EP2079088A2 - Switching device, in particular voltage switching device with two switched switch contact pairs arrayed in a row for interrupting an electricity flow. - Google Patents

Abstract

The switchgear (1) has two switch contact pairs (2, 3) for breaking a flow path (4) of current. A discharge packet (5) is arranged in a region of the switch contact pairs for discharging electric arcs (6) that are developed while opening the flow path, where opening paths (7) of the switch contact pairs run parallel or anti-parallel to each other. The switch contact pairs are switched in series such that same current (i) flows in the electric arcs in same direction. The discharge packet is arranged in a region between the two opening paths.

Description

The invention relates to a switching device with two series-connected switching contact pairs for interrupting a current path and with at least one arranged in the region of the switching contact pairs erase package for deleting the arcs resulting from the opening of the current path. The switching contact pairs are arranged such that their opening paths are substantially parallel or antiparallel to each other.

The invention relates in particular to switching devices, in particular to power switching devices in the low voltage range, that is up to voltages of about 1000 volts. Such switching devices are designed in particular for interrupting current paths in the event of a short circuit or in an overcurrent situation. Furthermore, the switching devices can be single-pole or multi-pole, in particular three-pole.

The considered power switching devices are e.g. so-called MCCB switching devices (for Molded Case Circuit Breaker). In such a switching device, the current to be interrupted is interrupted before it reaches its maximum value by the switch contacts of the MCCB are pulled apart by electromagnetic repulsion of adjacent conductors and so the power is interrupted. The maximum current can be in the one to three-digit kA range.

Alternatively or additionally, the switching contacts may be e.g. be operated by means of a preferably electromagnetically actuated actuator. The actuator may e.g. be controlled by an overcurrent detection unit.

The or in the range of switching contact pairs or the double contact used extinguishing packages are used for cooling the hot arc plasma when opening the switch contacts. By cooling the plasma, the electrical conductivity is reduced in such a way that the resistance in the arc is increased, the counter voltage is increased and the current is interrupted.

The problem with the current switching devices is that the arcs that occur when opening the switch contacts tend rather to not run into the cold sheets. To remedy this problem, it is e.g. known to use so-called Blasmagnete. Nevertheless, this solution is not satisfactory or too expensive for all switching operations.

Based on the above-mentioned prior art, it is therefore an object of the invention to provide an improved switching device.

The object of the invention is achieved by a switching device, in particular by a power switching device, having the features of patent claim 1. Advantageous embodiments are specified in the dependent claims 2 to 11.

According to the switching contact pairs are connected in series such that the same current flowing in both arcs flows spatially in the same direction. The extinguishing package is arranged in the area between the two opening tracks.

An essential basic idea of the invention is that rectified currents attract each other due to the acting Lorentz force. In other words, the two arcs through which the same current flows attract each other. Because the erase packet is arranged between the two arcs, they are driven into the erase package, so to speak. The two arcs are cooled rapidly and consequently the current advantageously interrupted quickly.

According to one embodiment of the invention, the switching contact pairs each have a movable switching contact and in each case a fixed contact. One of the movable switching contacts is electrically connected to the fixed contact of the other switching contact pair. The remaining two switching contacts are each connected to the current path. By this circuit arrangement ensures that the current flows in the two arcs in the same direction.

According to a further embodiment, the two movable switching contacts are each pivotally mounted about a pivot point. It adjoin the two free ends of the movable switch contacts to the extinguishing package, with a minimum air gap of a few millimeters is maintained. The free ends of the switching contacts usually each have a switching contact piece. Due to the pivotable mounting is advantageously a quick opening of the switch contacts possible.

According to another embodiment, the free ends of the two movable switch contacts move in the same direction when opening. Alternatively, the free ends of the two movable switch contacts can move away from each other when opening.

According to a particular embodiment, the switching contact pairs each have two movable switching contacts, which then move away from each other when opening. The free ends of the switching contacts adjoin the extinguishing package. It is one of the movable switching contacts electrically connected to the respective movable switching contact of the other switching contact, which moves when opening substantially in the opposite direction.

The simultaneous opening of the switching contact pairs allows in comparison to the previous solution an even faster opening, that is an even faster construction of an air separation path between two switching contacts of a switching contact pair. The opening of the switch contact pairs can followed by one actor each. It may alternatively or additionally be due to electromagnetic repulsion of the switching contacts, in particular by the flowing short-circuit current. In the latter case, the geometric arrangement and design of the switching contacts takes place so that substantially repulsive forces act on the two movable switching contacts. This can be done for example by a known U-shaped design of the fixed contacts.

