EP3146550B1 - Switching device - Google Patents

Description

The invention relates to a switching device according to the preamble of claim 1.

When an electrical current is switched off, and therefore when a live, conductive connection is cut, an arc occurs. Especially when switching high currents, in the range of several hundred to a thousand amperes, special precautions are necessary to ensure that the arc that arises during switching is extinguished. A non-extinguishing arc can lead to a total loss of the switching device and a fire in the area around the switching device. In addition, due to the arc, which represents a conductive electrical connection, a current continues to flow in the circuit in question, which should be switched off, which leads to a risk to people and systems, especially when the switching device is designed as a circuit breaker.

It is well known and widely used that switching devices which are designed and provided for switching high currents have a so-called arc quenching chamber in which a so-called stack of quenching plates is arranged. These are in each case spaced apart potential-free sheets which are arranged in their own plastic holder. In the case of such switchgear, the resulting arc is conducted or guided into the stack of quenching sheets and is to be quenched there by division and cooling.

It has been shown that, in particular in the case of switching devices which do not have a snap-off mechanism and which also have only small housing dimensions, a safe extinguishing of an arc at high currents cannot be ensured by means of a stack of quenching plates. In addition, the installation of the stack of quenching sheets in question requires a considerable amount of construction work, since in addition to the considerable dimensions of the same, its handling is also complex to manufacture.

The JP H9 293421 A should describe an arc extinguishing device for a switching device, with at least one conductor loop being arranged on the side of a fixed contact, which is used both for supplying the electrical current to Fixed contact, as well as about the electromagnetic effect that serves to extinguish the arc. Furthermore, the movable switching contact is arranged on a shift drum.

The WO 2014/073026 A1 describes a switching device with a fixed contact, a U-shaped arc runner flanking the opening path of the movable contact. This U-shaped arc runner can have lateral "wings", but as a whole is not connected to the fixed contact, but is held in the insulating housing of the switching device.

The JP S58 131629 A describes a contact area of a switching device, which has a classic quenching chamber with quenching plates, wherein a U-shaped clamp made of iron and soft ferrite is further arranged on the side of the fixed contact.

The GB 2 285 178 A describes a switching device with quenching plates, a U-shaped bracket being arranged directly next to the fixed contact as part of the arc quenching device.

The object of the invention is therefore to provide a switching device of the type mentioned at the outset, with which the disadvantages mentioned can be avoided, with which an arc which arises can be safely extinguished even when high currents are switched off, and which has a simple and space-saving design.

According to the invention this is achieved by the features of claim 1.

As a result, arcs can be reliably extinguished even when high currents are switched off, for example in the range of a thousand amperes, even if the switching device in question does not have a snap-off mechanism. As a result, a switching device can be formed which has a simple and space-saving structure, which can also be easily implemented in the context of automated production. Such a switching device does not require a stack of quenching sheets to extinguish a switching arc, as a result of which the structure is significantly simplified and, at the same time, high currents can be reliably switched off. This allows the simple construction of the switching device Protection of people and facilities can be improved. A switchgear in question has the ability to safely switch off high currents, and this with a structurally simplified arc quenching device and reduced space requirements.

The subclaims relate to further advantageous refinements of the invention.

Reference is hereby expressly made to the wording of the patent claims, as a result of which the claims are inserted at this point by reference into the description and are considered to be reproduced verbatim.

• Fig. 1 eine bevorzugte Ausführungsform eines gegenständlichen Schaltgeräts in axonometrischer Ansicht, sowie ohne oberer Gehäuseschale;
• Fig. 2 eine Baugruppe des Schaltgeräts gemäß Fig. 1, bestehend aus Summenstromwandler, Schaltwalze, Schaltkontakten sowie Anschlüssen in einer ersten axonometrischen Ansicht;
• Fig. 3 die Baugruppe gemäß Fig. 2 in einer zweiten axonometrischen Ansicht;
• Fig. 4 die Baugruppe gemäß Fig. 2 im Seitenriss, sowie mit geschlossenen Schaltkontakten;
• Fig. 5 die Ansicht gemäß Fig. 4 in teilweise geschnittener Darstellung;
• Fig. 6 die Ansicht gemäß Fig. 4 mit geöffneten Schaltkontakten, sowie ohne Schaltwalze;
• Fig. 7 die Ansicht gemäß Fig. 5 mit geöffneten Schaltkontakten;
• Fig. 8 einen Kontaktarm gemäß den Fig. 1 bis 7 in axonometrischen Ansicht;
• Fig. 9 eine Anordnung aus Festkontakt, Festkontaktträger, Anschlussklemme und Lichtbogenlöscheinrichtung gemäß den Fig. 1 bis 7 in axonometrischen Ansicht; und
• Fig. 10 die Lichtbogenlöscheinrichtung gemäß Fig. 9.

