PROTECTIVE DEVICE FOR PROTECTING AN ELECTRIC LOAD

Abstract

A protection device for protecting an electrical load, from a short-circuit current, comprising a line arrangement having a first electrical line and a second electrical line for supplying the electrical load with electrical energy, the first electrical line having a first line constriction having a reduced line cross-section and the second electrical line having a second line constriction having a reduced line cross-section, the first line constriction and the second line constriction being arranged adjacent to each other, and comprising at least one insulation layer which electrically insulates the first line constriction from the second constriction the at least one insulation layer being thermally destructible in dependence on temperature.

Claims

1. A protective device for protecting an electric load, which is electrically connected downstream of the protective device, before a short-circuit current, comprising: a line arrangement having a first electrical line and a second electrical line configured to supply the electric load with electrical energy, wherein the first electrical line has a first line narrow section with a reduced line cross section and the second electrical line has a second line narrow section with a reduced line cross section, wherein the first line narrow section and the second line narrow section are arranged adjacent to each other; and at least one insulation layer which electrically isolates the first line narrow section from the second line narrow section, wherein the at least one insulation layer is thermally destructible as a function of temperature; wherein the first line narrow section and the second line narrow section are electrically heatable by a current flow and the at least one insulation layer is thermally loadable, such that the at least one insulation layer is thermally destroyed when reaching a threshold amount of the current through the line arrangement, causing the first electrical line to electrically conductively connect with the second electrical line.

2. The protective device according to claim 1, wherein the at least one insulation layer is formed by a cover of the first electrical line and/or the second electrical line.

3. The protective device according to claim 1, wherein the at least one insulating layer is configured to melts or evaporate upon reaching a threshold temperature of the at least one insulating layer.

4. The protective device according to claim 3, wherein a selectable characteristic of the at least one insulation layer defines a time interval, such that upon reaching or exceeding a threshold temperature for at least one time interval, the at least one insulation layer becomes electrically conductive or destroyed through one or both of the first line narrow section or the second line narrow section.

5. The protective device according to claim 1, wherein the first line narrow section and the second line narrow section are immovable with respect to each other to prevent repulsion of the first line narrow section and the second line narrow section from each other.

6. The protective device according to claim 5, further comprising a printed circuit board, wherein the first line narrow section and the second line narrow section are fixed on the printed circuit board.

7. The protective device according to claim 1, wherein at least one of the at least one insulation layer or the second electrical line is adapted to be non-destructive, wherein an electrical switch-on current or a rated current of the protective device is a multiple of a permanently flowing current through the first electrical line and/or the second electrical line.

8. The protective device according to claim 1, wherein the at least one insulating layer is formed by one or more of: an insulating varnish on the first line narrow section or the second line narrow section or a cover around the first line narrow section or the second line narrow section.

9. The protective device according to claim 1, wherein the line arrangement comprises a third electrical line adapted to supply the electric load with electrical energy, and a third line narrow section arranged adjacent to the first line narrow section or the second line narrow section.

10. The protective device of claim 9, wherein the first line narrow section, the second line narrow section, and the third line narrow section are disposed adjacent one another.

11. The protective device according to claim 9, wherein the at least one insulation layer is arranged between the first line narrow section, the second line narrow section, and the third line narrow section, wherein the at least one insulation layer is adapted to electrically isolate each of the line narrow sections from the other of the line narrow sections.

12. The protective device according to claim 1, wherein the first line narrow section and the second line narrow section are arranged adjacent to and crossing each other in a first contact region.

13. The protective device according to claim 12, wherein the third line narrow section is arranged adjacent to the first line narrow section or the second line narrow section in a second contact region, and wherein the third line narrow section is electrically isolated from the first line narrow section or the second line narrow section by at least one insulating layer in the second contact region, and wherein the first contact region and the second contact region are spaced from each other.

