MELTING CONDUCTOR AND FUSE

Abstract

The invention relates to an use of a melting conductor (1) for a DC fuse (2) and a high-voltage high-power fuse (2) (HH-DC fuse), wherein the melting conductor (1) comprises an electrically conductive melting wire (3), wherein the melting wire (3) comprises at least two overload narrow sections (4) in the form of a cross-sectional constriction, wherein, preferably between the two immediately successive overload narrow sections (4) a first layer (7) comprising solder and/or surrounding the outer shell surface (6) of the melting wire (3) circumferentially at least in some areas, preferably completely, is provided in at least one first section (5), and wherein a second layer (9) surrounding the outer shell surface (6) of the melting wire (3) circumferentially at least in some areas, preferably completely, is provided adjacent to each of the overload narrow sections (4) in a respective second section (8).

Claims

1. A melting conductor for a DC fuse and a high-voltage high-power fuse (HH-DC fuse), wherein the melting conductor comprises an electrically conductive melting wire, wherein the melting wire comprises at least two overload narrow sections in the form of a cross-sectional constriction, wherein, between the two immediately successive overload narrow sections, a first layer comprising solder and/or surrounding the outer shell surface of the melting wire circumferentially at least in some areas is provided in at least one first section, wherein a second layer surrounding the outer shell surface of the melting wire circumferentially at least in some areas is provided adjacent to each of the overload narrow sections in a respective second section, and wherein the melting wire comprises between two directly successive overload narrow sections at least one short circuit narrow section formed as a cross-sectional constriction.

2. The melting conductor of claim 1, wherein the minimum width and/or the shape of the cross-sectional constriction of the overload narrow section differs from the minimum width and/or the shape of the cross-sectional constriction of the short circuit narrow section.

3. The melting conductor of claim 1, wherein the minimum width of the cross-sectional constriction of the overload point is greater than the minimum width of the cross-sectional constriction of the short circuit narrow section, wherein the ratio of the minimum width of the cross-sectional constriction of the overload point to the minimum width of the cross-sectional constriction of the short circuit narrow section is between 1.01:1 to 3:1.

4. The melting conductor of claim 1, wherein the second layer is at least substantially directly adjacent to the overload narrow section and/or in that the second layer is firmly connected to the outer shell surface of the melting wire.

5. The melting conductor of claim 1, wherein the second layer comprises and/or consists of a plastic and/or poly(organo)siloxane as material wherein the second layer is designed to be electrically insulating.

6. The melting conductor of claim 1, wherein the solder of the first layer comprises as material a metal alloy and/or consists thereof, wherein the metal alloy comprises cadmium, lead, tin, zinc, silver and/or copper, preferably a metal alloy comprising tin and/or silver, and wherein the first layer is electrically conductive.

7. The melting conductor of claim 1, wherein a plurality of short circuit narrow sections is provided between two directly successive overload sections, wherein between two overload sections between 2 to 15 short circuit narrow sections are provided and/or wherein the first section comprising the first layer is arranged between two directly successive short circuit narrow sections on the outer shell surface of the melting wire.

8. The melting conductor of claim 1, wherein the second sections comprising the second layer are arranged on the outer shell surface of the melting wire in such a way that the two overload narrow sections and the short circuit narrow sections and/or the short circuit narrow sections arranged between two directly successive second sections and/or second layers are provided.

9. The melting conductor of claim 1, wherein the overload narrow section is formed by recesses comprising an at least substantially rectangular edge.

10. The melting conductor of claim 1, wherein the short circuit narrow section is formed by recesses comprising an at least substantially circular arc section-shaped edge.

11. The melting conductor of claim 1, wherein the short circuit narrow sections arranged between the overload narrow sections are at least substantially regularly spaced and/or that the distance between two directly adjacent short circuit narrow sections and/or the distance between a short circuit narrow section and the directly adjacent overload narrow section are at least substantially regularly spaced and/or in that the distance between a cross-sectional constriction of the short circuit narrow section and/or the overload narrow section and the immediately neighboring cross-sectional constriction of the short circuit narrow section and/or the overload narrow section is designed to be at least substantially the same.

