摘要 |
O F T H E D I S C L O S U R E An a.c. operated arc welding apparatus comprises a controlled frequency converter which substantially increases the frequency of the alternating current and the output of which is connected to the welding electrodes via a transformer and a rectifier. The connection between the rectifier and the welding electrodes includes a shunt capacitance having an imperience low enough to attenuate the alternating current components of the welding current to a level acceptable from the acoustic aspect, the said connection of further comprising means for preventing the capacitor from adversely affecting the rectifier and frequency converter and also comprising a cho?e arranged between the capacitor and the electrodes to prevent the capacitor from adversely effecting the welding properties. |