The Lincoln Electric Company

Kenneth Anthony Golonka

Dale L Bilczo

Wayne Edwin Hoffman

John Arthur Overman

John Ernest Carroll

William Charles Downing

A three phase electric arc welding power supply using SCR rectifiers for output control which has improved output characteristics, fault protection and current and voltage controls. The main power transformer includes two secondaries connected in a double wye with the neutral points supplying power to one of the output terminals a pair of independent inductances are in series, one with each set of secondaries. Increased phaseback of the SCR's may be effected without the use of additional inductance in the output circuit. The fault protection circuit has a time-current trip curve closely approximating the time-current overload curve of the SCR's whereby the minimum size SCR's for a given maximum current output is obtained. The control circuit is fast responding and gives either: constant voltage output; or variable voltage, constant current output with both line voltage compensation and with increase of current when the arc is shorted and the arc voltage drops below a predetermined amount. Improved firing circuits for the main and pilot SCR's are provided.

Electric arc welding power supply

A multi-phase SCR-rectifier controlled arc welding power source having improved operating and internal protection characteristics. The transformer has an improved core and winding design having a built-in internal reactance and a core arrangement which is scrapless and very compact. The output has an adjustable, drooping, volt-ampere curve such that the welding current may be readily preset or adjusted to any desired value. The power source includes an unusually high inductance for a three phase source so as to give a very stable arc with a control circuit having provisions to properly control the conduction angle of the SCR's so as to overcome the disadvantages of such a large choke on starting or short circuiting so as to give optimum welding characteristics. Further the ratio of short circuit current to welding current is controlled and decreases with an increase in the welding current. Protection against damage of the power source is provided in the event of extended short circuit or overload. Compensation for line voltage variation is also provided.

Growing community of inventors

Richmond Heights, OH, United States of America

Kenneth Anthony Golonka