14. The protective device according to claim 13, wherein the third line narrow section is arranged adjacent to the first line narrow section or the second line narrow section in a third contact region, and wherein the third line narrow section is electrically insulated from the first line narrow section or the second line narrow section by at least one insulating layer in the third contact region, and wherein the second contact region and the third contact region are arranged at a distance from each other.

15. The protective device according to claim 14, wherein the first line narrow section and/or the second line narrow section are thermally conductive such that when a threshold to temperature is exceeded at the first contact region, the threshold temperature is also exceeded at the second contact region or the third contact region.

16. The protective device according to claim 1, wherein the at least one insulation layer is formed from an encapsulation of the first line narrow section or the second line narrow section.

17. The protective device according to claim 1, wherein the line arrangement for each electrical line has an input terminal and an output terminal respectively.

18. A protection system for protecting an electric load from a short circuit current, comprising: a protective device, comprising: a line arrangement having a first electrical line and a second electrical line configured to supply the electric load with electrical energy, wherein the first electrical line has a first line narrow section with a reduced line cross section and the second electrical line has a second line narrow section with a reduced line cross section, wherein the first line narrow section and the second line narrow section are arranged adjacent to each other; and at least one insulation layer which electrically isolates the first line narrow section from the second line narrow section, wherein the at least one insulation layer is thermally destructible as at function of temperature; wherein the first line narrow section and the second line narrow section are electrically heatable by a current flow and the at least one insulation layer is thermally loadable, such that the at least one insulation layer is thermally destroyed when reaching a threshold amount of the current through the line arrangement, causing the first electrical line to electrically conductively connect with the second electrical line; wherein the line arrangement has, for each of the first electrical line and the second electrical line, an input terminal and an output terminal; a power supply line for supplying the electric load with electrical energy, comprising two electrical lines configured to transport electrical energy to the electric load, wherein the electrical lines are each electrically connectable with one of the input terminals of the line assembly; and a shutdown device connected upstream of the protective device, wherein the shutdown device is adapted to prevent the transport of electrical energy to the protective device when an electric short-circuit current flows through the protective device by interrupting an electrical connection between the power supply line and the protective device in the presence of an electrical connection between the first electrical line and the second electrical line; wherein the electric load is connectable to the output terminals of the protective device.

19. The protective device of claim 4, wherein the selectable characteristic of the at least one insulation layer is a thickness of the at least one insulation layer.

20. The protective device according to claim 7, wherein the multiple is one of: five times the permanently flowing current or ten times the permanently flowing current.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Further examples will be explained with reference to the accompanying figures. They show:

[0042] FIG. 1 shows a protective device according to an example;

[0043] FIG. 2 shows a protection system according to an example; and

[0044] FIG. 3 shows a protective device according to one example.

DETAILED DESCRIPTION

[0045] FIG. 1 shows a schematic representation of the protective device 100 for protecting an electric load, which is connected downstream of the protective device 100. The protective device 100 comprises a line arrangement 101 with a first electrical line 103 and a second electrical line 105 for supplying the electric load with electrical energy. The first electrical line 103 has a first line narrow section 107 with a reduced line cross-section, and the second electrical line 105 has a second line narrow section 109 with a reduced line cross-section. The first line narrow section 107 and the second line narrow section 109 are disposed adjacent to each other. Furthermore, the protective device 100 comprises at least one insulation layer 111, which electrically isolates the first line narrow section 107 from the second line narrow section 109, wherein the at least one insulation layer 111 is thermally destructible depending on temperature. The first line narrow section 107 and/or the second line narrow section 109 are electrically heated by a current flow and the at least one insulating layer 111 is thermally acted upon to thermally destroy the at least one insulating layer 111 upon reaching a predetermined current of the current through the line assembly 101 and thereby the first electrical line 103 to be electrically connected to the second electrical line 105.

[0046] The at least one insulation layer 111 is formed by a cover of the first electrical line and the second electrical line 105. The at least one insulation layer 111 is further adapted to be non-destructive in respect to a flow of an electrical turn-on and/or rated current through the first electrical line 103 and/or the second electrical line 105 in a predetermined time interval. The current of the electrical turn-on and/or rated current is a multiple, in particular a fivefold or tenfold, of the current of an electric current flowing permanently through the first electrical line 103 and/or the second electrical line 105.

