EP0798750A2 - Current limiting resistor with PTC-behaviour - Google Patents

Current limiting resistor with PTC-behaviour Download PDF

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Publication number
EP0798750A2
EP0798750A2 EP97810116A EP97810116A EP0798750A2 EP 0798750 A2 EP0798750 A2 EP 0798750A2 EP 97810116 A EP97810116 A EP 97810116A EP 97810116 A EP97810116 A EP 97810116A EP 0798750 A2 EP0798750 A2 EP 0798750A2
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EP
European Patent Office
Prior art keywords
resistance body
double
resistor according
varistor
resistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP97810116A
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German (de)
French (fr)
Other versions
EP0798750B1 (en
EP0798750A3 (en
Inventor
Dr. Glatz-Reichenbach
Felix Dr. Greuter
Gerhard Mauthe
Zdenek Pelanek
Claus Dr. Schüler
Jorgen Dr. Skindhoj
Ralf Dr. Strümpler
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ABB Research Ltd Switzerland
ABB Research Ltd Sweden
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ABB Research Ltd Switzerland
ABB Research Ltd Sweden
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Publication of EP0798750A2 publication Critical patent/EP0798750A2/en
Publication of EP0798750A3 publication Critical patent/EP0798750A3/en
Application granted granted Critical
Publication of EP0798750B1 publication Critical patent/EP0798750B1/en
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/13—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material current responsive
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C1/00—Details
    • H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
    • H01C1/1406—Terminals or electrodes formed on resistive elements having positive temperature coefficient
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C13/00—Resistors not provided for elsewhere
    • H01C13/02—Structural combinations of resistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/027—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient consisting of conducting or semi-conducting material dispersed in a non-conductive organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
    • H01C7/12—Overvoltage protection resistors

Definitions

  • the invention is based on an electrical resistor according to the preamble of claim 1.
  • a resistor detects and limits short-circuit or overcurrents flowing in a load circuit. Only then does a switch in the load circuit interrupt the limited current. The switch can therefore be designed for a low breaking power compared to the short-circuit power.
  • a current-limiting resistor of the aforementioned type is described for example in US 5,313,184 A.
  • Such a resistor contains two connection electrodes between which a resistor body exhibiting PTC behavior and a varistor are arranged in parallel with one another.
  • the resistance body and the varistor contact each other over the entire insulation distance between the two connection electrodes.
  • resistors can be connected in series. Such an arrangement is relatively complex, since both between the individual resistance bodies and between the individual Varistors metal electrodes are arranged. In the normal operating state of the resistor, the current is conducted through a series connection of several resistor bodies with PTC behavior, between which a metal electrode is arranged in each case.
  • the contact resistance between a metal electrode and the material of the resistance body is generally relatively high and, with a resistance typical for current limiting tasks with a total resistance of approximately 50 m ⁇ , contributes just as much as the material of the resistance body to the overall resistance.
  • metal electrodes and the filler-filled polymers usually used as material for the resistance body have different electrical conductivities and different coefficients of thermal expansion. This can result in mechanical stresses inside the resistor, which may impair its mechanical and electrical properties.
  • the invention has for its object to provide a current-limiting resistor with PTC behavior, which can be produced in a simple and inexpensive manner and has both a high nominal current carrying capacity and a wide voltage range as well as great operational reliability.
  • the resistor body exhibiting PTC behavior is designed in such a way that it ensures both the electrical contact to the connection electrodes and to the varistor. This saves metal electrodes serving for electrical contacting of the varistor.
  • the resistor according to the invention can be produced extremely inexpensively and in a method which is particularly suitable for series production.
  • the one holding the varistor and the connection electrodes and usually one Resistive bodies formed of filler-filled polymer can namely be produced very inexpensively in a common plastic processing method, such as by injection molding.
  • the material of the resistance body designed as a filler-filled polymer, adapts particularly well to the body of the varistor, which body generally consists of a metal oxide ceramic, it is also possible, if appropriate, to dispense with a planar contact metallization which is normally provided in the varistor.
