EP2393096B1 - Easy to interrupt low voltage circuit breaker, in particular current protection switch - Google Patents

Description

TECHNICAL AREA

The present invention relates to a simple interrupting low-voltage switching device, in particular to a circuit breaker. In low-voltage distributors, such switching devices serve the rapid and reliable protection of low-voltage consumers, in particular lines, electric motors, systems or apparatus.

In this case, it is of decisive importance that, when a current is interrupted, the switching arc arising when a contact point of the switch is opened does not remain on contact points of the contact point, but gets as fast as possible into an arc extinguishing chamber of the switch, in which it is cooled and deleted by division into partial arcs.

Therefore, in addition to the contact point and the arc extinguishing chamber, the low-voltage switching device, in addition to two terminals, power connections and a triggering device for detecting the current in the switch also arc guide rails that guide the switching arc from the contact point to the arc extinguishing chamber, and means that support the guiding of the switching arc.

STATE OF THE ART

Low-voltage switchgear of the type mentioned are described in DE 195 24 915 C2 and in DE 33 34 852 A1 , In these devices, a first current conductor connecting a fixed contact of the contact point to a first terminal of the switch ( DE 195 24 915 C2 ), or in a second conductor connecting a movable contact of the pad with a second terminal ( DE 33 34 852 A1 ), one around the contact point Guided blown loop molded. This blown loop is therefore traversed by the current to be disconnected and generates a magnetic blower field. This blast field supports the intrinsic field of the switching arc. The switching arc is therefore additionally accelerated on its way from the contact point to the arc extinguishing chamber. There are thus achieved a shortening of the arc run time and, accordingly, an improved quenching behavior and an increase in the switching capacity of the switch.

PRESENTATION OF THE INVENTION

The invention, as indicated in the claims, the object is to provide a simple interrupting low-voltage switching device of the type mentioned, which is characterized despite a simple structure by a short arc runtime and a good erase behavior.

• eine erste und eine zweite Anschlussklemme,
• eine Kontaktstelle mit einem Festkontakt und mit einem beweglichen Kontakt,
• einen ersten Stromleiter, der die erste Anschlussklemme mit dem Festkontakt elektrisch leitend verbindet,
• einen zweiten Stromleiter, der die zweite Anschlussklemme mit dem beweglichen Kontakt elektrisch leitend verbindet,
• eine mit dem ersten Stromleiter elektrisch leitend verbundene erste Lichtbogenlaufschiene,
• eine zweite Lichtbogenlaufschiene,
• einen dritten Stromleiter, der den zweiten Stromleiter mit der zweiten Lichtbogenlaufschiene verbindet, und
• eine zwischen der ersten und der zweiten Lichtbogenlaufschiene angeordnete Lichtbogenlöschkammer.

The simple interrupting low-voltage switching device according to the invention comprises:

• a first and a second terminal,
• a contact point with a fixed contact and with a moving contact,
• a first conductor electrically connecting the first terminal to the fixed contact,
• a second conductor electrically connecting the second terminal to the movable contact,
• a first arc runner electrically connected to the first conductor;
• a second arc runner,
• a third conductor connecting the second conductor to the second arc track, and
• an arc quenching chamber disposed between the first and second arc runners.

In this switching device, the interruption of a current, the movable contact moves on a plane against the second arc track and forms when opening the contact point lying in the plane through which Distance of the separating contacts certain switching distance. In addition, a foot point, held on the moving contact, of a switching arc formed when the contact point is opened passes from the moving contact to the second arc running rail, and the current commutes in the third current conductor.

The first conductor of this switching device has a parallel to the plane, the switching path bridging and arranged on the side facing away from the arc quenching chamber side of the switching path first conductor section. The third conductor has a parallel to the plane, the switching path bridging second conductor portion. During the interruption process, both the first and the second conductor sections conduct the current counter to their direction in the switching arc.

