JPH01143768A - Arc welding machine for ac-dc - Google Patents

Abstract

PURPOSE:To facilitate manufacturing and operating the title welding machine by combining a single-phase transformer provided with a center tap at a secondary side, two reactors wound on the same iron core, three thyristors with different combination at the time of AC and DC welding, an ignition phase control circuit therefor and an AC-DC changeover circuit. CONSTITUTION:The center tap is provided at the secondary side of the single- phase transformer 1 and the thyristors 2, 3 and 4, the reactors 5 and 6 wound on the same iron core, the AC-DC changeover circuit 7, the ignition phase control circuit 8 for the thyristors, a torch 9 for welding and base metal 10 are provided. At the time of DC welding, signals from the ignition phase control circuit 8 are supplied to the thyristors 2 and 3 by the AC-DC changeover circuit 7 to operate these and the thyristor 4 is not operated and a single-phase full- wave rectifying circuit is formed. At the time of AC welding, ignition signals are supplied to the thyristors 2 and 4 and the two thyristors with the different rectifying direction of secondary side winding are made in a continued state to supply an AC current. By this method, the AC-DC changeover is made possible by a small-sized switch without changing over a large amount of current by a main circuit and an arc is not generated and safety is kept.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an AC/DC arc welding machine capable of AC welding of aluminum, etc., and DC welding applied to welding of iron, stainless steel, etc. using an arc welding device. It is something.

Conventional technology A circuit diagram of a conventional AC/DC arc welding machine is shown in Fig. 2.

In Fig. 2, 6 and 6 are reactors with windings provided on the same core, 8 is a thyristor phase control circuit, 9 is a welding torch, 10 is a base material, 11 is a single-phase transformer, 12 and 1
3 is a thyristor, 14 and 16 are diodes, and 16 is a large AC/DC changeover switch for switching between AC welding and DC welding.

This type of AC/DC arc welding apparatus switches the welding method by mechanically changing the connection of the main circuit using a large switch.

In order to enable DC welding with the AC/DC arc welding machine shown in FIG. 2, the AC/DC changeover switch 16 is used to switch the main circuit so that the connections of the main circuit are as shown in FIG.

In addition, in order to enable AC welding, the main circuit connection must be
As shown in the figure, the AC/DC selector switch 16 is activated.

Problems to be Solved by the Invention As described above, conventional AC/DC arc welding machines have the following drawbacks because the main circuit on the secondary side of the welding device is switched using a large switch. Ta.

(1) Since a large changeover switch is used, the internal wiring is complicated and manufacturing costs are high.

(Oi) The large changeover switch is designed to be operated manually, so it is difficult to control it remotely.

(Unable to operate the changeover switch during welding 0 Means for solving the problem In the present invention, a center tap is provided on the secondary side in order to solve the drawbacks of conventional AC/DC arc welding machines. a single-phase transformer, two reactors wound on the same core, three thyristors with different combinations of thyristors used during AC welding and DC welding, an ignition phase control circuit for the thyristors, and the An AC/DC switching circuit is provided to select which of the three thyristors is to be activated.

Function: In the AC/DC arc welding machine of the present invention, switching between AC and DC welding can be performed as follows without mechanically changing the connection of the main circuit using a large switch.

In other words, when performing DC welding, two thyristors installed on both sides of the winding of a single-phase transformer must be activated so that the secondary main circuit becomes a center-tapped single-phase full-wave rectifier circuit. When performing AC welding, ensure that the two thyristors with different rectification directions attached to one end of the secondary winding of the single-phase transformer are in a conductive state. . In this manner, the present invention enables switching between AC welding and DC welding by switching the direction of current flow using a thyristor instead of switching the flow of current with a switch.

Embodiment A circuit diagram of an embodiment of the AC/DC arc welding machine of the present invention is shown below.
As shown in the figure. In Figure 1, 1 is a single-phase transformer with a center tap on the secondary winding, 2°3.4 is a thyristor, 6 and 6 are two reactors wound on the same core, and 7 is a single-phase transformer with a center tap on the secondary winding. AC/DC switching circuit, 8 is a thyristor firing phase control circuit, 9
1 is a welding torch, and 10 is a base material.

