Trial manufacture of measuring instrument of the electromagnetic braking force by eddy current

渦電流による電磁制動力を測定している．金属板に磁極を近づけるあるいは金属板から遠ざけた時，両者には力が作用する．磁石の移動速度と力の関係を調べるためにミシンを改造した実験器を試作している．測定した結果，磁石の移動速度に対して発生する力が比例することを明らかにしている．誘導される電流が磁石の移動速度に密接に関係していることを再確認している．The measuring instrument of the electromagnetic braking force by eddy current is produced experimentally. The force occurs both when a magnetic pole is close to a metal plate and when, it was kept away. Experiment vessel which remodeled the sewing machine in order to examine the relationship between magnetic mobile speed and force, is produced experimentally. The experimental results show that there is the force which arises is proportional to the speed of the mobile magnet. They also confirmed that the induced current is closely related to the speed of the mobile magnetic pole.