1500 r.p.m.

    D.

     2000 to 2500 r.p.m.


  3. The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are

  4. A.

     0.5 to 0.8 Wb/m²

    B.

     0.8 to 1.0 Wb/m²

    C.

     1.1 to 1.35 Wb/m²

    D.

     1.4 to 1.8 Wb/m²


  5. The electrical power to a meggar is provided by

  6. A.

     battery

    B.

     permanent magnet D.C. generator

    C.

     A.C. generator

    D.

     any of the above


  7. In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made

  8. A.

     equal to that of armature mmf

    B.

     less in comparison with the armature mmf

    C.

     large in comparison with the armature mmf

    D.

     none of the above


  9. Various adjustments in an energy meter include

  10. A.

     light load or friction

    B.

     lag and creep

    C.

     overload and voltage compensation

    D.

     temperature compensation

    E.

     all of the above


  11. For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used?

  12. A.

     1.0 to 1.2 A/mm²

    B.

     1.5 to 2.0 A/mm²

    C.

     2.2 to 3.2 A/mm²

    D.

     3.2 to 4.2 A/mm²


  13. The rectifier instrument is not free from

  14. A.

     temperature error

    B.

     wave shape error

    C.

     frequency error

    D.

     all of the above


  15. Instrument transformers are

  16. A.

     potential transformers

    B.

     current transformers

    C.

     both (A) and (B)

    D.

     power transformers


  17. In order to achieve high accuracy, the slide wire of a potentiometer should be

  18. A.

     as long as possible

    B.

     as short as possible

    C.

     neither too small not too large

    D.

     very thick


  19. In D.C. machines the number of slots per pole usually lies

  20. A.

     between 2 to 4

    B.

     between 6 to 8

    C.

     between 9 to 16

    D.

     between 20 to 30