A new current measurement method in resistance spot welding

A method of measuring the high current in resistance welding processes is investigated. A measuring unit is developed by using a strain gage attached on the outer surface of a steel ring. The steel ring is placed around a section of the secondary loop of the welding machine and is deformed by electromagnetic forces induced by the high welding current. The circumferential constituent of the ring deformation is then used to obtain a signal voltage proportional to the secondary welding current. The strain gage signal of ring deformation is enough to determine the welding current in resistance spot welding, especially when direct current is used for the welding.<
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