An improved method for measuring rotational power loss in electrical steels

Abstract An improved method of measuring rotational power loss in electrical steels has been developed. The technique is based on the use of apparatus in which signals from orthogonal B and H coils are processed electronically to derive the rotational power loss in a single sample of electrical steel magnetized under known conditions. The wattmeter operates over a frequency range from 20 to 1000 Hz and can be used to quickly measure rotational loss in non-oriented or grain-oriented electrical steel to an accuracy better than ±2%, a considerable improvement over existing thermocouple techniques. The paper describes the instrument and its capabilities before presenting a series of rotational loss measurements obtained on a series of nonoriented electrical steels.