SU935225A1 - A.c. arc welder - Google Patents

Description

(5) DEVICE FOR ARC WELD AC.

I

The invention relates to the welding industry, namely to the power sources of the AC welding arc and can be used in welding with a fusible and non-consumable electrode.

An AC arc welding device is known that includes a welding transformer (and an arc stabilization unit.

A device for alternating current welding is known, which contains a welding transformer with increased magnetic dissipation and an arc stabilization unit, in which the arc stabilization unit is made in the form of a series-connected auxiliary winding of the welding transformer, a thyristor switch with a control circuit and a capacitor, and is connected in parallel to the arc gap tl.

The disadvantage of this device is the complexity of the welding trans (| yrmator) design associated with the need to adjust the welding current, which is achieved by changing the magnetic flux linkage between the primary and secondary windings of the welding transformer.

In addition, a disadvantage of the known device is the need to use a special device for welding in shielding gas with a non-consumable electrode, which provides the initial excitation of the arc without contact of the electrode with the product, since when the arc is excited by a short circuit of the arc gap

15 of the electrode in the weld, which reduces the quality of the welded joint, and is unacceptable for responsible welded joints.

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Claims (1)

The aim of the invention is to improve the quality of the welded joint by improving the stability of the arc excitation and simplifying the device. The goal is achieved by the fact that the device for arc welding with alternating current, containing a welding transformer c. developed magnetic scattering and block, excitation and stabilization of the arc, consisting of thyristors, diodes and capacitors, a pulse transformer is introduced into it, one of the primary windings of the welding transformer is connected to two chains consisting of a series-connected diode, in parallel with which a capacitor is connected , and the thyristor, while the anode of the first thyristor is connected to the connection of the anode, diode and cathode of the thyristor, and the cathode of the second thyristor is connected to the connection of the cathode, diode and anode of the thyristor of the other chain, The anode of the latter is connected to the cathode of the first thyristor and to the second output of the primary winding of the welding transformer in parallel with which a circuit is connected, consisting of a series-connected capacitor and the primary winding of a pulse transformer, I, FIG. 1 shows a circuit diagram of the device; figure 2 - plot of the welding current. The device contains a welded transformer 1, in series with one of the outputs of the primary winding of which two parallel circuits are connected, each of which consists of diodes 2 and 3i of shunt capacitors t and 5. thyristors 6 and 7- To the junction point of the cathode of diode 2 and thyristor 6 one circuit is connected to the cathode of one additional thyristor .8, and to the junction point of the anode of the diode 3 and the cathode of the thyristor 7 in the other circuit is connected the anode of the second additional thyristor 9- The cathode of the additional additional thyristor 9 is connected to the anode of the first additional The main thyristor 8 and the other output of the primary winding of the welding transformer 1. Parallel to the primary winding of the welding transformer 1, a primary is connected to the winding of the pulse transformer 11 through the pass-through capacitor 10. The secondary windings of the welding transformer 1 and the pulse transformer 11 are connected in series with the arc gap. The secondary winding of the welding transformer 1 is shunted by a protective capacitor 12. The control of the thyristors is carried out by the control unit 13 The device operates as follows. At a positive half-wave of the supply voltage, the signal from the control unit 13 opens thyristor 6 and a voltage equal to the sum of the instantaneous value of the supply voltage and the voltage on the precharged capacitor is applied to the primary winding of the welding transformer 1. The voltage from the secondary winding of the welding transformer 1 applied to another gap. At the same time, the sum of the above voltages is applied to the primary winding of the pulse transformer 11 through the pass-through capacitor Yu. A high-voltage pulse from the secondary winding of the pulse transformer 11 is applied to the arc gap through the protective capacitor 12 and causes its breakdown. Lights up arc. When the supply voltage is close to the amnitic one, the signal from the control unit 13 opens the thyristor 9) and a capacitor B is charged. If the supply voltage is negative, the process proceeds in the same way as in the sequence described above. In this case, the thyristors 7 and 8 are unlocked. The welding current is adjusted. By changing the unlocking angle of the thyristors 6 and 7.. An alternating current arc welding device uses a welding transformer with fixed primary and secondary coils, with a low no-load voltage (45 V), which reduces the consumption of active materials for its manufacture. I In addition, due to the effect of an overvoltage equal to the sum of the instantaneous value of the supply voltage and voltage on a precharged capacitor k or 5. applied to the primary windings of the welding and pulse transformers, when unlocking the thyristors 6 or 7 on the secondary winding of the welding the transformer is over-energized. This allows welding on alternating current with both melting and melting electrode in protective gas without an additional special device. The economic effect from using the proposed device is 300 rubles. Claims An alternating current arc welding apparatus comprising a welding transformer with advanced magnetic dissipation and an arc excitation and stabilization unit consisting of thyristors, diodes, and capacitors, in order to improve the quality of the welding line due to improved stabilization initiating the arc and simplifying the device; a pulse transformer is introduced into it; one of the terminals of the primary winding of the welding transformer is connected to two parallel chains consisting of About the connected diode, in parallel to which a capacitor is connected, and a thyristor, the first thyristor anode is connected to the anode, diode and thyristor cathode connections, and the second thyristor cathode is connected to the cathode connection, diode and anode of the thyristor, the anode of the latter is connected to the cathode of the first thyristor and the second output of the primary winding of the welding transformer, in parallel with which a circuit of a series-connected capacitor and the primary winding of a pulse transformer is connected. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 523769, cl. At 23 K 9/00, 18.11.7 (prototype). L-KF 7 H-J