The invention is described in more detail with reference to the accompanying drawings, in which a merely preferred embodiment is shown as an example. It shows:

• Fig. 1 a preferred embodiment of an objective switching device in an axonometric view, and without an upper housing shell;
• Fig. 2 an assembly of the switching device according Fig. 1 , consisting of total current transformer, switching drum, switching contacts and connections in a first axonometric view;
• Fig. 3 the assembly according to Fig. 2 in a second axonometric view;
• Fig. 4 the assembly according to Fig. 2 in side elevation, as well as with closed switch contacts;
• Fig. 5 the view according to Fig. 4 in a partially sectioned representation;
• Fig. 6 the view according to Fig. 4 with open switching contacts and without switching drum;
• Fig. 7 the view according to Fig. 5 with open switch contacts;
• Fig. 8 a contact arm according to the 1 to 7 in axonometric view;
• Fig. 9 an arrangement of fixed contact, fixed contact carrier, terminal and arc extinguishing device according to the 1 to 7 in axonometric view; and
• Fig. 10 the arc extinguishing device according to Fig. 9 .

Fig. 1 shows a preferred embodiment of a switching device 1, wherein the switching device 1 has at least one fixed contact 2, which is arranged on a fixed contact carrier 3, and a movable contact 4, which is arranged on a movable contact arm 5, the movable contact 4 for contacting the fixed contact 2 is provided, and wherein the switching device 1 has an arc extinguishing device 6, the arc extinguishing device 6 laterally arranged and / or integrally formed on the fixed contact carrier 3 and an opening path 14 of the movable contact arm 5 at least partially flanking extensions 7.

As a result, arcs can be safely extinguished even when switching off high currents, for example in the range of a thousand amperes, even if the switching device 1 in question does not have a snap-off mechanism. As a result, a switching device 1 can be formed which has a simple and space-saving structure, which is also simple in the context of automated production can be implemented. Such a switching device 1 does not require a stack of quenching plates to extinguish a switching arc, as a result of which the structure is significantly simplified and, at the same time, high currents can be reliably switched off. As a result, the protection of people and systems can be improved with a simple construction of the switching device 1. A switchgear 1 in question has the ability to safely switch off high currents, and this with a structurally significantly simplified arc extinguishing device 6 and a reduced space requirement.

The 2 to 10 show individual parts or assemblies of the preferred embodiment of the switchgear 1 according to FIG Fig. 1 .

The switching device 1 in question can be designed as any configuration of a switching device 1. It is preferably provided that the switching device 1 is designed as a circuit breaker, especially as a residual current circuit breaker 13.

Fig. 1 shows the preferred embodiment of the relevant switching device 1 as a residual current circuit breaker 13, an upper housing shell is not shown to show the interior of the switching device 1 in question, which is arranged in the lower housing shell 23 shown. A four-pole version of a residual current circuit breaker 13 is shown, which accordingly has four switching paths, and the corresponding connection terminals 11, 12 for connecting the three phases and the neutral conductor of a three-phase network. In the switching device 1 shown, a summation current transformer 22 is arranged, through which connection cables 24 are guided, which are connected at one end to a first connection terminal 11 and at the other end to a movable contact arm 5. The switching device 1 in question furthermore has a manual control element 21 and an electromechanical arrangement in order to cause the switching contacts 2, 4 to disconnect or open when a specifiable electrical state occurs. The structure of a residual current circuit breaker 13 is not discussed further at this point, since the switching device 1 in question is preferably not limited to this configuration, and the general structure of a residual current circuit breaker 13 is known per se.

