The efficiencies of transformers compared with that of electric motors of the same power are____________?
A. about the same
B. much smaller
C. much higher
D. somewhat smaller
E. none of the above
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
An ideal transformer is one which has_____________?
A. no losses and magnetic leakage
B. interleaved primary and secondary windings
C. a common core for its primary and secondary windings
D. core of stainless steel and winding of pure copper metal
E. none of the above
Two transformers operating in parallel will the load depending upon their____________?
A. leakage reactance
B. per unit impedance
C. efficiencies
D. ratings
Silicon steel used in lamination’s mainly reduces___________?
A. hysteresis loss
B. eddy current losses
C. copper losses
D. all of the above
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
If a transformer is continuously operated the maximum temperature rise will occur in_______________?
A. core
B. windings
C. tank
D. any of the above