GB883052A - Improvements relating to rectifier electric welding arrangements - Google Patents

Abstract

883,052. Control systems for arc welding. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. June 19, 1958 [July 17, 1957], No. 22680/57. Class 38 (4). In an electrically driven controller for the voltage and/or current of a rectifier electric welding arrangement, an impedance is varied by a light-weight means which may be operated remotely. The welding plant (Fig. 1, not shown) comprises a three-phase transformer and two sets of star-connected rectifiers. The output to the welding electrodes is controlled by a saturable inductor having a winding through which direct current is passed, the direct current being supplied by a separate rectifier set and varied by a rheostat R5 which is rotated in either direction by a motor under the control of a remote two-way switch. The switch, which is connected to the motor circuit by three leads, may be mounted on the welder's hand shield or electrode holder. The motor and reduction gear Y (Fig. 2) are mounted on a panel 16 having on one side the leads 11, 12, 13 from the switch and on the other a shaft on which is a pulley 19 driven by the motor. An endless belt drives a large pulley 20 from the small pulley 19. A frictional surface on the pulley engages the knob 26 which is coupled to the rheostat R5 via the shaft 17. A coarse adjustment of the output is effected by manually turning the knob 26 with the pulley 20 disengaged by moving it against the compression of the spring 22. Also coupled to the shaft 17 is an arm 23 which cooperates with two limit switches 27 so as to prevent the shaft 17 being turned too far.