GB410494A - Improvements in and relating to electric arc welding systems - Google Patents

Abstract

410,494. Arc welding. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Soc. Generale de Constructions Electriques et Mecaniques (Als-Thom) ; 38, Avenue Kleber, Paris.) Nov. 16, 1933, No. 32005. Convention date, Nov. 17, 1932. [Class 39 (iii).] The welding electrode 4 in an arc welding system is fed by a motor 3 which, on closure of a push button 8 is energized through a switch 15 by the difference of the voltage of the exciter 2 of the main generator 1, and the voltage across the arc. A relay 7 energized by closure of the push-button 8 also effects closure of the main welding circuit at 6 and of a holding circuit at 15. When welding current flows in the main circuit, after drawing and striking of the arc, a switch 16 operates and energizes a coil 11 which moves a switch 10 so that the motor 3 is supplied with the arc voltage alone. A short circuit across a controller 13 in the field circuit of the motor 3 is also removed when the switch 10 operates. During starting, the motor 3 is, in effect, energized from the difference of the voltages of the generators 1 and 2 and moves the electrode 4 forward to strike the arc but during drawing of the arc it is energized by the difference of the voltage across the arc and that across the exciter 2. An additional contact 21 on the switch 10 is provided connected to a line 22 for supplying additional motors from across the exciter 2 in an automatic welding system where the work is fed forward. Specification 179,613, [Class 39 (iii)], is referred to.