Question

Mumetal has ________

(a) low permeability, high loss

(b) high permeability, medium loss

(c) medium permeability, high loss

(d) high permeability, low loss

The question was posed to me in an internship interview.

My question is based upon Design Features of Current Transformers topic in portion Extension of Instrument Ranges of Electrical Measurements

Answer 1

The correct choice is (c) medium permeability, high loss

To explain I would say: Mumetal is an alloy of nickel, iron and copper. It has a high permeability, low loss and small retentivity. It has a maximum permeability of 90,000 at a flux density of 0.35 W/m^2.