PURPOSE: To enable free selection of a ratio of molten quantities of base metal and wire making a bead shape good by supplying specific voltage for regeneration of an arc, connecting a resistor in parallel to 2 inverted parallel control rectifying elements connected in series to an arc load in a A.C. power supply circuit.
CONSTITUTION: In the A.C. power supply circuit E1 of wire 1, a circuit having 2 inverted parallel control rectifying elements SCR1 and SCR2, to which the resistor R is connected in parallel, is inserted in series. By the coupling coil L in the power supply circuit consisting of the power source E2, the transformer for high frequency TrHP, the capacitors C1 and C2, the spark gap G and the base metal 2, voltage more than 70V necessary at the time of reversing the arc polarity is supplied. The elements SCR1 and SCR2 take partial charge of a reverse and a positive polarity arc respectively. Since there is an independent arc restarting circuit besides the output phase control, respective output can be adjusted at will. Adjusting the latter to less than 50%, selection of molten quantities of the wire 1 and the base metal 2 is possible. Also, since the resistor R is connected to the circuit, no arc breaking happens.
YAMAMOTO SHIYOUICHI
MATSUMOTO KATSUMITSU
