Core loss reduction through a laser scribe on Fe-based amorphous ribbon surface for transformer cores

Abstract

Core loss reduction of an Fe-based amorphous ribbon for distribution transformer cores by laser scribe is researched and the efficacy of core loss reduction by laser scribe is compared with that by fish scale-formation during ribbon casting. Core loss reduction by laser scribe is found to be more effective than fish scale and the reduction is prominent in a 53 kg single phase core tested. Core loss reduction is realized through the reduction of anomalous eddy current loss by domain refinement. Although a fish scale ribbon shows refined magnetic domains in static magnetic domain observation, effective magnetic domains are not refined and the reduction of anomalous eddy current loss by fish scale is small. Core building factor, the ratio of core loss of a transformer core to that of a strip ribbon, is found to be increased due to higher anomalous eddy current loss in a 53 kg single phase core tested. Building factor is reduced from about 2 to 1.5 by reducing anomalous eddy current loss by laser scribe.