Welding Generators

Welding power supplies may also use generators or alternators to convert mechanical energy into electrical energy. Modern designs are usually driven by an internal combustion engine but older machines may use an electric motor to drive an alternator or generator.

In this configuration the utility power is converted first into mechanical energy then back into electrical energy to achieve the step-down effect similar to a transformer. Because the output of the generator can be direct current, or even a higher frequency ac current, these older machines can produce DC from AC without any need for rectifiers of any type, or can also be used for implementing formerly-used variations on so-called heliarc (most often now called TIG) welders, where the need for a higher frequency add-on module box is avoided by the alternator simply producing higher frequency ac current directly.

Additional types of welders also exist, besides the types using transformers, motor/generator, and inverters. For example, laser welders also exist, and they require an entirely different type of welding power supply design that does not fall into any of the types of welding power supplies discussed previously. Likewise, spot welders require a different type of welding power supply, typically containing elaborate timing circuits and large capacitor banks that are not commonly found with any other types of welding power supplies.