EP2960917A1 - Arc extinguishing chamber for an electromagnetic switching device - Google Patents

Abstract

The invention relates to an arc extinguishing chamber for an electromagnetic switching device with a fixedly positioned contact piece (1) and a movable contact piece arranged opposite thereto (2), which is arranged in a contact slide (3), and with arc splitter stacks (4) perpendicular to the switching pieces (1,2) are arranged. The invention is characterized in that starting from the contact pieces (1, 2) via spaces in the splitter stack (4) and via a flow channel (9) above the splitter stack (4), which is partially aligned in the direction of cooling fins (12) , which are arranged laterally next to the switching pieces (1,2), a return flow channel (8) is formed which removes a resulting arc defined.

Description

The invention relates to an arc extinguishing chamber for an electromagnetic switching device with a fixedly positioned contact piece and a movable contact piece arranged opposite thereto, which is arranged in a contact slide, and with splitter plate packages which are arranged perpendicular to the contact pieces.

In switching devices with such arc extinguishing chambers created when switching off electrical currents at the opening contact points an arc. This arc causes wear at the contact points due to erosion of the contact material and delays the disconnection of the circuit, since the current continues to flow through the arc until it extinguishes. To limit the damage caused by the arc, electrical switching or protective devices are equipped with an arc extinguishing device above a certain power.

Such arc extinguishing device often consists of an arc chamber with Lichtbogenleitblechen and various components, which fulfill, among other things, fluidic tasks.

The arc chamber is often filled as a package of punched quenching plates, which are arranged in parallel and kept at a distance. Around the quenching plates, a strip of insulating material, usually a Vulkanfieberstreifen folded, which keeps the quenching plates at a distance and summarized into an assembly. In the insulating strip openings are punched, which influence, among other things, the flow conditions in the arc chamber. The baffles are located at the top and bottom of the arc chamber. The upper arc guide plate together with a movable contact bridge forms a contact point.

In the arc extinguishing device, the arc migrates from the contact point into the arc chamber. When opening the contact point, an arc is formed between the contacts that are separated from each other. Electromagnetic forces move the arc towards the arc extinguishing chamber. The arc base points of the arc at the exit points of the arc guide plates thereby migrate away from the contact point along the arc guide plates electrically connected to the circuit.

The arc guide plates are shaped and arranged so that they lead the arc as quickly as possible to the arc chamber. Inside the arc chamber, the arc is then extinguished. During the described process, current or thermomechanical forces occur between the quenching plates and the arc guide plates. If the arc guide is not fixed stable enough, which often does not succeed due to the structural conditions often, they touch the outer quenching plates and weld with them. As a result, the efficiency of the arc chamber for further deletion processes is reduced.

For particularly strong arcs, as they occur as a result of short-circuit shutdown, there is a risk that they pass through the arc chamber and short circuit behind it. In this case, the extinguishing effect of the arc chamber is no longer present.

In order to avoid the shorting of the arc in the space behind the arc chamber, various solutions are known. For example, it is possible to keep the arc guide plates relatively short, that is, not to the end of the arc chamber, where the quenching plates end.

Another possibility is the complete abandonment of the lower arc guide plate. Usually, the very short arc guide are either not mechanically supported, or it is for support used additional plastic part, which, however, associated with additional costs. The solution with short baffles has the significant disadvantage that under certain circumstances not the entire volume of the inner part of the arc chamber is optimally utilized during the deletion process.

The mechanism of action is accordingly that the flow of current across the arc creates a magnetic flux which is deflected by ferromagnetic parts near the contact point such that a force acts on the arc which drives it away from the contact point to an arc extinguishing system.

Due to the urgent need to carry away and extinguish an arc resulting after a switching operation in order to avoid wear or destruction of the contact pieces and other elements of the switching device, the requirement continues to arise, in particular in the case of high-frequency switching on or switching off of the switching device. to reduce the relatively high heating of the device.

Accordingly, the object of the present invention is to provide an arc extinguishing chamber for an electromagnetic switching device which extinguishes a switching arc as effectively as possible and transported away.