According to one embodiment, the switching contact pairs each have two switching contacts which pivot away from one another when opening. Alternatively, the switching contact pairs may each have two, parallel to each other when opening moving away switching contacts.

In these two cases, no pivoting movement of the switching contacts, but a linear guided movement of the switching contacts away from each other. Preferably, the movable contacts are then movably connected via a movable strand to the connection conductor or to the current path.

According to a further embodiment, the erase packet consists of an electrically non-conductive material. Such a material is e.g. a thermoplastic or a ceramic. This prevents the two deletion packages from taking the "shortcut" over the deletion package. In such a case, the voltage path required to extinguish the current would no longer suffice, and consequently the current would not be interrupted or interrupted too slowly.

The aforementioned quenching packet should preferably also have a partition made of an electrically non-conductive material. In this case, it is ensured with particular certainty that when the two arcs run in, there is no connection between the two arcs and thus a shortcut through the erase packet.

According to a further embodiment, the erase package is made of an electrically conductive material, in particular of a metal such as iron. The extinguishing package in this case necessarily has a partition made of an electrically non-conductive material. The particular advantage is that the high and rapid heat absorption capacity of the metallic extinguishing package particularly fast erasure of the two arcs is possible.

FIG 1

ein Beispiel für ein erfindungsgemäßes Schaltgerät nach einer ersten Ausführungsform in einer Seitenansicht,

FIG 2

das Schaltgerät gemäß FIG 1 in einer Draufsicht,

FIG 3

eine zweite Ausführungsform des erfindungsgemäßen Schaltgerätes in einer Seitenansicht,

FIG 4

eine dritte Ausführungsform des erfindungsgemäßen Schaltgerätes in einer Seitenansicht,

FIG 5

eine vierte Ausführungsform des erfindungsgemäßen Schaltgerätes in einer Seitenansicht mit geschlossenen Schaltkontakten und

FIG 6

das Schaltgerät gemäß FIG 5 mit öffnenden Schaltkontakten.

The invention as well as advantageous embodiments of the invention will be described in further reference to the following figures. Show it

FIG. 1

an example of an inventive switching device according to a first embodiment in a side view,

FIG. 2

the switching device according to FIG. 1 in a plan view,

FIG. 3

A second embodiment of the switching device according to the invention in a side view,

FIG. 4

A third embodiment of the switching device according to the invention in a side view,

FIG. 5

a fourth embodiment of the switching device according to the invention in a side view with closed switch contacts and

FIG. 6

the switching device according to FIG. 5 with opening switch contacts.

FIG. 1 shows an example of a switching device 1 according to the invention according to a first embodiment in a side view. In the case of the switching device 1 shown, two switching contact pairs designated by the reference symbols 2, 3 are provided for interrupting a current path 4. The current i to be interrupted by the inventive switching device 1 flows in the FIG. 1 left to right. In the example of FIG. 1 the switching contact pairs 2, 3 each have a movable switching contacts 21, 31 and in each case a fixed contact 22, 32.

According to the invention, the switching contact pairs 2, 3 are connected in series in such a way that the same current i flowing in the two arcs 6 flows spatially in the same direction. The current direction is symbolized by an arrow approximately in the middle of the two arcs 6. This is achieved for the present embodiment in that exactly one of the movable switching contacts 31 is electrically connected to the fixed contact 22 of the other switching contact pair 2. The remaining switching contacts 21, 32 are each connected to the current path 4 via a connecting conductor 8.

In the present FIG. 1 Thus, the current i coming from the left flows over the left partial arc 61 of the first switching contact pair 2 from top to bottom. It continues to flow via the connecting conductor 8 to the movable switching contact 31 of the right switching contact pair 3 to continue from there via the right part of the arc 62 from top to bottom to the right flow path 4 on. In a corresponding manner, the current directions are reversed when the current i would flow from right to left into the switching device 1. In this case too, the same current i flowing in both arcs 6 flows spatially in the same direction, ie from bottom to top.