12. The melting conductor of claim 1, wherein the length of the cross-sectional constriction of the overload narrow section is greater than the length of the cross-sectional constriction of the short-circuit narrow section.

13. The melting conductor of claim 1, wherein the first and/or the second layer is/are a coating.

14. The melting conductor of claim 1, wherein the melting wire comprises an at least substantially rectangular cross-sectional shape and/or is formed as a flat strip and/or that the melting wire, the first and/or second layer have an at least substantially circular outer cross-section.

15. The melting conductor of claim 1, wherein the melting wire comprises metal as material, wherein the material comprises preferably at least substantially pure silver and/or a silver alloy and/or copper and/or a copper alloy.

16. The melting conductor of claim 1, wherein the melting conductor comprises an alternating sequence of directly successive overload narrow sections, with short circuit narrow sections arranged between two directly successive overload narrow sections, wherein the overload narrow sections are at least substantially regularly spaced.

17. The melting conductor of claim 1, wherein the ratio of the maximum width of the fuse wire to the minimum width of the cross-sectional constriction of the overload narrow section and/or the cross-sectional constriction of the short circuit narrow section is between 1:0.6 and 1:0.2.

18. The melting conductor of claim 1, wherein the melting conductor is in the HH-DC fuse for fuse protection of a DC transmission having an outer fuse box, wherein at least one melting conductor wound around a electrically insulating winding body is arranged in the fuse box.

19. The melting conductor of claim 18, wherein the fuse box is at least partially open at two end faces, wherein at least one contact cap designed for electrical contacting is arranged on the end face of the fuse box.

20. The melting conductor of to claim 18, wherein the DC voltage of the DC current and/or the rated voltage of the fuse is greater than 1 kV.

21. The melting conductor of claim 18, wherein the smallest breaking current of the fuse is greater than 3 A, and/or in that the smallest breaking current of the fuse is greater than or equal to the rated current.

22. The melting conductor of claim 18, wherein the rated breaking capacity (rated value of maximum breaking current) is greater than 1 kA.

23. The melting conductor of claim 18, wherein the transmitted direct current and/or the rated current range is greater than 5 A.

24. The melting conductor of claim 18, wherein the product of the direct current and the direct voltage protected by the fuse is greater than 5 kW.

25. The system having a consumer which can be supplied by direct current, having at least one fuse of claim 18, wherein the direct current transmitted to the consumer can be protected by the fuse, wherein the power of the consumer is greater than 5 kW.

Description

[0146] It shows:

[0147] FIG. 1 a schematic view of a melting conductor according to the invention,

[0148] FIG. 2 a schematic perspective illustration of a fuse according to the invention,

[0149] FIG. 3 a schematic cross-sectional view of a further embodiment of a fuse according to the invention,

[0150] FIG. 4 a schematic perspective illustration of a melting conductor according to the invention wound around a winding body,

[0151] FIG. 5 a schematic cross-sectional view of a further embodiment of a fuse according to the invention,

[0152] FIG. 6a a schematic perspective illustration of a further embodiment of a melting conductor according to the invention,

[0153] FIG. 6b a schematic cross-sectional view along cut A-A of FIG. 6a,

[0154] FIG. 6c a schematic cross-sectional view along cut B-B of FIG. 6a,

[0155] FIG. 7 a schematic principle representation of a use of a fuse according to the invention for fuse protection of a direct current transmission, and

[0156] FIG. 8 a schematic diagram of a further embodiment of the use of a fuse according to the invention for fuse protection of the DC transmission.

[0157] FIG. 1 shows a melting conductor 1. As can be seen in FIG. 3, the melting conductor 1 is intended for use for a DC fuse 2, especially a high voltage high power DC fuse 2 (HH-DC fuse). The fuse 2 may be provided for fuse protection of a DC application, as shown schematically in FIGS. 7 and 8.

