Isolator

Abstract

The isolator has a busbar, which passes through a cavity (20) delimited by a cavity wall (24), and a separating piston for splitting the busbar at at least one predetermined breaking point. The separating piston can be moved in the cavity (20) towards the busbar by means of a drive. Furthermore, there is provision for a fuse conductor (2) having at least one separating point (5, 6) that can be opened by a separating element (10, 11; 17; 104, 104'). The at least one separating point (5, 6) is arranged in a separating chamber (7, 8; 15a, 15b) filled with an arc-quenching material. According to the invention, after separation, one separating-point end (31) of the fuse conductor (2) is pulled out of the separating chamber (7, 8; 15a, 15b), and the other separating-point end (31') is located within the arc-quenching material. After separation, there is preferably at least a portion of a gap (30) with a thickness of at most 1 mm between the two separating-point ends (31, 31'). As a result, arcs at relatively low currents of, for example, 2 kA are reliably quenched despite high inductance, because they are squeezed in the gap. This effect can be further improved by providing a seal (201).

Description

Circuit breaker

[0001] The present invention relates to a current disconnector with a busbar penetrating a cavity bounded by a cavity wall, a separating piston for separating the busbar at at least one predetermined breaking point, wherein the separating piston can be moved towards the busbar in the cavity by a drive, preferably a pyrotechnic drive, and with a fuse conductor having at least one separation point separable by a separating element, such that separation at the at least one separation point creates two separation point ends in the fuse conductor, which are spaced apart from each other after separation, wherein the at least one separation point is arranged in a separation chamber which is / are filled with an arc-quenching material.

[0002] With the energy transition towards renewable energy sources, the number of electrically powered vehicles has increased, and with it, the need for safety devices for their operation. While protecting vehicles against the effects of short circuits is already well-addressed, the ever-expanding charging infrastructure presents new challenges due to high currents and inductances. The energy generated is too great for current-generation disconnectors, necessitating the development of new solutions. Scaling up existing disconnectors to larger dimensions is possible but not economically viable; however, the use of fusible links or fuse conductors offers significant potential.

[0003] Current disconnectors, particularly for electric vehicles, where a fuse conductor is present, are known, for example, from DE 112022005160 T5, WO 2020 / 204154 A1, US 2024 / 258055 A1, or CN 213601831 U. These disclose current disconnectors in which the fuse conductor is mechanically pulled apart and thereby severed. However, an arc can occur when the fuse conductor is severed, which is particularly difficult to extinguish at "low" currents of less than 2 kA and high inductances. At higher currents, the fuse conductor, which is made of copper, for example, burns away anyway. At lower currents and high inductances, however, the arc burns for a relatively long time between the two ends of the disconnect point, which move away from each other, even if a sand bedding is present. Due to the presence of the arc, current separation is not ensured, or at least not immediately.

[0004] The aim of the present invention is to find an efficient and economical current disconnector that ensures rapid current separation and prevents or quickly extinguishes any arcing that may occur in the fuse conductor. Furthermore, the solution should also be applicable to current disconnectors from the prior art mentioned above.

[0005] According to the invention, this is achieved by a current separator of the type mentioned at the outset in such a way that, after the separation, one end of the separation point is pulled out of the separation chamber and the other end of the separation point lies within the arc-quenching material.

[0006] The term "pulled out of the separation chamber" encompasses both the condition that one end of the separation point lies precisely within the wall of the separation chamber and the condition that it is pulled out beyond the wall of the separation chamber. In both cases, this ensures that the arc burns over the longest possible distance filled with arc-quenching material. If the other end of the separation point lies at least 0.5 mm, preferably at least 2 mm, and most preferably at least 3 mm within the arc-quenching material, the arc must overcome a corresponding distance within this material; one end of the separation point must be moved a corresponding distance to be pulled out of the separation chamber. All these specifications apply to tripping at relatively low currents, where the fuse conductor does not vaporize over a large area anyway.

