EP2238659B1 - Electric protection element with a short circuit device - Google Patents

Abstract

An electrical protection component with a short-circuiting device includes a gas-filled surge arrester that includes at least two electrodes. Preferably, one electrode in each case is arranged at the ends of the surge arrester. The electrical protection component has a thermal short-circuiting device, wherein the thermal short-circuiting device includes a clip having at least two sections. At least a first section of the clip is attached to the surge arrester by snap action. At least a second section of the clip at least partly surrounds the first section and is spaced apart from the first section by means of a fusible element. The second section has a short-circuiting link at an end. The short-circuiting link electrically connects the electrodes of the surge arrester to one another in the case where the fusible element melts.

Description

From the publication EP 0962037 B1 a gas-filled surge arrester with external short-circuiting device is known.

An electrical protection device with short-circuiting device according to the preamble of claim 1 is made WO-A-87/06399 known.

It is an object of the present invention to provide an electrical protection device with short-circuit device, which has an improved mountability.

The object is achieved by an electrical protection device with short-circuiting device according to claim 1.

Advantageous embodiments of the electrical protection component are the subject of dependent claims.

It is an electrical protection device with short-circuiting specified, which has a surge arrester. The surge arrester has a hollow body, on which at least two electrodes are arranged. A surge arrester with two electrodes has a one-piece ceramic hollow body. In a 3-electrode arrester, the ceramic hollow body is divided into two separate parts by means of a middle electrode. The two parts are arranged with a first side on a central electrode. On a second side of the two parts, an end electrode is arranged in each case.

The electrical protection component has a thermal short-circuit device. The short-circuit device includes a clip that is snapped onto the surge arrester of the electrical protection device.

The clip has at least two sections. At least a first section of the clip is snapped onto the surge arrester and encompasses this by more than half. The first section of the shorting bar thus serves preferably for fastening the shorting bar to the surge arrester. At least the ends of the first section have mechanical contact with the surge arrester. However, in a further embodiment, the ends of the first section may also be spaced from the surge arrester, wherein at least a portion of the first section is arranged on the surge arrester such that the short-circuiting device can still be securely fastened to the surge arrester. The remainder of the first portion may rest on or be spaced from the surge arrester.

The clip includes at least a second portion surrounding the first portion and spaced from the first portion by a fuser member. The second portion has at one end a shorting bar that is radially spaced from the surge arrester. In the case of melting of the fuse element, the shorting bar electrically connects at least two external electrodes of the surge arrester.

The first section of the clip preferably surrounds the surge arrester by more than half. This will prevent the clip from firing the shorting mechanism is pushed away from the surge arrester. The first section of the clip thus serves as an abutment for the shorting bar.

In the case of a surge arrester having three electrodes, the third, middle electrode may have a slightly larger diameter than the two hollow bodies and the two end electrodes. The middle electrode may preferably project beyond the hollow bodies and the end electrodes in the radial direction.

Preferably, the clip comprises a bent ribbon which may have one or more recesses. The recesses serve to ensure that the clip can be fixed against slipping in the area of the middle electrode in the case of a 3-electrode arrester. The recesses preferably have the width of the central electrode, so that the central electrode protrudes partially into the recesses of the clip. Slippage of the clip in the axial direction is thereby suppressed.

In the region of the fusible element is preferably a recess, which is preferably somewhat smaller in size than the fusible element, so that the fusible element can not slip through the recess and would make it difficult to snap the shorting clips on the surge arrester.

In a further embodiment, the melting element has a gradation on at least one side, so that at least a part of the melting element protrudes into the recess. As a result, the melting element at least partially makes direct contact with the middle electrode of the Surge arrester on. Thus, there is a nearly optimal heat transfer from the surge arrester to the fuse.

In a further embodiment, the recess in the region of the melting element is preferably so large that the central electrode protrudes so far through the recess that the middle electrode has a direct contact with the melting element. Thus, there is also a nearly optimal heat transfer from the surge arrester to the fuse element.

The clip preferably comprises an elongated ribbon, with the shorting bar being wider than the rest of the clip.

In a preferred embodiment, the first and second portions of the clip are formed by a one-piece part.

In a further embodiment, however, it is also possible that the clip is composed of at least two parts.

Preferably, the first portion of the clip is formed by a first part and the second portion by a second part.

In a further embodiment, however, it is also possible for the second section to be formed by regions of the first part and of a second part.

Preferably, in a composite of several parts clip the parts of the clip made of different materials.

However, it is also possible that the parts of the clip made of the same material.

