Question

Turns ration for a C.T. is _________

(a) n = ^Np ⁄ Ns

(b) n = ^Ns ⁄ Np

(c) n = ^1 ⁄ Np

(d) n = Ns

The question was asked during an interview.

My doubt stems from Instrument Transformers in chapter Extension of Instrument Ranges of Electrical Measurements

Answer 1

Right option is (a) n = ^Np ⁄ Ns

To explain I would say: The turns ratio for a P.T. is defined as the ratio of the number of turns in the primary to the number of turns in the secondary. It is given by the relation

n = ^Np⁄Ns.