Comparative study of the design and development of direct drive brushed and brushless DC motors with samarium cobalt, neodymium-iron-boron and ceramic magnets

Permanent magnet direct drive brushed and brushless DC motors are described. The impact of the characteristics of the magnet materials on the design and performance is discussed. The design and performance characteristics of these motors with 50 mm and 150 mm outside diameters are presented and compared. Some aspects of manufacture and application are given. The conclusion is drawn that, irrespective of applications, at the present time motors with samarium cobalt magnets are preferred without any hesitation