Preferably, at least the shorting bar is made of an electrically conductive material.

For this purpose, in particular a material with resilient properties is suitable. So that the clip of the short-circuiting device can exert permanent pressure on the fusible element, in particular a material comprising beryllium copper is suitable for this purpose. Beryllim copper is particularly well suited for a short circuit clip as it retains its spring force even in the event of excessive heating. Beryllium copper has a long-lasting spring force. Beryllium copper has better electrical conductivity than spring steel. The flat strip for the clip can be produced inexpensively and without great technical effort from example beryllium copper by stamping.

The flat strip is brought in one embodiment, for example by bending in the desired shape. In the case of a two-part clip, the two prepared parts are joined together and mechanically joined together. For example, the two parts are directly connected to each other by means of a welded connection.

The clip is preferably snapped onto it in the region of a middle electrode of the surge arrester.

In a further embodiment, it may also be a 2-electrode arrester, wherein the short-circuit bar is mechanically connected in this case, for example by means of a ring or a clamp in the region of the hollow body with the surge arrester.

The melting element is preferably designed such that it melts at unacceptably high heating of the surge arrester. The fusible element may be made of a material comprising solder. In addition, materials comprising plastic are suitable. Particularly suitable are forms that have the largest possible volume with a small amount of material. In this case, in particular hollow body, such as tubular body are suitable.

By such a melting element of the shorting bar can be spaced. In the case of an excessive heating of the surge arrester body with cavities melt faster than equal full body. As a result, the electrical protection component has a fast reaction time.

The fusible element is preferably arranged such that the shorting bar is spaced from the external electrodes by the fusible element. In the case of melting of the fuse element, the clip presses on the outer electrodes of the surge arrester and electrically connects them together. In the case of a surge arrester with an additional middle electrode, the shorting bar connects the outer electrodes to the middle electrode.

Preferably, it is a surge arrester in SMD design. It is also possible that this is a Surge arrester with wire contacts for conventional mounting is.

The shorting clip is designed such that the already pre-assembled shorting clip including the fuse element is snapped onto the surge arrester, in particular after the surge arrester has been soldered onto, for example, a mounting substrate. However, the short circuit clip can also be snapped onto the surge arrester before installation.

The short-circuit clip thus has the advantage that it can be snapped on after soldering or soldering on the surge arrester. The melting element is already arranged in the preassembled short circuit clip, so that the melting element does not have to be retrofitted.

Especially with surge arresters in SMD design, the problem is that during the soldering process, the surge arrester is heated inadmissibly high and thus comes into the thermal response of the short-circuiting device. This leads in particular to surge arresters in SMD design to restrictions which leads to manufacturing difficulties. Compared to conventional surge arresters with short-circuiting devices, which are soldered by hand, thus additional cooling during the soldering process, which protects the surge arrester from excessive heating, is not required. Likewise, during wave soldering or reflow soldering, a specially adapted temperature profile which precludes excessive heating is no longer necessary in this case.

The objects described above will be explained in more detail with reference to the following figures and embodiments.

Figur 1a

zeigt ein elektrisches Schutzbauelement mit einstückigem Kurzschlussclip im Querschnitt,

Figur 1b

zeigt ein elektrisches Schutzbauelement mit Kurzschlussclip nach Fig. 1a von unten,

Figur 1c

zeigt die Abwicklung des Kurzschlussclips aus Fig. 1a,

Figur 2a

zeigt eine weitere Ausführungsform eines elektrischen Schutzbauelements mit mehrteiligem Kurzschlussclip im Querschnitt,

Figur 2b

zeigt die Abwicklung des Kurzschlussclips aus Figur 2a,

Figur 3a

zeigt eine weitere Ausführungsform eines elektrischen Schutzbauelements mit mehrteiligem Kurzschlussclip im Querschnitt,

Figur 3b

zeigt die Abwicklung des Kurzschlussclips aus Figur 2a,

Figur 4a

zeigt ein elektrisches Schutzbauelement mit einstückigem Kurzschlussclip im Querschnitt, wobei das Schmelzelement von dem Überspannungsabieiter beabstandet ist,

Figur 4b

zeigt einen Teil des Kurzschlussclips mit Schmelzelement gemäß Figur 4a,

Figur 5a

zeigt ein elektrisches Schutzbauelement mit einstückigem Kurzschlussclip im Querschnitt, wobei das Schmelzelement einen direkten Kontakt zu dem Überspannungsableiter aufweist,

Figur 5b

zeigt einen Teil des Kurzschlussclips mit Schmelzelement gemäß Figur 5a,

Figur 6a

zeigt ein weiteres elektrisches Schutzbauelement mit einstückigem Kurzschlussclip im Querschnitt, wobei das Schmelzelement einen direkten Kontakt zu dem Überspannungsabieiter aufweist,

Figur 6b

zeigt einen Teil des Kurzschlussclips mit Schmelzelement gemäß Figur 5a.

