Optimal Arrangement of Current Leads to Minimize Electromagnetic Force

An electric current produces a magnetic field around a current lead, which attracts or repels other current leads. The electromagnetic forces interacting between current leads show different tendencies according to the arrangement of the current leads on the top flange of the cryostat and the distances between them. In the case of high-current electric power devices or high-field magnets, the optimal arrangement of the current leads that can minimize the electromagnetic force acting on them is one of the safety issues to be considered. In this paper, the electromagnetic forces exerted on current leads were examined theoretically. The results were confirmed by measuring the strain variations of the current leads using a strain gauge to determine the influence of the electrical and geometrical parameters. From these results, the optimal arrangement method is discussed with three pairs of current leads particularly for high-current electric power devices or high-field magnet applications.