Magnetostatic measurement method and sensor for assessing local hysteresis properties in ferromagnetic materials

摘要

Method and sensor for obtaining comparative measurements of hysteresis loss in a ferromagnetic sample. A permanent magnet, polarized normal to the sample surface, is positioned on one side of the surface and is movable along a line of travel between motion limits. A field sensor is mounted in fixed spatial relation on the opposite side of the sample surface at the center of the line of travel. The magnet is moved in forward and reverse directions between the motion limits. The longitudinal magnetic field intensity and the coincidental magnet to field sensor longitudinal distance are sensed at a plurality of distances along the forward and reverse line of travel. For each distance, the difference, D(x), between forward and reverse magnetic fields is calculated and plotted against distance for determining the comparative hysteresis of the sample.