[0047] The first line narrow section 107 and the second line narrow section 109 are immovably adapted to prevent repulsion of the first line narrow section 107 and the second line narrow section 109 from each other. The line arrangement 101 further comprises a third electrical line 113 which is adapted to supply the electric load with electrical energy and has a third line narrow section 115, which is arranged adjacent to the first line narrow section 107 and/or the second line narrow section 109.

[0048] The at least one insulation layer 111 is arranged between the first line narrow section 107, the second line narrow section 109 and the third line narrow section 115, wherein the at least one insulation layer 111 is formed to electrically isolate the line narrow sections 107, 109, 115 from the further line narrow sections. Thus, the first line narrow section 107 is electrically insulated from the second line narrow section 109 and the third line narrow section 115 by means of the at least one insulation layer 111 and the second line narrow section 109 is electrically insulated from the third line narrow section 115.

[0049] The first line narrow section 107 and the second line narrow section 109 are arranged in a first contact region 117 adjacent to each other, in particular crossed. The third line narrow section 115 is arranged in a second contact region 119 adjacent to the first line narrow section 107 and is electrically insulated from the first line narrow section 107 by means of the at least one insulation layer 111 in the second contact region 119. The first contact region 117 and the second contact region 119 are arranged at a distance from one another. The third line narrow section 115 is disposed in a third contact region 121 adjacent to the second line narrow section 109 and is electrically insulated by the at least one insulating layer 111 in the third contact region 121 of the second line narrow section 109, wherein the second contact region 119 and the third contact region 121 are spaced from each other. Furthermore, the third contact region 121 is arranged at a distance from the first contact region 117.

[0050] The first line narrow section 107, the second p line narrow section inch 109 and/or the third line narrow section 115 are thermally conductive to realize when exceeding the predetermined temperature at the first contact region 117 an exceeding the predetermined temperature at the second contact region 119 and/or the third contact region 121.

[0051] The line arrangement 101 has, for each electrical line 103, 105, 113, an input terminals 123, 125, 127 and an output terminals 129, 131, 133, respectively. To the input terminals 123, 125, 127, in each case an electrical access line of a power supply line can be connected, and to the output terminals 129, 131, 133 each have an electric load, or a terminal of an electric load can be connected.

[0052] FIG. 2 shows a schematic representation of a protection system 200 for protecting an electric load 203 from a short-circuit current. The protection system 200 includes a protective device 100, which is connected upstream of the electric load 203. The protective device 100 comprises a line arrangement 101 having a first electrical line 103 and a second electrical line 105 for supplying the electric load 203 with electrical energy. The first electrical line 103 has a first line narrow section 107 with a reduced line cross-section, and the second electrical line 105 has a second line narrow section 109 with a reduced line cross-section. The first line narrow section 107 and the second line narrow section 109 are arranged adjacent to one another, wherein the line arrangement 101 for the first electrical line 103 and the second electrical line 105 each have an input terminal 123, 125, 127 and an output terminal 129, 131, 133.

[0053] Furthermore, the protective device 100 comprises at least one insulation layer 111, which electrically isolates the first line narrow section 107 from the second line narrow section 109, the at least one insulation layer 111 being temperature-dependently thermally destructible. The first line narrow section 107 and/or the second line narrow section 109 are electrically heated by a current flow and the at least one insulating layer 111 is thermally acted upon to thermally destroy the at least one insulating layer 111 upon reaching a predetermined current of the current flowing through the line assembly 101 and thereby the first electrical line 103 to be electrically connected to the second electrical line 105.

[0054] Furthermore, the protection system 200 includes a power supply line 205 for supplying the electric load 203 with electrical energy, which comprises at least three electrical leads 207, 209, 213 for transporting electrical energy to the electric load 203, wherein the electrical leads 207, 209, 213 are electrically connected with one of the input terminals 123, 125, 127 of the line assembly 101, respectively.

