Building Factor Evaluation of the Stator Core Made of Ultrathin Electrical Steel Sheet for the High-Speed Motor

Abstract

We are developing a low-loss stator core for high-speed and small-size motors using an ultrathin electrical steel sheet. This stator core for a high-speed motor was produced using a 0.08mm-thick ultrathin electrical steel sheet. Additionally, in order to evaluate the iron loss of the high-speed motor stator core, we constructed a high-speed building factor evaluation system. This evaluation system is composed of high-speed A/D converters, a D/A converter, and a high-speed power amplifier. TheB-Hcurve and the iron loss of the high-speed motor stator core (0.08mm_Core), which was made of the 0.08mm-thick ultrathin electrical steel sheet, were measured using the outer excitation method and the high-speed building factor evaluation system. The iron loss of the 0.08mm_Core was about 66% of the iron loss of the ordinary-speed motor stator core (the 0.35mm_Core) which was made of a 0.35mm-thick electrical steel sheet. Each iron loss in two kinds of cores was measured using the outer excitation method at the excitation frequency (fex) 1000Hz and the maximum excitation magnetic flux density (Bexmax) 1.0T. From experimental results, the iron loss of the 0.08mm_Core in the high frequency excitation was very small.