Method of classifying characteristics of permanent magnet in ring form

摘要

A method for classifying the characteristics of permanent magnets formed as rings with axial magnetisation has application in the manufacture of passive magnetic bearings. The ring (1) is supported on a table (2) at the end of a vertical shaft (3) rotated by a stepping motor (5) in the bearings (4) and is orientation referenced via the inkjet marker (14). A pair of Hall-Effect directional sensors (7) are set at 45 degrees (23) to the plane (22) of the ring (1) and register the positions of any magnetic inhomogeneity and angular error as a result of their differential signals when the ring (1) is rotated to a programme determined by the controller (11) together with the evaluation and display modules (12,13,15).