SI9700332A

SI9700332A - Surge protection device

Info

Publication number: SI9700332A
Application number: SI9700332A
Authority: SI
Inventors: Vladimir Murko; Cristian Macanda
Original assignee: ISKRA ZAŠČITE d.o.o.
Priority date: 1997-12-31
Filing date: 1997-12-31
Publication date: 1999-06-30

Abstract

The invention is based on the problem of how to provide a cost effective surge protection device which can be widely used, based on the use of at least one varistor (1) while substantially surpassing the current problematic low divertion power and at the same time allow indication and if required remote signalling as a consequence of major voltage overloads. For this purpose according to the invention the varistor (1) features a cover (129), which holds a spring (119), which is soldered to the contact nose (108) being electrically connected to the varistor (1). In case of overload the specified soldered connection between the spring (109) and the contact nose (108) gives in, which makes the spring (109) bounce and the electric connection between them is disconnected.

Description

Prenapetostna zaščitna napravaSurge protection device

Izum se nanaša na prenapetostim zaščitno napravo, namreč na napravo, ki je namenjena za zaščito drugih v taisti električni tokokrog povezanih električnih naprav pred prenapetostnimi preobremenitvami.The invention relates to an overvoltage protective device, namely an apparatus intended to protect others in the same electrical circuit of connected electrical devices from overvoltage overloads.

Pri tem izum temelji na problemu, kako pri cenovno sprejemljivi in za široko uporabo predvideni prenapetostni zaščitni napravi, zasnovani na uporabi vsaj enega varistorja, omogočiti bistveno preseganje doslej problematično nizkih odvodnih moči ter pri tem tudi omogočiti indikacijo in po potrebi daljinsko signalizacijo okvar zaradi večjih napetostnih preobremenitev.The invention is based on the problem of how, at an affordable and widespread use, an overvoltage protection device based on the use of at least one varistor can substantially exceed the previously problematic low drainage power, while also allowing the indication and, if necessary, remote signaling of failures due to higher voltage overload.

Znano je da je varistor spremenljiv upor, katerega upornost se spreminja v odvisnosti od električne napetosti, kateri je izpostavljen. Prav tako je znano, da so varistorji podvrženi staranju oz. se sčasoma iztrošijo, tako da se njihove karakteristike med uporabo sčasoma spremenijo. Razen tega varistor po električnem preboju prepušča velik trajni tok, iz česar izhaja možnost poškodbe okoliških naprav, ni pa izključena tudi možnost požara. Temu se v praksi skušajo izogibati na različne načine. Eden od načinov je ta, da pred varistor in v stiku z njim vgradijo klasično termično varovalko. Druga možnost je ta, da varistorju prigradijo kovinsko ali plastično steno, ki tišči varistor v bližino termične varovalke. Pri tem naj bi toplota z varistorja kar najhitreje prestopila na termično varovalko in povzročila aktiviranje le-te ter s tem prekinitev električnega toka. Toda v praksi se dogaja, da se z varistorjem serijsko vezane termične varovalke pri električni preobremenitvi (npr. ob udaru strele ali ob hujši napetostni preobremenitvi) zaradi razmeroma velike količine sproščene toplote zvarijo in odtlej ne služijo svojemu namenu. Še več, ostanejo v trajnem kratkem stiku ne glede na velikost kratkostičnega toka, ki je višji od nazivnega toka in teče skozi varovalko in poškodovani varistor. Povrhu vsega prigraditev varovalk v tesnem naleganju k varistorjem - s ciljem, da bi toplota s poškodovanega varistorja povzročila čimprejšnji odklop varovalke - pri tovrstnih rešitvah narekuje potrebo po dodatnih sestavnih delih in dodatni montaži na tiskano vezje kot tudi vrsto napajalnih delov tiskanih vezij. V tej smeri so znane repšitve takoimenovanih zaščitnih doz proizvajalcev Phoenix (Nemčija), Citel (Francija) in Iskra Zaščite (Slovenija). Zaradi zapletenosti tovrstnih naprav se proizvajalci kljub tveganju požara raje odločajo kar za vgradnjo varistorjev brez termične zaščite.The varistor is known to be a variable resistor whose resistance varies depending on the electrical voltage to which it is exposed. Varistors are also known to be subjected to aging or. they wear out over time, so that their characteristics change over time. In addition, the varistor leaves a large permanent current after an electrical break, resulting in the possibility of damaging the surrounding devices, but does not exclude the possibility of fire. In practice, they try to avoid this in different ways. One way is to install a classic thermal fuse in front of and in contact with the varistor. Alternatively, a metal or plastic wall can be attached to the varistor, which pushes the varistor close to the thermal fuse. In doing so, the heat from the varistor should pass as quickly as possible to the thermal fuse and cause it to activate and thereby interrupt the electric current. However, in practice, it is the case that, with a varistor, the series-coupled thermal fuses in electrical overload (such as lightning or severe voltage overload), due to the relatively large amount of heat released, do not serve their purpose. Moreover, they remain in permanent short circuit, regardless of the size of the short-circuit current, which is higher than the rated current and flows through the fuse and the damaged varistor. On top of that, fuses in close contact with varistors - with the aim of causing heat from the damaged varistor to disconnect as soon as possible - in such solutions require the need for additional components and additional mounting on the printed circuit board, as well as a series of printed circuit boards. In this direction, known are the repackaging of the so-called protective doses of manufacturers Phoenix (Germany), Citel (France) and Iskra Zaschita (Slovenia). Due to the complexity of such devices, manufacturers, despite the risk of fire, prefer to install varistors without thermal protection.

