Time‐averaged and instantaneous magnetic loss characteristics of different products of electrical steel for frequencies of 16 2/3 Hz up to 500 Hz

Abstract

Traditionally, products of electrical SiFe steel are focussed on applications for frequencies of 50–Hz. However, the recent developments of electric drive systems yielded a strong extension of the range from f = 16 2/3 Hz up to ca. 500 Hz. In spite of high industrial relevance, the literature offers the corresponding data on the material’s magnetic energy losses in very rare ways. This paper reports a first comparative, multi-parametric study on eight different steel products that comprise non-oriented steels (NO), grain-oriented steels (GO) and scribed grain-oriented steels (SGO). Consistently at IEC-standardized samples, they were analysed for the whole frequency range that was split into low frequency (LF) and medium frequency (MF), with 80 Hz as the border. Data is presented on time-averaged total losses P, on the corresponding hysteresis losses PH and eddy current losses PE. LF proved to be governed by PH and MF rather by PE, however, with strong variations. Further, instantaneous magnetization power functions p(φ) were determined for basic insights into the involved temporal developments of energy dissipation. GO-steels yielded profiles close to rectified co-sinus functions that can be fully attributed to dissipative losses. On the other hand, p(t) of NO-steels and SGO-steels prove to include negative segments that reflect potential energy power, in the course of alignments of atomic moments in instants of high induction. Examples of industrial relevance of the accumulated data are steel production technology, product categorization, failure tracing and energy conversion.