METHOD FOR MEASURING SHIELDING CAPABILITY OF MAGNETIC ANISOTROPIC STEEL MATERIAL PLATE

摘要

PURPOSE: A method for measuring a shielding capability of a magnetic anisotropic steel plate is provided, which measure the shielding capability of the steel material more accurately at a variable frequency. CONSTITUTION: After preparing a random steel material plate of a regular square having a magnetic anisotropy, a voltage(V-horizontal) over both ends of a secondary coil(103) is measured by inserting the steel plate between a pair of cores(102,104) in a yoke type faced with a constant gap each other where coils(101,103) are wound, and then a voltage(V-vertical) is measured by rotating the steel material plate by 90 deg. When there is no steel plate between the cores, a voltage(Vo) over the secondary coil is measured. Then, a shielding effectiveness of the steel plate is obtained from the above voltage ratio. The shielding effectiveness is expressed as an equation of shielding effectiveness(dB) = - 20log(V/Vo).