Local Iron Loss Distribution in Iron Cores with a Thermographic Camera

Abstract

It is well known that magnetic properties deteriorate and iron losses increase due to strains induced in motor cores made of electrical steel sheets during those manufacturing process. We have developed a thermal measurement system of the iron loss distributions with a thermography camera in order to clarify the deterioration degree of the magnetic properties depending on different processing methods. In this paper, firstly the iron loss distributions in rectangular specimen of the electrical steel sheet cut with different cutting methods are measured with the thermal measurement system and those results are compared. Three cutting methods are used in this investigation; the wire electric discharge cut, laser cut and water jet processing. Also effect of lamination method is investigated by using the samples welded after processed with the wire electric discharge cutting to be a rectangular sheet. It was shown that the variations of the iron loss distributions in width direction were measurable with the presented method and the largest degradation occurred around welding position.