Evaluation of Loss Generated by Edge Burrs in Electrical Steels

In large motor cores, faults caused by edge burrs between the core laminations can result in short circuit currents which may be large enough to cause burning or complete machine failure. This study simulates the impact of edge burrs on large motor lamination (300mm*300mm) by applying artificial shorts to lamination edges. This twofold study has investigated the impact of short circuit and the impact of short circuit positions on total power loss. Multiple shorts have been applied at different positions. It has been found that the induced eddy-currents are largely dependent on the fault position (edge burrs) and the number of shorted laminations even when only two laminations are involved. This study was further extended to include power loss separation into three components, the power loss separation has been applied to the case of higher power losses obtained under specific short circuit conditions at different magnetizing frequencies. Power loss separation has shown a significant increase in eddy current loss components with increasing number of shorted laminations.