Question

Magnitude of flux in an energy meter varies __________

(a) due to abnormal currents and voltages

(b) due to high resistance and inductance values

(c) due to changes in the transformer turns

(d) due to the induced e.m.f in the windings

This question was addressed to me during an interview.

This intriguing question originated from Errors in Single Phase Energy Meters topic in chapter Measurement of Power and Related Parameters of Electrical Measurements

Answer 1

Correct option is (a) due to abnormal currents and voltages

For explanation: In the driving system of an energy meter, magnitude of flux can be incorrect as a result of abnormal values of currents and voltages. This occurs due to a change in the resistance of the pressure coil circuit.