APPARATUS FOR ELECTRIC WELDING WITH SAFETY VOLTAGE OF IDLE STROKE AND WITH ENHANCED STABILITY OF IGNITION AND BURNING OF WELDING ARC Russian patent published in 2000 - IPC

FIELD: welding equipment, possibly welding by means of open arc or plasma arc of alternating or direct electric current in condition of non-stable mains voltage. SUBSTANCE: input of power switch 1 is connected with automatic switch 2 of mains circuit; its output is connected with input of electric welding converter 3 whose power output is connected with welding electrode 4 and whose signal output is connected with input of relay 5 of electric current of arc. Input of shaper 6 of idle-mode pulses is connected with input of switch 1; regulating input of shaper 6 is connected with setter 7 for setting voltage of idle mode; output of shaper 6 is connected with first input of adder 8 and with input of shaper 9 of welding-mode pulses. Regulating input of shaper 9 is connected with controller 10 of electric current of arc; its logic input is connected with output of relay 5 and its output - with second input of adder 8. Output of adder 8 is connected with control input of power switch 1. Circuits 1,5,6,7,8 and their connections form control unit 11. Power switch 1 acts as switching unit and simultaneously as quick-action regulating unit. Apparatus provides stable limitation of voltage at idle mode for providing safety operation of welding operator; at welding and cutting it provides enhanced stability of ignition and burning of welding arc in condition of slagged surface, at short-period reduction of electric current of arc lower than critical value, at large fluctuations and surges of mains electric current. EFFECT: enhanced reliability and safety degree of electric welding process. 3 cl, 3 dwg