The primary current in a current transformer is 300 A and there are 2 turns in the primary. To circulate 5 A current in the secondary, the number of secondary turns should be _____.
DSSSB - 2023,
Answer: B
The secondary needs 120 turns. In a current transformer the ampere-turns on the two sides are equal, so the primary current times the primary turns equals the secondary current times the secondary turns.
\[ 300 \times 2 = 5 \times N_s \Rightarrow N_s = 120 \]
The values 60, 200 and 400 would give a secondary current of 10 A, 3 A and 1.5 A for the same primary current, and not 5 A. So the second option is correct.
Please log in or register to report this question.