SU446162A1 - Apparatus for argon arc and microplasma welding - Google Patents

Description

one

The invention is related to welding production.

A device for argon dutov and microplasma welding is known, containing a power circuit with thyristor isolation, connected to the forward and reverse polarity power supply rectifiers, a thyristor control unit, a power source of the pilot arc connected in parallel with the output strands of rectifiers arc stabilization unit, made in the form of low-power high-frequency sources of increased idle voltage.

However, the known device is inconvenient in that it is not reliable when the arc is excited during the change of polarity of the latter.

The proposed device is distinguished by the fact that the uncoupling thyristors are connected in series to the circuit of the connection of different polarities of the rectifiers of the forward and reverse polarity arc power circuits, the junction point of the thyristors is interconnected

: is connected to the common output terminal of the arc supply, and the switching capacitor is connected parallel to the thyristors. This increases the reliability of the excitation of the arc when changing its polarity. ; With the aim of improving the energy performance and reliability of the power supply, the power supply of the power generators is expediently implemented in the form of a three-phase multiwinding transformer with a bias regulator.

FIG. 1 is a schematic diagram of the proposed device; in fig. 2 - The basic electrical circuit of the electronic switch.

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Claims (2)

The device for argon-arc and microplasma welding consists of a power circuit with T and T, j thyristors, which are connected to the outputs of the rectifiers B and Bij, supplying the direct and reverse polarity arcs. Parallel to the output circuits of detectors B, and 67, low-power high-frequency sources U and a high no-load voltage forming the stabilization unit are connected. For power supply of the pilot arc, the device for argon-arc and microplasma welding is equipped with a high-voltage device. Thyristor control electrodes T, and T are connected to the output of the thyristor control unit BU. For powering rectifiers B., -Bi and high-frequency sources U and On, a three-phase transformer Tr is provided in the device, which has a primary winding W ;, output volts and a bias regulator W with winding. . .,.,. Parallel to the thyristors T and T, a switching capacitor t is connected, with which inductance L, can be inserted in series. The device also contains electrodes E and E 2 and product .11. The ignition of the pilot arc occurs from the rectifier B. When the ionizing column of the arc touches the product, the direct polar arc is energized, which is powered from rectifier Bj through the open thyristor Ti. The open signal to the control electrode of the thyristor T is supplied from the control unit CU. A current flows through the circuit 3. Capacitor C is charged with current 3 to voltage V-j -Vj. A positive potential is applied to the thyristor cathode T, and it opens when the ignition pulse is applied. At the moment of simultaneous opening of T, and the capacitor C is discharged along the circuit -j T2 - b. When de. of a capacitor C on the inductance, a counter EMF arises, which, with its potential equal to, closes both thyristors T and T. The control signal from BV is dual-pulse. When a second ignition pulse is applied to the control electrode of the thyristor T2, the capacitor C is charged through the circuit Jj. Now, when a two-pulse control signal is applied, the thyristor electrode 1-1 6N is opened. The capacitor C is discharged along the circuit) p, on the inductance a counter-coupling capacitor will arise which covers both thyristors. Upon arrival of the second control pulse, an open thyristor T-j flows through the current J of the direct arc and -.e. Thus, at the termination of a single-arc arc, favorable conditions are created for initiating an arc of reverse polarity. Since the number of commutating capacitor C ngp occurs in a circuit not connected to the arc gap, therefore, the switch circuit can be used in argon-arc welding when the reverse arc is excited: the product-electrode. At the same time, no large discharge currents occur, which deteriorate the quality of the weld. The described above process of switching the socket to occur without an additional element - inductance L ,. To improve the reliability of the switch, a small amount of iHOCTb i has been introduced. , carrying out switching; for any parameters of the circuit. A symmetrical transformer Tp is used as the power source for the direct and reverse polarity transformers, which is controlled by the Ts1unta bias. There are no moving parts in the IB design of the transformer, which increases its reliability in comparison with known sources. Claim 1. Arrangement for argon-arc and microplasma welding, containing a power circuit with thyristor isolation, connected to the direct current arc and reverse polarity power supply units, a thyristor control unit, a power supply for the drivers, a switching capacitor , the standby power supply of the pilot arc and the arc stabilization unit connected in parallel to the output circuits of the rectifiers, made in the form of low-power high-frequency sources of increased idling voltage, characterized by the NTO, with the aim of Understanding the reliability of the arc during polarity switching, the thyristors are connected in series to the connection circuit of the polarity outputs of the forward and reverse polarity arc power supply circuits, the connection point of the thyristors is connected to each other to the common output terminal of the arc power supply, and the switching capacitor is connected in parallel to the thyristors . 2. The device according to claim 1, so that, in order to improve energy performance and reliability, the power source of rectifiers is made in the form of a three-phase, multi-transformer, accurate transformer with a bias regulator. w | W, Gr Wr w,