[0007] It is particularly advantageous if, after separation, at least a portion of a gap with a thickness of at most 1 mm, preferably at most 0.5 mm, and most preferably at most 0.2 mm, remains between the two ends of the separation point. The arc is compressed in this gap, causing it to extinguish even more quickly than by the arc-quenching material alone. Preferably, the length of the gap, or the portion of the gap, that remains between the two ends of the separation point after separation is at least 0.2 mm, more preferably at least 0.5 mm, more preferably at least 1 mm, and most preferably at least 3 mm.

[0008] The gap squeezes the arc, leading to rapid extinguishing even at very high inductances. This allows for a quick and complete electrical isolation. "Between the two ends of the gap" refers to the area where a potentially forming arc would lie, so that it is either suppressed during its potential formation or extinguished much faster after it forms than it would be without the gap. In any case, this encompasses the distance traveled between the ends of the gap.

[0009] It is particularly advantageous if the gap opposite the isolation chamber is reduced in cross-section by a seal, at least when the current disconnector is triggered. Since manufacturing tolerances prevent the gap from being made arbitrarily thin, such a deformable seal can provide an additional barrier to the electric arc.

[0010] The gap must, of course, be formed in an electrically non-conductive material; otherwise, the arc would burn on both sides of the gap, and the current would flow alongside the gap through the electrically conductive material. To achieve this cost-effectively, it is preferred that the gap be formed in a plastic material, preferably injection-molded. It is particularly advantageous if the plastic is made of the same material as the housing of the current disconnector, as this allows for manufacturing the housing from a single injection-molded upper and lower part.

[0011] Preferably, the arc-quenching material consists of SiO2, Al2O3, or compounds of these materials, e.g., ZrSiO4. Using these materials, particularly as sand, reduces the external impact, as it reduces pressure surges caused by the electric arc.

[0012] The present invention is particularly easy to implement if the gap is located in a wall through which the fuse conductor extends and which separates the break point of the fuse conductor from other areas. This wall can, in particular, be a wall of the separation chamber, thus also ensuring that the sand remains in the area of ​​the break point. When the fuse conductor is cut, one of the break point ends is drawn at least into the gap, or even out of it, so that the arc must burn in at least part of the gap and is accordingly compressed.

[0013] Alternatively, the separating element can be designed as a piston that is movable within a chamber, creating a gap between the piston and a wall of the chamber, with the severed section of the fuse wire partially located within this gap. For one end of the separating element to be pulled out of the separating chamber by the piston, the severed section of the fuse wire must partially extend into the gap between the piston and the chamber walls. If the piston, and therefore the gap, is longer, the arc must burn in the remaining portion of the gap. For a gap of constant thickness, the piston and the chamber are designed with a trapezoidal cross-section of the same shape. An exact rectangular cross-section is difficult to produce using injection molding, as draft angles are typically incorporated for easy demolding.

[0014] The present invention is explained in more detail with reference to the accompanying drawings. They show: a first embodiment of a current disconnector according to the invention in the non-tripping state; the same in the tripped state; a second embodiment of a current disconnector according to the invention in the non-tripping state; the same in the tripped state; a third embodiment of a current disconnector according to the invention in the non-tripping state; the same in the tripped state; a fuse conductor in an intact state; this fuse conductor after mechanical separation; an embodiment of the gap with a fuse conductor; a second embodiment of a gap; a section through the plane of the fuse conductor of a fourth embodiment with a piston in the non-tripping state; a detail at the top left of the fuse conductor in the tripped state and on an enlarged scale; a fuse conductor of a fifth embodiment, before separating elements were sprayed on, in a frontal view.this safety conductor with molded-on separating elements in oblique view; this safety conductor, installed in the lower part of a fuse module with the cover removed in top view; and a detail at the top left of the tripped state and in enlarged scale.

[0015] Figure 1 shows a section through the plane of the fuse conductor of a first embodiment of a current disconnector according to the invention. In this example, the fuse conductor is located below the busbar, i.e., on the side of the busbar furthest from the igniter.

