Development of active magnetic bearings for high speed rotors

A magnetically fully levitated rotor system has been designed and built. It consists of stator and rotor bearings for the rotating shaft, an electronic control system, an optical sensing system, and power amplifiers. For an application in which the rotor spins at high speeds in a vacuum, its position is controlled by infrared light sensors. The system has been shown to spin at frequencies of up to 140 Hz, and an extension of the rotational frequency to 1000 Hz is envisaged. The rotor vibrations have been shown to occur at theoretically predicted frequencies. The amplitudes of radial vibrations were kept below +or-22 mu m and mainly occurred at around +or-10 mu m. >