DE1540758C

DE1540758C - Protection circuit for welding power sources

Info

Publication number: DE1540758C
Authority: DE
Inventors: Franz 8023 Pullach; Pawlik Rudolf 8190 Wolfratshausen Tajbl
Original assignee: Messer Griesheim GmbH
Current assignee: Messer Griesheim GmbH
Publication date: 1972-11-23

Description

Der Schweißstrom fließt bei ordnungsgemäßem Anschluß des Werkstückes 8 über die Leitung 5, den Schweißbrenner6, das Werkstücke und die Werkstückleitung 7.When the workpiece 8 is properly connected, the welding current flows via the line 5, the Welding torch6, the work piece and the work piece lead 7th

Bei nicht einwandfreiem Anschluß der Werkstückleitung 7 an das Werkstück 8 τ oder erst recht bei Fehlen dieses Anschlusses — tritt nach Einschalten des Schweißgleichrichters 1 die erfindungsgemäße Schutzschaltung in Tätigkeit. Der Schweißstrom fließt dann über das Relais 15 und den Widerstand 16 zum Nulleiter 3, wobei das Relais 15 den Schalter 17 öffnet. Dadurch wird der Strom durch das Primärschütz 10 unterbrochen und der Netzschalter 13 geöffnet. Nach Behebung des Fehlers kann der Schalter 17 mit einem Rückstellknopf 18 am Relais 15 wieder geschlossen werden.If the workpiece lead 7 is not properly connected to the workpiece 8, or even more so when If this connection is absent, the welding rectifier 1 according to the invention occurs after the welding rectifier 1 is switched on Protection circuit in action. The welding current then flows through the relay 15 and the resistor 16 to Neutral conductor 3, the relay 15 opening the switch 17. This will get the current through the primary contactor 10 interrupted and the power switch 13 opened. After eliminating the error, the switch can 17 can be closed again with a reset button 18 on the relay 15.

Das Relais 15 wird zweckmäßigerweise auf eine Auslösestromstärke von 5 bis 1OA eingestellt. Als Begrenzungswiderstand 16 eignet sich ein Justierwiderstand, der bei einer Leistung von 100 W auf einen Wert zwischen 5 und 10 Ohm eingestellt werden kann.The relay 15 is expediently set to a tripping current strength of 5 to 10A. When Limiting resistor 16 is an adjustment resistor that has a power of 100 W. a value between 5 and 10 ohms can be set.

Das Ausführungsbeispiel läßt sich mit geringfügigen Abwandlungen auch auf andere Schweißstromquellen, wie Schweißtransformatoren, Schweißumformer usw., anwenden.The exemplary embodiment can also be used with other welding power sources, with minor modifications. such as welding transformers, welding converters, etc.

Hierzu 1 Blatt Zeichnungen1 sheet of drawings

Claims

. ■■■. 1 '2'. - ■ 'In electrical engineering, patent claims in general: known to use a protective circuit with 1 overcurrent release in the neutral conductor for such cases.

1. Protective circuit for the welding circuit, but this has not proven itself in the case of arc welding yon welding power sources such as welding transformers, as they allow the special eigenmators, welding rectifiers or welded shafts of such systems, through their secondary converters, for operation in zeroed systems are conditional, not fair,
Using an overcurrent release, the object of the present invention is

characterized in that the work 'is based on a protective circuit for the welding piece lead (7) to develop the welding circuit via the OK circuit for welding power sources, a current relay (15) with the neutral conductor (3) of the reliably preventing damage to other devices " Primary circuit of the welding power source (1) changes while providing the necessary protection for the is connected and the current relay (15) with a welding power source and also for the welder Primary contactor (10) is so in operative connection, guaranteed.

that this on activation of the relay (15) S ^1, this object is achieved in that the Werkden primary circuit of the welding current source (1) piece of pipe of the welding circuit through a power Interrupts. relay to the neutral conductor of the primary circuit of the

'2. Protective circuit according to claim 1, characterized in that the welding current source is connected' and the current is characterized in that the relay in the connecting line is operatively connected to a primary contactor between the workpiece lead (7) and the neutral conductor (3) ao stands that this when the current relay responds to the an adjustable limiting resistor (16) with the primary circuit of the welding power source below Power relay (15) is connected. breaks. ··. ■ '·

In a further refinement of the concept of the invention, there is between

The workpiece lead and neutral lead are adjustable

Limiting resistor in series with the current relay, which adjusts the protective relay to a

The invention relates to a protective circuit for the desired trigger strength enables
the welding circuit of welding power sources, this simple solution provides the guarantee of a

such as welding transformers, welding rectifiers 30 safe shutdown of the welding power source 'from or welding converter, for operation in a zeroed network in the event that the workpiece lead is improper systems is connected to the workpiece using an overcurrent adapter or solution. this connection is accidentally not made at all.

It is known that for safety reasons, on the other hand, an adjustment of the triggering effect Protective measures for arc welding 35 Amperage on the protective relay to a suitable 'systems of all kinds as well as for the automatic value that the protective circuit at insignificant Welding necessary electrically operated auxiliary stray currents, which the protective lines devices such as trolleys, turntables, controls of auxiliary devices do not yet endanger, do not respond etc., are mandatory. For light Another significant advantage of the invention

Arc welding equipment is used as a protective measure in 40 according to the circuit is to be seen in the fact in practice most frequently applied the nulluiig, that the welder through it before crossing the where the system parts to be protected are connected to the mains voltage on the welding circuit, e.g. with Neutral conductors are connected. , defective insulation, is protected without the

In the practice of arc welding, the protective relay setting has to be changed has shown that this protective measure, which 45 needs.

exclusively to the supply network directly. In the drawing, an embodiment of the

bar related system parts refers, invention shown schematically,
In itself, there are considerable disadvantages: In this example, a welding rectifier 1 brings about when the workpiece lead of the welding via the leads 2 and the neutral conductor 3 ah the power source is improperly connected to the workpiece 50 supply network 4. From welded joints or completely forgotten. In this case rectifier 1, the line 5 to the welding then does not flow the welding current, as intended, burner 6 or the workpiece line 7 to the work from the power source via the welding torch, the piece 8. The auxiliary power source 9 is used for the input and workpiece and the workpiece lead to power off the welding rectifier 1. It is source back, but from the workpiece via the 55 on the one hand with the primary contactor 10 and on the other hand auxiliary device, the z. B .: can be a landing gear, and with the off switch 11 and the on switch 12 its protective line to the neutral conductor, thereby disconnected. The primary contactor 10 acts on the scarf-controllable stray currents occur. ter 13 and 14. According to the invention, the workpiece-Since the current strengths of the welding currents can be up to line 7 via a protective relay 15 and an adjustable 7000A, in this case the 60 bar resistance 16 burns connected to the neutral conductor 3, ordinary protective line of the auxiliary device Immediately The relay 15 acts on a switch 17.
through. This is the protective measure for this. To switch on the system, the on / off switch is used

Device lifted and there is a risk of 12 actuated. This gives the primary contactor 10 over Accidents. Also protective lines by itself close 11, 12 and 17 power and closes the switch 13 . not directly connected to the welding system 65 and 14. After releasing the power button 12 cooperating tools or tools - the current flows from the auxiliary power source 9 via U, Machines can burn out if these 14 and 17 pass through the primary contactor 10, i.e. h., the are accidentally in contact with the workpiece. Switches 13 and 14 remain closed.