Effects of Spin-Up Rate on Internal Resonance in a High- $Tc$ Superconducting Bearing System

This paper investigates the transient behaviors of a rotor passing through resonance in a high- Tc superconducting bearing system. Such a low-damping multidegree-of-freedom system, which is subjected to nonlinear force, can show complex dynamical behaviors, in which energy transfer occurs between modes through nonlinear coupling. Our numerical and experimental results show that, in a system of a high-Tc superconducting bearing, internal resonance can occur even in transient cases where the rotor passes through resonance. The effects of the internal resonance and also the effects of the spin-up rate on the transient dynamics of the rotor have been examined and clarified by changing the period of increasing voltage applied to a direct-current motor for rotating the rotor.