Arrester

Abstract

An arrester is disclosed. In an embodiment, the arrester includes a first electrode, a second electrode, a switching contact, a first discharge space between the first and second electrodes and a short-circuiting mechanism suitable for short-circuiting the first and second electrodes and for switching a state of the arrester, wherein, in a first state, at least one electrode of the first and second electrodes is not electrically conductively connected to the switching contact and, in a second state, the at least one electrode is electrically conductively connected to the switching contact.

Claims

1-14. (canceled)

15. An arrester comprising: a first electrode; a second electrode; a switching contact; a first discharge space between the first and second electrodes; and a short-circuiting mechanism suitable for short-circuiting the first and second electrodes and for switching a state of the arrester, wherein, in a first state, at least one electrode of the first and second electrodes is not electrically conductively connected to the switching contact and, in a second state, the at least one electrode is electrically conductively connected to the switching contact.

16. The arrester according to claim 15, further comprising an arrester body in which the first discharge space is provided, wherein either the first electrode or the second electrode and the switching contact are arranged on end sides of the arrester body, and wherein the switching contact is arranged outside the first discharge space.

17. The arrester according to claim 15, wherein, in the first state, both the first and second electrodes are not electrically conductively connected to the switching contact and, in the second state, both the first and second electrodes are electrically conductively connected to the switching contact.

18. The arrester according to claim 15, wherein the arrester is configured to switch from the first state to the second state by short-circuiting the first and second electrodes.

19. The arrester according to claim 16, further comprising a second discharge space, which is provided in the arrester body between the switching contact and either the first electrode or the second electrode.

20. The arrester according to claim 19, wherein the second discharge space has a higher ignition voltage than the first discharge space.

21. The arrester according to claim 15, wherein the first discharge space is sealed in a gas-tight manner and is filled with gas.

22. The arrester according to claim 19, wherein the second discharge space is ventilated.

23. The arrester according to claim 19, wherein a spacing of mutually facing sides of the first and second electrodes is smaller than a spacing of mutually facing sides of the switching contact and the electrode in the second discharge space.

24. The arrester according to claim 15, wherein the short-circuiting mechanism comprises a deflected contact, a deflection of which is relaxed by development of heat.

25. The arrester according to claim 15, wherein the short-circuiting mechanism comprises an arm, which is suitable for short-circuiting the first and second electrodes and the switching contact.

26. The arrester according to claim 25, wherein the arm is deflected by a meltable spacer in such a way that the arm is spaced apart at least from one of the first and second electrodes, and wherein, after the spacer has melted, the arm short-circuits the first and the second electrodes by spring force.

27. The arrester according to claim 26, wherein the meltable spacer is arranged between a central region of the arm and the electrode in the central region of an arrester body and ends of the arm, which extend in a direction of end sides of the arrester body, are spaced apart from the switching contact and the other electrode.

28. The arrester according to claim 25, wherein the arm is deflected by a meltable spacer in such a way that the arm is spaced apart from the switching contact, and wherein, after the spacer has melted, the arm short-circuits the switching contact with the first and second electrodes.

29. The arrester according to claim 28, wherein the meltable spacer is arranged between a central region of the arm and the electrode in the central region of an arrester body and ends of the arm, which extend in a direction of end sides of the arrester body, are spaced apart from the switching contact and the other electrode.

30. An arrester comprising: a first electrode; a second electrode; a switching contact; a first discharge space between the first and second electrodes; a second discharge space having a higher ignition voltage than the first discharge space; and a short-circuiting mechanism, which is suitable for short-circuiting the first and second electrodes and for switching a state, wherein, in a first state, at least one electrode of the first and second electrodes is not electrically conductively connected to the switching contact and, in a second state, the at least one electrode is electrically conductively connected to the switching contact.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention is illustrated below with the aid of drawings.

[0025] FIG. 1 shows a side view of an exemplary embodiment of an arrester.

[0026] FIG. 2 shows a sectional view of the exemplary embodiment of the arrester.

[0027] FIG. 3 shows an equivalent circuit diagram of the exemplary embodiment of the arrester.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0028] FIG. 1 shows a side view of an exemplary embodiment of an arrester 10. Said arrester has a combination of fail-short and switching contact. The arrester 10 is preferably a gas discharge tube having a discharge space 8 (not illustrated in FIG. 1) filled with gas and serves as a surge arrester for protecting against surge pulses.

[0029] The arrester 10 comprises a cylindrical arrester body 1 made of an insulating material. A switching contact 2 and a first electrode 3 are provided on the end sides of said arrester body 1. The switching contact 2 and the first electrode 3 are each designed as an end-side closure cap of the arrester body 1. The outer sides of the switching contact 2 and the first electrode 3, which outer sides terminate the end sides of the arrester body 1, may be formed in a mirror-symmetrical manner.

