Overvoltage protection device with at least one surge arrester and a thermally triggerable, spring-pretensioned short-circuit switching device connected in parallel to the surge arrester

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.

Description

technical field [0001] The invention relates to an overvoltage protection device having at least one overvoltage arrester and a thermally actuatable, spring-pretensioned short-circuit switching device connected in parallel with the surge arrester, wherein the aforementioned devices form a structural unit, the thermal actuation device being arranged in the region where the surge arrester is expected to heat up when it is overloaded, And it is provided as a stop, through which no operating current or pulse current flows, which releases the unlocking slide of the switching device in the event of a thermal overload, as stated in the preamble of claim 1 . Background technique [0002] A varistor-based surge arrester is known from DE 295 19 313 U1, in which it is ensured that the impermissible heat that occurs at the varistor in the event of damage is transferred directly to the thermal trigger. For this purpose, there is a support wall in the plug connector, wherein the piezore...

AI Technical Summary

Problems solved by technology

[0010] In combination with overvoltage protection devices with fuses or mechanical switching devices, the disadvantage is that a short-circuit current always has to flow in order to respond or trigger these elements in the sense of multiples of the rated current of the switching device or fuse

[0011] This current, typically in the hundreds of amperes or into the kiloampere range, may cause damage or bursting of voltage limiting components and may present a fire hazard to the device itself or to adjacent installations

[0012] Therefore, if the fault current occurring in the overvoltage protection device is greater than the fault current that can be eliminated by the thermal disconnection device itself, but smaller than the trigger current of the backup protection device, such as a fuse device, the arrester may be damaged due to the above-mentioned results

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