Post Assembly Magnetization Patterns in Rare-Earth Permanent-Magnet Motors

This paper illustrates a method for verifying the full magnetization of a rare-earth permanent-magnet motor when it is magnetized using a post-assembly method. The usual method of manufacturing a rare-earth magnet machine is to premagnetize before assembly, however, the assembly can be cumbersome. It is possible to magnetize after assembly. This is a critical procedure. If the magnetizing current is too low, then incomplete magnetization occurs. If it is too high, then the winding will overheat and be damaged. A simple method can be used to ascertain the correct magnetization current and this is put forward here. The method is verified experimentally