22V、38V。 The 451 Shanghai Tongtian Electric Welding Machine has two power supply options: 22V and 38V. It can choose 22V single voltage and 38 V three voltages. When the welding machine works, it will produce arc light, and there will also be smoke and dust. Everyone should try to avoid using electric welding machine in rainy days, because it is easy to be electrocuted when using electric welding machine in rainy days, and there will be potential safety hazards.