Po drugi strani so znane izvedbe odklopov vročega varistorja, pri Čemer gre za to, da poškodbe varistorja ne pridejo takoj do izraza, ker je varistor vgrajen v zaščitnem ohišju. Take izvedbe, npr. proizvajalca Dehn & Sohne (Nemčija) so drage in zahtevne ter primerne kvečjemu za strogo specialne izvedbe in za ozko opredeljene funkcije, ki jih lahko vršijo.On the other hand, there are known variations of disconnections of the hot varistor, in which case the damage to the varistor does not immediately occur because the varistor is installed in a protective housing. Such embodiments, e.g. manufactured by Dehn & Sohne (Germany) are expensive and demanding and, at the most, suitable for strictly specialized designs and for the narrowly defined functions they can perform.

Nadalje so znane izvedbe po dveh varistorjev in plinskega odvodnika, ki naj bi predstavljale kompletno enofazno zaščito energetskega napajanja. Vendar so primerne za razmeroma nizke obremenitve, npr. do največ 5kA impulza oblike 8/20, kar je npr. na voljo pri modulu s komercialno označbo VC 2809, ki ga proizvaja Dehn & Sohne (Nemčija). Vsi drugi odklopni mehanizmi samo nekoliko močnejših naprav (nominalni varovalni tok nad 5kA) so že izjemno zapleteni, izdelujejo pa jih (po podatkih iz katalogov za leto 1996 in 1997) Kleinhuis (Nemčija), Obo Betterman (Nemčija), Dehn & Sohne (Nemčija), Felton Guilliaume (Avstrija, Francija) ter Soule in Lagrand (oba Francija), seveda pa tudi Iskra Zaščite (Slovenija).In addition, two varistors and a gas arrester are known to provide complete single-phase protection of the power supply. However, they are suitable for relatively low loads, e.g. up to a maximum of 5kA pulse of 8/20 shape, e.g. available from the commercial designation module VC 2809 manufactured by Dehn & Sohne (Germany). All other disconnecting mechanisms of only slightly larger devices (rated over 5kA) are already extremely complex and are manufactured (according to 1996 and 1997 catalogs) by Kleinhuis (Germany), Obo Betterman (Germany), Dehn & Sohne (Germany) ), Felton Guilliaume (Austria, France) and Soule and Lagrand (both France), and of course the Spark of Protection (Slovenia).