[0158] FIG. 1 further shows that the melting conductor 1 comprises an electrically conductive melting wire 3. The melting wire 3 comprises at least two overload narrow sections 4 formed as cross-sectional constrictions. In a first section 5—at least once on the melting wire 3—a first layer 7 comprising and/or consisting of solder is provided, which circumferentially surrounds the outer shell surface 6 of the melting wire 3 at least in areas, preferably completely.

[0159] The first layer 7 and/or the first section 5 can be arranged at least once on the outer shell surface 6 of the melting wire 3, especially in the central area of the melting wire 3.

[0160] Furthermore, FIG. 1 shows that adjacent to each of the overload narrow sections 4, in each case in a second section 8, a second layer 9 is provided circumferentially surrounding the outer shell surface 6 of the melting wire 3 at least in some areas, preferably completely.

[0161] The overload narrow sections 4 are arranged in succession in the longitudinal direction L of the melting wire 3.

[0162] In the embodiment example shown in FIG. 1, it is provided that the first section 5 is provided between the two directly successive overload narrow sections 4. The first layer 7 need not thereby be arranged centrally between the two overload narrow sections 4, but may be so in further embodiments.

[0163] In addition, FIG. 1 shows that the melting wire 3 comprises at least one short circuit narrow section 10 in the form of a cross-sectional constriction between two directly successive overload narrow sections 4. In the illustrated embodiment example, the minimum width 11 and the shape of the cross-sectional constriction of the overload narrow section 4 differ from the minimum width 12 and the shape of the cross-sectional constriction of the short circuit narrow section 10. The minimum widths 11, 12 of the cross-sectional constrictions ultimately provide the smallest width in the region of a cross-sectional constriction. For example, the short circuit narrow section 10 comprises different widths in the area of the cross-sectional constriction.

[0164] According to the shape and the minimum width 11, 12 of the cross-sectional constriction, the response behavior of the melting conductor 1 in the case of tripping—for overload protection—can be adjusted accordingly.

[0165] In the embodiment example shown in FIG. 1, it is provided that the minimum width 11 of the cross-sectional constriction of the overload narrow section 4 is larger than the minimum width 12 of the cross-sectional constriction of the short circuit narrow section 10. Thereby, the ratio of the minimum width 11 of the cross-sectional constriction of the overload narrow section 4 to the minimum width 12 of the cross-sectional constriction of the short circuit narrow section 10 may be between 1.15:1 to 1.5:1. In further embodiments, the aforementioned ratio may be between 1.01:1 to 3:1.

[0166] It is not shown that the shape of the cross-sectional constriction and/or the minimum width 11 of the overload narrow section 4 is at least substantially the same and/or identical in construction to the shape of the cross-sectional constriction and/or the minimum width 11 of the short circuit narrow section 10.

[0167] FIG. 1 shows that the second layer 9 is immediately adjacent to the overload narrow section 4. In addition, FIG. 1 shows that the second layer 9 is firmly connected to and/or adheres to the outer shell surface 6 of the melting wire 3, preferably in a substance-bonded and/or adhesive bonding manner.

[0168] Not shown is that the second layer 9 comprises and/or consists of a plastic and/or poly(organo)siloxane as material, preferably as arc extinguishing agent. In further embodiments, the second layer 9 may at least substantially consist of silicone. The second layer 9 may alternatively or additionally be designed to be electrically insulating.

[0169] FIG. 5 shows that the second layer 9 is at least substantially directly adjacent to the cross-sectional constriction of the overload narrow section 4, but does not protrude and/or penetrate into the area of the cross-sectional constriction of the overload narrow section 4.

[0170] Further not shown is that the solder of the first layer 7 comprises and/or consists of a metal alloy as material. In further embodiments, the metal alloy may comprise and/or consist of cadmium, lead, tin, zinc, silver and/or copper. Further, a metal alloy comprising tin and/or silver may be provided. The first layer 7 may be designed to be electrically conductive.

[0171] In addition, FIG. 1 shows that a plurality of short circuit narrow sections 10 are provided between two directly successive overload narrow sections 4—as viewed in longitudinal direction L. In the illustrated embodiment, three short circuit narrow sections 10 are provided between two overload sections 4. In further embodiments, between two and 15 short circuit narrow sections 10 can be provided between two directly successive overload narrow sections 4.

