Question

Transformation ratio of an instrument is defined as ____________

(a) ratio of primary to secondary phasor

(b) ratio of secondary to primary phasor

(c) reciprocal of the primary phasor

(d) reciprocal of the secondary phasor

The question was posed to me at a job interview.

My question is taken from Ratios of Instrument Transformers in chapter Extension of Instrument Ranges of Electrical Measurements

Answer 1

Right choice is (a) ratio of primary to secondary phasor

For explanation I would say: For an instrument transformer, the transformation ratio is defined as the ratio of the magnitude of the actual primary phasor to the magnitude of the secondary phasor.