The present invention is further based on a switching path described. An electrical path through the switching device 1 is referred to as the switching path, which is electrically conductive in a state in which switching contacts 2, 4 which are assigned to one another are in electrically conductive contact with one another. The relevant switching contacts 2, 4 are formed in the switching device 1 in question by a fixed contact 2, therefore a switching contact fixed within the housing of the switching device 1, and a movable contact 4. A plurality of fixed contacts 2 and movable contacts 4 can also be provided for each switching path, which is referred to as multiple interruption or double interruption.

The switch contacts, therefore the fixed contact 2 and the movable contact 4 are each preferably made of silver. The electrical conductors running through the switching device 1 are preferably formed comprehensively from a copper alloy.

The fixed contact 2 is arranged on a fixed contact carrier 3, in particular welded onto it. The fixed contact carrier 3 is preferably designed as part of the second connection terminal 12, although a separate configuration and connection to the second connection terminal 12 can also be provided.

The movable contact 4 is arranged on a contact arm 5 which, according to the preferred embodiment shown, is mounted in a movable switching drum 10. In the preferably provided switching drum 10, the movable contact arms 5 of any further switching paths are also stored, so that all switching paths are always switched during a switching operation.

The movable contact 4 is preferably welded to the movable contact arm 5. The flexible conductor 24 coming from the summation current transformer 22 is preferably fastened to an end of the contact arm 5 facing away from the movable contact 4.

The switching device 1 has an arc extinguishing device 6. This arc extinguishing device 6 comprises extensions 7 formed or arranged on the side of the fixed contact carrier 3. These extensions 7 flank an opening path 14 of the movable contact arm 5 at least or only in regions laterally. The two extensions 7 are therefore on the fixed contact carrier 3 arranged and / or shaped in such a way that they laterally delimit or flank a space through which space the movable contact arm 5 moves when it moves away from the fixed contact 2 in the course of a switch-off process.

When the movable contact 4 is separated from the fixed contact 2, an arc is formed. At a certain distance of the movable contact 4 to the fixed contact 2, this arc jumps from the fixed contact 2 to the lateral extensions 7, which are at the same potential as the fixed contact 2. When the movable contact 4 is further removed from the fixed contact 2, the arc remains, which can now also be a pair of arcs, exist between the extensions 7 and the movable contact 4, with no springing back to the fixed contact 2. The arc in question extinguishes at the latest at the next subsequent zero crossing of the switched voltage.

The arc extinguishing device 6 in question is preferably formed only by the extensions 7. In other words, the preferred arc extinguishing device 6 has no stack of quenching plates and is therefore free of stacked quenching plates.

The fixed contact carrier 3 is preferably angled in the opening direction 15 of the contact arm 5, as a result of which the extensions 7 can be arranged simply to the side of the opening path 14 of the movable contact arm 5 in numerous switchgear designs.

The extensions 7 are each connected to the fixed contact carrier 3. However, it is preferably provided that - in the opening direction 15 of the movable contact 4 - a gap 19 is arranged between the fixed contact 3 and a first edge 18 of each of the extensions 7. An arc can be forced through this gap 19 in a specific, predetermined way. It has turned out to be advantageous that the first edge 18 of the extensions 7 is arranged essentially in the extension of a contact area of the fixed contact 3 with the movable contact 4, whereby a particularly advantageous guiding of any arcing can be achieved.

According to the preferred embodiment shown, the extensions 7 are each formed essentially at right angles to the fixed contact carrier 3 and form a U-shaped region.

The extensions 7 preferably have a height 16 that decreases away from the fixed contact 2. In particular, the extensions 7 have a trapezoidal surface 17. Through these measures, both an effective discharge of the arc can be achieved and a high stability and service life of the arc extinguishing device 6 formed in this way. It can also be provided at this point that the surface has a different geometric shape, with a decrease from the fixed contact 2 Height 16.

