Optimization of a single strip tester to measure magnetic properties of electrical sheet steel at medium frequencies

摘要

A reliable simulation and design of inductive components requires knowledge of the core material's magnetic properties. Usually no such data is available for medium frequencies, thus magnetic properties have to be measured. IEC 60404-10 suggests to measure magnetic properties in a frequency range between 400 Hz and 10 kHz by means of an Epstein frame, which however requires high apparent power [1]. Furthermore the mean magnetic path length has to be known to measure the magnetic field strength. Standards such as IEC 60404-10 state a constant length of 940 mm which in reality depends on multiple factors, including frequency and peak flux density. Therefore errors will inevitably be made [2,3]. Singe sheet testers, which are not as popular as Epstein frames, however have some advantages over the Epstein frame [1,2,4,5]. To decrease the apparent power demand when measuring Epstein frame sized samples as well as to reduce systematical errors, an optimized single sheet tester, also called single strip tester or SStT, has been developed for medium frequencies and high flux densities.