EP2795643B1 - Direct current circuit breaker - Google Patents

Description

The invention relates to a switching device suitable for direct current operation, which comprises at least one contact pair with a first contact and a second contact, at least one of the two contacts being movable and the two contacts in contact with one another in an switched-on state and in a switched-off state of the switching device are out of contact with each other. Furthermore, the switching device comprises an arc driver arrangement which generates a magnetic field at least in the region of the contact pair, and a first arc guide arrangement by means of which an arc occurring between the contacts is conducted with a first current direction to an extinguishing device for extinguishing the arc.

Such a switching device is from the EP 2 061 053 A2 known. To create a switching device for direct current applications, it is proposed there to use the housing of a switching device for alternating current applications, with at least one magnet additionally being provided which has a magnetic field with field lines which run essentially transversely to the separation paths of the current paths of the alternating current switching device. In the housing, three receiving areas are provided for one current path, each current path being assigned a movable switching contact element and two fixed switching contact elements lying opposite one another. The three movable switching contact elements can be moved together between a closed position, which corresponds to the switched-on state of the switching device, and an open position, which corresponds to a switched-off state of the switching device. The individual current paths are each assigned two arc extinguishing devices, each of which is designed in the form of individual, mutually superposed, electrically insulated quenching plates. In addition, each current path has two separating paths, which, when the movable switch contact elements are open, between their ends and the form first and second fixed switching contact elements assigned to these ends. When the switch contact elements are opened, an arc is formed along the separation paths, which can be extinguished with the aid of the arc extinguishing devices. Since, in direct current applications, the extinguishing of an arc cannot be achieved on account of a zero crossing of the current, as in alternating current applications, it is necessary in the case of direct current applications to provide a magnetic field which drives the arc into one of the arc extinguishing devices. This magnetic field is formed by permanent magnets, a magnetic field being built up with field lines in an orientation which run transversely to the separating distances and generate a Lorenz force on arcs forming along these separating distances, which drives the arcs in the direction of one of the arc extinguishing devices. Here, an arc is driven between a first contact pair in the direction of a first arc quenching device and the arc between a second contact pair in a second arc quenching device. Since the movement of the arcs depends on the current direction, the switching device is only suitable for one current direction, ie polarity. If the switching device were also operated in a reverse current direction, the arcs would not be driven into the arc quenching devices, but in the opposite direction to a switching bridge. Even if you reversed the magnetic polarity of one of the arc extinguishing devices, one of the arcs would always run towards the switching bridge, which would result in a reduced service life, since the switching bridge or other components would be damaged or even destroyed in the long term.

The EP 0 789 372 B1 also shows a switching device of the type mentioned. A fixed contact is provided with a fixed arc runner, which is designed in the shape of a circular arc. A movable arc runner is provided on a movable contact, an arc being able to form between the two arc runners and being moved in different directions via the arc driver arrangement depending on the current direction. Depending on the current direction of the arc, the arc is centered either in a first direction of rotation or in a second direction of rotation opposite to the first direction of rotation deflected, the center point corresponding to the center point of the fixed sheet runner. An arc with a first current direction is directed into a first arc runner channel and an arc with a second current direction opposite to the first current direction is directed into a second arc runner channel. The two sheet runner channels run around the center and are separated from each other by an insulating wall. The arc runner channels are each part of a quenching device for quenching the arc. The quenching devices further comprise quenching plates which are arranged to run radially with respect to the stationary sheet runner. The quenching plates are arranged such that they cover both sheet runner channels and are therefore part of both quenching devices.

The publication DE19 46 065 U. relates to a polarity-independent arc quenching device for DC switching devices. Arcs that form between contact pairs of a fixed contact and a contact of a movable switching bridge are blown in different directions depending on the polarity. For this purpose, an arc guide arrangement is provided for each blow-out direction. Depending on the blow-out direction, the arcs are driven into an upper package of quenching plates or a lower package of quenching plates. The upper package and the lower package of quenching plates are separated from one another by a guide plate of the arc guide arrangement. A first arc guiding arrangement and a first packet of quenching plates are thus provided for the one blow-out direction. A second arc guide arrangement and a second packet of quenching plates are provided for a second blow-out direction. One of the packets of quenching plates is only used if a first current direction is present and another pack of quenching plates is only used if a second current direction that is opposite to the first current direction is present. This leads to a relatively large amount of space required.

Another switching device discloses the DE 16 40 804 A1 , There, depending on the polarity of the arc, it is driven either upwards or downwards by a magnet driver arrangement. The quenching chambers are arranged side by side or one above the other.