[0016] A fuse conductor 2 is located in a housing 1 and is electrically connected in parallel to the conductor ends 3 and 4 of a busbar. The electrical connection is made via connectors 23. Break points 5 and 6 (melting points) are located in separation chambers 7 and 8, which are filled with sand (shown here as dotted lines). Approximately in the center is a rotating element 9 with separating elements 10 and 11. The fuse conductor 2 is attached to the separating elements 10 and 11, so that a rotational movement of the rotating element 9 causes the fuse conductor 2 to break at the break points 5 and 6 in the separating chambers 7 and 8. The rotating element 9 is driven by an auxiliary piston 13 via four curved guide rails 12. This piston has opposing recesses in its wall and is secured against rotation by a (positive-locking) linear guide – the rectangular hole 14 is visible. In this embodiment, the guide rails 12 ad represent a steep thread.The breaking of the safety conductor 2 takes place at the separation points 5, 6 with reduced cross-section; double trapezoidal conductor strands with the smallest cross-section in the center of the respective field are particularly preferred. It is further advantageous if the safety conductor 2 has an active (= meltable) length of > 50 mm and dedicated separation points whose (total) cross-sections are smaller than the cross-section of the remaining safety conductors. It is also preferred that the safety conductor 2 is not interrupted in the area between separation element 10 or 11 and the adjacent mechanical separation point 5 or 6, thus allowing unimpeded withdrawal.

[0017] Figure 1 shows a section through the plane of the fuse conductor 2 of the first embodiment in the tripped state. In this example, the fuse conductor 2 is located below the busbar, i.e., on the side of the busbar furthest from the igniter.

[0018] By igniting the igniter in the upper part of the circuit breaker, the central section of the busbar is punched out by a (disconnecting) piston and pressed against the auxiliary piston 13, which is secured against rotation by the rectangular hole 14. If a current flows through the conductor ends 3, 4 of the busbar, it commutates to the fuse conductor 2. The rotating element 9 is rotated by means of grooves in the auxiliary piston 13, which engage with the guide rails 12 ad. The fuse conductor 2 is attached to the disconnecting elements 10, 11 and is severed at the disconnection points 5, 6 by the rotational movement in the disconnection chambers 7, 8. During this separation and the elongation of the distance between the severed ends of the fuse conductor 2 in the disconnection chambers 7, 8, any arc that may occur is, in most cases, extinguished in the sand bed.

[0019] At high inductances and relatively low currents, where the fuse conductor 2 does not melt over a significant length, the arc may continue to burn even if the fuse conductor 2 is embedded in sand. Therefore, to ensure that any arc that may occur is quickly extinguished in this case, according to the invention, one end 31 of the fuse conductor 2, when moved between and completely out of the sand bed, moves into a gap 30. The arc is squeezed through the gap 30 and thus quickly extinguished. The other end 31' of the fuse conductor remains in the sand bed, so that the arc is also extinguished by the sand.

[0020] Figure 1 shows a section through the plane of the fuse conductor 2 of a second embodiment of a current disconnector according to the invention. In this example, the fuse conductor 2 is located above the busbar, i.e., on the side of the busbar closest to the igniter.

[0021] The separation chamber 8 is arranged around the central cavity 20 for the separating piston. This central cavity 20 is bounded by an annular wall 24, which in turn is surrounded by an annular outer wall 22. The wall 24 and the outer wall 22 define a separation chamber 8. The safety conductor 2 is located in the sand-filled separation chamber 8 and is electrically connected in parallel to the conductor ends 3 and 4 of the busbar. In this embodiment, the safety conductor 2 encircles the central cavity 20 by approximately 180°. The electrical connection is made via a connector 23 to conductor end 3 and conductor end 4 of the busbar, respectively.

[0022] In chamber 16, the safety conductor 2 is guided around a movable separating element 17. The connection to the connection point is made by means of a tab that is deformable upon triggering. This chamber 16 is connected to the central cavity 20 by an overflow channel 18. The safety conductor 2 has a separation point 6 in the separating chamber 8.

[0023] When the igniter of the circuit breaker is triggered, the separating piston moves against the center section of the busbar and breaks it out. Once the separating piston has moved far enough for the seal to pass through the overflow channel 18, the separating element 17 is pressurized, tearing the fuse conductor 2 at the break point 6 and pulling it out of the separating chamber 8.

