New core structure and manufacturing method for high efficiency of permanent magnet motors

This paper presents a new core structure we call "a joint-lapped core" for a permanent magnet motor. Since the joint-lapped core can be deformed into a suitable form to winding, the wires aligned and a high space factor is achieved (75%). Furthermore, it is clarified that circularity and rigidity of the joint-lapped core are improved to the same grade as a nonseparate core by shrink-fit in a frame. As a result of applying this core to the motor for compressors, efficiency is improved by 2.6 point at the maximum compared with the motor with nonseparate core.