| 摘要 |
PROBLEM TO BE SOLVED: To set the grain size of soft magnetic metal powder in a proper range so that eddy current loss in a dust core becomes sufficiently low.SOLUTION: A single grain size equivalent diameter dof soft magnetic metal powder, which is expressed by the following equation, is set to 210 μm or less to make eddy current loss at a frequency of 3,000 Hz less than 150 W/kg. In the equation, drepresents the single grain size equivalent diameter [m] of the soft magnetic metal powder, drepresents the number average grain size [m] of the soft magnetic metal powder, and &sgr; represents the standard deviation [m] of the grain sizes of the soft magnetic metal powder. |