[0024] Figure 1 shows a section through the plane of the safety conductor 2 of the second embodiment of a current disconnector according to the invention in the tripped state. Driven by the gas pressure from the overflow channel 18, the safety conductor 2 was torn off at the separation point 6 and pulled out of the separation chamber 8.

[0025] Here, too, a similar principle applies as in and. However, in this case, the disconnect end 31 of the fuse conductor 2 remains in the gap 30, whereas in this case it is completely withdrawn from the gap 30 and thus from the separation chamber 8. This further enhances the effect of the gap 30, as the gap 30 now compresses the arc along its entire length. Thus, complete electrical isolation of the fuse conductor 2 is ensured.

[0026] Figure 1 shows a section through the plane of the fuse conductor 2 of a third embodiment of a current disconnector according to the invention in the non-tripping state. In this example, the fuse conductor 2 is located above the busbar, i.e., on the side of the busbar closest to the igniter.

[0027] The separating chambers 15a and 15b are arranged around the central cavity 20 for the separating piston. An intermediate wall 25 is located between the wall 24 and the outer wall 22, resulting in two concentric separating chambers 15a and 15b. Each chamber contains a section of the fuse conductor 2, with the two sections connected to the conductor ends 3 and 4 of the busbar, respectively. The electrical connection is made via the connectors 23. In this particular embodiment, the section of the fuse conductor 2 in separating chamber 15a encircles the central cavity 20 approximately 360°, and the other section in separating chamber 15b approximately 180°, thus facilitating easy contact with the conductor ends 3 and 4. A special feature is chamber 16, in which the safety conductor 2 is passed through slots on the separating element 17 in the form of a loop and fixed to the separating element 17, so that the two sections are electrically connected to each other.The space behind the separating element 17 is connected to the interior of the central cavity 20 via the overflow channel 18 (shown here in a simplified manner).

[0028] Figure 1 shows a section through the plane of the fuse conductor 2 of the third embodiment in the triggered state. After the detonator is triggered, the separating piston cuts through the busbar and as soon as the seal of the separating piston has passed the overflow channel 18, the gas pressure acts on the separating element 17, which moves circumferentially with respect to the central axis 21 of the current disconnector and tears off and pulls out the fuse conductor 2 at the break points 5, 6 (predetermined breaking points).

[0029] In this embodiment, two slots 30 are provided, in each of which a disconnect end 31 of the safety conductor 2 is located, and any arc that may occur is forced through the slot 30. The other disconnect end 31' remain in the sand bed of the separation chambers 15a and 15b, respectively.

[0030] Figure 1 shows a safety conductor 2 in its unbroken state. Four break points 5 with reduced cross-sections are visible. The cross-section is reduced in each case by three rhombus-shaped cutouts 35, and additionally by a reduction in the width of the safety conductor 2. The remaining cross-section is smallest at the break point 5 shown on the left. It is particularly advantageous to apply the tensile force, indicated by an arrow 36, to this side and to fix the other side, indicated by a fixed bearing 37, since the safety conductor 2 then almost certainly breaks at this break point 5 shown on the left. Between the rhombus-shaped cutouts 35, the remaining webs have a double trapezoidal shape, indicated by a dotted line at one web 38. These webs 38 have the smallest cross-section in the middle, but this is not necessary for the embodiment according to the invention.In the event of an overcurrent, the fuse conductor 2 begins to melt at the discontinuities 5, reducing its cross-section and thus acting as a fuse. According to the invention, a melted end piece is completely pulled out of the sand bed.

[0031] Naturally, the reduced cross-sections can also have the same residual cross-section in the conductor tracks; then the separation due to friction in the sand usually occurs in the field adjacent to the introduction of the tensile force.

[0032] The diagram shows the safety conductor 2 in its torn state. As previously described, the entire torn piece is pulled out of a sand-filled separation chamber.