The low-voltage switching device according to the invention therefore has instead of a complex Blasschleife in the vicinity of the switching path and the two arc run rails on the two formed by the first and second conductor portion current return. These power returns are easy to design and take up little space. Since the current to be interrupted in the two conductor sections is guided in each case against its direction in the switching arc, push both conductor sections together from the switching arc. Since the third conductor and thus the second conductor section integrated into it lead only after the transition of the arc root on the second arc run the current to be interrupted, are from this time particularly large electromagnetic forces available, the fast on the two arc runners switching arc in drive the arc extinguishing chamber. Since the second conductor section is involved in the structure of the electromagnetic forces only after the commutation of the current in the third conductor, it can like the first conductor section on the side facing away from the arc extinguishing chamber side of the switching path, but can also be arranged on the arc extinguishing chamber side facing the switching path be. In any case, the low-voltage switching device according to the invention is characterized by a simple structure, a short arc duration and a good extinguishing ability.

The first conductor section may extend predominantly parallel to the switching path, while the second conductor section may have a smaller distance from the arc extinguishing chamber than the first conductor section. In a further developed switching device according to the invention, the switching arc can be erased particularly quickly and safely. This is mainly because the second conductor section positioned closer to the arc extinguishing chamber acts on the switching arc after the current commutation with greater electromagnetic forces than the first conductor section, and since the arc is driven particularly rapidly into the arc extinguishing chamber after its transition to the arc running rails.

In order to change the direction of the switching arc between the switching path and the quenching chamber strongly, typically by 90 °, with arcuately running arc runners, to rapidly drive the switching arc into the arc quenching chamber, the second conductor section may be inclined relative to the first conductor section.

The transition of the moving contact on the moving contact arc on the second arc run rail and thus the commutation of the current to be interrupted in the second conductor section can be facilitated if the second conductor has a parallel to the plane extending third conductor section, in which the current before commutation is guided against its direction in the switching arc.

In order to achieve electromagnetic forces that promote the transition of the switching arc from the movable contact to the second arc run rail and thus facilitate the commutation of the current to be disconnected in the second conductor section, the first and the third conductor portion respectively spaced from the plane to both sides of the Be arranged level, wherein the distance of the first conductor portion is smaller than the distance of the third conductor portion.

The third conductor section can be designed to be flexible and, in a production-wise advantageous manner, can be attached with one of its two ends in an electrically conductive manner on an end of a contact carrier of the movable contact brought out of the plane. The other end of the third Conductor portion may be electrically connected to a power connector of a built-in second conductor coil of a short-circuit current release.

An effect of the electromagnetic forces which promotes the entire interruption process can be achieved if the second and third conductor sections are arranged on the same side of the plane, with the proviso that the second conductor section is closer to the plane than the third conductor section.

In a low-voltage switchgear according to the invention, wherein the first terminal, the pad, the first and second arc run rails, the arc extinguishing chamber and the second terminal are sequentially arranged in line, the second current conductor may be one between the second terminal and the arc extinguishing chamber Having arranged fourth conductor section, which is aligned perpendicular to the quenching plates of the arc quenching chamber and in which the current to be interrupted when entering the switching arc in the arc extinguishing chamber has the same sense as the switching arc. In such an embodiment, the shrinkage of the switching arc in the arc quenching chamber is promoted even more and, accordingly, the arc time is additionally shortened.

BRIEF DESCRIPTION OF THE FIGURES

Fig.1

eine Seitenansicht der stromführenden Aktivteile eines als Leitungsschutzschalter ausgebildeten Niederspannungsschaltgeräts nach der Erfindung beim Unterbrechens eines Kurzschlussstroms,

Fig.2

eine von rechts in Richtung von Pfeilen II-II geführte Aufsicht auf einen als Lichtbogenlöscheinrichtung ausgeführten Teil des Schalters gemäss Fig.1, und

Fig.3

eine längs Pfeilen III-III geführte Draufsicht auf die Lichtbogenlöscheinrichtung gemäss Fig.2.