Po izumu je ustvaijena nova zasnova prenapetostne zaščitne naprave, namreč take vrste, ki obsega odklopni mehanizem invsaj en varistor v odvisnosti od električne napetosti spremenljive prevodnosti, zahvaljujoč katerima se pri električnih preobremenitvah oz. prenapetostih prekine električni tokokrog skozi prenapetostno zaščitno napravo in s tem tudi skozi napravo, ki jo prenapetostna zaščitna naprava varuje proti preobremenitvam. Pri tem pa po izumu odklopni mehanizem obsega vsaj en varistor, pri katerem je preko varistorske keramike nanešena električno prevodna plast, preko katere je nameščena kontaktna plošča, obsegajoča kontaktni nos ter prednostno tudi vsaj en kontakt za daljinsko signalizacijo in kontakt za ozemljitev. Pri tem je na varistorju nameščen pokrov odklopnega mehanizma, v katerem je vstavljena priključno-odklopna vzmet, ki je prispajkana na kontaktni nos omenjene plošče in v primeru električne preobremenitve odvihtljiva iz električnega stika z omenjenim nosom. Omenjena vzmet je npr. na kontaktni nos prispajkana z nizkotemperatumo spajko in iz povezave z nosom odvihtljiva s stalitvijo omenjene spajke zaradi električnega toka vnaprej določljive jakosti, ki teče skozi vzmet, ki je sicer prednostno zankasto zasnovana in opremljena z izven pokrova nameščenim priključkom. Omenjeni pokrov je izveden iz prozornega ali vsaj prosojnega električno neprevodnega gradiva. Po potrebi oz. v primeru daljinske signalizacije okvar je v pokrovu nameščen tudi dodatni kontaktni priključek, proti kateremu je po stalitvi spajke od nosa odvihtljiva vzmet. V splošnem pa naprava nudi številne aplikacije in je na voljo v številnih kombinacijah, pri čemer v alternativni izvedbi obsega vsaj dva varistoija, od katerih je vsak opremljen s pokrovom, obsegajočim po eno vzmet. Možna je tudi vgradnja več kombinacij hkrati. Prednosti pričujoče rešitve pa se kažejo tudi v prihranku na prostoru, kar je npr. pri uporabi pri tiskanih vezjih lahko izjemno pomembno.According to the invention, a new design of an overvoltage protection device has been introduced, namely of a type comprising an isolation mechanism of an invariant one varistor, depending on the electrical voltage of variable conductivity, thanks to which, in the case of electrical overloads or. overvoltage breaks the electrical circuit through the overvoltage protection device and thus through the device which is protected by overvoltage protection device. According to the invention, the disconnect mechanism comprises at least one varistor, in which an electrically conductive layer is applied over varistor ceramics, through which a contact plate is mounted, comprising a contact nose, and preferably at least one remote signaling and grounding contact. In this case, a cover of the disconnect mechanism is mounted on the varistor, in which a connection-disconnecting spring is inserted, which is soldered to the contact nose of said plate and, in the case of electrical overload, detaches from electrical contact with said nose. Said spring is e.g. to the contact nose soldered with a low-temperature solder and detached from the nose connection by the displacement of said solder due to a pre-determinable electric current flowing through a spring, which is otherwise preferably loop-shaped and fitted with an out-of-cover connection. Said cover is made of transparent or at least transparent electrically non-conductive material. If necessary, in the case of remote fault signaling, an additional contact connector is also installed in the cover, against which a spring is detachable after the nose is soldered away. In general, however, the device offers many applications and is available in many combinations, in an alternative embodiment comprising at least two varistos, each equipped with a cover comprising one spring. It is also possible to install several combinations simultaneously. The advantages of the present solution are also reflected in space savings, for example. when used with printed circuits can be extremely important.