The object of the present invention is to provide a switching device which can be operated independently of polarity and which is constructed as simply as possible.

The object is achieved by a switching device according to claim 1. It is suitable for direct current operation and comprises at least one contact pair with a first contact and a second contact, at least one of the two contacts being movable and the two contacts in contact with one another when the switching device is switched on and out of contact when the switching device is switched off to each other. Furthermore, the switching device comprises an arc driver arrangement which generates a magnetic field at least in the region of the contact pair, and a first arc guide arrangement by means of which an arc occurring between the contacts is conducted with a first current direction to an extinguishing device for extinguishing the arc. In addition, a second arc guide arrangement is provided, by means of which an arc occurring between the contacts with a second current direction opposite to the first current direction is directed to the quenching device for quenching the arc.

It is advantageous here that the two arc guiding arrangements are designed according to the invention in such a way that the arc is directed into the same quenching device regardless of its current direction. Here are no special isolating Partitions required to direct the arc into different quenching devices or into different areas of the same quenching device. A permanent magnetic field is preferably generated by means of permanent magnets in order to provide a magnetic field in a simple manner and independently of the current.

The first arc guiding arrangement is designed in such a way that an arc with a first current direction is deflected in a first direction of rotation and directed to the quenching device. The second arc guide arrangement is arranged such that an arc with a second current direction is deflected in a direction opposite to the first direction of rotation and is directed to the quenching device. This means that the arc is deflected regardless of its current direction and is driven into the quenching device. The distances that the arc must travel to reach the quenching device are preferably of the same length in order to ensure the same switching behavior of the switching device in both current directions.

The first contact is preferably an immobile fixed contact and the second contact is a movable contact. According to the invention, the arc is deflected around the second contact onto a side of the second contact which faces away from the first contact. The arc is thus deflected onto the back of the movable contact, the quenching device being arranged on the back of the movable contact. The arc is driven in a direction in the quenching device that is approximately parallel to the direction of movement of the movable contact. When the contact pair is opened, the movable contact moves in the direction of the quenching device, so that the arc can be conducted in the shortest possible way into the quenching device.

According to the invention, the quenching device is designed as a deion quenching chamber with a multiplicity of quenching plates which are electrically insulated from one another and arranged parallel to one another. It is thus possible to use standardized components and preferably to provide the extinguishing device as a preassembled structural unit which can be inserted into a housing of the switching device. Here are the quenching plates are preferably aligned parallel to the direction of movement of the at least one movable contact.

The arc guide arrangements each have a first guide plate and a second guide plate, the two first guide plates running in opposite directions and in the direction of the quenching device, starting from the first contact. The first two baffles can hold the extinguishing device between them. The second guide plates are preferably designed without interruption, also in the transitions between the fixed contact carrier and the second guide plates. This avoids standing arcs, which can lead to burn-off and thus to a shorter service life.

The two second guide plates are preferably arranged on a contact carrier which carries the second contact, and can run in opposite directions. In a first variant of the second guide plates, it is provided that the second guide plates are angled at their free ends in the direction of the extinguishing device. The baffles therefore remain essentially plate-shaped, which simplifies the manufacture of the baffles. A second variant is characterized in that the second guide plates are bent in a ring at their free ends. The second guide plates each form a ring section with a larger diameter in relation to the material thickness, so that the arc is deflected more easily. However, the production is more complicated than with plate-shaped second guide plates.

In a preferred embodiment, the arc driver arrangement comprises at least one permanent magnet which is arranged between two pole plates, the contact pair being arranged between the pole plates. A magnetic field that is as homogeneous as possible is generated by the two pole plates.

The switching device can be designed as a double-interrupting switching device with two contact pairs, the two contact pairs each having a first contact and a second contact. In this case, the second contacts are arranged on a bridge contact piece which is movable with respect to the first contacts. When switched on State of the switching device, the second contacts are each in contact with one of the first contacts, the bridge contact piece electrically connecting the two second contacts to one another.

Figur 1

einen perspektivischen Längsschnitt durch ein erfindungsgemäßes Schaltgerät,

Figur 2

eine perspektivische Darstellung der Schaltanordnung des Schaltgeräts gemäß Figur 1 ohne Gehäuse,

Figur 3

eine Seitenansicht der Schaltanordnung in vereinfachter Darstellung und

Figur 4

eine Lichtbogentreiberanordnung für ein Schaltgerät gemäß Figur 1.