[0033] Figure 1 shows a rectangular gap 30 with a break-end end 31 of the fuse conductor 2, which has a rectangular cross-section, within it. The gap 30 has a thickness 30d, and the fuse conductor 2 has a thickness 31d. The smaller the thickness 30d of the gap 30, the more effectively and quickly the arc is extinguished when the break-end end 31 is withdrawn from the gap 30. The thickness in the area of ​​the fuse conductor is particularly relevant, as the arc burns from one break-end end 31 to the other break-end end 31'. To ensure efficient arc extinguishing, it is therefore advantageous if the gap 30 has a small thickness, at least over the width 31b of the fuse conductor 2.

[0034] The gap 30 need not be rectangular, but can have any shape suitable for suppressing an electric arc. An elliptical gap 30 is shown as an example. If a non-rectangular gap 30 is used, an area-equivalent surface must be created, specifically in the area of ​​the fuse conductor 2 or in the area where the electric arc burns, to determine the gap thickness. The area-equivalent surface can be a rectangle or a circular segment, depending on the shape of the gap. The idea behind this is to create a moderate, compensating contour. Extreme values, such as those caused by cracks, are not to be considered, since the ability of the gap 30 to extinguish the electric arc is not affected by cracks of small thickness.

[0035] The thickness 30d of the gap 30 is preferably a maximum of 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm or 0.05 mm.

[0036] Figure 1 shows a section through the plane of the fuse conductor of a fourth embodiment in the untried state. The section plane is located below the plane of the main conductor. The circuit breaker has a housing 1 with a central cavity 20. The main conductor (the busbar) passes through this central cavity 20, as shown, in a plane parallel to and above the plane of the drawing, running vertically (parallel to the y-axis of the plane of the drawing). Above the main conductor is a disconnecting piston, which can be pressed against the main conductor by an igniter. When the circuit breaker is tripped, the igniter fires, presses the disconnecting piston against the main conductor, and cuts out a piece, the so-called circuit board, in the middle between two predetermined breaking points. This circuit breaker thus corresponds to the conventional design as described, for example, in WO 2021 / 007604 A1.

[0037] Below the main conductor is the structure shown in the figure below. A safety conductor 2 runs around the central cavity 20. The safety conductor 2 is connected to the main conductor via connectors 106 and 107. In this example, connector 106, via a cross-connection located below the plane of the image, creates a connection to connector 113, which is connected to the main conductor as a return path upwards. Connector 107 is directly connected to the main conductor upwards. Thus, the safety conductor 2 bridges the circuit board and is electrically connected in parallel to the main conductor.

[0038] This safety conductor 2 runs through a total of eight separation chambers 7, which are bounded by walls 114. In the area of ​​the safety conductor 2, these walls 114 are perforated (perforations 114', see figure). Between the separation chambers 7 are chambers 16, each containing a separating element in the form of a piston 104, which is radially displaceable within the chamber 16 and projects into the central cavity 20 with an inclined surface 103. This inclined surface 103 slopes downwards from the outside to the inside, i.e., away from the detonator. The separation chambers 7 are filled with an extinguishing agent bedding 108, e.g., a sand bed. The safety conductor 2 rests against the pistons 104 at their radially outer surface. On the other side of the safety conductor 2, a termination piece 110 is arranged, which closes off the adjacent opening 114' in the wall 114, so that no sand can enter the chambers 16 and the piston 104 can move freely radially outwards.

[0039] Above the separation chambers 7, but below the main conductor, is an auxiliary piston. Therefore, after triggering, the separation piston, driven by the gas pressure of the detonator, pushes the circuit board against the auxiliary piston and also pushes the latter downwards, i.e., in the direction away from the detonator. In the central cavity 20, the auxiliary piston passes over the inclined surfaces 103 and thereby pushes the pistons 104 radially outwards. This disconnects the safety conductor 2 in each separation chamber 7.

[0040] Figure 1 shows a section of the triggered state and is enlarged. The pistons 104 have separated the safety conductor 2 in the separation chambers 7 and displaced the severed sections 112 outwards. As can be seen, the separation point end 31' is located within the extinguishing agent bed 108, at a certain distance from the piston 104. The material previously located between the separation point ends 31', i.e., the severed section 112, is now bent in a U-shape around the piston 104, with the separation point ends 31 located in the gap 30 between the piston 104 and the walls 114.