Furthermore, the deletion package 5 according to the invention between the two opening paths 7, that is, between the free ends of the switching contacts 21, 22, 31, 32, respectively. The opening tracks 7 are characterized by an arrow opposite the direction of the flow. The opening of the switching contact pairs 2, 3 takes place in accordance with the illustration shown from bottom to top. Furthermore, the two movable switching contacts 21, 31 are each pivotally mounted about a pivot point 10. The two free ends of the switching contacts 21, 31, that is in particular the switching contact pieces 11 of the two switching contacts 21, 31, adjoin the extinguishing package 5.

As the FIG. 1 further shows the two arcs 6 are moved by the acting Lorentz force F in each case towards the extinguishing package 5 out. The Lorentz force F is the cross product of the current i as well as of the magnetic field, ie the magnetic induction B1, B2. For the left partial arc 61, the current i flows perpendicular to the magnetic field B1, which is generated by the right current i in the partial arc 62. Due to the Lorentz force F, the left partial arc 61 is pressed into the extinguishing package 5, so to speak. In the right part of the FIG. 1 the magnetic field B2 is shown, which is generated by the left current i in the left partial arc 61. In this case, the right partial arc 62 is pressed by the acting Lorentz force F to the left in the extinguishing package 5. This is symbolized by the dashed representation of the two arcs 6. The two arcs 6 are thus cooled rapidly and the current i is interrupted quickly.

The reference symbol E denotes a sectional plane perpendicular to the image plane of the FIG. 1 runs and to which the switching contact pairs 2, 3 are arranged symmetrically. The reference character L designates the longitudinal extension or symmetry axis of the deletion package 5. By the reference numeral 9, a partition wall is referred to, which electrically separates the two arcs 6 from each other. The not further designated plates of the extinguishing package 5 itself are exemplified of an electrically non-conductive plastic, such as made of a thermoplastic. The thermoplastic may be, for example, a polybutylene terephthalate (= PBT) or a polyoxymethylene (= POM). Such thermoplastics are characterized by a high mechanical strength, by a very good dimensional stability and by an excellent heat aging behavior.

The extinguishing package 5 can moreover be made of a magnetic material, in particular of a ferromagnetic material. In this case, the two arcs 6 are further pressed by the magnetic amplification in the deletion package 5 shown. An electrically non-conductive plastic and at the same time magnetically conductive plastic can e.g. be a previously described thermoplastic, in whose matrix ferromagnetic particles, such as metallic iron, cobalt, nickel particles or alloys thereof are introduced. Such a plastic preferably has a magnetic permeability of more than 10.

Alternatively, the plastic may also be an electrically conductive plastic, if a corresponding electrically non-conductive partition wall 9 is inserted in the extinguishing package 5 in order to electrically separate the two switching contact pairs 2, 3 from each other. Conductive plastics can e.g. by the addition of electrically conductive substances, such as metals, carbon black or graphite, or by suitable doping of electrically non-conductive polymers.

FIG. 2 shows the switching device 1 according to FIG. 1 in a top view. In this illustration, it can be seen that the connecting conductor 8 is guided around the extinguishing package 5 and around the switching contact pair 3 in order to effect a corresponding current flow in the opposite direction. The reference character Q denotes a transverse symmetry axis of the erase packet 5. By the reference numeral S, the pivot axes of the pivotally designed switching contacts 21, 31 are designated.

FIG. 3 shows a second embodiment of the switching device 1 according to the invention in a side view. In the example shown, the movable switching contacts 21, 31 move linearly from the fixed contacts 22, 32 along the registered opening path 7 away from bottom to top. The movement takes place in the example of FIG. 3 in each case via an actuator designated by the reference numeral 12. The two actuators 12 are preferably summarized to an actuator 12. In addition, the two movable switching contacts 21, 31 are electrically connected via a movable strand to the current path 4 and to the connecting conductor 8, respectively.

FIG. 4 shows a third embodiment of the switching device 1 according to the invention in a side view. In this case, the free ends of the two movable switching contacts 21, 32 'are formed such that they move away from each other when opening. The illustrated left switch contact 21 moves from bottom to top. In contrast, the right movable switch contact 32 'moves from top to bottom. Also in this embodiment, the two arcs 6 are driven by the acting Lorentz force F in the extinguishing package 5.

FIG. 5 shows a fourth embodiment of the switching device 1 according to the invention in a side view with closed switching contacts 21, 22 ', 31, 32'. The latter are each arranged pivotably about a pivot point 10. The contact pieces 11 of the switching contact pairs 2, 3 lie in a ground plane G, which is arranged perpendicular to the sectional plane E. The switching contact pairs 2, 3 shown are preferably arranged in mirror image to both planes G, E. The free ends of the switching contacts 21, 22 ', 31, 32' in turn adjoin the extinguishing package 5.

