Field and loss measurements in Epstein frame and sheet testers

The magnetic properties of sample sheets have been measured in an Epstein frame by the conventional method, and are compared with the results obtained simultaneously using a small tangential coil between the sheets in the Epstein frame, The loss values measured by the two methods on samples cut from oriented and non-oriented steels in the same Epstein frame do not differ significantly. A measure of the differences in the loss measurements can be defined as the differences in the predicted effective mass by averaging the losses arising in the legs and in the corner of the Epstein sample core. Thus, there is no reason why the measurements in the sheet testers and the Epstein frame should not be in good agreement.