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

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 are attracting growing attention for high-speed drives. Surface mounted permanent magnet synchronous machines request a glass or carbon fibre bandage to fasten the magnets to the rotor surface at high speed. At rotors with "buried" magnets the rotor iron itself fixes the magnets. The 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 FE-calculations.