FIG. 6 shows the switching device 1 according to FIG. 5 with opening switching contacts 21, 22 ', 31, 32', which move away from each other. It is one of the movable switching contacts 22 'electrically connected to the respective movable switching contact 31 of the other switching contact pair 2, which moves when opening substantially in the opposite direction. In this case, the two movable switching contacts 21, 32 'pivot in the counterclockwise direction SL and the two other movable switching contacts 22', 31 in the clockwise direction SR. Also in this embodiment, the current i flows again in the same spatial direction, that is, from top to bottom.

As in all embodiments shown, the current i flow in the two arcs 6 spatially in the same direction, regardless of whether the current i flows over the current paths 4 from left to right or vice versa from right to left. The switching device 1 according to the invention is thus suitable for interrupting direct currents as well as alternating currents.

LIST OF REFERENCE NUMBERS

1

Switching device, power switching device, MCCB

2, 3

Switching contact pairs

4

current path

5

extinguishing package

6

electric arc

7

opening track

8th

Connecting conductor, connecting track

9

partition wall

10

Fulcrum, joint

11

contact piece

12

actuator

13

braid

21, 31,

movable switching contact

22 ', 32' 22, 32

fixed contact

61, 62

Partial arcs

i

electricity

e

plane of symmetry

G

ground plane

L

longitudinal extension

F

Strength, Lorentz force

B1

magnetic field, magnetic induction of the second part arc

B2

magnetic field, magnetic induction of the first part arc

S

Rotary axis, swivel axis

SL

counterclockwise

SR

clockwise

Claims (11)

Switching device, in particular power switching device, with two series-connected switching contact pairs (2, 3) for interrupting a current path (4) and with at least one in the region of the switching contact pairs (2, 3) arranged deletion package (5) for deleting the opening when the current path (4 ) resulting arcs (6), wherein the switching contact pairs (2, 3) are arranged such that their opening paths (7) are substantially parallel or antiparallel to each other,
characterized, - That the switching contact pairs (2, 3) are connected in series such that in the two arcs (6) flowing the same current (i) flows spatially in the same direction and - That the deletion package (5) is arranged in the region between the two opening tracks (7). Switching device according to claim 1,
characterized,
in that the switching contact pairs (2, 3) each have a movable switching contact (21, 31) and a fixed contact (22, 32) each, electrically connecting one of the movable switching contacts (31) to the fixed contact (22) of the other switching contact pair (2) is and that the remaining switching contacts (21, 32) are each connected to the current path (4). Switching device according to claim 2,
characterized,
in that the two movable switching contacts (21, 31) are each pivotably mounted about a pivot point (10) and that the two free ends of the movable switching contacts (21, 31) adjoin the extinguishing packet (5). Switching device according to claim 3,
characterized,
that the free ends of the two movable switching contacts (21, 31) move in opening in substantially the same direction. Switching device according to claim 3,
characterized,
that the free ends of the two movable switching contacts (21, 32 ') move away from each other when opening. Switching device according to claim 1,
characterized,
in that the switching contact pairs (2, 3) each have two movable switching contacts (21, 22 ', 31, 32') which move away from one another during opening, that the free ends of the switching contacts (21, 22 ', 31, 32') deleting the erase packet (5) and that one of the movable switching contacts (22 ') with the respective movable switching contact (31) of the other switching contact pair (2) is electrically connected, which moves when opening substantially in the opposite direction. Switching device according to claim 6,
characterized,
in that the switching contact pairs (2, 3) each have two switching contacts (21, 22 ', 31, 32') which pivot away from each other when opening. Switching device according to claim 6,
characterized,
in that the switching contact pairs (2, 3) each have two switching contacts (21, 22 ', 31, 32') which move away from one another in parallel when opening. Switching device according to one of claims 1 to 8,
characterized,
that the extinguishing package (5) consists of an electrically non-conductive material. Switching device according to claim 9,
characterized,
and that the extinguishing package (5) has a partition (9) made of an electrically non-conductive material. Switching device according to one of claims 1 to 8,
characterized,
that the extinguishing package (5) of an electrically conductive material, in particular of a metal, and in that the extinguishing package (5) has a partition (9) made of an electrically non-conductive material.

Images