In case priori welded spots exist on workpiece near a welding point in progress, they become the paths of welding current leakage. The leakage in tum causes the decrease in welding current, thus resulting in the deterioration of weld quality. Up to now, the method suitable for measuring the shunt current has not been developed yet. In this study, a method of measuring shunt current is presented as a prestep to compensate for the deterioration of weld quality due to the shunt effect. To measure this, two coils are set up symmetrically around the upper electrode. Since it is difficult to measure the shunt current directly, the shunt current is obtained by integrating the difference of induced voltages obtained from the two coils. To evaluate the performance of the proposed measuring method, a series of experiments are conducted by varing the number of coil tums, the distance between two coils, the coil diameter and the shunt distance. The experimental results are discussed in detail.
