Grades Layout Impact ON Performance Of Mixed Grade Magnetic Cores

Due to an increasing demand for power transformers with lower losses and cost, mixing several grades in the same core could be an innovative answer for both performance and economics points of view. The objective of this paper is to analyze, for a defined proportion of two grain oriented electrical steel (GOES) grades mixed in the same magnetic core, the impact of the layout of these grades. After running experiments on a simplified but realistic step-lap core, the authors demonstrate that some grade layouts lead to a more beneficial impact on core losses than others. An experimental analysis of flux density distribution in packets of the same grade is made in order to understand the core losses tendencies. Especially, considering a core placed horizontally, the authors analyzed the impact of placing a grade in the middle or at the bottom of the stack, allowing to analyze the effect of the weight on the flux density.