Primeri izvedbe prenapetostne zaščitne naprave bodo v nadaljevanju opisani na osnovi priložene skice, pri čemer kažejo' sl·. 1 shematično prikazan prvi primer izvedbe prenapetostne zaščitne naprave, sl. 2 shematično prikazan, v opisu podrobneje obrazložen del varistorja naprave po sl. 1, sl. 3 prav tako shematično v narisu prikazan in v opisu podrobneje obrazložen del varistorja naprave po sl. 1, sl. 4 del po sl. 3 v pogledu od strani, sl. 5 z električnimi priključki opremljen varistor po sl. 2 - 4, v narisu, sl. 6 sklop kontaktnega nosa na varistorju in priključno-odklopne vzmeti, spet v narisu, sl. 7 nadaljnji primer izvedbe naprave, opremljene z dodatnim kontaktom v pokrovu odklopnega mehanizma, sl. 8 indikacijo preobremenitve z odvihtenjem vzmeti, sl. 9 električno shemo stanja po sl. 8, sl. 10 indikacijo preobremenitve z LED-diodo, sl. 11 električno shemo stanja po sl. 10, sl. 12 indikacijo preobremenitve z dvema LED-diodama, sl. 13 električno shemo najbolj splošne izvedbe naprave po izumu, sl. 14 nadaljnji primer izvedbe naprave z dvema varistorjema.Examples of embodiments of an overvoltage protection device will be described below on the basis of the attached sketch, showing 'en ·. 1 is a schematic view of a first embodiment of an overvoltage protection device, FIG. 2 is a schematically illustrated, detailed explanation of the part of the device varistor of FIG. 1, FIG. 3 is also a schematically illustrated and explained section of the device varistor according to FIG. 1, FIG. 4 illustrates in FIG. 3 is a side view, FIG. 5 shows a varistor according to FIG. 2 - 4, in the outline, FIG. 6 is a view of the contact nose assembly on the varistor and the connection spring disconnectors; 7 is a further embodiment of an apparatus equipped with an additional contact in the cover of the cut-off mechanism, FIG. 8 is an indication of spring overload by means of a spring, FIG. 9 is a schematic diagram of FIG. 8, FIG. 10 shows an LED overload indication; FIG. 11 is a schematic diagram of FIG. 10, FIG. 12 shows an overload indication with two LEDs; FIG. 13 is an electrical diagram of the most general embodiment of the device according to the invention; 14 is a further embodiment of a dual varistor device.

sl. 15 splošno vezalno shemo ene od možnih izvedb naprave po izumu, in sl. 16 splošno vezalno shemo nadaljnje od možnih izvedb naprave po izumu.FIG. 15 is a general schematic diagram of one of the possible embodiments of the device of the invention, and FIG. 16 is a general schematic diagram of a further embodiment of the device according to the invention.

Pričujoči izum se torej ukvarja s prenapetostno zaščitno napravo, obsegajočo odklopni mehanizem 42 in vsaj en varistor 1 v odvisnosti od električne napetosti spremenljive prevodnosti, zahvaljujoč katerima se pri električnih preobremenitvah oz. prenapetostih prekine električni tokokrog skozi prenapetostno zaščitno napravo in s tem tudi skozi ščiteno napravo 100, ki je z obravnavano prenapetostno zaščitno napravo varovana proti električnim preobremenitvamThe present invention is therefore concerned with an overvoltage protection device comprising a disconnect mechanism 42 and at least one varistor 1 depending on the electrical voltage of the variable conductivity, due to which, in the case of electrical overloads, or. overvoltage interrupts the electrical circuit through the overvoltage protection device and thus also through the shielded device 100, which is protected against electrical overloads by the overvoltage protection device under consideration.

Po izumu je pri prenapetostni zaščitni napravi (sl. 1) odklopni mehanizem 42 nameščen na termičnem varistoiju 1. Slednji je izveden na ta način, daje (sl. 2) na varistorsko keramiko 104 v obliki npr. kvadratne ali okrogle tablete nanešena električno prevodna, prednostno pastozna plast 105, na kateri je nameščena značilno zasnovana kontaktna plošča 106 (sl. 3 in 4), obsegajoča vsaj en kontaktni nos 108 in več pritrdilnih nosov 210, 211, prednostno npr. vsaj tri. Pri tem je na voljo več zunanjih priključkov, namreč kontaktov 109 za daljinsko signalizacijo ter vsaj en kontakt 110 za ozemljitev (sl. 5). V danem primeru je varistor 1 galvaniziran in prevlečen s plastjo 114 ustrezne izolacijske mase (sl. 6)According to the invention, in the case of an overvoltage protection device (Fig. 1), the switching mechanism 42 is mounted on a thermal varisto 1. The latter is arranged in such a way that (Fig. 2) is applied to varistor ceramics 104 in the form of, e.g. square or round tablets deposited electrically conductive, preferably paste layer 105, on which is mounted a typically designed contact plate 106 (Figs. 3 and 4) comprising at least one contact nose 108 and more fixing noses 210, 211, preferably e.g. at least three. There are several external connections available, namely remote signaling terminals 109 and at least one grounding terminal 110 (Fig. 5). In this case, varistor 1 is galvanized and coated with a layer 114 of suitable insulating material (Fig. 6)

