Theoretical Analysis and Experiments of the Nonlinear Vibration in a Vertical Rigid Rotor supported by the Magnetic Bearing System

(Case Considering the Delay of Control Force)

Abstract

Active magnetic bearings (AMB) have been widely used in various kinds of rotating machinery. However, since the magnetic force is nonlinear, nonlinear phenomena may occur when the rotating speed becomes higher and delay of control force increases. In this paper, the magnetic force is modelled to include the effect of the delay of electric current for control, and the AMB force is represented by a power series function of the electric current for control and shaft displacement. The nonlinear theoretical analysis of vertical rigid rotor-AMB system is demonstrated. The effects of the delay of electric current for control and other AMB parameters on the nonlinear phenomena are clarified theoretically and experimentally.