The welder assembles the most three part of welding transformer, welding tongs and water cable as one, and the volume is reduced by 75%, weight is reduced by 80% and 72.3% power savings. the welder has bearings turntable hanging device, can be mobile welding in x, y, z arbitrary 3d direction used by the balancer, it is movable and light. it has 14 different types, 400 species welding tongs supply for the choice of different materials, different thickness, different work places and different welding processes. welding transformer without freezing, not hot, suitable for the area of different climate. welder technical parameters not only cover all dn3 series (sub-suspersion) mobile spot welder, and the performance is better than dn3 series welder. the welder can be used matching with robots. the safety performance of the welder is a leading international standards and better performance than national standards it is widely used in the automobile, motorcycle, aviation, quilts, sheet metal structural components, medical equipment, light industrial machinery, household appliances and other fields. And it can welding carbon steel sheet, coated steel sheet, stainless steel sheet, aluminum sheet metal. Wooden cases