Question

Small torque for energy meter is provided __________

(a) by a supply

(b) by a shading loop

(c) by unshaded loop

(d) by a transformer

I got this question by my school teacher while I was bunking the class.

The origin of the question is Friction and Overload Compensation topic in portion Measurement of Power and Related Parameters of Electrical Measurements

Answer 1

Correct choice is (b) by a shading loop

To explain I would say: Friction can be compensated in an energy meter by making use of a shading loop. It is placed between the central limb of the shunt magnet and a disc. Figure below illustrates the same.