[0030] Both the switching contact 2 and the first electrode 3 may comprise elongated, for example, wire-shaped, connection regions 21, 31 at which the arrester 10 can be contact-connected using solder. A second electrode 4 is provided in a central region of the arrester body 1. Said second electrode also has an elongated, for example, wire-shaped, connection region 41.

[0031] The arrester 10 further comprises a short-circuiting mechanism 5 with a deflected arm 6, which is spaced apart from the arrester body 1 by means of a spacer 7, with the result that there is no contact with the switching contact 2 and the first electrode 3. In this exemplary embodiment, the spacer 7 is made of a material with a low melting point, for example, what is known as a solder bead, which is positioned between the second electrode 4 and the central region of the arm 6 in such a way that the ends of the arm 6 are spaced apart from the switching contact 2 and the first electrode 3.

[0032] When the spacer 7 melts, a spring force causes the arm to move toward the arrester body 1, to contact the first electrode 3 and the switching contact 2 and therefore to short-circuit the first and second electrode 3, 4 and the switching contact 2. The spring force may arise, for example, by way of a spring component on the arm and/or material elasticity.

[0033] The described short-circuiting mechanism 5 makes it possible to switch from a first state, in which the switching contact 2 and the first and the second electrode 3, 4 are not electrically conductively connected, to a second state, in which there is an electrically conductive connection, that is to say a short-circuit, between the switching contact 2 and the electrodes 3, 4.

[0034] The short-circuiting mechanism 5 is triggered by an overcurrent and the accompanying development of heat, which leads to melting of the spacer 7.

[0035] FIG. 2 shows a sectional view of the exemplary embodiment of the arrester from FIG. 1.

[0036] A discharge space 8, which may also be referred to as a spark gap, is provided in the arrester body 1 between the first and second electrode 2, 3. The discharge space 8, which is delimited by the inner walls of the arrester body 1 and the sides 32, 43, facing toward the discharge space, of the first and second electrode 3, 4, is gas-tightly or hermetically sealed and is filled with gas. The sides 32, 43, facing toward the discharge space 8, of the first and second electrode 3, 4 are configured and shaped in such a way that, when the voltage between the two electrodes 3, 4 increases to the sparkover voltage, the resultant electric field leads to ionization of the gas located in the discharge space 8. Said gas becomes conductive and the gap is short-circuited by a spark.

[0037] The arrester body 1 comprises a further discharge space 9 between its central region and that of the switching contact 2. Said further discharge space 9 or spark gap is spatially separated from the discharge space 8, with the result that there are two separate spark gaps, between the potential points b-c and the potential points a-c.

[0038] The discharge space 8, that is to say the spark gap b-c, fulfills the function of a conventional spark gap, which ignites when the sparkover voltage is exceeded. In contrast, the further discharge space 9, that is to say the spark gap a-c, serves as a dummy without the actual arrester function described above. There is no provision for said further discharge space to ignite. The further discharge space 9 has a very high ignition voltage. It may be designed to be ventilated. This ignition gap corresponds to an open switch. As an alternative or in addition, the second electrode 4 and the switching contact 2 may be designed in such a way that the spacing between them is greater than that between the first and the second electrode 3, 4, as a result of which the sparkover voltage is also greater. When the short-circuiting mechanism is triggered, one side of the arm 6 short-circuits the two-electrode arrester with the first and second electrode 3, 4; the other side of the arm 6 closes the switch and produces a conductive connection to the electrodes 3, 4.

[0039] FIG. 3 shows an equivalent circuit diagram of the exemplary embodiment of the arrester.

[0040] The potential nodes b, c, between which the arrester 10 is coupled, correspond to the switching contacts 31, 41 of the first and second electrode 3, 4. A switch is coupled between the potential node a, which corresponds to the switching contact 2, and the potential node b. A switch is also coupled between the potential nodes b, c. The switches 11 are coupled to one another in such a way that the connections between the abovementioned potential nodes are either interrupted simultaneously or there is an electrically conductive connection.

[0041] The circuit diagram illustrates the functioning of the arrester. If the short-circuiting mechanism is not triggered, the switches 11 are open. The switches 11 close upon triggering of the short-circuiting mechanism.

[0042] The external appearance of the arrester 10 and the dimensioning of the parts thereof advantageously correspond to a conventional three-electrode arrester. The switching contact 2 is shaped like one of the external electrodes of the three-electrode arrester. By retaining the design of a three-electrode arrester, short-circuiting mechanisms that are designed for three-electrode arresters can also be used for the described arrester having the function of a two-electrode arrester with switch.

[0043] The features of the exemplary embodiments can be combined.