RU1838059C - Single-phase current welding source - Google Patents

Description

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The invention relates to welding equipment, in particular to devices providing power to the welding arc during welding in shielding gas and manual arc welding, and may find application in the engineering industry.

The purpose of the invention is to improve the quality and overall dimensions of the source, to obtain smooth adjustment of the welding voltage.

The drawing shows a power source.

It contains a step-down transformer 1 with taps along the primary 2 and secondary 3 windings, the primary winding 2 of which is connected to an alternating current source, and the secondary winding 3 is connected to rectifiers assembled in a half-wave circuit with a midpoint on semiconductor valves, one the rectifier connected to the full secondary turns is welding, assembled on valves 4 and 5, connected to the output terminal of the source. A part of the secondary winding of the source W1, connected in series with the rest of the secondary winding W2, is wound and placed separately from the primary 2 and part of the secondary winding W2, wound on one coil and thereby having a rigid external characteristic. On the same part of the secondary winding W2 with a rigid external characteristic, a second rectifier for gates 6, 7 and a voltage multiplier is assembled, consisting of capacitors 8 and 9, connected by one terminal to the secondary winding W2, and the other by charging semiconductor valves 10 and 11, which in turn are connected by their anodes to the midpoint of the welding rectifier. To the connection points of the capacitors 8 and 9 with the semiconductor charging valves 10 and 11, capacitor discharge circuits consisting of the discharge semiconductor valves 12 and are connected. 13, the cathodes of which are connected together with the cathodes of the valves 6 and 7, are connected to the output of the welding rectifier through the inductor 14 and then to the output terminal of the source,

The work of the source is as follows. If the anode of the diode 6 has a negative potential, the capacitor 8 is charged through the diode 10, and the capacitor 9 is discharged in an arc through the diode 13 and the inductor 14. At a positive potential on the anode of the diode 6, the capacitor 8 is discharged through the diode 12 and the inductor 14. Con a negative potential arises at the anode of diode 7, the capacitor 9 is charged through diode 11, and the capacitor 8 is discharged into an arc through diode 12 and inductor 14. At a positive potential at

The anode of diode 7 is charged through an inductor 14 and diode 13 by an arc 9. If the voltage of the welding rectifier assembled on diodes 4 and 5 is higher than the voltage on the anodes of diodes 7 and 6, then the voltage doubler is locked and not working. Conda is the voltage below, then the doubler works. The discharge of the arc voltage doubler during the lowering of the voltage on the welding rectifier makes it possible to recharge the arc, which improves the stability of the welding process.

The secondary winding 3 of the transformer 1 is designed so that the portion of the winding W2 serving to power the voltage multiplier is wound together with the primary winding 2 and has a rigid external characteristic. The second part of the secondary winding W1, (creating a complete secondary

voltage at start sequence 0

0

but with the first part of the secondary winding W2) is wound with a separate coil, and spaced relative to the primary winding. This design allows you to learn the falling external characteristics of the welding rectifier,

Consequently, the power source has a combined characteristic: the voltage multiplier providing arc feed is supplied with a hard rectified voltage, and the welding rectifier is supplied with a voltage having a falling characteristic. Such a source circuit

0 eliminates the need for a welding choke, limiting itself to a small choke 14 in the discharge circuit of the voltage multiplier. A voltage multiplier is connected to the arc through an interrogator 5 selector 14, which limits the discharge current. The limitation of the short circuit current in the welding rectifier due to the external characteristic improves the quality of the welding process and allows reducing the weight and size characteristics of the source.

If thyristors are used as valves 4 and 5, the source operation is similar to that described above, the difference

5 only in that, I regulate the unlock angle of the thyristors. the voltage of the welding rectifier is continuously adjustable.

If thyristors are used as gates 10 and 11, the operation of the circuit is similar to that described with the difference that it is possible to control the start time of the discharge of the capacitors of the voltage multiplier, which improves the stability of arc burning.

The developed source makes it possible to improve the quality of welding and the overall dimensions of the source by eliminating the welding choke, to obtain smooth control of the welding voltage, and to increase the stability of the arc burning.

Claims (3)

1. A power source for welding by a single-phase current, comprising a step-down transformer with soldering in the primary and secondary windings, a primary winding connected to an AC mains, a secondary winding connected to two half-wave rectifiers made on semiconductor valves, the first rectifier The cutter is switched on for the total number of turns of the winding and connected to one output of the source, and the second rectifier is connected to the secondary taps - 10 fifteen twenty 25 windings, as well as a inductor, first capacitor and discharge valve, characterized in that two charge valves, a second capacitor and discharge valve are introduced into it, and a part of the secondary winding between the solders is made with a rigid characteristic, rectifiers are made according to the scheme with a midpoint, and the first capacitor plates are connected to the secondary windings and the anodes of the valves of the second rectifier, the cathodes of which are connected through the corresponding discharge valves to the second plates of the capacitors and through the corresponding charge dnye valves - to an intermediate point rectifiers connected to the second output of the source to the first output of which is connected via a throttle second rectifier. 2. A source according to claim 1, characterized in that the rectifier valves are made on thyristors. 3. A source according to claim 1, characterized in that the discharge valves are made on thyristors.