[0041] After the disconnection of the safety conductor 2, any arcs that may occur (indicated by dotted lines) propagate both in the extinguishing agent bed 108 of the separation chambers 7 and in the gap 30. The area of ​​the safety conductor 2 in the extinguishing agent bed 108 may have openings which, in the event of a larger overcurrent, melt like fuse elements in the extinguishing agent bed 108 and increase energy absorption. The gap 30 between the piston 104 and the wall 114 of the separation chamber 7 ensures that any arc that forms is further compressed and thus extinguished more quickly after it occurs. The gap 30 must not be "easily bypassed" by the arc; that is, the arc must not have sufficient space in the gap 30 to continue burning. The gap 30 is generally designed so that the arc is compressed.

[0042] The example shows eight pistons 104; in addition to the version with eight pistons 104, variants with two and four pistons are particularly preferred; in the variant with four pistons, the arrangement at an angle of 45° to the longitudinal axis of the main conductor is particularly preferred.

[0043] The embodiment described last consists of a relatively large number of individual parts, which increases the assembly effort. This is improved in the following fifth embodiment.

[0044] The safety conductor 2 has two conductor ends 202a, b, which serve for contact, four sets of two separation points 5, 6, and three support areas 204 between them. The cross-section of the conductor ends 202a, 202b can be doubled in this example by bending over extensions of the sheet metal indicated by dashed lines. The separation points 5, 6 are formed by thin sections of the safety conductor 2. In the embodiment shown here, the thin sections are trapezoidal with the thinnest cross-section towards the center of the separation points 5, 6.

[0045] Figure 1 shows this fuse conductor 2 with molded-on isolating elements 104' in an oblique view. These isolating elements 104' are located partly in front of and partly behind the fuse conductor 2, with the two parts of the isolating elements 104' shown here being connected by holes in the fuse conductor 2 located between the isolating points 5 and 6. Bevels 103', which serve to drive the isolating elements 104' in the circuit breaker, are clearly visible, as will be explained further below.

[0046] Additionally, positioning elements 208 (see) can be sprayed onto the support areas 204, and insulating elements 109a, 109b (see) can be applied in the area of ​​the ladder ends 202a, b. Recesses in the positioning elements 208 ensure a connection between adjacent sand chambers during subsequent shoring.

[0047] Before assembly, the safety conductor 2 is essentially bent into a circular shape, and the conductor ends 202a, b are bent in a direction favorable for further installation.

[0048] Figure 1 shows this fuse conductor 2 with molded-on separating elements 104', positioning elements 208, and insulating elements 209a, b in its bent state within a lower part 211 of a fuse module. The fuse conductor 2 is positioned within the lower part 211 by the separating elements 104' and the positioning elements 208. The central cavity 20 within the lower part 211 is clearly visible, as is the fact that the inclined surfaces 103' of the separating elements 104' project into this central cavity 20. This lower part 211 is closed off by a cover (not shown) to form the fuse module.

[0049] The separating elements 104' are located in chambers 16, which are bounded by walls 114. The safety conductor 2 runs between the chambers 16 in sand-filled separating chambers 7. The separating chambers 7 are thus separated from the chambers 16 by walls 114, these walls 114 being interrupted in the area of ​​the safety conductor 2 (openings 114', see figure), so that the sand extends there to the separating elements 104'. A thin gap 30 is present between the separating elements 104' and the walls 114 (see figure), which is sealed against the separating chambers 7 by a gasket 201.

[0050] The seal 201 is attached to the walls 114', which can be easily achieved, for example, by a two-component injection molding process, and is located entirely within the gap 30 even when not triggered. It thus prevents sand from entering the gap 30. However, when not triggered, the seal can also be located at least partially outside the gap 30, for example, on the safety conductor 2 or on the separating element 104'. It then enters the gap 30 during triggering. The seal can be achieved particularly easily by filling the openings 114' with liquid silicone, which then polymerizes, after the safety conductor 2 has been inserted. This material is then drawn in by the separating element end 31 on both sides of the safety conductor 2 during triggering, thus reducing the gap 30.This effect is important because the achievable gap thicknesses are limited for assembly reasons and is particularly helpful in separating small currents.