The drawings described below are not to be considered as true to scale. Rather, for better representation, individual dimensions can be enlarged, reduced or distorted. Elements which are identical or which assume the same function are designated by the same reference numerals.

FIG. 1a

shows an electrical protection device with one-piece shorting clip in cross section,

FIG. 1b

shows an electrical protection device with shorting clip after Fig. 1a from underneath,

Figure 1c

shows the handling of the shorting clip Fig. 1a .

FIG. 2a

shows a further embodiment of an electrical protection device with a multi-part shorting clip in cross section,

FIG. 2b

shows the handling of the shorting clip FIG. 2a .

FIG. 3a

shows a further embodiment of an electrical protection device with a multi-part shorting clip in cross section,

FIG. 3b

shows the handling of the shorting clip FIG. 2a .

FIG. 4a

shows an electrical protection device with integral shorting clip in cross section with the fuse element spaced from the surge arrester;

FIG. 4b

shows a part of the shorting clip with fuse according to FIG. 4a .

FIG. 5a

shows an electrical protection device with one-piece shorting clip in cross section, wherein the fusible element has a direct contact with the surge arrester,

FIG. 5b

shows a part of the shorting clip with fuse according to FIG. 5a .

FIG. 6a

shows a further electrical protection component with one-piece shorting clip in cross-section, wherein the fusible element has a direct contact with the surge arrester,

FIG. 6b

shows a part of the shorting clip with fuse according to FIG. 5a ,

In FIGS. 1a and 1b an electrical protection device is shown, which comprises a surge arrester 1. The surge arrester 1 has at the ends in each case an electrode 2, which in FIG. 1b are shown. The surge arrester 1 has a central electrode 8, which projects beyond the hollow body and the electrodes 2 in the radial direction. On the surge arrester 1, a short circuit clip 3 is snapped, having a first portion 4, the ends 4a and 4b on the surge arrester 1 present. A portion of the first portion 4 between the two ends 4a and 4b may be spaced from the surge arrester 1 and does not need to rest flush on the surge arrester 1.

A second section 5 of the clip 3 is spaced from the surge arrester 1. The second section 5 has a shorting bar 6 at one end. The shorting bar 6 of the second section 5 is spaced from the first section 4 b and thus also from the surge arrester 1 by means of a fusible element 7. Normally, the shorting bar 6 is biased by the spring force of the clip 3 and presses on the fusible element 7. The shorting bar 6 is designed such that it electrically connects the two electrodes 2 in the case of melting of the fusible element 7. In the case of inadmissibly high heating of the surge arrester 1, the melting element 7 melts and thereby clears the way for the shorting bar 6, which presses on the melting element 7. By the spring force of the shorting clip 3, the shorting bar 6 thus presses on the outer electrodes 2 of the surge arrester 1.

In the Figure 1c is a settlement of the shorting clip 3 from FIGS. 1a and 1b shown. The shorting clip 3 has the shorting bar 6 at one end of the second section 5. The width over the majority of the length of the shorting clip 3 is preferably smaller than the width of the shorting bar 6. For saving material and weight, the shorting clip 3 may have one or more recesses 9a, 9b. The recesses 9a, 9b are in the illustrated embodiment in a first portion 4 of the Short circuit clips 3. However, it is also possible that the second section 5 has more recesses.

The FIG. 2a shows a further embodiment of an electrical protective device with a short-circuiting device. On a surge arrester 1, which has one electrode at each end, a clip 3 is snapped. The clip 3 consists in this embodiment of two parts, wherein a first part forms a first portion 4 and a second portion 5 is formed by a second part. The first section 4 has two ends 4a and 4b which rest on the surge arrester 1. The area of the first section 4 between the two ends 4a and 4b may be spaced from or resting on the surge arrester 1. At one end of the second section 5, a shorting bar 6 is arranged. The shorting bar 6 presses on a melting element 7, which is arranged between the shorting bar 6 and the end 4 b of the first section 4 and thus also between the shorting bar 6 and the surge arrester 1. In the case of inadmissibly high heating of the surge arrester 1, the melting element 7 melts and thereby clears the way for the shorting bar 6. In the case of melting the melting element 7, the shorting bar 6 thus presses on the electrodes 2 and connects them electrically to one another.

