DE2333594A1 - Universal welding set for alternating or direct current - suitable for plasma-arc or tungsten-inert gas welding - Google Patents

Abstract

A power-supply unit with transformer and rectifier, plus controls for the current, inert-gas and coolant, has switches used to isolate the D.C. supply and switch in a second, continuously-adjustable, A.C. transformer which is pref. housed in a separate box. The advantage is that a D.C. welding set can be rapidly converted for use with a.C. by means of simple switches and the typa of A.C. transformer readily available in most workshops, so that the inert-gas and coolant controls on the D.C. set can be used in A.C. welding.

Description

MESSER GRIESHEIM GMBH ^{MG 818}

Password: DC and AC plasma welding

Facility
Inventor: Gobes

Device for shielding gas arc welding with direct and alternating current

The present invention relates to a device for gas-shielded arc welding with direct and alternating current, in particular for plasma and / or TIG equilibrium and alternating current welding.

They are devices for shielding gas direct current arc welding known, in which an AC transformer in a power source housing with downstream rectifier, as well as controls for the shielding gas supply, the welding power supply, the cooling etc. are arranged. In these devices, the output of the rectifier is via a first line with a Welding torch and connected to a workpiece via a second line. The AC transformer is with these Devices dimensioned for the maximum required parameters (current, voltage) and designed to be non-adjustable. In order to However, these devices can also be used with different operating parameters (current and voltage), For example, if the non-adjustable transformer is followed by a current- or voltage-controlled transducer, The current or voltage can be changed and adjusted as required via its control winding. A disadvantage with these Facilities is that these can only be used for shielding gas arc welding with direct current. An arc welding with alternating current, as is the case with aluminum, for example

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required to achieve optimal SchwaIßnabxqualitgten is not feasible with these facilities.

In addition, devices for gas-shielded arc welding with alternating current have become known which essentially consist of an adjustable transformer, the corresponding controls for the inert gas supply, the cooling etc. are assigned. A change in the operating parameters (current and voltage) will occur in most of these facilities achieved in that a stray core of the transformer is adjusted. A disadvantage with these facilities is that these can only be used for inert gas alternating current arc welding. A DC welding is with these facilities are not possible.

The object of the invention is a device for gas-shielded arc welding with a first power source housing in which a first AC transformer with a downstream Rectifiers, as well as controls for the inert gas supply, the Welding power supply, cooling, etc. arranged sir.d and the output of the rectifier via a first line to a welding torch and via a second line to a Workpiece is connected to form such that this device for both direct current arc welding as well can be used for alternating current arc welding.

The invention consists in that switching contacts for DC circuit interruption in the first and / or second line are provided between the rectifier and the burner or workpiece and that the first or second line continues in the Area between the switching contacts and the torch or the workpiece are assigned connections to which a second, preferably Infinitely adjustable AC transformer can be connected is.

The invention makes it possible to carry out both direct current and alternating current arc welding with one device to execute. It is particularly advantageous that one is only available for

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Gleiohstromohweißungen designed power source rait simple Means (switching contacts and connections) as well as by connecting a simple one that is available in almost every welding workshop AC transformer can be converted into an AC welding device. It is of particular advantage that the control for the protective gas valves, the cooling, etc., which is present in the direct current welding device, continues from ^ can be used. In an advantageous development of the invention it is proposed that the second AC transformer is arranged outside the first power source housing in a separate housing box.

The invention is explained in more detail below with reference to the drawing and with reference to further advantageous features.

