Apparatus for regulating welding current

Claim 1

FOR USE WITH AN ARC WELDER WHICH WELDS SEAMS IN A WORKPIECE DRAWN BY A DRAW-OFF DEVICE PAST A WELDING ELECTRODE MEANS, APPARATUS FOR SUPPLYING WELDING CURRENT TO THE WELDING ELECTRODE MEANS IN ACCORDANCE WITH THE VELOCITY OF DRAW-OFF OF THE WORKPIECE COMPRISING: A.C. REACTOR COIL MEANS INCLUDING AN INPUT WINDING MEANS ADAPTED TO RECEIVE THE ALTERNATING CURRENT, OUPUT WINDING MEANS FOR DELIVERING WELDING CURRENT TO THE WELDING ELECTRODE MEANS AND D.C. CONTROL WINDING MEANS FOR RECEIVING A DIRECT CURRENT WHOSE AMPLITUDE CONTROLS THE AMPLITUDE OF THE WELDING CURRENT DELIVERED BY SAID OUTPUT WINDING MEANS; A SOURCE OF DIRECT CURRENT WHOSE AMPITUDE IS A FUNCTION OF THE VELOCITY OF DRAW-OFF COMPRISING A TACH-GENERATOR MECHANICALLY DRIVEN BY SAID DRAW-OFF DEVICE AND INCLUDING AN EXCITER CIRCUIT AND AN ARMATURE CIRCUIT; MEANS INCLUDING FIRST RESISTOR MEANS FOR CONNECTING SAID ARMATURE CIRCUIT TO SAID D.C. WINDING MEANS; AND MEANS INCLUDING SECOND RESISTOR MEANS FOR ELECTRICALLY ENERGIZING SAID EXCITER CIRCUIT FOR LINERARIZING THE WELDING CURRENT VERSUS DRAW-OFF VELOCITY CHARACTERISTIC CURVE AND FOR PERMITTING THE ADJUSTMENT OF THE BASE AND THE SLOPE OF THE SAID CURVE.