The 9 and 10 show the preferred embodiment of the extensions 7, as described above. The extensions 7 are part of a separate arc extinguishing part 20, which according to the preferred embodiment in question is a part separate from the fixed contact carrier 3, which is preferably connected to this by a rivet, as in FIGS Fig. 5 , 7 and 9 shown, wherein the relevant rivet can be integrally formed with the fixed contact carrier 3. Due to the separate design of the arc extinguishing part 20, this can be formed from a different material than the fixed contact carrier 3, for example from an iron material. It can also be provided that the extensions 7 are integrally formed on the fixed contact carrier 3.

The contact arm 5 preferably has an end region 8 which extends beyond the movable contact 4, as in particular in FIG Fig. 8 clearly visible. This end region 8 is preferably formed in one piece with the rest of the movable contact arm 5, and preferably forms, and as in FIGS Fig. 5 and 7 to recognize a stop for the movable contact 4.

It is preferably provided that only the opening path 14 of the end region 8 is flanked in some areas by the extensions 7 of the fixed contact carrier 3. In the state in which the movable contact 4 bears against the fixed contact 2, the extensions 7 therefore extend according to the preferred embodiment, as in particular in FIGS Fig. 4 and 5 shown, not up to the contacts 2, 4, but only flank the end region 8.

In order to support the dissipation of an emerging arc away from the contact point in the direction of the extensions 7, it is preferably provided that the end region 8 of the contact arm 5 together with a region of the fixed contact carrier 3 arranged opposite this form a blow horn 9. An arc creates a plasma, which creates a local overpressure. This can be used to additionally direct or drive the arc. The horn 9 is a region that widens away from the contact point, hence the point of origin of a switching arc, hence a horn.

It is preferably provided that the end region 8 of the contact arm 5 has a thickness that decreases away from the movable contact 4, or that the end region 8 of the contact arm 5 is curved and / or angled in the direction of movement of the contact arm 5. The thickness is measured in relation to the thickness of the movable contact arm 5 in the area of the movable contact 4, the reference height being the rear surface of the movable contact arm 5 in the area of the movable contact 4.

Claims (9)

1. Switching device (1), in particular residual-current circuit breaker (13), wherein the switching device (1) has at least one stationary contact (2) that is arranged on a stationary contact support (3), and a movable contact (4) that is arranged on a movable contact arm (5), wherein the movable contact (4) is provided to come into contact with the stationary contact (2), and wherein the switching device (1) has an arc-extinguishing device (6), wherein the arc-extinguishing device (6) comprises extensions (7) that are arranged laterally on the stationary contact support (3) and at least in some areas flank an opening path (14) of the movable contact arm (5), wherein the contact arm (5) has an end region (8) which extends beyond the movable contact (4), characterised in that only the opening path (14) of the end region (8) of the contact arm (5) is flanked in some areas by the extensions (7) of the stationary contact support (3).
2. Switching device (1) according to claim 1, characterised in that the arc-extinguishing device (6) is formed only by the extensions (7).
3. Switching device (1) according to claim 1 or 2, characterised in that the arc-extinguishing device (6) is free of stacked extinguishing plates.
4. Switching device (1) according to any of claims 1 to 3, characterised in that the stationary contact support (3) is angled in the opening direction (15) of the contact arm (5).
5. Switching device (1) according to any of claims 1 to 4, characterised in that the extensions (7) are each formed substantially at right angles to the stationary contact support (3).
6. Switching device (1) according to any of claims 1 to 5, characterised in that the extensions (7) have a height (16) which decreases away from the stationary contact (2), in particular that the extensions (7) have a trapezoidal surface (17).
7. Switching device (1) according to any of claims 1 to 6, characterised in that the end region (8) of the contact arm (5), together with a region of the stationary contact support (3) arranged opposite thereto, form a wind horn (9).
8. Switching device (1) according to any of claims 1 to 7, characterised in that the end region (8) of the contact arm (5) has a thickness which decreases away from the movable contact (4).
9. Switching device (1) according to any of claims 1 to 8, characterised in that the movable contact arm (5) is mounted in a switching drum (10) of the switching device (1).

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