2. The number of stages of the current regulating switch can be selected according to the thickness and material of the weldment. After electrifying, the power indicator light should be on. Adjust the spring compression nut and change its compression degree to get the electrode pressure.
3. After the above adjustment, the cooling water can be connected first, and then the power supply can be connected to prepare for welding. The procedure of welding process: put the weldment between two electrodes, step on the pedal, and the upper electrode contacts the weldment and applies pressure. When the pedal is continuously depressed, the power contact switch is turned on, so the transformer starts to work, and the secondary circuit is electrified to heat the weldment. After welding for a certain period of time, the pedal is released, the electrode rises, the power supply is cut off first, and then it is restored to its original state by the tension of the spring, and the single-point welding process is over.
4. Preparation and assembly of weldments: Before welding, all dirt, oil stain, scale and rust on steel weldments must be removed. For hot rolled steel, it is best to remove the oxide scale at the welding place by pickling, sandblasting or grinding wheel. Although the uncleaned weldment can be spot welded, it seriously reduces the service life of the electrode and reduces the production efficiency and quality of spot welding. For medium and low carbon steel with thin coating, it can be welded directly.