RU1834761C - Power source for electric welding - Google Patents

Abstract

The invention relates to DC power supplies for electric arc welding. SUMMARY OF THE INVENTION: the source comprises a single-phase welding rectifier of a lightweight construction - without smoothing the choke from the welding circuit. This is achieved by introducing a make-up current into the main welding circuit, which ensures that the arc burns when the main welding current reaches zero, while the recharge is provided from the additional winding located on the shunt, which is connected to the rectifier via a phase-shifting capacitor. 2 ill.

Description

The invention relates to DC power supplies for electric arc welding with piece electrodes or a non-clad electrode in an inert gas environment.

The purpose of the invention is to reduce the mass and dimensions of a single-phase rectifier by eliminating the dips in the welding current to zero without the use of smoothing throttle. As the supply transformer in the proposed rectifier, a known transformer is used, in which the primary and secondary windings are spaced on the terminals of the main magnetic wire, between them in the magnetic core is a magnetic shunt, separated from the magnetic core by non-magnetic gaps, a reactive winding is wound on the magnetic shunt, connected in series with the secondary windings of the transformer according to or counter to thereby increase or decrease the welding current accordingly.

Figure 1 shows a diagram of the proposed rectifier; figure 2 - waveform currents.

The rectifier consists of a transformer, on the main magnetic circuit 1 of which the primary windings 2 and secondary windings are mounted 3. Between the primary and secondary windings, a shunt 4 magnetic circuit is inserted into the main magnetic circuit, on which a reactive winding 5 with solderings is installed to provide current and additional low-current winding 6. Secondary winding 3 is connected in series with reactive 5 and connected to two AC terminals of a three-phase rectifier bridge formed by two groups of diodes 7 and 8, with

With

with

N 4

ABOUT

S

in this, each group of diodes is connected in series with the anode-cathode. The plus of the bridge is connected to the welding electrode 10, and the minus to the item being welded 9 (when welding at the opposite polarity).

The low-current winding 6 is connected to a third AC terminal of a three-phase bridge formed by diodes 12 connected in series through a series-connected capacitor 11; the other terminal of this winding is connected to the secondary terminal of a non-reactive one.

The three-phase bridge in this case serves as a synthesis of two parallel-connected single-phase bridges, moreover, one group of diodes, in this case 8, is common.

Diodes 7 and 8 are power and transmit full welding current, diodes 12 are low current, which, together with diodes 8, transmit a recharge current limited by the reactance of capacitor 11.

The rectifier works as follows:

when voltage is applied to the primary winding in the main magnetic circuit, the main flux is induced, which almost completely penetrates the secondary winding, since there is a non-magnetic gap between the main magnetic circuit and the shunt magnetic circuit and almost no branching magnetic flux into it. When the electrode 10 is shorted to the product 9, due to the reaction of the secondary winding, the flux of the main magnetic circuit is displaced into the magnetic circuit of the shunt, the adhesion of the main flux to the secondary winding weakens and the induced EMF decreases. Thus, a steeply dropping current-voltage characteristic is created, which is most favorable for arc welding with piece electrodes.

At the same time, an EMF is induced in the weak-current winding. which causes the flow of a feed current, the value of which is limited by the reactance of the capacitor and the phase of the current, feed 90 electrical degrees ahead of the phase of the main welding current and thereby eliminate dips to zero of the main welding current.

The value of the EMF of the low-current winding

can be selected above the EMF of the secondary winding, which helps to improve the ionization of the arc gap during the welding process, while at idle the EMF in this winding is practically absent, which

favorable in terms of safety.

The manufactured prototype rectified to a current of 60 ... 100 A showed good welding properties in domestic

welding electrodes for direct current.

The economic effect of the present invention is expected due to a decrease in metal consumption due to the absence of

smoothing throttle.

Claims (1)

SUMMARY OF THE INVENTION An arc welding power source comprising a transformer with spaced primary and secondary windings, between which a shunt magnetic circuit is provided having a non-magnetic gap with the main magnetic circuit of the transformer, and a reactive coil spanning shunt, characterized in that, in order to stabilize the burning of the welding arc by eliminating current dips to zero and increasing the degree of ionization of the welding gap, it is equipped with a three-phase rectifier bridge, a switch, a capacitor and an additional winding of the shunt, moreover, the reactive winding is made with solders that are connected to the contacts of the switch, a common terminal which is connected to the first bridge / reactive input terminal, the secondary and auxiliary windings are connected in series, the connection point of the secondary winding to the first terminal of the additional winding connected to the second input terminal of the bridge, and the second output of the additional winding through the capacitor to the third input terminal of the bridge, the output terminals of which are connected to the output terminals of the source. 7 | p§l2 f -about 8 T 8 1L1 p % k Fig: 1