Magnetic properties of reduced Dy NdFeB permanent magnets and their usage in electrical machines

This paper describes the magnetic properties of different permanent magnet materials and their industrial usage as crucial components of permanent magnet electric machines. As the prices of rare earth materials, especially neodymium-iron-boron (NdFeB), has been rising rapidly during the last few years and has been quite unstable during the past decade, the search of new cheaper and yet durable alloys has started. One of the possibilities of cutting the price of NdFeB alloys is the decreasing of the dysprosium (Dy) content of such material. Possibilities of using these new materials in electrical machines as well as potential risks are analyzed in the paper. An overview of the development of low Dy magnets is presented. Necessity of further investigations is pointed out.