VARISTOR WITH DEFINED WEAK SPOT WITHIN ITS STRUCTURE

The invention refers to varistors featuring a deliberately and position defined weak spot on the structure of varistors and inside of them with the basic purpose of upgrading the varistor featuring a thermal disconnector in surge protection modules. The varistor with the deliberately integrated weak spot inside the structure according to requirement number 1 is characterised in that inside the varistor body (1) there is a weak spot (2) of circular shape with depth (2a) and the spot on the body (1) can be selected randomly considering the varistor size. The varistor despite the weak spot (2) where the local overheating of the body (1) takes place does not negatively affect the energy absorption of the varistor. Upon the passing of the current through the varistor regardless of the reason for such a current, there is always a slightly higher current running through the weak spot (2) of the varistor body (1) compared to the remaining structure. Upon the process of adequate current distribution inside the varistor this can be triggered at the defined integrated weak spot (2) of the varistor and the process of local heating is started which due to the high conductive factor quickly spreads across the complete varistor body (1). In the case of high but short power overloads the temperature is quickly transferred from the weak spot (2) to the whole varistor body (1), while in the case of longer overloads the deliberately integrated weak spot (2) acts as a relatively constant source of temperature which enables the upgraded thermal disconnecting system to perform the adequate reaction and to physically disconnect from the system. Izum se nanaša na varistorje z namensko definirano in pozicijsko določeno šibko točko na in v strukturi varistorjev z osnovnim namenom nadgradnje varistorja s termičnim odklopom v prenapetostnih zaščitnih modulih. Varistor z namensko vgrajeno šibko točko v strukturi po zahtevku 1 je značilen po tem, da je v telesu (1) varistorja šibka točka (2) v krožni obliki z globino (2a) in je lahko mesto na telesu (1) poljubno izbrano z ozirom na velikost varistorja. Varistor navkljub šibki točki (2), kjer potekalokalno pregrevanje telesa (1), ne poslabša energijske absorbcije varistorja. Pri prehodu toka skozi varistor, ne glede na vzrok nastanka tega toka, steče skozi šibko točko (2) telesa (1) varistorja vedno nekoliko večji tok kot pa čez vso preostalo strukturo. Ob procesu ustrezne delitve toka skozi varistor se le-ta sproži v definirano vgrajen