Under the operation of transformer, pneumatic AC pulse spot welding machine utilizes the general mains supply to lower the voltage and increase the electric current. Such kind of low voltage but large current will be transmitted from the electrode to the linked point of two work pieces. On the linkage, due to the resistance of work piece, high temperature will occur so the metal will therefore generate high heat to make the work pieces in the molten condition. Thus, the purpose of welding the two pieces of work pieces is achieved. The power of the pneumatic AC pulse spot welder that we produce is from 3KVA to 600KVA.It can be used to weld 10mm of iron and metals like stainless steel. It is applicable to all kinds of hardware.