With reference to drawings, an embodiment of the invention will be explained in more detail below. Hereby shows:

Fig.1

a side view of the live active parts of a designed as a circuit breaker low-voltage switchgear according to the invention when interrupting a short-circuit current,

Fig.2

a guided from the right in the direction of arrows II-II view of an executed as arc quenching part of the switch according to Fig.1 , and

Figure 3

a longitudinal arrows III-III guided top view of the arc quenching device according to Fig.2 ,

WAYS FOR CARRYING OUT THE INVENTION

In all figures, like reference numerals refer to like parts. The in Fig. 1 illustrated circuit breaker has in a line lying in order a terminal 10, an arc quenching device with a single-break pad 20, with two arc runners 30, 40 and with an arc extinguishing chamber 50 and a terminal 60 on. The contact point 20 includes a fixed contact 21 which is held in an electrically conductive manner on a conductor 10 connected to the terminal 10, and a cooperating with the fixed contact 21 movable contact 22 in an electrically conductive manner on a pivotally mounted about an axis 23 contact carrier 24 is held. The contact carrier 24 is connected via a sectionally flexible conductor 80 formed in an electrically conductive manner with the terminal 60. The arc runner 30 is electrically connected to the current conductor 70, whereas the arc runner 40 is electrically connected to the current conductor 80. The arc runners 30, 40 extend in one of the FIGS. 2 and 3 apparent level E. Between the two arc run rails 30 and 40, an arc quenching chamber 50 is arranged, which has a stack of parallel aligned and spaced apart quenching plates 51.

The current conductor 70 has a rigidly formed conductor section 71, which extends parallel to the plane E, whereas the current conductor 80 has a conductor section 81 which extends parallel to the plane but is flexible, typically in the form of a stranded wire. From the FIGS. 1 and 3 It can be seen that each of the two sections 71, 81 extends at least in sections parallel to a lying in the plane E switching path S, which forms when opening the switch between the separating contacts 21, 22. In manufacturing technology advantageously, the conductor portion 71 - as in the FIGS. 2 and 3 shown - with one of its two ends on a guided out of the plane Traverse 72 electrically connected to the contact 21. The movable contact 22 is electrically conductively connected to the one end of the contact carrier 24 which can also be used for double-break switches. The other end of the contact carrier 24 is electrically conductively connected via the conductor section 81 in manufacturing technology advantageously with a power connection 82 of an integrated in the conductor 80 coil 83 of a short-circuit current release of the switch.

The power connection 82 and the arc running rail 40 integrated into the current conductor 80 are connected to one another by a conductor piece 84 configured as a stranded wire, which has a conductor section 85 running parallel to the plane E according to FIG Figure 3 has a smaller distance from the plane E than the conductor portion 81. Both the conductor section 85 and the conductor section 71 bridge the switching path S and therefore have a longitudinal extent corresponding to the switching path when the switch is open.

When the switch is closed, the movable contact 22 is supported to form contact force on the fixed contact 21. An indicated by arrows short-circuit current C then flows from the terminal 10 via the conductor 70, the fixed contact 21, the movable contact 22, the contact carrier 24 and the current conductor 80 to the terminal 60. To interrupt the short-circuit current C, the contact point 20 is opened and this case the contact carrier 24 resp. the movable contact 22 is pivoted in the plane E counterclockwise about the axis 23. In this case, the movable contact 22 separates from the fixed contact 21 to form a footing on the two contacts 21, 22, lying in the plane E switching arc L. Also in the plane E is located in Figure 3 characterized switching path S.

As in the FIGS. 1 and 3 shown, the short-circuit current C to be interrupted in the two conductor sections 71 and 81 is guided in each case against its direction in the switching arc L. Therefore, the two conductor sections push the switching arc L due to electromagnetic forces. The two conductor sections 71 and 81 are arranged so that a directed towards the quenching chamber 50 component of the electromagnetic forces has sufficient size to ensure a rapid transition of the on the movable contact 22 located to ensure the base point of the switching arc from the contact 22 on the arc guide rail 40.