Na omenjenem kontaktnem nosu 108 je pritrjena, prednostno z nizkostopinjsko spajko prispajkana priključno-odklopna vzmet 119, ki je v bistvu zankasto zasnovana, kot je to prikazano na sl. 1. Zahvaljujoč takšni zasnovi vzmeti 119 je možno po eni strani računati s primernimi vzmetnimi lastnostmi, po drugi strani pa vzmet 119 sama služi tudi kot ploščat zunanji kontakt, zaradi česar je nanjo pritrjen v danem primeru okrogel napetostni priključek 124.At said contact nose 108 is attached, preferably with a low-grade solder, a soldered spring-disconnected spring 119 which is essentially loop-shaped, as shown in FIG. 1. Thanks to such a design, the spring 119 can be calculated on the one hand with suitable spring properties, and on the other hand, the spring 119 also serves as a flat external contact, resulting in a circular voltage connection 124 being attached to the case.

Vzmet 119 je' izvedena iz gradiva razmeroma velike električne upornosti in se zato pri nazivnem toku, ko bi npr. sicer morala odklopiti termična varovalka, toliko segreje, da popusti nizkotemperatuma spajka med vzmetjo 119 in nosom 108. Karakteristike, potrebne za doseganje tega učinka, je možno doseči z izbiro več parametrov, namreč električne upornosti vzmeti 119, velikosti prečnega prereza vzmeti 119 ter dolžine poti toka po vzmeti 119 oz. oblike vzmeti 119.Spring 119 'is derived from material of relatively high electrical resistance and is therefore, at rated current, when e.g. otherwise it has to disconnect the thermal fuse so much that it lowers the solder low temperature between the spring 119 and the nose 108. The characteristics required to achieve this effect can be achieved by choosing several parameters, namely the electrical resistance of the spring 119, the cross-sectional size of the spring 119, and the path length spring current 119 oz. spring shapes 119.

Priključno-odklopna vzmet 119 je vstavljena v ustreznem utoru 127 pokrova 129, ki ga obsega obravnavani odklopni mehanizem 42 (sl. 1). Pokrov 129 je prednostno izveden iz prozornega ali vsaj prosojnega električno neprevodnega gradiva in tako zasnovan, da s svojo obliko omogoča pravilno lego in tudi namestitev vzmeti 119 v ustreznih položajih. Tako je vzmet 119 pritrjena, namreč prispajkana na kontaktnem nosu 108, v splošnem pa odvihtljiva v položaj po sl. 8.The disconnecting spring 119 is inserted in the corresponding groove 127 of the cover 129 enclosed by the disconnect mechanism 42 in question (Fig. 1). The cover 129 is preferably made of transparent or at least translucent electrically non-conductive material and is designed in such a way that its shape allows the correct position and also the placement of the spring 119 in the appropriate positions. Thus, spring 119 is fastened, namely soldered to contact nose 108, and generally detachable to the position of FIG. 8.

Pri napravi po izumu lahko preko termičnega varistorja 1 teče npr. tok 16A, pri čemer termični varistor 1 deluje kot prevodnik in hkrati kot toplotna varovalka, s tem da do omenjene nazivne vrednosti toka varistorske lastnosti v smislu neprevodnosti še ne pridejo do izraza.In the apparatus according to the invention, e.g. current 16A, wherein the thermal varistor 1 acts as a conductor and at the same time as a thermal fuse, so that the said nominal value of the current of the varistor property in terms of nonconductivity is not yet expressed.

Pač pa pri večjih trajnih tokovnih obremenitvah pride do odklopa tako zaradi neprevodnosti samega varistorja 1, kot tudi zaradi pregretja z nizkotemperatumo spajko izvedene povezave med nosom 108 in vzmetjo 119, zaradi česar pride do odvihtenja vzmeti 119 in torej prekinitve električnega kontakta med njima.However, at higher continuous current loads, disconnection occurs due to both the nonconductivity of the varistor 1 itself, as well as overheating of the nose 108 and the spring 119 with the low-temperature solder, which causes the spring 119 to be distorted and therefore the electrical contact between them is interrupted.

