SU1558594A1 - Apparatus for arc welding - Google Patents

Abstract

The invention relates to welding, in particular, to power sources for electric welding by a direct current arc. The purpose of the invention is to reduce weight and size parameters while the device retains the function of welding current smoothing. The device consists of an adjustable frequency converter with a control unit, a rectifier according to a single-phase zero rectifier circuit and a transformer. The transformer contains a two-part network winding and a two-part valve winding. One part of the network and one part of the valve windings are placed on one rod, the other parts of the windings on the other rod. Both parts of the network and both parts of the valve windings are respectively interconnected in series according to each other. The vent winding has a midpoint lead. In the magnetic core of the transformer introduced ferromagnetic element located between the rma with a gap. To increase current smoothing, an additional winding can be introduced, consisting of two counter-connected parts. From the output of the frequency converter, the overvoltage voltage is applied to the primary winding of the transformer. The welding current is controlled by the control unit. 1 hp f-ly, 4 ill.

Description

The invention relates to welding, in particular, to power sources for electric welding by a direct current arc.

The purpose of the invention is to reduce the overall dimensions while the device retains the function of welding current smoothing.

FIG. 1 shows a block diagram of a device for arc welding; in fig. 2 - constructive scheme of the transformer; in fig. 3 - constructive scheme of the transformer with an additional winding; in fig. 4 shows the relationship between the initial-continuous current and the splitting coefficient.

The arc welding device is powered from source 1 and contains an adjustable frequency converter 2, a control unit 3, a transformer 4, a rectifier 5 according to a single-phase zero rectifier circuit. The frequency converter may consist of a rectifier and an inverter. The control unit contains

ate

ЈЈ

00

ate &

Ougo voltage saw, reverse coupler, device comparing generator voltage and reverse

The transformer contains the primary winding consisting of two in series and according to the connected parts 6 and 7, with part 6 placed on the core 8 of the magnetic circuit and part 7 on the rod 9. The valve winding consists of two parts 10 and 11. Part 10 is placed on the rod 8, part 11 - on the rod 9. Parts 10 and 11 are connected in series according to. The valve winding has an average output of 12.

The execution of the rectifier according to the zero scheme predetermines the connection to part 10 of valve 13, to part 11 of valve 14. The cathodes of the valves are interconnected at point 15.

The magnetic circuit contains a ferromagnetic element 16 located between the roms 17 and 18 symmetrically in the window of the magnetic circuit. The element is made, for example, from electrical steel of the magnetic core material. The cross section of the element is chosen so that magnetic saturation does not take place (for example, so that magnetic induction does not exceed 1.7 T). At the same time, it is possible to make a ferromagnetic element between the rmma with or without a gap.

The specified implementation of the ferromagnetic element in combination with the location of the parts of the mains and valve windings on different rods on the rods, provides K „4.

Welding product 19 is connected to pin 12, and electrode 20 to pin 15.

When an additional winding is introduced into the transformer (Fig. 3), it is made of two oppositely connected parts 21 and 22, each of which is placed respectively on rods 8 and 9. At the same time, electrode 20 is connected to terminal 23.

When the device for welding electric power is operated at the frequency of power supply 1, for example, an alternating current network of 50 Hz, it is fed to the input of frequency converter 2. From the output of the latter, the voltage of a significantly increased frequency is applied to

the primary winding, consisting of parts 6 and 7, transformer 4. From the secondary winding, consisting of parts 10 and 11, transformer 4 electric

with

0

five

about

five

A rectifier through a rectifier, including valves 13 and 14, is supplied to the welded product 19 and the electrode 20. The welding current is controlled by the control unit 3. Regulation can be carried out either by changing the frequency of the pulse generator, or by changing the voltage of the feedback link.

In parts 10 and 11 of the secondary winding, currents containing constant and variable components flow during welding. The constant components in parts 10 and 11 cause the constant components of magnetic fluxes, one of which (24) closes along the way: rod 8, left part of the beam 18, ferromagnetic element 16, left part of the wire 17, other component 25 - along the way: rod 9, right part of roma 18, ferromagnetic element 16, right part of roma 17,

When the welding current changes, the magnetic fluxes 24 and 25, which induce electromotive forces in parts 10 and 11 of the valve winding, prevent the welding current from changing, which is equivalent to the introduction of a smoothing throttle into the welding circuit.

As can be seen from the graph (Fig. 4) obtained by an analytical method, the welding current Ij of the initial continuous mode depends on the splitting coefficient Kp between the parts of the valve winding (the initial continuous mode is the boundary between the intermittent and continuous welding current). When K «4, the current of the initial-continuous mode is less than at K. 4, i.e. in the first case, the continuous welding current mode occurs at a lower current. It follows that the smoothing effect of the welding current with Kp 4 is more pronounced, i.e. over the entire range of adjustable welding current.

The additional winding, consisting of parts 21 and 22, amplifies the constant components of the magnetic fluxes 24 and 25. The additional winding smoothes the welding current as a normal wire - sel.

The required splitting coefficient is achieved at the floor-by-floor arrangement of the windings by selecting the section of the ferromagnetic element, its length and position in the window of the magnetic circuit. With

virtually obtained splitting coefficient of 6.6, smoothing properties of the transformer.

,five

Claims (2)

1. A device for arc welding, containing a series-adjustable frequency converter with a control unit, a rectifier for a single-phase zero rectifier circuit and a transformer, the network and valve windings of which consist of two parts, one part of the network 15 and one part of a valve windings on one rod are magnetic conductor; the second parts of the network and valve windings are placed on the other rod; both parts of the network and valve 20 windings, respectively, are interconnected in series with publicly The valve winding has a midpoint output, characterized in that, with a chain of weight and weight indicators, by eliminating the autonomous smoothing Lilter and performing the function of smoothing the welding current of a transformer, the transformer magnetic conductor is provided with a ferromagnetic element located between its romes, the splitting coefficient between More than four parts of the valve winding are selected. 2. The device according to claim 1, characterized in that, in order to enhance the effect of smoothing the welding current, the transformer is provided with an additional winding consisting of two counter-connected parts placed respectively on the first and second rods of the magnetic conductor and connected in series with the electrode.