GB550384A - Improvements in methods and apparatus for welding by electric discharges - Google Patents

Abstract

550,384. Supply systems for welding arcs. SVENSKA AKTIEBOLAGET GASACCUMULATOR. March 23, 1940, No. 5348. Convention date, March 23, 1939. [Class 38 (iv)] A welded seam is produced by a sequence of unidirectional current discharges between an electrode 36 and the parts 37, 38 to be joined. The arc space may be ionized in any known way, if necessary, and preferably by unidirectional spark discharges in synchronism with the current discharges. A source of direct current 65 may be arranged to give heavy current impulses reinforcing the current discharges from a condenser 25 which is alternatively charged from an A.C. source and discharged into the weld. The switching means used are preferably grid-controlled gas filled discharge tubes 16, 28 which with a like tube 56 are timed by a distributer so that high potential impulses from a transformer 44, energized through the tube 56 from an auxiliary condenser 61, and the discharge of the main condenser 25 through the tube 28 are synchronized and the charging circuit through the tube 16 completed at suitable times also. The reverse voltage from inductances 34, 41 used to choke back the spark potentials may be excluded from the condenser 25 by a shunt path containing a rectifier 73. A full wave circuit is also described. Specifications 257,951, [Class 39 (i)], 295,817, [Class 38 (ii)], 395,748 and 432,250, [Group XXXVII], are referred to.