2013 年 21 巻 2 号 p. 116-121
Achieving a high efficiency in rotating machines is especially important in terms of saving energy. It is well known that the efficiency of a rotating machine such as the induction motor is not 100%. The manufacturing process of a rotating machine increases iron loss. This problem is called the building factor problem. The cause of this problem is a residual tensile stress and a residual compressive stress in the stator core caused by the manufacturing process. It is well known that the circumferential iron loss distribution of the stator core was changed by a residual tensile and compressive stress in the stator core. In addition, they also influence the axial iron loss distribution. Therefore, it is necessary to know their influences on the axial iron loss distribution. In this paper, iron loss and other magnetic properties of an actual stator core of the complex configuration was evaluated by using a small excitation inner core under the external compressive force. The results indicate that magnetic properties such as iron loss (Wi) of the laminated actual stator core clearly depend on the axial position, the circumferential position and the external stress.