In the FIG. 2b the two unwound parts of the shorting clip 3 are off FIG. 2a shown. The shorting clip 3 has the first section 4. Between the two ends 4a and 4b of the first portion 4 a plurality of recesses 9a, 9b are arranged. The recesses 9a, 9b serve to guide the clip 3 on the middle electrode 8. The recesses 9a, 9b preferably have a width on, which corresponds to the width of the central electrode 8. Preferably, the melting element 7 is at least on the edges of the recess 9a. Through the recesses 9a, the fusible element 7, which has a gradation in the size of the recess 9a, a direct thermal contact with the central electrode 8. The second portion 5 of the shorting clip 3 has at one end a shorting bar 6. The first section 4 is firmly connected to the second section 5 via at least two connection points. Preferably, the second portion 5 is connected to the first portion 4 by means of welding spots, one or more welding lines or one or more welding surfaces. The width of the first section 4 preferably corresponds to the width of the second section 5. The width over most of the length of the shorting clip 3 is preferably smaller than the width of the shorting bar 6 at the end of the second section 5.

The FIG. 3a shows a further embodiment of an electrical protective device with a short-circuiting device. On a surge arrester 1, which has an outer electrode 2 at the ends, a short-circuit clip 3 is snapped. The shorting clip 3 in this embodiment consists of two parts, a first part forming a first section 4. A second section 5 of the shorting clip 3 is formed by a tab 4c of the first part and a second part, wherein the two parts of the second section 5 are interconnected via at least two connection points. The first section 4 has two ends 4a and 4b which rest on the surge arrester 1. A portion of the first portion 4 between the two ends 4a and 4b may be spaced from the surge arrester 1. At one end of a second section 5, a shorting bar 6 is arranged. The shorting bar 6 presses on a melting element 7, which is arranged between the shorting bar 6 and the end 4 b of the first section 4 and thus also the surge arrester 1. In the case of melting of the fusible element 7, the shorting bar 6 thus presses on the outer electrodes 2 and connects them electrically to one another and to the middle electrode 8.

In the FIG. 3b the two unwound parts of the shorting clip 3 are off FIG. 3a shown. The shorting clip 3 has the first section 4. Between the two ends 4a and 4b of the first section 4, a recess 9a is arranged. A tab 4c of the first section 4 forms with a second part of the second section 5, wherein the tab 4c is firmly connected at least two connection points with the second part. Preferably, the second part is connected to the tab 4c of the first section 4 by means of welding. The second section 5 of the shorting clip 3 has a shorting bar 6 at one end. The width of the region 4c of the first part preferably corresponds to the width of the second section 5. The shorting clip 3 preferably has its greatest width in the region of the shorting bar 6 at the end of the second section 5.

The FIG. 4a shows a further embodiment of an electrical protective device according to the FIG. 1a , At a surge arrester 1, an integral short-circuit clip 3 is arranged, which has a first portion 4 and a second portion 5. The second section 5 of the shorting clip 3 is by means of a fusible element 7 in the region of the shorting bar 6 from the first section 4 of Short circuit clips 3 spaced. In the illustrated embodiment, the melting element 7 has a size sufficient for the melting element 7 to rest on at least two sides of the edge of the recess 9a of the first section 4 of the shorting clip 3. The melting element 7 has in the FIG. 4a no direct contact with the central electrode 8 and thus not to the surge arrester 1 on.

In the FIG. 4b is an end 4b of the first portion 4 of the shorting clip 3 after FIG. 4a shown, wherein the end 4b has a recess 9a. In the region of the recess 9a, a melting element 7 is arranged. The melting element 7 is preferably arranged such that it rests on at least two sides of the edge of the recess 9a.

The FIG. 5a shows a further embodiment of an electrical protective device as in FIG. 1a is shown. The melting element 7, which is arranged between the first section 4 and the second 5 section of the shorting clip 3, has a step 10 on at least one side in the illustrated embodiment. The gradation 10 is preferably only so large that the melting element 7 protrudes with the step 10 in the recess 9a. The predominant part of the fusible element 7 preferably has a size which is at least sufficient for the fusible element 7 to rest on at least two sides of the edge of the recess 9a. The melting element 7, by means of the step 10, preferably has a direct contact with the central electrode 8. The melting element 7 has in the FIG. 5a Thus, the best possible thermal contact with the central electrode 8 and thus to the surge arrester 1 on.

