The power supply unit for resistance welding is particularly important for the quality of resistance welding, which can output high current and low voltage. Output welding machine current is usually 1-100KA, no-load voltage of fixed welding machine is usually 12V mobile welding machine 24V internal. The power supply unit is also known as the power circuit.
Usually consists of resistance welding transformer, power regulator series changer, main power switch, welding circuit, but in the capacitor discharge welder, DC shock wave welder and three-phase low frequency welder main circuit, also includes primary rectifier and polarity changeover switch, inverter welder, primary rectifier, inverter and secondary rectifier components, secondary rectifier welder also includes secondary rectifier components, etc.
Power and can be easily carried out to adjust the selection of large capacity, low leakage resistance resistance resistance transformer to do welding power. For example, on the flash butt welding machine for oil pipelines, the capacity can reach 6000KVA and the output welding current can reach 1000KA. Meanwhile, in order to meet the process requirements, the welding power is usually adjusted by changing the number of turns of the primary winding coil of the resistance welding transformer, and the phase shift controller in the control equipment is used to uniformly adjust the welding power under a certain number of stages.
The main power source (solder resist transformer) generally has no no-load applications and a low load continuity rate. According to the executive standard, the frontal load continuity rate of the resistance welding transformer is 50%, which is the design basis. However, from the efficiency characteristics of welding production, point, convex, see 20 times, seam welding machine more than 50-100 times.