[0172] Furthermore, FIG. 1 shows that the first layer 7 and/or the first section 5 comprising the first layer 7 is arranged between two directly successive short circuit narrow sections 10 on the outer shell surface 6 of the melting wire 3. The first section 5 may—but need not—be provided at least substantially centrally between two short-circuit narrow sections 10.

[0173] In addition, FIG. 1 shows that the second sections 8 comprising the second layer 9 are arranged on the outer shell surface 6 of the melting wire 3 in such a way that the two overload narrow sections 4 and, in the embodiment shown, the short circuit narrow sections 10 arranged between the overload narrow sections 4 are provided between two directly successive second sections 8 and/or second layers 9—running in longitudinal direction L. Ultimately, the second sections 8 “enclose” and/or “frame” the two directly successive overload narrow sections 4 and the short circuit narrow sections 10 arranged therebetween.

[0174] FIGS. 1 and 6a show that the overload narrow section 4 is formed by recesses 13 comprising an at least substantially rectangular edge. The recesses 13 can be created by punching, in particular by means of rectangular punches.

[0175] Furthermore, it is shown in FIG. 1 that the corner and/or the corner area of the recess 13 comprises a rounding. By means of the recesses 13 comprising at least substantially the rectangular edge, a cross-sectional constriction of the overload narrow section 4 comprising an at least substantially rectangular cross-sectional shape can be formed.

[0176] Based on the detailed representation of the short circuit narrow section 10 in FIG. 1, it is readily apparent that the short circuit narrow section 10 is formed by recesses 14 comprising an at least substantially circular arc section-shaped edge. The recesses 14 can be created by punching. Especially the cross-sectional constriction of the short-circuit narrow section 10 and/or the overload narrow section 4 is designed at least substantially mirror-symmetrical—especially with respect to the center axis of the melting wire 3.

[0177] FIG. 6a shows that the cross-sectional constriction of the short circuit narrow section 10 comprises an at least substantially circular arc section-shaped contour—in the plan view of the melting wire 3. The contour of the cross-sectional constriction of the overload narrow section 4 can be designed straight, in particular wherein rounded corners and/or roundings are provided in the corner regions of the cross-sectional constriction of the overload narrow section 4.

[0178] The short circuit narrow sections 10 shown in FIG. 1 are spaced at least substantially regularly between the overload sections 4—viewed in longitudinal direction L. Especially the short circuit narrow sections 10 comprise at least substantially the same distance 15 from each other. In further embodiments, the distance 15 can be between 5 and 30 mm, in particular between 10 and 20 mm.

[0179] FIG. 1 further shows that the distance 16 between a short-circuit narrow section 10 and the immediately neighboring overload narrow section 4 is designed to be at least substantially equal. The distance 16 always results between the cross-sectional constriction of the overload narrow section 4 to the next cross-sectional constriction, namely the cross-sectional constriction of the short circuit narrow section 10. This distance 16 is especially equal. In further embodiments, the distance 16 may correspond to the distance 15.

[0180] Furthermore, the distance 17 between a cross-sectional constriction of the short circuit narrow section 10 and/or overload narrow section 4 to the immediately adjacent cross-sectional constriction of the short circuit narrow section 10 and/or overload narrow section 4 can be designed to be at least substantially the same. The distance 17 can be designed both as a distance 15 and as a distance 16.

[0181] The distance 17 may also be designed to be at least substantially the same regardless of the short circuit narrow section 10, namely in embodiments in which no short circuit narrow section is provided, and/or regardless of the plurality of short circuit narrow sections 10, namely in embodiments in which only a single short circuit narrow section 10 is provided between two immediately neighboring overload narrow sections 4. The distance 17 ultimately provides the distance between two immediately neighboring cross-sectional constrictions—viewed in the longitudinal direction L of the melting wire 3—, wherein the cross-sectional constriction can be formed both by a short circuit narrow section 10 and by an overload narrow section 4. Finally, the cross-sectional constrictions on the melting wire 3 are in particular regularly spaced.

