Low weight rotor, for electrical machines - is a recessed permanent magnet moulded from barium hexa:ferrite, polypropylene and lubricant

摘要

A rotor for an electrical machine is a cylindrical permanent magnet on a shaft and with a number of circumferentially spaced poles. It has internal coaxial recesses and the poles lie on the cylindrical shell at the points of min. distance between those recesses and the shell. The rotor is produced by placing the shaft in a mould, and moulding a permanently magnetic mix. of 90% barium hexaferrite, 6.5% polypropylene, and aluminium stearate round it. Weight of permanent magnet is very low compared with its magnetic properties.