[0051] The seal can be applied, for example, to at least one side of the gap 30 or to the safety conductor 2 using injection molding, for instance, from TPE. Alternatively, the sealant can also be applied in liquid or paste form; silicones (one- and multi-component), polyurethanes, latex, and similar rubber-like materials are preferred; however, epoxies, acrylates, etc., are also conceivable. Such a seal is also advantageous in the other embodiments.

[0052] This fuse module can interact with a drive unit, which is essentially constructed like the upper housing part 8 with cover plate 12 of WO 2022 / 011410 A1 (reference numbers 8 and 12 refer to this document); that is, conversely, the lower housing part 10 of this document is replaced by a fuse module as shown here. This drive unit has a central cavity which is aligned with the central cavity 20. A separating piston, which can be driven by a detonator, is located in the central cavity of the drive unit. In the event of detonation, the separating piston separates a circuit board along a notch from a main conductor, analogous to that described in WO 2022 / 011410 A1, subsequently breaking off an element from the cover and moving it into the central cavity 20 of the fuse module. This broken-off element corresponds to the auxiliary piston 13 described above.

[0053] For the present invention, it is relevant that the bent conductor ends 202a, b of the fuse conductor 2 are connected to the main conductor on both sides of the circuit board, for example by ultrasonic welding, or by means of additional connecting elements (screws). The sand-filled fuse module acts as a fuse, which in this example is permanently electrically connected in parallel to the main conductor.

[0054] The movement of the broken-off element is transferred via the inclined surfaces 103' to the separating elements 104', which thus move radially outwards and tear the fuse conductor 2. Any resulting arc is extinguished by elongation (due to the continued movement of the separating elements 104') and cooling (the arc is in contact with the safety sand). At high currents, the fuse conductor 2 burns away in the areas of the separation points 5, 6, causing further elongation of the arc in the sand bed. At low currents, the break occurs at a distance from the separating element 104', so that the torn-off pieces 112 of the fuse conductor 2 form a U-shape around the separating elements 104' and move outwards with them, extending beyond the sand bed. Consequently, the arcs are partly in the sand and partly in the gap between the separating elements 104' and the walls 114.In addition, the arc must also overcome the seal 201, which has an additional extinguishing effect.

[0055] The fuse conductor 2 is initially embedded in a sand bed, which facilitates its breaking. This effect can be further enhanced by connecting the conductor strands at the break points 5 and 6. Such a connection can be achieved by welding on a wire 205, as shown, for example, in the area of ​​the left thin section 5. This wire 205 hardly alters the electrical resistance, but significantly increases the mechanical resistance required to push the fuse conductor 2 radially outwards through the sand.

[0056] It is important that any arcing occurs only in the area of ​​the separation points 5, 6, which are initially located in the sand bed. Therefore, it is important that the cross-section of the safety conductor 2 is reduced less by the holes in the areas between the separation points 5, 6 and in the support areas 204 than the cross-section of the safety conductor 2 is reduced by the cutouts in the area of ​​the separation points 5, 6. In other words, the cross-section of the safety conductor 2 should be larger in the area between the separation points 5, 6 and in the support areas 204 than in the area of ​​the separation points 5, 6.

[0057] The cross-section in the area between the separation points 5, 6, in the support areas 204, and in the area of ​​the conductor ends 202a, b can be increased by increasing the thickness of the fuse conductor 2 in these areas. This can be achieved by initially having corresponding strips (indicated by dashed lines) protruding from the fuse conductor 2, which are then folded over to the corresponding areas. Initially, a good electrical connection between the folded strips and the areas to which they are folded is not necessary, because in the event of a short circuit, arcs will form in any gap that may exist, leading to automatic welding or contacting. However, metallic reinforcements can also be welded on, for example, using ultrasound, to increase the thickness.