[0055] The protection system 200 further comprises a shutdown device 211, which is connected upstream of the protective device 100 and is adapted to interrupt the electrical connection between the power supply line 205 and the protective device 100 in the presence of an electrical connection between the first electrical line 103 and the second electrical line 105, in order when an electrical short-circuit current flows through the protective device 100 to prevent the transport of electrical energy to the protective device 100. The electric load 203 can be connected to the output terminals 129, 131, 133 of the protective device 100.

[0056] The protective device 100 further comprises a printed circuit board 201, wherein the first line narrow section 107, the second line narrow section 109 and/or the third line narrow section 115 are fixed on the circuit board 201.

[0057] The first line narrow section 107, the second line narrow section 109 and the third line narrow section 115 are disposed adjacent to each other. In particular, the line narrow sections 107, 109, 115 intersect in the first contact region 117, the line narrow section in the first contact region 117 being electrically insulated from each other by means of the at least one insulation layer 111.

[0058] FIG. 3 shows a schematic representation of the protective device 100 for protecting an electric load, which is electrically connected downstream of the protective device 100, before a short-circuit current. The protective device 100 comprises a line arrangement 101 with a first electrical line 103 and a second electrical line 105 for supplying the electric load with electrical energy. The first electrical line 103 has a first line narrow section 107 with a reduced line cross-section, and the second electrical line 105 has a second line narrow section 109 with a reduced line cross-section. The first line narrow section 107 and the second line narrow section 109 are disposed adjacent to each other. Furthermore, the protective device 100 comprises at least one insulation layer 111, which electrically isolates the first line narrow section 107 from the second line narrow section 109, wherein the at least one insulation layer 111 is thermally destructible depending on temperature. The first line narrow section 107 and/or the second line narrow section 109 are electrically heated by a current flow and the at least one insulating layer 111 is thermally acted upon to thermally destroy the at least one insulating layer 111 upon reaching a predetermined current of the current through the line assembly 101 and thereby the first electrical line 103 to be electrically connected to the second electrical line 105.

[0059] The at least one insulation layer 111 is formed by a cover around the first line narrow section 107, the second line narrow section 109 and/or the third line narrow section 115. In particular, the at least one insulation layer 111 encloses the printed circuit board 201.

[0060] The line arrangement 101 comprises a third electrical line 113, wherein the electrical lines 103, 105, 113 at a first end of the electrical lines 103, 105, 113 each have an input terminal 123, 125, 127 and at a second end of the electrical lines 103, 105, 113 each have an output terminal 129, 131, 133. The line arrangement 101 is adapted to transport electrical energy in the form of an alternating electrical current with an electrical voltage by means of the electrical lines 103, 105, 113 from a supply line connection to an electric load. In particular, an alternating current is transmitted via the electrical lines 103, 105, 113, which has a different phase with respect to the respective other electrical lines. In particular, the phase may be shifted by 30° between the first electrical line 107 and the second electrical line 109 and may be shifted between the second electrical line 109 and the third electrical line 113 by a further 30°, so that a phase difference of 60° between the first electrical line 107 and the third electrical line 113 is realized.

LIST OF REFERENCE NUMBERS

[0061] 100 protective device [0062] 101 line arrangement [0063] 103 first electric line [0064] 105 second electrical line [0065] 107 first line narrow section [0066] 109 second line narrow section [0067] 111 insulation layer [0068] 113 third electrical line [0069] 115 third line narrow section [0070] 117 first contact area [0071] 119 second contact area [0072] 121 third contact area [0073] 123 input terminal [0074] 125 input terminal [0075] 127 input terminal [0076] 129 output terminal [0077] 131 output terminal [0078] 133 output terminal [0079] 200 protection system [0080] 201 PCB [0081] 203 electric load [0082] 205 supply main line [0083] 207 electrical supply line [0084] 209 electrical supply line [0085] 211 shut-off device [0086] 213 electrical supply line