Design of an Extremely Efficient, Rare-Earth Free, 5 kW Motor in a NEMA 210 Frame

This paper presents the design of a dual-rotor, conical air gap, axial flux motor with ferrite permanent magnets. This unorthodox topology, which does not use rare earth magnets, enables the design to achieve a much higher efficiency than comparable commercially available NEMA 210 frame motors. Various design aspects, such as winding arrangement and cone angle, are evaluated through 3D finite element analysis, and the selected design has been prototyped and tested. The prototype achieves a peak efficiency above 96.7
^%
and exceeds an efficiency of 96% over a wide range of torques and speeds.