A preferred embodiment is explained in more detail below with reference to the figures. Show here:

Figure 1

2 shows a perspective longitudinal section through a switching device according to the invention,

Figure 2

a perspective view of the switching arrangement of the switching device according to Figure 1 without housing,

Figure 3

a side view of the switching arrangement in a simplified representation and

Figure 4

an arc driver arrangement for a switching device according to Figure 1 ,

The Figures 1 to 3 show the switching device 1 according to the invention in perspective views, wherein in Figure 2 a housing 6 of the switching device is not shown for the sake of clarity and in Figure 3 in addition, the arc driver arrangement was omitted. The Figures 1 to 3 are described together below.

The electrical switching device 1 comprises a total of two poles, ie two switching paths, namely a first switching path 2 and a second switching path 3. The two switching paths 2, 3 are each provided with a switch, as explained in more detail below, and can thus be electrically interrupted. The two switching paths 2, 3 can each be integrated in a direct current circuit and serve to interrupt a current flow. In Figure 1 the first switching path 2 is shown on the left and the second switching path 3 on the right. In the following, the first switching path 2 will first be explained in a representative manner, the second switching path 3, in mirror image, being constructed in principle identically. Differences will be explained later. In the present case, the two switching paths 2, 3 are with regard to the arc line and delete differently designed. To clarify two variants, both variants were shown in the switching device 1. However, the switches can also be completely identical.

The switching device 1 comprises a housing 6 in which the switches are accommodated, as explained in more detail below. The first switching path 2 comprises a first connection 4 and a second connection 5 for connecting the first switching path 2 to connections of a direct current circuit. The two connections 4, 5 are guided in the same direction on the same side of the housing 6. The first connection 4 leads to a first contact pair 7, which is arranged in a first switching chamber 26 of the housing 6. The second connection 5 leads to a second contact pair 8, which is arranged in a second switching chamber 27 of the housing 6. The two switching chambers 26, 27 are electrically insulated from one another in the housing 6 and are arranged side by side. The first connection 4 is electrically connected to a first fixed contact carrier 10, on which a first contact 9 of the first contact pair 7 is arranged. A second contact 11 is movably arranged to the first contact 9. The second contact 11 is in the in Figure 1 shown representation vertically adjustable. The second contact 11 is provided on an electrically conductive contact carrier in the form of a bridge contact 12, which is adjustable via a switching bridge 13. In a switched-on state, the first contact 9 and the second contact 11 are kept in contact with one another. In one in Figure 1 Switched off state shown, the two contacts 9, 11 are kept out of contact with each other. The bridge contact 12 also carries a second contact of the second pair of contacts 8, which is concealed and therefore not visible here, the bridge contact 12 electrically connecting the two second contacts 11 to one another. The second contact of the second contact pair 8 is adjustably arranged to a first contact of the second contact pair 8 via the bridge contact piece 12 and the switching bridge 13, the first contact of the second contact pair 9 being arranged on a second fixed contact carrier which is electrically connected to the second connection 5 , By adjusting the switching bridge 13, the first switching path 2 is thus either closed or interrupted at both contact pairs 7, 8.

When the switching bridge 13 is moved into an open position, arcs can form between the contacts 9, 11 of the two contact pairs 7, 8 and must be extinguished. For this purpose, a first quenching device 14 is provided vertically above the first pair of contacts 7 and a second quenching device vertically above the second pair of contacts 8, not shown here for the sake of clarity, the two quenching devices 14 being constructed identically to one another. The first quenching device 14 is arranged on a side of the bridge contact piece 12 facing away from the first contact 9. The first quenching device 14 comprises first quenching plates 15, which are arranged parallel to one another and run parallel to the adjustment direction of the bridge contact piece 12.

In order to be able to move an arc which forms between the first contact 9 and the second contact 11 in the direction of the first quenching device 14, a first arc driver arrangement 16 is provided. In order to drive an arc, which is formed between the contacts of the second contact pair 8, into the second quenching device, a second arc driver arrangement 17 is provided. Figure 4 shows an example of the first arc driver arrangement 16, which shows a permanent magnet 28. The permanent magnet 28 is arranged between two flux guide pieces 29, 30 running parallel to the permanent magnet 28. The flux guide pieces 29, 30 and the permanent magnet 28 are in turn arranged between an outer pole plate 18 and an inner pole plate 19. Overall, the first arc driver arrangement 16 has an essentially U-shaped profile. Furthermore, the inner pole plate 19, which faces the interior of the switching device 1 and is arranged adjacent to the second arc driver arrangement 17, has a slot 33 through which the bridge contact piece 12 is guided around the second contacts 11 of the two arranged between the pole plates 18, 19 To connect contact pairs 7, 8 with each other.

