非磁性金属板判別のための空心円形コイルのサイズ検討

抄録

　The purpose of this study is to find a suitable diameter of the coil for discrimination of non-magnetic metal plate. The same values of in inductance are designed for coils having different diameter to generate same magnetic flux at a constant current, and the discrimination of the metal plate was evaluated by the eddy current testing. The target metal is chosen only an aluminum and opposed to coil. Changes in the inductance of the coil were measured using an impedance analyzer with the distance as a parameter. To find a general solution, normalized parameters are introduced using coil diameter, coil distance and side length of the metal plate. As a result, it is preferable to increase the average diameter at the point where the distance between the coil and the metal plate is equal to the rate of the average diameter of the coil. For discrimination of non-magnetic metal plate, coil average diameter is preferably the same as the width of the metal plate.