Authors: Katsuhiko Mori, Ryoji Nakayama, Kinji Kanagawa
Abstract: A high-speed motor and a DC brush-less motor for factory automation (FA) were made
to investigate the applicability of the powder magnetic core to motor application. The performances
of these motors were compared with the similar motors having conventional electromagnetic steel
core. Although the permeability and saturated magnetization of powder magnetic core were less
than those of electromagnetic steel core, the output performances of each core motor were almost
the same. The FA motor with powder magnetic core using three-dimensional magnetic circuit
showed higher torque than the electromagnetic steel core motor with the same volume.
1317
Authors: Kazuo Asaka, Chio Ishihara, Yuuji Enomoto, Motoya Ito
Abstract: Recently, SMC(Soft Magnetic Composite) materials were studied for their applications in
many fields. We have developed a superior SMC for use as motor cores and are studying their
applying effects [1]. It shows almost the same motor output power as laminated Si-steels of 0.35mm
in thickness, although core loss of SMC is about 1.5 times that of the laminations. As shown in the
results, the SMC motor core is sufficient for real use as a motor core. Furthermore, a 3-D shaped
motor core made of SMC can improve approximately 20% of the output compared with the same
size motor made of laminations.
1369
Authors: I. Hernández, J.M. Cañedo, J.C. Olivares-Galván, Pavlos S. Georgilakis
Abstract: This paper presents comparative results of an electromagnetic study performed in two different wound core transformer configurations in order to know the best configuration that reduce excitation current and core losses. The results show that octagonal wound-core (OWC) reduces the excitation current and eddy-current losses with respect conventional-wound core (CWC). The results were obtained applying 2D and 3D FEM simulations, taking into account the non-linear properties of the core. In the last part of this paper, several grades of grain oriented electrical steels and the combination of them are analyzed to find the best mixing percentage to reduce eddy-current losses and excitation current.
477
Authors: Yong Ming Yang, Xing Mou Liu, Xu Duan
Abstract: In this paper, a method for earth potential computation of layered soil structure is discussed. To calculate thermal field of the transformer with dc bias, simulation models using MAXWELL and COMSOL are proposed. Based on the electromagnetic analysis, electric power loss resulted in temperature rise is calculated. Under the case of normal operation of transformer, a research was carried out to compare the abnormal changes of temperature of transformer. It worked out that if there are different DC parts in transformer, the loss will increase with DC bias and the temperature of transformer core will also increase. If it is increasing continuously and no preventive measures are taken soon, the thermal aging of some parts in transformer will speed up and gradually affect the normal operation of transformer. The research lays the groundwork for further research of transformer DC bias and aging.
481