Induction and permanent-magnet synchronous machines for high-speed applications

Solid-rotor induction motors are mechanically very robust and therefore potential candidates for highspeed electric drives. Permanent magnet machines offer better electromagnetic characteristics. These two types of machine are compared for high-speed applications. Electromagnetic, thermal and mechanical aspects are discussed. The permanent magnet machines are considered to be the best solution for applications in which the surface speed of the rotor remains below 250 m/s. For very large speeds and powers, a solid-rotor induction motor is preferred