Capacitor stabilization of arc-welding transformers

SINCE THE PROCESS of metallic arc welding was discovered, some of this welding has been done with alternating current. The fact that a transformer, with no moving parts and its resultant simplicity, could be used always has made the use of alternating current for welding desirable. When only bare welding electrodes were available, it was necessary to have a welding transformer with the secondary voltage so high as to be dangerous to the operator. Even with this high open-circuit voltage, the arc with the bare electrode was so unstable that it was very difficult to maintain. Consequently, the transformer was never popular as a power source for welding until the bare welding electrodes had been replaced by the modern coated electrode.