[0182] The distance between two immediately neighboring overload narrow sections 4 can be between 50 to 80 mm, especially between 60 to 70 mm.

[0183] In the embodiment example shown in FIG. 1, it is provided that the length 18 of the cross-sectional constriction of the overload narrow section 4 is greater than the length 19 of the cross-sectional constriction of the short circuit narrow section 10. Ultimately, the cross-sectional constriction of the overload narrow section 4 may be designed to be at least substantially elongated. The length 18 of the cross-sectional constriction of the overload narrow section 4 can be between 1 and 3 mm and especially 2 mm±0.5 mm. The length 19 of the cross-sectional constriction of the short circuit narrow section 10 may be 1.5±0.5 mm.

[0184] In further embodiments, the first and/or the second layer 7, 9 can be designed as a coating.

[0185] FIG. 1 shows that the first layer 7 is applied to the top side of the melting wire in the first section 5, at least substantially with a circular shape—as seen in cross section.

[0186] The second layer 9 can be applied to the outer shell surface 6 of the melting wire 3 at least substantially in a ring shape, encasing and/or surrounding the melting wire 3.

[0187] FIGS. 6b and 6c show the cross-sections of a further embodiment of the melting conductor 1, wherein both the first layer 7 and the second layer 9 have been applied in their respective sections 5 and 8 at least substantially completely sheathing and/or surrounding the outer shell surface 6 of the melting wire 3.

[0188] FIG. 6a shows that the melting wire 3 comprises an at least substantially rectangular cross-sectional shape. In the illustrated embodiment, the melting wire 3 is designed as a flat strip that can comprise a plurality of cross-sectional constrictions. Thereby, the melting wire 3 may comprise a strip thickness and/or height of 0.04±0.01 mm when designed as a flat strip. The maximum width 10 of the melting wire 3 can be 1.5±0.5 mm.

[0189] FIG. 6a shows in perspective how the recesses 13, 14 design the cross-sectional narrow sections of the overload narrow section 4 and the short circuit narrow section 10.

[0190] In further embodiments, it may alternatively be provided that the melting wire 3, the first and/or the second layer 7, 9 comprise an at least substantially circular outer cross-section.

[0191] It is not shown that the melting wire 3 comprises metal as material. The metal may be at least substantially pure silver. In particular, the silver comprises a degree of purity of 99.99%. The aforementioned degree of purity provides the proportion of Ag (silver) in the metal material. This is also referred to as fine silver.

[0192] In a further embodiment, it may be provided that the melting wire 3 comprises and/or consists of copper and/or a copper alloy as material.

[0193] It can be seen schematically from FIGS. 3 and 4 that the melting conductor 1 comprises an alternating sequence of directly successive overload narrow sections 4. Especially a sequence-like succession of the overload narrow sections 4 and especially of the short circuit narrow sections 10 arranged between the overload narrow sections 4 is provided. In the alternating sequence of the overload narrow sections 4, an at least substantially identical design of two directly successive overload narrow sections 4 and especially of the short circuit narrow sections 10 provided between the overload narrow sections 4 is especially provided. The overload narrow sections 4 are at least substantially regularly spaced in the embodiment example shown in FIG. 3 and comprise an at least substantially equal distance from one another. The “pattern” of the cross-sectional constrictions arranged between two second sections 8 shown in FIG. 1 and the respective shape of the cross-sectional constrictions corresponding thereto are thus provided especially repetitively along the longitudinal direction L of the melting wire 3.

[0194] The first section 5 in particular does not repeat, so that the melting conductor 1 as a whole comprises only at least one first layer 7; and in particular independently of the number of overload narrow sections 4. However, the second layer 9 is provided in particular adjacent to each overload narrow section 4.

[0195] In the embodiment example shown in FIG. 1, it is provided that the ratio of the maximum width 20 of the melting wire 3 to the minimum width 11, 12 of the cross-sectional constriction of the overload narrow section 4 and/or the cross-sectional constrictions of the short circuit narrow section 10 is between 1:0.4 to 1:0.35. In further embodiments, the aforementioned ratio may be between 1:0.6 to 1:0.2, thereby having any value within the specified interval.