In order to achieve a sufficiently dimensioned force component with simple means, the conductor section 71 is arranged on the side facing away from the arc extinguishing chamber 50 side of the switching path S. Because the conductor section 81 is likewise arranged on this side, that is to say above the switching path S, a force component of the repulsive, electromagnetic forces which particularly promotes the transition of the arc root point to the arc running rail 40 is achieved at the beginning of the interruption process.

If the conductor section 81 is arranged below the switching path S, that is, if it is located on the side of the switching path S facing the arc-quenching chamber 50, then it has - as shown in FIGS FIGS. 2 and 3 can be seen - a greater distance to the plane E than the conductor portion 71. Also in this case, a sufficiently large for the transition of the arc root force component is achieved.

A force component exerting the aforementioned effect is achieved with certainty if the conductor sections 71 and 81 are positioned in a plane normal to the plane E and laid through the switching path S normal plane N equidistant to the plane E, and if in the normal plane N of ( Leading the current C) conductor section 71 to (the current C leading) conductor section 81 guided straight line G - based on the course of the arc bars 30, 40 - on the side facing away from the arc extinguishing chamber 50 side of the - the base of the arc L receiving - switching path S - So above the switching path - runs.

At the transition of the arc root from the movable contact 22 to the arc rail 40, the current C commutates in the current conductor 80 and is now guided by the arc L 'on the arc rail 40, the conductor 84 and the conductor 80 to the terminal 60. In the conductor section 85, the short-circuit current has the same sense of direction as before in the conductor section 81. The repulsive, electromagnetic forces are now generated in the two conductor sections 71 and 85. These forces drive the arc on the two arc runners 30 and 40 switching arc L 'in the Arc quenching chamber 50 of the switch in which it is divided by the quenching plates 51 in partial arcs, cooled and deleted.

As can be seen, the conductor section 85 has a smaller distance from the plane E than the conductor section 81. The component of the electromagnetic forces driving the switching arc L 'is thus increased. At the same time, the conductor section 85 is guided closer to the arc extinguishing chamber 50 than the conductor section 71. By this measure, the running of the switching arc L in the arc extinguishing chamber 50 is particularly effectively supported.

In order to generate sufficiently large, electromagnetic forces at the beginning of the interruption process, runs - as in Fig.1 shown - the conductor portion 71 mainly parallel to the switching path S. Extends - as in Fig.1 shown - the switching path S mainly parallel to the quenching plates 51 and accordingly change the arc running rails 30, 40 between the switching path S and the quenching chamber 50 their direction by about 90 °, it is advantageous, the conductor portion 85 relative to the first conductor portion 71, respectively. the quenching plates 51 typically arranged inclined by 30 to 60 °. After the commutation of the current then in spite of the curved course of the arc runners 30, 40 of the arc L 'and the conductor portion 85 are arranged over a substantial part of the path of the arc L' predominantly parallel to each other.

In order to facilitate the switching arc entering the arc quenching chamber 50 and its division into the partial arcs, the conductor 80 has a arranged between the terminal 60 and the arc extinguishing chamber 50 conductor portion 86 which is aligned perpendicular to the quenching plates 51 and only a small distance to Arc quenching chamber 50 has. The short-circuit current to be interrupted has the same sense of direction in this section as in the switching arc L '. Therefore, the short-circuit current in the conductor section 86 generates electromagnetic forces, the switching arc S resp. tighten the partial arcs and thus additionally improve the extinguishing capacity of the switch.

