Turbomolecular vacuum pump having virtually zero power magnetic bearing assembly with single axis servo control

摘要

A turbomolecular vacuum pump utilizes a virtually zero power magnetic bearing assembly with a single axis sevo control and has an optimized L/D ratio and an optimized number of pole faces. In such a structure, radial stiffness is low and radial damping is high so that single axis control is possible. A frusto-conical mechanical bearing structure is shown as a fail-safe back- up for the magnetic suspension system taught.