In the drawing, 10 is a device known per se for plasma direct current welding, as sold for example by the applicant under the name PCW 100 will. The device has a first power source housing 11 in which a first AC transformer 12 is arranged. The Viechseistromtransformator 12 is connected on the primary side to an alternating current network 13 and is on the secondary side with a transducer 14 in connection. The transducer 14 has a control winding 15 which is connected to a transductor current adjustment device 16 is connected to set the welding current. The transducer 14 is a three-phase rectifier 17 connected downstream, the output of the rectifier 17 via a first line 18 and a choke 33-with a commercially available plasma welding torch 19 and is connected to a workpiece 21 via a second line 20. Furthermore is in the power source housing 11 a control device for the inert gas supply, the cooling liquid supply to the burner 19 etc. provided. This control device 22 is via lines 23 »which are connected to the first Viechseistromtransformator 12 are supplied with electrical energy. The exit (Protective gas lines, cooling lines for the plasma torch, etc.) is only indicated schematically and with for the sake of simplicity

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24 designated. Furthermore, a high-frequency ignition device, denoted by 34, is provided within the housing 11, which serves to ignite a pilot arc between the burner electrode 19a and the burner nozzle 19b. The one required to ignite Pilot arc current is supplied via secondary line 35, among other things. According to the invention is in the first and / or second line 18 or 22, a switching contact 25 for interrupting the DC circuit between rectifier 17 and Burner I9 provided. In addition, the first line 18 and the second line 20 are in the area between the Switching contact 25 and the welding torch I9 or between the switching contact 25 and the workpiece 21, connections 26 and 27 assigned. A second, preferably continuously adjustable, alternating current transformer is connected to the connections 26 and 27 28 can be connected. As can be seen from the drawing, the second AC transformer 28 is external to the first Power source housing 11 arranged in a separate housing box 29 and via lines 30 and 31 with the plasma torch 19 or the workpiece 21 connected.

In a plasma direct current welding with the inventive Device, the main switch 32 between the transformer 12 and the supply network 13 and at the same time the contact 25 and 25 'closed. The second AC transformer 28 is in this case either by releasing the lines 30 and 31 from the connections 26 and 27 or through opening of a contact 36 provided in line 30 between plasma torch I9 and workpiece 27 is electrically isolated. With a device of this type can be carried out in a manner known per se. Should for example a welding can be carried out on a workpiece 21 made of aluminum, for which purpose a V / Echselstrom as the welding current is required, the direct current circuit is interrupted by opening the contact 25 and possibly the contact 25 ' and by closing the contact 36 or by connecting the lines 30 and 31 to the connections 26 and 27 the second AC transformer and thus the AC circuit are connected to torch I9 and workpiece 21. There

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the main switch 32 remains closed in this case too, the control device 22 is still supplied with electrical energy via the lines 23 and via the scheraatlsch with 24 designated output of the control device 22 the plasma torch 19 which is also required for AC welding Gas and cooling water are supplied according to a preset program.

The above statements show that by connecting a commercially available adjustable AC transformer, in which for example, current and voltage is carried out by changing the schematically illustrated scattering core 28a, to a commercially available one Plasma direct current welding source also welded current welding are optimally executable.

In the above-mentioned exemplary embodiment, the invention was based on a plasma welding device explained. The invention is of course also applicable to gas-shielded arc welding devices Can be used advantageously for V / IG and possibly MIG welding.

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Claims (1)

Expectations . ^ Equipment for shielding gas arc welding with DC and alternating current, in particular for plasma and / or TIG direct and alternating current welding, with a first power source housing in which a first AC transformer with downstream rectifier, as well as controls for the inert gas supply, the welding power supply, the cooling, etc. are arranged, with the output of the rectifier connected to a welding torch via a first line and to a workpiece via a second line is, characterized in that in the first and / or second Line (18,20) switching contacts (25,25 ') for interrupting the DC circuit between rectifier (17) and 3 renner (19) or workpiece (21) are provided and that furthermore the first or second line (18, 20) in the area between the switching contacts (25, 25 ') and the Burner (19) or the workpiece (21) connections (26, 27) are assigned to which a second, preferably stepless adjustable AC transformer (28) can be connected. 2. Device according to claim 1, characterized in that the second AC transformer (28) is external to the first power source housing (11) is arranged in a separate housing box (29). June 18, 1973
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