SU589099A1 - Apparatus for a.c. arc welding with stabilized arc - Google Patents

Description

The device is intended for welding on alternating current with melting electrodes and can be used for welding aluminum and its alloys with a tungsten electrode.

A device for stabilizing an AC arc in argon-arc welding of aluminum with a non-consumable electrode 1 is known.

This device stabilizes the arc at the beginning of one — from the half-periods of the arc at that time, as many types of welding require stabilization and arc — at the beginning of each half-period of the arc; the charge of the switching capacitance in the known device does not depend on the state arc gap, while due to various reasons the conductivity of the arc gap may decrease, which requires an automatic increase in the voltage of the stabilizing pulse in order to maintain a burning arc.

In the proposed device for arc

AC welding with arc stabilization, containing a welding transformer, circuit. of in series of inductance, capacitance and triac with a triac control unit, the triac control unit is made of a rectifying bridge and a pulse transformer, the primary winding of which is connected through parallel connected resistance and capacitance parallel to the arc gap and the secondary winding of the welding transformer; connected inductance, capacitance and triac is connected between the arc gap and one of the phases of the power supply, the network in the antiphase sensation to the primary winding of the welding transformer.

FIG. 1 shows an AC arc welding device with arc stabilization, in which the primary winding of a welding transformer is connected to two phases of a three-phase supply network, an embodiment; in fig. 2 - a device for arc welding with alternating current with arc stabilization, in which the primary winding of the welding transformer is connected to one of the phases and the neutral wire of the three-phase supply network, an embodiment.

A device for arc welding with alternating current with arc stabilization contains a welding transformer 1, an arc gap 2 between the welding head 3 and the product 4. A circuit consisting of a series-connected reactor 5, a capacitor 6 and a triac 7, a pulse transformer 8, the primary winding of which connected in parallel to arc gap 2 through circuit 9-10 and bridge rectifier 11.

The proposed device works as follows.

When the arc voltage passes through zero, the triac control circuit, consisting of a pulse transformer 8 and circuit 9-10, produces a pulse opening triac 7, and the capacitor 6 pulses through a circuit including phase A, reactor 5, arc gap 2 and zero three-phase network. The charging voltage of the capacitor 6 depends on the magnitude of the phase shift between the voltage on the arc and the voltage of the phase from which the stabilizing circuit is fed to the reactor 5, the capacitor 6 and the triac 7. The highest voltage of the charging capacitor 6 can be obtained by feeding the primary the winding of the welding transformer is from two phases B and C (see fig. 1) or from one phase B (see fig. 2), and the capacitor 6 can be charged from any free phase. After charging the capacitor 6, the triac 7 closes. At the beginning of the next half-period of the arc voltage, a new impulse comes to open the triac 7 and the capacitor 6 is pulsed to recharge along the same circuit, but in the opposite direction. The capacitor recharging voltage in the steady state depends on the quality factor of circuit 5-6, the magnitude of the phase shift between the phase voltage and the voltage across the arc, and may significantly exceed the network voltage. Recharge current pulses and are stabilizing pulses. The capacitor 6 is charged and recharged at a time when the voltage across the arc passes through zero and due to this, the arc is stabilized. The arc is stabilized by this device in both half periods.

AC, and therefore this device for welding with alternating current with arc stabilization and can be widely used for various types of welding, including

for argon-arc welding with alternating current with a non-consumable electrode, for welding ferrous metals with a melting electrode in a CO 2 environment, manual welding with alternating current with melting electrodes of the UONII type, etc.

Claims (1)

1. USSR author's certificate number 138294 cells. At 23 K 9/06, 1960. 5 6 -Tw Ln