Triple Epstein Frame First-Level Weighted Processing Method for Determining the Effective Path Length of the Epstein Frame

Abstract

Based on double Epstein frame measurement method, double Epstein frame measurement experiments are carried out for 30P120 silicon steel samples using two pairs of Epstein frames (namely 2E (25-20) and 2E (20-17.5)) magnetic measuring devices, to study factors affecting the mean path length of the Epstein frame. 3D simulation proves the preconditions of double Epstein frame method, that is equivalent magnetic flux density of corresponding corner positions. On this basis, a weighted processing method is proposed to determine the effective path length of standard 25cm Epstein frame and to compare with that of double Epstein frame method, which processes the mean path length determined by the different specific losses of the Epstein frame (i.e., the uniform areas, the corner areas and the impact zones between them of the whole Epstein frame). Not only the method excludes the effect of the magnetic characteristics inhomogeneity of samples in the corner double-lapped structure areas, but also considers the influence of the specific power losses in the different parts determining the mean path length. The obtained experimental results confirm the correctness of the method in this paper for determining the specific total loss of electrical steel sheet.

Determination of Specific Losses in the Limbs of an Epstein Frame Using a Three Epstein Frame Methodology Applied to Grain Oriented Electrical Steels

“…The Epstein frame is a standardized magnetic circuit regularly used to qualify the properties of electrical steel grades [ 1 ]. Some works [ 2 , 3 , 4 , 5 , 6 ] are still devoted to identifying the exactness of the method. A weak point is linked to the use of a magnetic path length which has been set to be equal to 0.94 [ 5 ].…”

“…Then, the impacts of the frequency and of the magnetization waveform are studied in [ 4 ]. Wang et al [ 6 ] have used three square shape Epstein frames of difference sizes to calculate the mean path length. Their limb lengths are equal to 17.5 , 20 and 25 respectively.…”