In the FIG. 5b is an end 4b of the first portion of the shorting clip 3 after FIG. 1a shown. The end 4b has a recess 9a, in the region of which a melting element 7 is arranged. The fusible element 7 protrudes with at least one step 10 into the recess 9a, preferably far enough that the fusible element 7 has a direct contact with the middle electrode.

The FIG. 6a shows a further embodiment of an electrical protective device as shown in the FIGS. 4a and 5a is shown. In the illustrated embodiment, the recess 9a is preferably so large that the central electrode 8 protrudes into the recess 9a far enough that it has direct contact with the melting element 7. The melting element 7 is preferably so large that it rests on at least two sides of the edge of the recess 9 a, wherein it compared to that in the FIGS. 5a and 5b illustrated embodiment, preferably does not protrude into the space generated by the recess 9a. The fact that the central electrode 8 protrudes into the recess 9a so far that it has a direct contact with the melting element 7, the best possible thermal contact with the fusible element 7 is present.

In the FIG. 6b is an end 4b of the first section of the shorting clip after FIG. 6a shown, wherein the end 4b has a recess 9a. In the region of the recess 9a, a melting element 7 is arranged. The recess 9 a is preferably so large that a part of the middle electrode 8 has a direct contact with the fusible element 7.

Although only a limited number of possible developments of the invention could be described in the embodiments, the invention is not limited to these. It is in principle possible to connect the clip from more than two parts, or to choose a different shape of the clip. For example, it is possible to connect two snapped on the surge arrester first sections with a second portion having a shorting bar at one end. As a result, for example, a more stable attachment of the shorting clip on the surge arrester is possible.

LIST OF REFERENCE NUMBERS

1

Surge arresters

2

electrode

3

clip

4

first section

4a, 4b

Ends of the first section 4

4c

flap

5

second part

6

Shorting bar

7

fuse

8th

middle electrode

9a, 9b

recess

10

gradation

Claims (15)

1. Electrical protection component with a short-circuiting device, comprising

   - a surge arrester (1), which comprises at least two electrodes (2),

   - a thermal short-circuiting device, wherein the thermal short-circuiting device comprises a clip (3) having at least two sections (4, 5),

   - wherein at least a first section (4) of the clip (3) is attached to the surge arrester (1) by snap action,

   - wherein a second section (5) comprises a short-circuiting link (6) at one end,

   - characterized in that at least the second section (5) of the clip (3) is spaced apart from the first section (4) by means of a fusible element (7), and

   - wherein the short-circuiting link (6) electrically connects the electrodes (2) of the surge arrester (1) to one another in the case where the fusible element (7) melts.
2. Electrical protection component according to Claim 1, wherein the first (4) and second (5) sections of the clip (3) are formed by an integral part.
3. Electrical protection component according to Claim 1, wherein the clip (3) is composed of at least two parts.
4. Electrical protection component according to Claim 3, wherein the first section (4) of the clip (3) is formed by a first part and the second section (5) is formed by a second part.
5. Electrical protection component according to any of the preceding claims, wherein the first section (4) engages around more than half of the surge arrester (1).
6. Electrical protection component according to any of the preceding claims, wherein at least the ends (4a, 4b) of the first section (4) have a mechanical contact with the surge arrester (1).
7. Electrical protection component according to any of Claims 3 to 6, wherein the parts of the clip (3) consist of the same material or wherein the parts of the clip (3) consist of different materials.
8. Electrical protection component according to any of the preceding claims, wherein the clip (3) has at least one cutout (9a, 9b) at least in the region of one section (4, 5).
9. Electrical protection component according to any of the preceding claims, wherein the clip (3) is attached to the surge arrester (1) by snap action in the region of a central electrode (8) of said surge arrester.
10. Electrical protection component according to Claim 9, wherein the cutout (9a, 9b) has a width corresponding to the width of the central electrode (8).
11. Electrical protection component according to Claim 10, wherein the clip (3) is fixed in the region of the central electrode (8) by means of the cutout (9a, 9b).
12. Electrical protection component according to Claim 9, wherein the clip (3) electrically connects the central electrode (8) to the external electrodes (2) in the case where the fusible element (7) melts.
13. Electrical protection component according to any of the preceding claims, wherein the fusible element (7) is designed in such a way that it melts in the event of impermissibly high heating of the surge arrester (1).
14. Electrical protection component according to any of the preceding claims, which is surfacemountable.
15. Electrical protection component according to any of the preceding claims, wherein the fusible element (7) has a direct thermal contact with the central electrode (8).

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