FEM-3D FOR METROLOGICALLY IMPROVED MAGNETIC MEASUREMENTS
Marija Cundeva-Blajer – Ljupco Arsov
The Epstein frame as an electrical steel sheet testing apparatus forms an unloaded transformer with a magnetic core of the electrical steel sheet test specimen. It is an electromagnetic system, with non-linearity introduced by the magnetic material under test. For exact metrological estimation of the magnetic characteristics of the electrical steel sheet, the magnetic field distribution has to be well known. The finite element method in three-dimensional domain, embedded in the original program package FEM-3D is used for exact calculation of the effective magnetic path length for three grades of reference test specimen under different magnetic polarizations. The leakage fluxes in the air are also numerically calculated. The FEM-3D results are used for exact design of the air flux compensation coil of the Epstein frame. The numerically derived results are experimentally verified through testing of the developed
prototype of new metrologically improved Epstein frame in a laboratory.
Keywords: finite element method, Epstein frame, magnetic measurements