  • Another advantage can be seen in the fact that the response point connected in parallel to the varistor and executing a PTC transition can be arranged at a distance from the varistor by suitable formation of the resistance body, in which a thermal feedback between the response point heated during the PTC transition and the Varistor is not to be feared.
  • the resistor according to the invention has more than two varistors connected in series, there are no metal electrodes between the individual varistors and between partial bodies of the resistance body which exhibit PTC behavior and which, like the varistors, are connected in series.
  • the cold resistance of the resistor is thus significantly reduced and, accordingly, the nominal current carrying capacity of the current-limiting resistor according to the invention is considerably improved.
  • a particularly high rated current carrying capacity is achieved if the resistance body is made in one piece.
  • the low contact resistance otherwise present between the individual sub-bodies is then completely eliminated.
  • the resistor can then be manufactured in a particularly cost-effective manner.
  • 1 to 6, 10 and 11 each show a side view of preferred embodiments of the current-limiting resistor according to the invention with two connection electrodes lying parallel to one another, a resistor body with PTC behavior arranged between the connection electrodes and one or more varistors contacted with the resistor body.
  • FIGS. 7 to 9 show a side view from the right of a part of the resistor designed according to FIGS. 1 and 2 designed as a contact point.
  • FIG. 12 shows a diagram in which the time profile of electrical variables is shown, which are typical for the behavior of the resistor designed according to FIG. 2 when a short-circuit current is limited, such as the voltage U PTC applied to the resistor body and the one conducted in the resistor body Current I PTC and the current I varistor carried in the varistor.
  • the current-limiting resistors shown in FIGS. 1 to 6, 10 and 11 each contain a resistance body 3, which is arranged between two metal connecting electrodes 1, 2 aligned parallel to one another and are in surface contact, and a varistor 40 or more varistors 40, 41, 42, 43, 44, 45.
  • the varistors 40-45 are preferably formed from a doped ceramic based on a metal oxide, such as ZnO, or a titanate, such as SrTiO 3 or BaTiO 3 , or a carbide, such as SiC.
  • the varistor 40 provided in the embodiments according to FIGS. 1, 2 and 10 has a breakdown voltage which is above the nominal voltage of the electrical system in which the resistor is used.
  • a plurality of varistors for example the varistors 40, 41, 42, 43, 44 and 45, are arranged in series in a stack. This varistor stack has a breakdown voltage which is also above the nominal voltage of the electrical system containing the current-limiting resistor.
  • the resistance body 3 consists of a material exhibiting PTC behavior and can be formed from a polymer, in particular thermoplastic or thermosetting, filled with an electrically conductive filler, such as, for example, conductive carbon black, TiC or TiB 2 .
  • the resistors according to the invention can be produced in a simple manner as follows: First of all, varistors 40 to 45 are produced using a process customary in varistor technology, such as by pressing or casting and subsequent sintering of a ceramic base substance doped with various metal oxides, such as ZnO. These varistors are plate-shaped and have a thickness of, for example, 2 mm. The varistors can be metallized on their flat sides to improve the current transfer.
  • a shear mixer is used to produce PTC material from a thermoplastic polymer, such as a polyethylene, and an electrically conductive, powdery filler, such as, for example, TiC.
  • the resistance body 3 is produced from the PTC material, for example by injection molding.
  • the varistor 40 or two or more of the varistors 40 to 45 are installed in the resistance body 3. Then the connection electrodes 1, 2 brought to the resistance body and fixed by exerting contact pressure. Since the resistance body 3 is made of compressible material and at the same time is designed to be elastically bendable in the pressure direction, the contact pressure also fixes the varistor or the varistors in the resistance body 3.
  • the resistance body 3 has two contact surfaces 50, 51 and a response point 60 which is connected in parallel with the varistor 40 via the two contact surfaces 50, 51.