The first arc driver arrangement 16 is also formed in one piece with a further first arc driver arrangement 16 'for the second switching path 3, the two first arc driver arrangements 16, 16' being formed in mirror image to a transverse plane of the switching device 1. The arc driver arrangements 16, 16 'of both current paths 2, 3 thus form an assembly which can be preassembled. The outer pole plates 18, 18 'and the inner pole plates 19, 19' of the two first arc driver arrangements 16, 16 'are each formed by a common sheet metal but separated from one another by a separating slot 31. This separation serves to homogenize the magnetic fields of the individual arc driver arrangements. Otherwise, a stronger magnetic field would form in the middle of the metal sheets, that is to say in the transition from one arc driver arrangement 16 to the other arc driver arrangement 16 ', than at the outer edges.

A continuous plate-shaped spacer 32 made of electrically insulating material is provided below the permanent magnets 28, 28 '. On the side facing away from the pole plates 18, 18 ', 19, 19', a shielding plate 35 is also provided on the spacer 32 in order to shield the magnetic fields generated by the permanent magnets 28, 28 'from below. This is intended to avoid influencing an actuating device for actuating the switching bridge 13. Below the switching device 1 there is usually an actuating device which has a magnetic switching coil, the permanent magnetic fields of the arc driver arrangements being able to negatively influence the switching behavior of the switching coil.

The arc guiding devices 20, 21 of the two contact pairs 7, 8 are of identical design, wherein in the following reference is made to the arc guiding devices 20, 21 of the first contact pair 7. A first arc guiding device 20 and a second arc guiding device 21 are provided on the first contact pair 7. The first arc guiding device 20 is used to conduct an arc with a first current direction. The second arc guiding device 21 is used to conduct an arc with a second current direction. Due to the magnetic field which is formed homogeneously between the pole plates 18, 19 from one pole plate 18, 19 to the other pole plate 19, 18 and thus perpendicular to an arc which forms between the first contact 9 and the second contact 11, a Lorenz force is exerted on the Arc exerted. Depending on the direction of the current, the arc is then in accordance with Figure 1 driven left or right. If the arc is in accordance Figure 1 Driven to the left, a first guide plate 22 is used and a second baffle 24 for driving the arc into the first quenching device 14. The first guide plate 22 is connected to the first fixed contact carrier 10 and initially runs in the in FIG Figure 1 Orientations of the switching device 1 shown horizontally to the left and is then deflected 90 ° and leads vertically upwards. The second guide plate 24 is formed on the bridge contact piece 12 and leads slightly bent upwards to the left. The arc therefore continues to form between these two baffles 22, 24 and is deflected upward by 90 °. In the further course, the arc will run along the rear side of the bridge contact piece 12 facing away from the first contact 9, the arc being driven successively into the gap between the individual first quenching plates 15. Blow-out openings 34 for blowing out the arc gases are provided on an upper side of the housing 6.

If the arc has a different current direction, it is driven to the right, the second arc guiding device 21 being embodied as a mirror image of a transverse plane to the first arc guiding device 20. Accordingly, a first guide plate 23 initially leads from the first fixed contact carrier 10 to the right and is then angled vertically upward at 90 °. Likewise, a second guide plate 25, which is formed by the bridge contact piece 12, is bent slightly upward, so that an arc is first deflected sideways to the right and then upwards. In the further course, the arc is driven to the rear of the bridge contact piece 12 on one side facing away from the first contact 9 and there is successively guided between the first quenching plates 15.

The first fixed contact carrier 10 and the first guide plates 22, 23 are U-shaped, the first guide plates 22, 23 being parallel and straight towards their ends. In this area, the two first baffles 22, 23 hold the first extinguishing device 14 between them, the baffles 15 being arranged parallel to the free ends of the first baffles 22, 23.

The arc guiding devices 20, 21 and the first quenching device for the first contact pair 7 are identical to the arc guiding devices and the second quenching device for the second contact pair 8.

In principle, the arc guiding devices 20 ', 21' of the second switching path 3 are constructed in the same way as the arc guiding devices 20, 21 of the first switching path 2. Components which correspond in their function are provided with the same reference numerals, but with a prime added. In the example shown, the second switching path 3 differ only with regard to the second guide plates 24 ', 25'. This further embodiment of the second guide plates 24 ', 25' is integrated in the same switching device 1 to simplify the illustration. In practice, preferably only one version of second guide plates 24, 14 ', 25, 25' would be installed in a switching device 1. The second guide plates 24 ', 25' are not only curved upwards, but are bent upwards to such an extent that they come into contact with the rear of the bridge contact 12 'and thus form closed rings. This is to ensure that the arcs can more easily follow the deflection to the rear of the bridge contact 12. The arrangement of the first quenching plates 15 'of the first quenching device 14' is such that they follow the shape of the second guide plates 24 ', 25' on their underside.