[0196] In FIG. 2, a fuse 2 for fuse protection of a DC application is shown. Especially a high voltage hight power DC fuse 2 is provided. The fuse 2 comprises an outer fuse box 21, wherein at least one melting conductor 1 wound around a winding body 22, in particular an electrically isolating winding body 22, is arranged in the fuse box 21 according to at least one of the embodiments described earlier.

[0197] It is not shown that a plurality of melting conductors 1 can also be wound around the winding body 22. The melting conductor 1 comprises a plurality of cross-sectional constrictions, wherein the design of the cross-sectional constrictions of the short circuit narrow sections 10 and the overload narrow sections 4 in combination with the first and second layers 7, 9 first enable the fuse 2 to be used as an HH-DC fuse 2.

[0198] FIG. 2 further shows that at least one contact cap 24 designed for electrical contacting is arranged on each end face of the fuse box 21.

[0199] FIGS. 7 and 8 show that the fuse 2 can be used to protect a direct current transmission, wherein in FIG. 7 the fuse 2 is arranged between a direct current source 27 and a consumer 29. The direct current transmitted to the consumer 29 flows through the fuse 2.

[0200] It is not shown that the fuse box 21 is designed to be at least substantially open at the two end faces 23.

[0201] FIGS. 3 and 5 show that the winding body 22 is designed to be at least substantially star-shaped. The star-shaped design of the winding body 22 is furthermore readily apparent from FIG. 5. The winding body 22 comprises—seen in cross-section—protrusions 25 and/or ridges, wherein recesses and/or depressions 26 are provided between the protrusions 25 and/or ridges. The protrusions 25 are thereby designed such that they can be used for at least substantially punctual support of the melting conductor 1. Between the protrusions 25, the melting conductor 1 does not rest on the surface of the winding body 22.

[0202] In the embodiment shown in FIGS. 7 and 8, the DC voltage of the DC current is greater than 1 kV and less than 100 kV. In further embodiments, the DC voltage may be between 1.5 kV to 50 kV or between 3 kV to 30 kV. In even more preferably embodiments, the rated voltage or the rated voltage range of the fuse 2 is greater than 1 kV and/or less than 100 kV and/or is between 1 kV to 100 kV, preferably between 1.5 kV to 50 kV.

[0203] Furthermore, in the case of the fuse 2 used in a DC network in FIGS. 7 and 8, it is provided that the smallest breaking current of the fuse 2 is 50 A±20 A. In even more preferably embodiments, the smallest breaking current of the fuse 2 may be greater than 3 A and/or less than 500 A and/or between 3 A to 700 A, preferably between 5 A to 500 A.

[0204] In further embodiments, the smallest breaking current of the fuse 2 can correspond to 1.5 times to 10 times the rated current, in particular wherein the minimum and/or smallest breaking current is directly dependent on the rated current of the respective fuse link.

[0205] The rated breaking capacity and/or the highest breaking current of the fuse 2 is greater than 1 kA and/or lies between 20 kA and 50 kA in the example shown in FIGS. 7 and 8.

[0206] The direct current source 27 shown in FIGS. 7 and 8 provides direct current with a current greater than 5 A. Especially, the current of the direct current and/or the rated current range is between 10 A to 75 kA.

[0207] As a function of the transmitted DC current and DC voltage, the product of the DC current and DC voltage protected by the fuse 2 may vary. In the embodiment example shown in FIGS. 7 and 8, the aforementioned product is 1000 kW±50 kW. In further embodiments, the product (mathematical multiplication) of the DC current and the DC voltage protected by the fuse 2 may be between 5 kW and 3000 MW, especially between 700 kW and 1000 MW.

[0208] Not shown is that a plurality of melting conductors 1 are arranged in the fuse box 3. In further embodiments, it may be provided that between 2 to 10 melting conductors 1 are used.

