GB767690A - "improvements relating to electric arc welding systems" - Google Patents

Abstract

767,690. Automatic welding control systems. BRITISH ELECTRICAL & ALLIED INDUSTRIES RESEARCH ASSOCIATION. June 15, 1954 [March 25, 1953], No. 8291/53. Class 38 (4). In a welding system in which the electrode is fed at a nominally constant rate, arc stability being achieved by a supply system with a drooping characteristic, the arc voltage is compared with a reference voltage and deviations are corrected by a slowly acting control to modify the rate of electrode feed. In one embodiment, Fig. 1, the electrode supplied from a compound D.C. generator G is fed forward by a motor DM having a shunt field regulator R adjusted via reduction gearing RG by a motor M having its armature energized by the resultant of the arc voltage and an opposing reference battery P. In a modification, Fig. 2 (not shown), an amplifying exciter supplies the motor M and has its field energized by the arc and reference battery. In a second modification, Fig. 7 (not shown), the electrode drive motor has a centrifugal governor which is adjusted by the motor M. In a third modification, Fig. 8 (not shown), the electrode drive motor has an infinitely variable gear adjusted by the motor M. In a fourth modification, Fig. 9, the electrode drive motor DM drives through a differential gear 7 with a second input from an auxiliary motor AM, the field regulator of which is adjusted by the motor M. In a fifth modification, Fig. 3 (not shown), the motor M is controlled by a polarized relay connected across the arc in series with the opposing reference battery. In a sixth modification, Fig. 4 (not shown), the polarized relay is controlled by a triode controlled by the arc voltage and the reference battery. In a seventh modification, Fig. 5 (not shown), the reference battery of Fig. 4 is replaced by a neon stabilizer. It is stated that the D.C. generator may be replaced by a transformer and rectifier; that an A.C. arc may be similarly controlled by first rectifying the voltage measured across the arc; and that a photo-cell or bolometer responsive to the arc may effect control in an unspecified manner. Specifications 767,688 and 767,689 are referred to.