In the above AC/DC arc welding machine, when performing DC welding, the ignition signal from the ignition phase control circuit 8 is supplied to the thyristors 2 and 3 by the AC/DC switching circuit 7. Therefore, only thyristors 2 and 3 operate, and thyristor 4 does not operate.

When the output of the secondary side of transformer 1 is in the direction of arrow M, current is supplied to the load through thyristor 2, and when it is in the direction of arrow B, current is supplied to the load through thyristor 3, so that current flows to the load. The current becomes direct current.

When performing AC welding, the ignition signal from the ignition phase control circuit 8 is supplied to the thyristor 2 and the thyristor 4. Therefore, when the voltage on the secondary side of the transformer 1 is in the direction of arrow M, current is supplied to the load through thyristor 2, and when it is in the direction of arrow B, current is supplied to the load through thyristor 4. is supplied with alternating current.

Effects of the Invention As described above, the AC/DC arc welding machine of the present invention has the following advantages because it does not require the use of a large switch to switch the main circuit through which a large current flows.

(1) Easy to manufacture. (Because the internal wiring is simple) (Easy to operate. (AC/DC switching is possible with a small switch) (Main) Safe. (Even if AC/DC switching is performed during welding, the large current can be mechanically cut off.) arc is not generated)

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an AC/DC arc welding machine showing an embodiment of the present invention, Fig. 2 is a circuit diagram of a conventional AC/DC arc welding machine, and Fig. 3 is a wiring diagram of the same welding machine during DC welding. , FIG. 4 is a wiring diagram of the same welding machine during AC welding. 1... Single phase transformer, 2, 3.4... Thyristor, 5.6... Reactor, 7...
...AC/DC switching circuit, 8...Ignition phase control circuit,
9...Welding torch, 10...Base material〇Name of agent Patent attorney Toshio Nakao and 1 other person 1st
Figure 3 If' Figure 4 ゝ) 3 Procedural amendment April 22, 1988 Dear Commissioner of the Patent Office 1 1 Display of case 1988 Special FF Wt f530234292 Name of invention AC/DC dual use arc welding machine 3 Amendment Relationship with the case filed by the patentee Patent application Address 1006 Kadoma, Kadoma City, Osaka Prefecture Name
(582) Matsushita Electric Industrial Co., Ltd. Representative Akio Tanii 4 Agent Address: 2, Matsushita Electric Industrial Co., Ltd., 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture, Claims: Secondary side winding of a single-phase transformer A tap is provided in the center of the line, a first thyristor and a first reactor are connected in series to one end of the secondary winding of the transformer, and a second thyristor and a second thyristor having a different rectification direction from the first thyristor are connected in series. The first thyristor and the first reactor are connected in series, and the rectifying direction is set between the winding ends of the first thyristor and the first reactor connected in series. a firing phase control circuit that connects a third thyristor in the same direction as the first thyristor and controls the firing phase of the thyristor; an AC/DC switching circuit that selects whether or not to put the first and third thyristors into operation; the center tap of the transformer and one end of the first and second reactors are connected to the output end of the welding machine; Features: AC/DC arc welding machine. Figure 1

Claims (1)

[Claims] A tap is provided in the center of the secondary winding of the single-phase transformer, a first thyristor and a first reactor are connected in series to one end of the secondary winding of the transformer, and the first thyristor and the first reactor are connected in series. A second thyristor with a different rectification direction and a second reactor magnetically coupled to the first reactor are connected in series, and are connected in parallel to a circuit in which the first thyristor and the first reactor are connected in series. A third thyristor whose rectification direction is the same as that of the first thyristor is connected between the connection point of the second thyristor and the second reactor and the other winding end of the transformer. and a firing phase control circuit for controlling the firing phase of the thyristor, and an alternating current circuit for selecting whether to put the first and second thyristors in the operating state or to put the first and third thyristors in the operating state. 1. An AC/DC arc welding machine, comprising a switching circuit, wherein a central tap of the transformer and one ends of the first and second reactors are connected to an output end of a welding machine.