Filtering circuit

Claim 1

A POWER SUPPLY FOR USE IN SHORTED ARC TRANSFER WELDING WHEREIN A CONSUMABLE ELECTRODE IS SHORTED PERIODICALLY TO CAUSE HEATING AND MELTING THEREOF WITH THE MOLTEN ELECTRODE METAL SPRAYED ONTO THE WORK WHEN AN ARC BETWEEN THE ELECTRODE AND WORK IS ESTABLISHED, SAID POWER SUPPLY COMPRISING: A SOURCE OF ALTERNATING CURRENT AT SUBSTANTIALLY THE WELDING VOLTAGE; RECTIFIER MEANS FOR CONVERTING SAID ALTERNATING CURRENT TO DIRECT CURRENT; OUTPUT TERMINAL MEANS FOR CONNECTION WITH THE ARTICLE TO BE WELDED AND TO A CONSUMABLE WELDING ELECTRODE; AND FILTER MEANS TO REDUCE THE RIPPLE IN THE OUTPUT WAVE FORM, TO PROTECT THE RECTIFIER MEANS FROM THE PEAK CURRENTS RESULTING WHEN THE ELECTRODE IS SHORTED AGAINST THE WORKPIECE, AND TO CONTROL THE RATE OF CURRENT RISE THROUGH THE ELECTRODE, SAID FILTER INTERCONNECTING SAID OUTPUT TERMINALS WITH SAID RECTIFIER MEANS AND INCLUDING: A FIRST AND SECOND IRON CORE INDUCTOR CONNECTED IN SERIES BETWEEN SAID RECTIFIER MEANS AND ONE OF SAID OUTPUT TERMINALS, SAID FIRST INDUCTOR CONNECTED ADJACENT SAID RECTIFIER MEANS AND HAVING AN ADJUSTABLE CONNECTION THEREON; AND A CAPACITOR HAVING ONE SIDE CONNECTED TO THE OTHER OF SAID OUTPUT TERMINALS AND THE OTHER SIDE CONNECTED TO THE ADJUSTABLE CONNECTION ON SAID FIRST INDUCTOR, SAID FILTER MEANS PROVIDING A HIGH OPEN CIRCUIT VOLTAGE TO ASSIST IN THE REESTABLISHMENT OF THE ARC AFTER MELTING THE ELECTRODE TO ASSIST IN METAL TRANSFER AND TO PROVIDE A LOWER, SUBSTANTIALLY CONSTANT VOLTAGE AT THE OUTPUT TERMINALS AS THE CURRENT SUBSEQUENTLY INCREASES WHEN SHORTING IS AGAIN EFFECTED, THE POSITIONING OF SAID ADJUSTABLE CONNECTION DETERMINING THE TIME CONSTANT OF THE FILTER AND BEING SO ADJUSTED THAT THE RATE OF CURRENT RISE OCCURRING WHEN THE ELECTRODE SHORTS AGAINST THE WORKPIECE CAUSES THE RAPID BUT CONTROLLED MELTING OF THE ELECTRODE AND THE REESTABLISHMENT OF AN ARC WITH THE SIMULTANEOUS TRANSFER OF A SPRAY OF METAL FROM THE ELECTRODE TO THE WORKPIECE WITHOUT CAUSING SPLATTER OF THE WELD MATERIAL.