This object is achieved by an arc extinguishing chamber having the features of patent claim 1. Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

According to the invention this object is achieved by an arc extinguishing chamber for an electromagnetic switching device with a fixedly positioned switching piece and a movable contact piece arranged opposite thereto, which is arranged in a contact slide, and with splitter plate packages which are arranged perpendicular to the switching pieces. The The invention is characterized in that starting from the switching pieces, via gaps in the splitter stack and a flow channel above the splitter plate, which is partially aligned in the direction of cooling fins, which are arranged laterally next to the switching pieces, a return flow channel is formed, the one emerging arc defines transported away.

The return flow channel according to the invention has a very short flow path, which leads via the splitter stack to the contact bridges, wherein the splitter stack are arranged perpendicular to the flow path. This allows fast feedback and increased flow on the arc and contributes to rapid arc movement to the quenching plates. In addition to the installed return flow channel cooling fins are arranged in the arc extinguishing chamber, which serve to cool and deionize the hot gas propagating in the quenching chamber in the direct phase after the shutdown and after the emergence of the return flow. The cooling fins direct the air flow into areas between the contact bridge and the wall, so that the return flow is utilized more effectively. The effective cooling after a switching operation is also supported by a convection movement, wherein an air flow of heated construction elements within the arc chamber to the housing wall or to the opening in the housing wall of the switching device is formed.

In a particularly advantageous embodiment of the invention, it may be provided that starting from the switching pieces via gaps in the splitter stack a further flow channel is arranged, which flows through a blow-out in the housing of the arc extinguishing chamber hot air to the outside. The flow channel above the splitter stack allows some of the hot air leaves the unit, while the other part is discharged in a flow channel supplied to the cooling fins. For this constructive Measure results in the advantage that a part of the hot air can already be performed outwardly defined.

In a special embodiment of the invention, another concept may be that the return flow channel is designed as a self-contained circuit which discharges the outflowing hot air into a continuous process. Due to the design of the return flow channel according to the invention as a circuit can thus be transported out of the device within a very short time resulting from a switching hot air.

In a further particularly advantageous embodiment of the invention, it may be provided that the structural design of the return flow channel is formed correlating with the size of the exhaust opening in the housing of the arc extinguishing chamber. In particular, it is possible according to the invention to form the return flow channel and the discharge openings in the housing of the arc extinguishing chamber in a manner correlating with the in particular high-frequency turn-on and turn-off processes. The structural measures in the arc quenching chamber for the return flow channel can be adapted to the switching frequency.

In a further particularly advantageous embodiment of the invention, it can be provided that the cooling fins are made of metal. Metal has the advantage that it is not subject to aging processes and is a good material to process.

It may also be provided according to the invention that the arc extinguishing chamber is used in a contactor.

The arc extinguishing chamber according to the invention for an electromagnetic switching device has a fixedly positioned contact piece and a movable contact piece arranged opposite thereto, which is arranged in a contact slide. On the side next to the switching pieces splitter stacks are arranged, which are parallel to each other and from each other spaced quenching plates are formed. The splitter stack are arranged perpendicular to the switching pieces. The arc extinguishing chamber is surrounded by a housing, in which exhaust openings are provided, which are preferably formed above and to the side of the splitter stack. Between contact slide and splitter stack cooling fins are arranged, which are preferably made of metal. Structurally, the switching pieces, the splitter stack and the cooling fins are arranged to each other such that there is a return flow channel extending from the switching pieces between the perpendicular to the switching pieces arranged quenching plates, via a flow channel above the quenching plates to the cooling fins and back to the switching pieces. In addition, a second flow channel results from the switching pieces between the quenching plates via a guide channel above the quenching plates to the exhaust openings.

The arc extinguishing chamber according to the invention is characterized by an improved extinguishing capability, which is made possible by a defined applied return flow channel. This is associated with a prolonged life of the switching device, which has been improved in particular by a convection cooling with cooling fins. The use of a return flow channel with cooling fins overall improves the heat balance of the switching device sustainable.

Further advantages and embodiments of the invention will be explained in more detail by means of embodiments and with reference to the drawing.

• Fig. 1 in einer perspektivischen Darstellung eine erfindungsgemäße Lichtbogenlöschkammer mit Rückströmungskanal;
• Fig. 2 in einer perspektivischen Darstellung einen Ausschnitt aus einer Lichtbogenlöschkammer mit Rückströmungskanal und Kühlrippen;
• Fig. 3 in einer perspektivischen Darstellung den erfindungsgemäßen Rückströmungskanal als Kreislaufprozess.

