Surge protection device, comprising at least one surge arrester and one short-circuit switching device which is connected in parallel with the surge arrester, can be thermally tripped and is spring-pretensioned

Abstract

The invention relates to a surge protection device, comprising at least one surge arrester and one short-circuit switching device which is connected in parallel with the surge arrester, can be thermally tripped and is spring-pretensioned, wherein the abovementioned means form one physical unit. The thermal tripping means is arranged in the region where heating of the surge arrester is expected when it is overloaded, and operating or surge current does not flow through said thermal tripping means. The thermal tripping means is in the form of a stop part which releases an unlocking slide of the switching device in the event of thermal overload. The switching device has two opposite contact pieces, wherein at least one of the contacts is of moveable design and is under spring pretension in the closing direction of the switching device. The opening state of the switching device is maintained by the unlocking slide, which is released by the thermal tripping means to close the switching device.

Claims

1. A surge protection device, comprising at least one surge arrester (5) and a switching device, the switching device being switchable between an open state and a closed state, wherein the above-mentioned means form a module, a thermal tripping means (4K) which is arranged in the region of the heating to be expected of the surge arrester (5) in the event of the overload thereof and is designed as a stop part through which operating current or impulse current does not flow, which releases an unlocking slide (4; 41) of the switching device (6) which moves in a movement path in the event of thermal overload, wherein the thermal tripping means stop part (4K) is thermally and mechanically coupled to the surge arrester (5) and blocks the movement path of the unlocking slide (4; 41), wherein the switching device (6) has two opposing, in particular interlocking contact parts (6a; 6b), wherein at least one of the interlocking contact parts (6b) is embodied as movable, characterized in that the movable interlocking contact part is movable in at least a first direction, the first direction being towards the other interlocking contact part, the switching device is embodied as a short-circuit switching device (6), which is connected in parallel with the surge arrester, can be thermally tripped, and is spring-pretensioned, and the movable contact part (6b) is under spring pretension (8) in the first direction, furthermore the open state of the switching device is secured by the unlocking slide (4) and can be released by the thermal tripping means stop part (4K) to close the switching device (6), wherein the unlocking slide has a first end and a second end disposed opposite the first end, wherein the first end of the unlocking slide includes a separating element, wherein the separating element is under spring pretension (9), in order to move rapidly away from the interlocking contact parts (6a, 6b) in case of short-circuit of the switching device (6).

2. The surge protection device according to claim 1, characterized in that at least sections of the interlocking contact parts (6a; 6b) are located inside a molded body (7), which forms an arc chamber, wherein the molded body (7) has an attachment (71), which is oriented at an angle which deviates from the movement direction of the movable interlocking contact part (6b).

3. The surge protection device according to claim 2, characterized in that the attachment (71) has a cavity for accommodating the separating element (41).

4. The surge protection device according to claim 1, characterized in that the contact parts (6a; 6b) of the switching device (6) have surfaces facing toward one another, wherein the surfaces have a contour to enlarge the current transfer surface and reduce the transfer resistance.

5. The surge protection device according to claim 4, characterized in that the surfaces of the interlocking contact parts (6a; 6b) are designed as cone and counter cone.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS(S)

(1) In the figures:

(2) FIG. 1 shows a schematic circuit diagram of the solution according to the invention having monitoring circuit U and short-circuiter 4; 6 and

(3) FIG. 2 shows a perspective illustration of a surge protection device according to the invention, designed as a plug part to be accommodated in a base part (not shown), wherein the molded body having switching device and the thermal tripping means are located inside the plug part.

DETAILED DESCRIPTION OF THE INVENTION

(4) The illustration of the schematic circuit diagram according to FIG. 1 proceeds from a surge protection means 1, in which the operating-impulse current path and the monitoring path U are functionally separated. The integrated switching device 6 is designed as a short-circuiter, wherein the surge arrester, for example, designed as a varistor, is identified with the reference sign 5. The unlocking of the switching device 6 is symbolized by the reference sign 4 in FIG. 1 and the thermal coupling element is identified as the thermal tripping means with 4K. The terminals of the surge protection means have the reference signs 2 and 3.