[0058] 1 Housing 2 Fuse conductor 3, 4 Busbar (main conductor) conductor ends 5, 6 Fuse conductor break points (thin sections) 7, 8 Breaking chambers 9 Rotating element 10, 11 Breaking elements on the rotating element 12 a - d Guide strips 13 Auxiliary piston 14 Rectangular hole in the auxiliary piston 15 a, b Breaking chambers (concentric) 16 Chamber 17 Breaking element (pressurized) 18 Overflow channel 20 Central cavity 21 Central axis (axis of rotation of the breaking element) 22 Outer wall 23 Connector 24 Wall around central cavity 25 Partition wall 30 Gap 30d Gap thickness 31, 31' Breaking point end of the fuse conductor 31b Fuse conductor width 31d Fuse conductor thickness 35 Cutouts 36 Arrow 37 Fixed bearing 38 Web 103, 103' Slanted surface 104, 104' Piston-shaped breaking element 106, 107 Connectors 108 Extinguishing agent bedding 110 End pieces 112 Separated sections 113 Connector, return 114 Wall of the separation chamber 114' Opening in the wall of the separation chamber 201 Seal 202a,b Conductor ends of the safety conductor 204 Support areas 205 Welded-on wire 208 Positioning elements 209a, b Insulating elements 211 Lower part,

[0059] DE 112022005160 T5

[0060] WO 2020 / 204154 A1

[0061] US 2024 / 258055 A1

[0062] CN 213601831 U

[0063] WO 2021 / 007604 A1

[0064] WO 2022 / 011410 A1

Claims

Current disconnector with a busbar penetrating a cavity (20) bounded by a cavity wall (24), a separating piston for separating the busbar at at least one predetermined breaking point, wherein the separating piston in the cavity (20) can be moved towards the busbar by a drive, preferably a pyrotechnic drive, and with a fuse conductor (2) having at least one separation point (5, 6) separable by a separating element (10, 11; 17; 104, 104'), such that separation at the at least one separation point creates two separation point ends (31, 31') in the fuse conductor (2), which are spaced apart from each other after separation, wherein the at least one separation point (5, 6) is arranged in a separation chamber (7, 8; 15a, 15b) which is filled with an arc-quenching material.are characterized in that, after separation, one separation point end (31) is pulled out of the separation chamber (7, 8; 15a, 15b) and the other separation point end (31') lies within the arc-quenching material. Current separator according to claim 1, characterized in that the other separation point end (31') lies at least 0.5 mm, preferably at least 2 mm, particularly preferably at least 3 mm within the arc-quenching material. Current separator according to claim 1 or 2, characterized in that after the separation between the two separation point ends (31, 31') at least a part of a gap (30) with a thickness of at most 1 mm, preferably at most 0.5 mm, particularly preferably at most 0.2 mm is located. Current separator according to claim 3, characterized in that the length of the gap or part of the gap which is located after the separation between the two separation point ends (31, 31') is at least 0.2 mm, preferably at least 0.5 mm, particularly preferably at least 1 mm, most preferably at least 3 mm. Current separator according to claim 3 or 4, characterized in that the gap (30) relative to the separation chamber (7, 8; 15a, 15b) is reduced in cross-section at least in the triggered state of the current separator by a seal (201). Current separator according to one of claims 3 to 5, characterized in that the gap (30) is formed in a plastic material and the plastic is preferably injection molded. Current separator according to one of claims 1 to 6, characterized in that the arc-quenching material consists of SiO2, Al2O3 or compounds of these materials, e.g. ZrSiO4. Current disconnector according to one of claims 1 to 7, characterized in that the gap (30) is located in a wall through which the fuse conductor (2) extends and through which the disconnect point (5, 6) of the fuse conductor (2) is separated from other areas. Current disconnector according to one of claims 1 to 7, characterized in that the disconnecting element (104, 104') is designed in the form of a piston which is displaceable in a chamber (16), that a gap (30) is formed between the piston (104, 104') and a wall (114) of the chamber (16) and that the cut-off piece of the fuse conductor (2) is partially located in the gap (30). Current separator according to claim 9, characterized in that the piston (104, 104') and the chamber (16) are trapezoidal with the same cross-sectional shape.

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