A. Unity
B. 0.75
C. 0.5
D. 0.2
Answer: D. 0.2
Explanation:
Under no load condition current drawn by transformer can be decomposed into two parts:
Magnetizing component of current (current which produces Flux in the transformer) (wattless current).
Current which takes into account of core or iron losses (eddy +Hysterisis loss) (watt full current)
Under No load condition:
Magnetizing component of current is 4 to 6% of full load current &
Current which takes into account of core or iron loss is 1 to 2% of full load current.
Therefore Magnetizing current is much greater than wattfull current hence at no load condition transformer had very low power factor of around 0.2 lag.