[0209] It is not shown that the DC application is a medium voltage DC application and/or a high voltage DC application. The medium voltage DC application comprises a DC voltage of up to 30 kV. A high voltage DC application comprises a DC voltage of more than 50 kV.

[0210] The fuse 2 may further be arranged to a medium voltage DC system, especially in a medium voltage DC system with at least one MVDC device.

[0211] Furthermore, it is not shown that the direct current source 27 is a photovoltaic system and/or photovoltaic area system (i.e., a solar farm) and/or a wind power system and/or a wind farm, especially an offshore wind farm. Especially, the aforementioned energy conversion plants provide direct current to the direct current grid. The power generated by the aforementioned power conversion plants can be transmitted to the consumer 29 in a secured manner by at least one fuse 2.

[0212] In addition, FIGS. 7 and 8 show a system 28 with a consumer 29 which can be supplied by direct current Especially the consumer 29 is an user and/or a plurality of consumers. Furthermore, the system 28 comprises a fuse 2 which is designed to protect the direct current transmitted to the consumer 29. It is not shown that the power of the consumer 29 is greater than 5 KW and less than 2000 MW. In particular, the fuse 2 is used in a direct current network.

[0213] FIG. 2 shows that the fuse box 21 is designed in the shape of a hollow cylinder and/or a tube. On the end face, the fuse box 21 is tightly enclosed by the contact caps 24, wherein the contact cap 24 can be placed on the fuse box 21.

[0214] FIG. 2 shows that the contact cap 24 covers at least part of the shell surface in the end region of the fuse box 21.

[0215] It is not shown that the contact cap 24 is associated to another top cap, which is placed in front of the contact cap 24 and at least partially covers the contact cap 24. In this case, the contact cap 24 represents the so-called inner auxiliary cap.

[0216] The fuse box 21 shown in FIG. 2 comprises a ceramic material. In further embodiments, the fuse box 21 can consist of a ceramic material. Alternatively or additionally, the fuse box 21 may comprise a plastic material, especially a gas fiber reinforced plastic material.

[0217] It is not shown that an extinguishing agent is provided in the fuse box 21. The extinguishing agent may be an extinguishing sand filling, preferably quartz sand, and/or air.

[0218] FIG. 4 shows that the melting conductor 1 is connected to the contact cap 24 in an electrically contacting manner.

[0219] It is not shown that the melting conductor 1 is at least partially, in particular completely, embedded in and/or surrounded by the extinguishing agent. In particular, the melting conductor 1 comprises an arc extinguishing agent by the design of the second layer 9 and/or by the material of the second layer 9.

[0220] Moreover, it is not shown that the fuse box 21 is at least substantially hermetically encapsulated.

[0221] The material for the winding body 22 may be hard porcelain.

[0222] In further embodiments, the winding body 22 may be designed such that a plurality of chambers is formed, in particular wherein a cross-sectional constriction is provided in one chamber.

[0223] Further not shown is that the contact cap 24 comprises a galvanic coating and/or a silver coating and/or comprises and/or consists of electrolyte copper and/or aluminum as material.

LIST OF REFERENCE SIGNS

[0224] 1 Melting conductor [0225] 2 Fuse [0226] 3 Melting wire [0227] 4 Overload narrow section [0228] 5 First section [0229] 6 Outer shell surface of 3 [0230] 7 First layer [0231] 8 Second section [0232] 9 Second layer [0233] 10 Short circuit narrow section [0234] 11 Minimum width of 4 [0235] 12 Minimum width of 10 [0236] 13 Recess of 4 [0237] 14 Recess of 10 [0238] 15 Distance between two short circuit narrow sections [0239] 16 Distance between short circuit narrow section and overload narrow section [0240] 17 Distance between cross-section constrictions [0241] 18 Length from 4 [0242] 19 Length of 10 [0243] 20 Maximum width of 3 [0244] 21 Outer fuse box [0245] 22 Winding body [0246] 23 End face [0247] 24 Contact cap [0248] 25 Protrusion of 22 [0249] 26 Depression of 22 [0250] 27 Direct current source [0251] 28 System [0252] 29 Consumer [0253] L Longitudinal direction