LIST OF REFERENCE NUMBERS

10

terminal

20

contact point

21

fixed contact

22

moving contact

23

axis

24

contact support

30, 40

Arc guide rails

50

Arc chute

51

splitters

60

terminal

70

conductor

71

conductor section

72

traverse

80

conductor

81

conductor section

82

power connection

83

Kitchen sink

84

power connection

85, 86

conductor sections

e

level

G

connecting line

L, L '

Switching arc

N

normal level

S

contact gap

Claims (8)

1. Easily interruptible low-voltage switching device, comprising a first connection terminal (10) and a second connection terminal (60), a contact point (20) with a fixed contact (21) and with a movable contact (22), a first electrical conductor (70), which electrically conductively connects the first connection terminal (10) to the fixed contact (21), a second electrical conductor (80), which electrically conductively connects the second connection terminal (60) to the movable contact (22), a first arc guide rail (30), which is electrically conductively connected to the first electrical conductor (70), a second arc guide rail (40), a third electrical conductor (84), which connects the second electrical conductor (80) to the second arc guide rail (40), and an arc quenching chamber (50), which is arranged between the first arc guide rail (30) and the second arc guide rail (40), in which easily interruptible low-voltage switching device, when a current (C) is interrupted, the movable contact (22) moves on a plane (E) towards the second arc guide rail (40) and, when the contact point (20) opens, a switching path (S) lying on the plane (E) and determined by the distance of the isolating contacts (21, 22) is formed, and in which a root point, which is held on the movable contact (22), of a switching arc (L) formed during opening of the contact point (20) passes from the movable contact (22) to the second arc guide rail (40) and in the process the current (C) commutates to the third electrical conductor (84), characterized in that the first electrical conductor (70) has a first conductor section (71), which runs parallel to the plane (E), bridges the switching path (S) and is arranged on that side of the switching path (S) which is remote from the arc quenching chamber (50), in that the third electrical conductor (84) has a second conductor section (85), which runs parallel to the plane (E) and bridges the switching path (S), and in that, during the interruption operation, the current (C) is guided both in the first conductor section (71) and in the second conductor section (85) counter to its direction in the switching arc (L, L').
2. Switching device according to Claim 1, characterized in that the first conductor section (71) runs predominantly parallel to the switching path (S), and in that the second conductor section (85) has a shorter distance from the arc quenching chamber (50) than the first conductor section (71).
3. Switching device according to Claim 2, characterized in that the second conductor section (85) is arranged so as to be inclined with respect to the first conductor section (71).
4. Switching device according to one of Claims 1 to 3, characterized in that the second electrical conductor (80) has a third conductor section (81) which runs parallel to the plane (E) and in which the current (C) is guided counter to its direction in the switching arc (L) prior to its commutation to the third electrical conductor (84).
5. Switching device according to Claim 4, characterized in that the first conductor section (71) and the third conductor section (81) are each arranged at a distance from the plane (E) on both sides of the plane, wherein the distance of the first conductor section (71) is shorter than the distance of the third conductor section (81).
6. Switching device according to either of Claims 4 and 5, characterized in that the third conductor section (81) is flexible and is fitted with one of its two ends electrically conductively on one end, passed out of the plane (E), of a contact carrier (24) of the movable contact (22), and in that the other end of the third conductor section (81) is electrically conductively connected to an electrical connection (82) of a coil (83) of a short-circuit current release, said coil being integrated in the second electrical conductor (80).
7. Switching device according to one of Claims 4 to 6, characterized in that the second conductor section (85) and the third conductor section (81) are arranged on the same side of the plane (E), wherein the second conductor section (85) has a shorter distance from the plane (E) than the third conductor section (81).
8. Switching device according to one of Claims 1 to 7, in which the first connection terminal (10), the contact point (20), the two arc guide rails (30, 40), the arc quenching chamber (50) and the second connection terminal (60) are arranged in series in a line, characterized in that the second electrical conductor (80) has a fourth conductor section (86), which is arranged between the second connection terminal (60) and the arc quenching chamber (50) and is aligned perpendicular to arc splitter plates (51) of the arc quenching chamber (50), and in which the current (C) to be interrupted has the same direction as the switching arc (L') when the switching arc (L') runs into the arc quenching chamber (50).

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