Fixation of buried and surface-mounted magnets in high-speed permanent-magnet synchronous machines

High-speed applications involve technical and economical advantages because, as direct drives, they avoid the gear as an additional mechanical drive component. Permanent-magnet synchronous machines (PMSMs) are attracting growing attention for high-speed drives. Surface-mounted PMSMs request a glass- or carbon-fiber bandage to fasten the magnets to the rotor surface at high speed. At rotors with "buried" magnets, the rotor iron itself fixes the magnets. This paper presents simple calculation strategies and discusses their limits for the mechanical design of high-speed machines with either surface-mounted or buried magnets. The results of the calculations are compared with finite-element calculations