Question

What is the ideal condition with respect to the primary current rating?

(a) ratio of secondary mmf to primary mmf should be high

(b) ratio of secondary mmf to primary mmf should be low

(c) ratio of excitation mmf to primary mmf should be high

(d) ratio of excitation mmf to primary mmf should be low

The question was posed to me by my school principal while I was bunking the class.

Question is from Design Principles topic in division Design of Current Transformers (CT) of Design of Electrical Machines

Answer 1

Right answer is (d) ratio of excitation mmf to primary mmf should be low

To elaborate: The primary current rating depends on exciting mmf and primary mmf. The ratio of the exciting mmf to the primary mmf should be low.