The no load current in a transformer lags behind the applied voltage by an angle of about_____________?

Related Mcqs:

1. In a given transformer for given applied voltage, losses which remain constant irrespective of load changes are______________?

   A. friction and windage losses
   B. copper losses
   C. hysteresis and eddy current losses
   D. none of the above

2. In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are__________?

   A. hysteresis and eddy current losses
   B. friction and windage losses
   C. copper losses
   D. none of the above

3. For given applied voltage, with the increase in frequency of the applied voltage?

   A. eddy current loss will decrease
   B. eddy current loss will increase
   C. eddy current loss will remain unchanged
   D. none of the above

4. The no-load current drawn by transformer is usually what per cent of the full-load current ?

   A. 0.2 to 0.5 per cent
   B. 2 to 5 per cent
   C. 12 to 15 per cent
   D. 20 to 30 per cent

5. In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of_________________?

   A. less than 15 A
   B. more than 15 A
   C. 15 A
   D. none of the above

6. In an actual transformer the iron loss remains practically constant from no load to full load because:____________?

   A. value of transformation ratio remains constant
   B. permeability of transformer core remains constant
   C. core flux remains practically constant
   D. primary voltage remains constant
   C. secondary voltage remains constant

7. 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

8. For a transformer, operating at constant load current, maximum efficiency will occur at______________?

   A. 0.8 leading power factor
   B. 0.8 lagging power factor
   C. zero power factor
   D. unity power factor

9. 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

10. 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