GB427931A - Improvements in and relating to methods of feeding arc welding circuits and apparatus therefor - Google Patents

Abstract

427,931. Supply systems for welding- arcs. SOUDURE ELECTRIQUE AUTOGENE, SOC. ANON., 58, Rue des Deux Gares, Brussels. May 24, 1934, Nos. 15555 and 15556. Convention dates, May 24, 1933 and March 5, 1934. [Class 38 (iv)] Systems depending on static transformers.- In a method of feeding an arc welding circuit with alternating current the potential difference has at the beginning of each alternation a peak of voltage which is sufficient for striking the arc, the remainder of the alternation corresponding to the voltage necessary for maintaining the arc. The three lines 1, 2, 3 of a threephase supply are connected to two single-phase transformers 4, 5. The secondaries of these transformers are connected in series with the load 8, 9, and the transformer 5 supplies voltage sufficient for maintaining the arc. The auxiliary transformer 4 has the core of its secondary winding 4b constructed of metal of high magnetic permeability whereby it is rapidly saturated and generates in the secondary winding a voltage of peaked form sufficient for striking the arc. The two voltages have a difference of phase of 120‹ so that the peak voltage is generated at the beginning of an alternation. The welding current is regulated by an arm 25 moving over the contacts 24 of a self-induction coil 23 In Fig. 6, the supply lines are connected to three single phase transformers, two of which are connected in V-formation to form a single transformer 5<1> for maintaining the arc. The voltage of the auxiliary transformer 4 is then either 90‹ or 180‹ different in phase from the voltage of transformer 51 in accordance with the connections of the latter.