Active control of vibrations in the case of asymmetrical high-speed rotors by using magnetic bearings.

Rotor bearing systems with long, fast running rotors and rotational symmetry broken in the stiffness, damping and moments of inertia are investigated. Since a magnetic bearing is used as an actuator in a control circuit, vibrations of the system can be controlled. A feedback control is designed with emphasis to the dangerous modes of oscillation of the rotor system caused by parametrical excitation. A small number of sensors and a controller with constant gain factors are used in order to obtain a low cost system. For illustration an elastically supported gas centrifuge with 12 degrees of freedom and asymmetrical stiffness and damping properties is considered. (A)