Dividing Repulsion Permanent Magnets for Enhancing Suspension Force Characteristics in a 1-axis Active Control Type Magnetic Levitation Pump

Magnetic levitation pumps can feed liquid cleanly without mechanical contact by magnetically suspending the rotor shaft integrated with the impeller. However, surfaces of the rotor and the stator need to be protected by resin bulkheads, and then the magnetic gap length is larger than generally electrical machine. Therefore, it is difficult to generate large suspension force for 1-axis active control type magnetic levitation pumps that passively stabilize the rotor in the radial direction with repulsive force of permanent magnets (PMs). This paper proposes a new structure of the repulsion PM which can generate high suspension force even wide gap length. Five structures of the repulsion PM are investigated, and the structure that is optimized for a 1-axis active control type is analyzed with 3-dimentional finite element method (3D-FEM).