LIST OF REFERENCE NUMBERS

1

switchgear

2

first switching path

3

second switching path

4

first connection

5

second connection

6

casing

7

first pair of contacts

8th

second pair of contacts

9

first contact

10

first fixed contact carrier

11

second contact

12

Bridging contact member

13

jumper

14

first extinguishing device

15

first baffle

16

first arc drive arrangement

17

second arc drive arrangement

18

outer pole plate

19

inner pole plate

20

first arc guiding device

21

second arc guiding device

22

first baffle

23

first baffle

24

second baffle

25

second baffle

26

first switching chamber

27

second switching chamber

28

permanent magnet

29

flux conductor

30

flux conductor

31

separating slot

32

spacer

33

slot

34

exhaust vent

35

shield

Claims (13)

1. Switching device (1) suitable for direct current operation, comprising at least one contact pair (7, 8) having a first contact (9) and a second contact (11), wherein at least one of the two contacts (11) is movable, and the two contacts (9, 11) are in contact with each other in a switched-on state of the switching device (1) and are not in contact with each other in a switched-off state of the switching device (1), an arc driver arrangement (16, 17) which generates a magnetic field at least in the region of the contact pair (7, 8), and a first arc guiding arrangement (20) by means of which an arc produced between the contacts (9, 11) with a first current direction is guided to a quenching device (14) for quenching the arc, wherein a second arc guiding arrangement (21) is provided, by means of which an arc produced between the contacts (9, 11) with a second current direction, which is opposite the first current direction, is guided to said quenching device (14) for quenching the arc, wherein the quenching device (14) is constructed as a deionizing quenching chamber having a plurality of quenching plates (15) which are electrically isolated from one another and arranged parallel to one another,
   characterised in that
   the first arc guiding arrangement (20) and the second arc guiding arrangement (21) are designed such that, independently of its current direction, the arc is deflected into the same quenching device due to the arc being guided along a rear side of a bridging contact member (12) facing away from the first contact (9), wherein the arc is successively driven into gaps between the individual quenching plates (15).
2. Switching device according to claim 1, characterised in that the first arc guiding arrangement (20) is arranged such that an arc with a first current direction is deflected in a first direction of rotation and guided to the quenching device (14), and in that the second arc guiding arrangement (21) is arranged such that an arc with a second current direction is deflected in a direction of rotation opposite to the first direction of rotation and guided to the quenching device (14).
3. Switching device according to any of the preceding claims, characterised in that the first contact (9) is an immovable fixed contact and the second contact (11) is a movable contact, and in that the arc is deflected around the second contact (11) onto a side of the second contact (11) facing away from the first contact (9).
4. Switching device according to any of the preceding claims, characterised in that the quenching plates (15) are oriented parallel to the direction of motion of the at least one movable contact (11).
5. Switching device according to any of the preceding claims, characterised in that the arc guiding arrangements (20, 21) each comprise a first guide plate (22, 23) and a second guide plate (24, 25), wherein the two first guide plates (22, 23) extend outwards from the first contact (9) in opposite directions from each other.
6. Switching device according to claim 5, characterised in that the first guide plates (22, 23) are break-free.
7. Switching device according to any of claims 5 or 6, characterised in that the two first guide plates (22, 23) receive the quenching device (14) between them.
8. Switching device according to any of claims 5 to 7, characterised in that the two second guide plates (24, 25) are arranged on a contact support (12), which carries the second contact (11).
9. Switching device according to claim 8, characterised in that the second guide plates (24, 25) extend outwards from the second contact (11) in opposite directions from each other.
10. Switching device according to claim 9, characterised in that the second guide plates (24, 25) are angled towards the quenching device (14) at their free ends.
11. Switching device according to claim 9, characterised in that the second guide plates (24, 25) are curved into a ring at their free ends.
12. Switching device according to any of the preceding claims, characterised in that the arc guiding arrangement (16) comprises at least one permanent magnet (28) arranged between two pole plates (18, 19), wherein the contact pair (7, 8) is arranged between the pole plates (18, 19).
13. Switching device according to any of the preceding claims, characterised in that two contact pairs (7, 8), each having a first contact (9) and a second contact (11), forming a double-break switching arrangement, are provided, wherein the second contacts (11) are arranged on a bridging contact member (12), which is movable with respect to the first contacts (9), and in that, in the switched-on state of the switching device (1), the second contacts (11) are each in contact with one of the first contacts (9), and the bridging contact member (12) electrically interconnects the two second contacts (11).

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