Question

For a P.T. the transformation ratio is given by which of the following relation?

(a) R = \(\frac{V_s}{V_p}\)

(b) R = \(\frac{1}{V_s}\)

(c) R = \(\frac{V_p}{V_s}\)

(d) R = Vp

This question was posed to me by my college professor while I was bunking the class.

This key question is from Ratios of Instrument Transformers topic in division Extension of Instrument Ranges of Electrical Measurements

Answer 1

Correct choice is (c) R = \(\frac{V_p}{V_s}\)

The explanation is: In a potential transformer, the transformation ratio is given by the ratio of the magnitude of the actual primary current to the magnitude of the actual secondary current.

R = \(\frac{V_p}{V_s}\)

where, R is the transformation ratio

       Vp is the actual primary winding voltage

       Vs is the actual secondary winding voltage.