Behavior of a Magnetically Suspended Rotor Dropped Into Auxiliary Bearings

Auxiliary bearings (ABs), as the back-up support when the Active Magnetic Bearing (AMB) system doesn’t work, play an important role on the assurance of AMB system’s safety. According to the structure design of ABs-rotor system on back-up helium circulator of 10MW high temperature gas-cooled reactor (HTR-10) equipped with AMB, this paper presents a simplified finite element model (FEM) in Ansys, applied in the transient response of the dropped rotor. The ABs load characteristics were determined based on Hertz contact theory. Furthermore, a special spring element named Combin40, which is coupled to a gap, was introduced to communicate information of displacement and force between auxiliary bearings which were simplified into nonlinear spring elements and rotor which was simplified into beam elements. Based on the developed FEM, the behavior of vertical and horizontal magnetically suspended rotor dropped into the ABs was analyzed respectively and the safety of the rotor and ABs was evaluated. The results provide an important reference to the ABs design and application in HTR-10 and High Temperature Reactor-Pebblebed Modules (HTR-PM).