The power transformer is a constant______________?

Related Mcqs:

1. Which of the following is the main advantage of an auto-transformer over a two winding transformer?

   A. Hysteresis losses are reduced
   B. Saving in winding material
   C. Copper losses are negligible
   D. Eddy losses are totally eliminated

2. The changes in volume of transformer cooling oil due to variation of atmospheric temperature during day and night is taken care of by which part of transformer?

   A. Conservator
   B. Breather
   C. Bushings
   D. Buchholz relay

3. Efficiency of a power transformer is of the order of________________?

   A. 100 per cent
   B. 98 per cent
   C. 50 per cent
   D. 25 per cent

4. A common method of cooling a power transformer is_______________?

   A. natural air cooling
   B. air blast cooling
   C. oil cooling
   D. any of the above

5. The maximum load that a power transformer can carry is limited by its________________?

   A. temperature rise
   B. dielectric strength of oil
   C. voltage ratio
   D. copper loss

6. In a power or distribution transformer about 10 per cent end turns are heavily insulated__________?

   A. to withstand the high voltage drop due to line surge produced by the shunting capacitance of the end turns
   B. to absorb the line surge voltage and save the winding of transformer from damage
   C. to reflect the line surge and save the winding of a transformer from damage
   D. none of the above

7. The purpose of providing an iron core in a transformer is to_____________?

   A. provide support to windings
   B. reduce hysteresis loss
   C. decrease the reluctance of the magnetic path
   D. reduce eddy current losses

8. No-load current of a transformer has_____________?

   A. has high magnitude and low power factor
   B. has high magnitude and high power factor
   C. has small magnitude and high power factor
   D. has small magnitude and low power factor

9. The voltage transformation ratio of a transformer is equal to the ratio of_______________?

   A. primary turns to secondary turns
   B. secondary current to primary current
   C. secondary induced e.m.f. to primary induced e.m.f
   D. secondary terminal voltage to primary applied voltage

10. Reduction in core losses and increase in permeability are obtained with transformer employing__________?

    A. core built-up of laminations of cold rolled grain oriented steel
    B. core built-up of laminations of hot rolled sheet
    C. either of the above
    D. none of the above