Here are shown schematically:

• Fig. 1 in a perspective view of an inventive arc quenching chamber with return flow channel;
• Fig. 2 in a perspective view a section of an arc extinguishing chamber with return flow channel and cooling fins;
• Fig. 3 in a perspective view of the return flow channel according to the invention as a cycle process.

Fig. 1 shows an arc extinguishing chamber according to the invention for an electromagnetic switching device, which has a fixedly positioned contact piece 1 and an oppositely arranged movable contact piece 2, which is arranged in a contact slide 3. Laterally next to the switching pieces 1, 2 splitter stacks 4 are arranged, which are formed of mutually parallel and spaced quenching plates 5. The splitter stack 4 are perpendicular to the switching pieces 1, 2 are arranged. The arc extinguishing chamber is surrounded by a housing 6, in which exhaust openings 7 are provided, which are preferably formed above and to the side of the splitter plate 4. Constructively, the switching pieces 1, 2 and the quenching plates 4 are arranged to each other such that there is a return flow channel 8, of the switching pieces 1, 2, between the perpendicular to the switching pieces 1, 2 arranged quenching plates 5, via a flow channel 9 above the quenching plates 5 and back to the switching pieces 1, 2 runs. In addition, a second flow channel 10 results from the switching pieces 1, 2, between the quenching plates 5, via a guide channel 11 above the quenching plates 5 to the exhaust openings. 7

In Fig. 2 is the arc extinguishing chamber according to the invention Fig. 1 shown, including the cooling fins 12, which are arranged between the contact slide 3 and the splitter stack 4. The return flow channel 8 including the cooling fins 12 results now from the switching pieces 1, 2, between the perpendicular to the switching pieces 1, 2 arranged quenching plates 5, via a flow channel 9 above the quenching plates 5 to the cooling fins 12 and back to the switching pieces 1, 2nd In this case, the cooling fins 12 lead the return flow directly to the contact pieces 1, 2.

In Fig. 3 the return flow channel 8 and the flow channel 10 is shown as a continuously circulating through process. The direction of the arrow symbolizes the flow direction.

The arc extinguishing chamber according to the invention is characterized by an improved extinguishing capability, which is made possible by a defined applied return flow channel. This is associated with a prolonged life of the switching device, which has been improved in particular by a convection cooling with cooling fins. The use of a return flow channel with cooling fins overall improves the heat balance of the switching device sustainable.

LIST OF REFERENCE NUMBERS

1

firmly positioned contact piece

2

movable contact piece

3

contact slide

4

Splitter assembly

5

splitter

6

casing

7

exhaust vent

8th

Backflow channel

9

flow channel

10

flow channel

11

guide channel

12

cooling fins

Claims (6)

Arc quenching chamber for an electromagnetic switching device with a fixedly positioned switching piece (1) and a movable switching piece arranged opposite thereto (2), which is arranged in a contact slide (3), and with splitter plate packages (4) perpendicular to the switching pieces (1,2 ) are arranged
characterized in that starting from the switching pieces (1,2) via gaps in the splitter stack (4) and via a flow channel (9) above the splitter stack (4), which is partially aligned in the direction of cooling fins (12), which laterally next the switching pieces (1,2) are arranged, a return flow channel (8) is formed, which removes a resulting arc defined. Arc quenching chamber according to claim 1,
characterized in that starting from the switching pieces (1,2) via gaps in the splitter stack (4), a further flow channel (10) is arranged, which flows via a blow-out opening (7) in the housing (6) of the arc extinguishing chamber hot air to the outside. Arc quenching chamber according to claim 1 or 2,
characterized in that the return flow channel (8) is designed as a self-contained circuit which discharges the outflowing hot air in a continuous process. Arc quenching chamber according to one of claims 1 to 3,
characterized in that the structural design of the return flow channel (8) with the size of the exhaust openings (7) in the housing (6) of the arc extinguishing chamber is formed correlating. Arc quenching chamber according to one of claims 1 to 4,
characterized in that the cooling ribs (12) are made of metal. Contactor with an arc extinguishing chamber according to one of claims 1 to 5.

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