Novel Passive Electrodynamic Magnetic Bearings

Abstract

Passive electrodynamic magnetic bearings (EDBs), which are categorized as magnetic bearings, are electromagnetic devices that offer contact and lubrication free bearing operation. Research into magnetic bearings stems from the need for high speed reliable operation. Different types of magnetic bearings such as active magnetic bearings (AMB) and passive magnetic bearings (PMB) have been proposed and investigated, despite the increased cost and complexities, associated with active control of AMBs, they are now employed in industrial applications. However, none electrodynamic PMBs are inherently unstable, and they can only be used in tandem with conventional mechanical bearings. On the other hand, EDBs eliminate the complexities and costs associated with control systems, however, the lack of in-depth understanding of their performance and design procedures, relatively lower stiffness and stability issues at lower speeds, have limited their application potential. In the paper, a novel homopolar EDB topology is proposed, and are analyzed using 3D-FEA. The performance in terms of restoring force, stability and eddy current losses are presented and compared. It is shown that the proposed EDB topology exhibits more than double the restoring force density, of the EDB topologies presented in the literature.