(5) The plug part implemented according to the invention comprises the surge protection device 1 having the surge arrester 5, the unlocking slide 4, and the molded body 7, which accommodates the switching device 6 having the contact parts 6a, 6b. In addition, plug contacts 2; 3 for the operating current supply are provided on the lower side of the plug part. Reference sign 10 according to FIG. 2 identifies a movable conductor section, to close the circuit from the plug contact in the left of the figure via the switching device to the varistor and therefrom to the plug contact in the right of the figure.

(6) FIG. 2 shows the disk-shaped varistor 5 having an applied metallic conductive surface, which extends into a region of expected strong heating of the varistor 5, wherein the thermal tripping means 4K is applied in this region.

(7) The switching device 6 comprises contact parts 6a and 6b (see FIG. 2), wherein in the example shown, the contact part 6b is mounted with pretension of a spring 8 so it is movable in the molded body 7.

(8) In the short-circuit position of the switching device 6, the movable contact part 6b is pressed against the fixed contact part 6a.

(9) The open state of the switching device 6 is thus secured by the means 4 and can be released by the thermal tripping means 4K to close the switching device 6.

(10) The open state of the switching device 6 is illustrated in FIG. 2. The position of the separating element 4 is also recognizable here, the location change of which in the event of the short-circuit is performed with assistance by the spring 9.

(11) The molded body 7 has an attachment 71, which is oriented at an angle which deviates from the movement direction of the movable contact part 6b.

(12) The attachment 71 comprises a cavity 39 for accommodating a section 41 of the separating element 4.

(13) The surfaces of the contact parts 6a and 6b facing toward one another can have a cone contour 37 with associated conical recess 35 in the counter contact part. In this way, the current transfer surface is enlarged and the transfer resistance between the contact parts is reduced. The flexible electrical connection means 10 is connected, on the one hand, to the movable contact part 6b and leads, on the other hand, to a molded-on terminal leg 33. The further electrical terminal 21 of the varistor 5 leads to the plug terminal 2.

(14) The internal contour inside the molded part 7 corresponds to the external contour of the movable contact part 6b in consideration of the required tolerances for the desired free mobility of the contact part in this regard.

(15) The surge-limiting component 5, preferably designed as a varistor, is thermally coupled according to the illustrations in the drawing via a thermal tripping means 4K to the unlocking and tripping system. There is no current flow through the thermal tripping element 4K in this case.

(16) The embodiment of the thermal tripping element can therefore be selected completely freely to optimize the response behavior and therefore to achieve a good tripping characteristic, specifically via appropriate positioning on the varistor 5 and/or dimensioning and selection of the material for the thermal tripping element with respect to thermal capacity and thermal conductivity. The thermal tripping element 4K can be manufactured as a separate part, which is permanently fastened using a solder or a heat-sensitive adhesive on the varistor. On the other hand, however, the thermal tripping means itself can also consist of a material which deforms in a yielding manner under the effect of heat.

(17) In the majority of cases, a very rapid and thermally sensitive tripping characteristic is desired. This can be implemented in that the thermal tripping means is connected in an optimally thermally conductive manner directly to the surge-limiting component or is manufactured from a thermally insulating envelope material, to avoid heat losses. Thermally conductive connections to quasi-parasitic heat sinks are avoided.

(18) Since the monitoring circuit is not in the operating current path in the solution according to the invention, the design of the thermal monitoring device can be dimensioned exclusively under the aspect of the failure behavior of the voltage-limiting component. Upon exceeding a set critical temperature, the thermal coupling to the surge-limiting element is canceled out. The thermal tripping means is moved away from the viewpoint of the spring force 9 and the unlocking slide 4; 41, so that the switching device passes into the short-circuit.

(19) In case of short-circuit, the current is conducted via the contact parts 6a and 6b, wherein the corresponding contact point is under spring pre-tension.

SEQUENCE LISTING

(20) Not Applicable