Passive Parallel Airgap Serial Flux (PASF) Magnetic Bearings

Specific load capacity - defined as the ratio of maximum sustainable weight to the total self-weight, is one of the most desirable characteristics in magnetic bearing design. Published literature suggests that conventional radial magnetic bearings have a specific load capacity in the order of 40:1. This paper presents a new class of magnetic bearings that can deliver substantially higher than 100:1. The bearing force is achieved through the integration of magnetic shear stress contributions caused when lines of magnetic flux are driven across a number of parallel annular airgaps at an angle to the normal - hence the name “parallel airgap serial flux” or “PASF”. The optimum designs that give the highest specific load capacity have been found via execution of thousands of finite element analyses across the whole design space. The mechanical stability of the PASF configurations has also been investigated.