[Show abstract][Hide abstract] ABSTRACT: Dust core is made by compressing insulated magnetic powder. One of the advantages of dust cores is magnetic isotropy, which makes possible 3D magnetic circuit designs. Therefore, it is expected that the size and weight of magnetic parts can be reduced. There is a strong demand to reduce core loss in dust cores so that they can be used in more magnetic parts-for example, in motor cores. This paper reports on an investigation of some methods for reducing core loss in dust cores and presents the magnetic properties of dust cores made from improved powder using these methods. Dust core with 28.6W/kg of iron loss was achieved; this is comparable to some electrical sheets.
[Show abstract][Hide abstract] ABSTRACT: This paper reports efficiency improvement of a doubly salient-pole homopolar machine with powder iron core. Powder iron core is composed of the metal magnetization powder with resin. It has advantages of low cost, isotropic magnetic property for three dimensions, a high flexibility of design, and low eddy-current loss at high frequency. This paper shows characteristics and performance comparisons between test machines composed of powder iron material and laminated silicon steel. Both machines are designed under the same specification except core material to evaluate the difference in materials. Experimental results demonstrate that the maximum efficiency is improved by about 1% at 9,000 r/min. In addition, it is shown that the machine efficiency can be influenced by flux pulsation in the thrust direction, through the three-dimensional (3-D) finite element method (FEM) analysis.