Pri tem je seveda omogočena tudi indikacija oz. signalizacija preobremenitve oz. motnje oz. okvare, in sicer na več načinov. Tako je npr. skozi prozoren oz. prosojen pokrov 129 vidna odvihtena vzmet 119. Druga možnost indikacije okvare je dana z odklopom napetosti na kontaktih 109, tako daje vsakokratno napajalno vezje zaščiteno kot pri varovanju s tokovno varovalko. Tretja možnost je dana s tem, da npr. zelena LED-dioda 142 sveti takrat, kadar pride do poškodb varistorske keramike 104. Pri četrti možnosti je dano daljinsko javljanje okvar, in sicer na ta način, da je v pokrovu 129 nameščen dodaten kontakt 161, na katerega se po odvihtenju zaradi električne preobreminitve nasloni vzmet 119 in ki je električno napajan s pomočjo priključka 124 na varistoiju. V tem primeru se npr. prižge rdeča LED-dioda 163.Of course, this is also enabled indication. overload signaling disorders or failures, in many ways. Thus, e.g. through transparent or. transparent cover 129 visible deflected spring 119. Another possibility of fault indication is given by disconnecting the voltage at terminals 109, so that the respective power supply circuit is protected as in the case of a current circuit breaker. A third possibility is given by e.g. green LED 142 illuminates when varistor ceramics 104. Damage is obtained in the fourth option, by remotely faulting, such that an additional contact 161 is placed in the cover 129, to which it rests after being distracted by electrical overload. spring 119 and which is electrically powered by the varistoi connection 124. In this case, for example, red LED 163 illuminates.

Pri nadaljnjih izvedbah naprave po izumu je vsekakor dana tudi možnost sočasne uporabe dveh varistorjev 170. Pri tem je med dvema varistorjema 170 nameščen skupni kontakt 172 za ozemljitev, vsak varistor 170 pa je opremljen s pokrovom 129. Kadar sta namreč vhodna priključka 177, 178 med seboj povezana, prav tako pa tudi izhodna priključka 207, 208, taka izvedba namreč omogoča dvakratno priključno odvodno moč. V splošnem pa naprava - kot rečeno - nudi številne aplikacije in je na voljo v številnih možnih kombinacijah.In the further embodiments of the device according to the invention, the possibility of simultaneous use of two varistors 170 is provided. In this case, between the two varistors 170, a common ground contact 172 is fitted, and each varistor 170 is provided with a cover 129. Where the input terminals 177, 178 between interconnected, as well as output terminals 207, 208, such an embodiment permits double drainage power. In general, however, the device - as mentioned - offers many applications and is available in many possible combinations.

Claims

PATENT APPLICATIONS

1. An overvoltage protection device comprising a tripping mechanism (42) and at least one varistor (1; 170) depending on the electrical voltage of the variable electrical conductivity, due to which, in the case of electrical overloads or overvoltage interrupts the electrical circuit through the overvoltage protection device and thus through the shielded device (100), which is protected against electrical overloads by the overvoltage protection device, characterized in that the tripping mechanism (42) is mounted on the varistor (1), in which an electrically conductive layer (105) is applied over varistor ceramics (104) and a contact plate (106) is mounted over the latter, comprising a contact nose (108) and at least one contact (109) for remote signaling and a grounding contact (110), wherein on the varistor (1) there is a cover (129) of the disconnect mechanism (42), in which a connection-disconnect spring (119) is inserted, which is soldered to the contact nose (108) of said plate (106) and, in the case of electrical overload, detaches from electrical contact with said nose (109).

Apparatus according to claim 1, characterized in that the spring (109) is soldered to the contact nose (108) by a low-temperature solder and detached from the connection with the nose (108) by the said solder due to the corresponding electric current of pre-determined flowing strength through the spring (119).

Device according to claims 1 and 2, characterized in that the spring (119) is loop-shaped.

Device according to any one of the preceding claims, characterized in that the spring (119) is provided with an attachment (124) located outside the lid.

Device according to any one of the preceding claims, characterized in that an additional contact connector (161) is mounted in the cover (129) against which a spring (119) is detachable from the nose (108).

Apparatus according to claim 1, characterized in that it comprises at least two varistors (170), each of which is provided with a cover (129) comprising one spring (119).

Device according to claims 1 and / or 6, characterized in that the cover (129) is made of transparent or at least transparent electrically non-conductive material.