  • the response point 60 is dimensioned such that it carries out a PTC transition if a current carried in the resistor exceeds a predetermined threshold value.
  • the resistance body is essentially U-shaped.
  • the contact surfaces 50 and 51 are each arranged on the inner surfaces of the legs of the U. This ensures that the varistor 40 is connected in an electrically conductive manner to the connection electrodes 1, 2 via the resistance body 3 without additional metal contacts.
  • an intermediate piece 70 made of metal or conductive polymer is additionally provided, which is arranged between a contact surface of the varistor 40 and the contact surface 51 of the resistance body 3. On the one hand, this intermediate piece enables the U to be widened. On the other hand, the intermediate piece 70 serves to absorb thermal energy from the varistor 40. Such energy is generated when a leakage current is passed through the varistor 40 due to an overvoltage occurring at the contact surfaces 50, 51.
  • the response point 60 is located in the curved connecting part of the U. This shifting of the response point to the outside protects the varistor 40 from thermal heating during a PTC transition and, on the other hand, the build-up of undesirable mechanical stresses in the PTC transition Resistor body 3 largely avoided.
  • the response point can have the same cross-section as the resistance body 3 in the region of the two contact surfaces 50, 51, since a local increase in the resistance is already ensured by the bending of the U.
  • the contact point will be designed as a material indentation which reduces the cross section of the U in the area of its bend.
  • the cross section of the resistance body 3 in the area of the response point 60 should be smaller than each of the two contact surfaces between the resistance body and the two connection electrodes 1, 2, since only then can the PTC transition to the response point 60 be shifted.
  • Structural designs of the contact point 60 can be seen from FIGS. 7, 8 and 9 and can be made by fitting the cross section of the U transversely to the plane of the drawing (FIG. 7) or in the direction of the legs of the U in the plane of the drawing (FIG. 8 in connection with the figures) 1 and 2), by arranging slots 601 (FIG. 9) which are guided in the direction of the ends of the U and run essentially parallel to one another, or in a particularly simple manner through round through holes.
  • the slotted embodiment of the contact point 60 is characterized in that the current is not only distributed uniformly over the narrowed cross section, but that when the PTC transition is carried out, the material of the contact point can move in practically all directions, thereby causing undesirable mechanical stresses can be avoided in the resistor body 3 in a particularly strong mass.
  • the current fed in via the connection electrode 1 flows via the resistance body 3 designed as U to the connection electrode 2. If a short-circuit current or an impermissibly high overcurrent occurs in the load circuit, this leads particularly to the response point 60 high current density to a PTC transition.
  • the ohmic resistance of the resistance body 3 increases very rapidly by several orders of magnitude in the region of the contact point 60 the current flowing through the resistor is quickly limited.
  • overvoltages that occur are dissipated by leakage currents. Since the varistor 40 in this case absorbs energy and is heated up considerably, it is particularly advantageous that the response point 60, which is also strongly heated by the PTC transition, is arranged spatially separated from the varistor 40.
  • the resistance body 3 has further contact surfaces, of which, for reasons of clarity, only the contact surfaces 52 and 53 which carry the varistor 41 at potential are designated.
  • the other contact areas such as. B. 52, 53, each parallel to one, e.g. 41, the other varistors 41 to 45, further contact points are connected, of which only the contact point 61 is shown for reasons of clarity.
  • these further contact points are formed locally decoupled from the varistors in the resistance body 3 and, in accordance with the contact point 60, carry out a PTC transition if the current carried in the resistor exceeds the predetermined threshold value.
  • the embodiments of the resistor according to the invention containing at least two varistors 40, 41 connected in series are provided for use in load circuits with high voltages. If a large current occurs, the response points 60, 61 connected in series carry out the PTC transition and the current flowing through the resistor is thus quickly limited. After the current at the connection electrodes 1, 2 has been limited, overvoltages which occur are dissipated by leakage currents which are conducted in the varistors 40, 41 connected in series. If one of the contact points, for example the contact point 61, speaks before the other contact points have responded, the occurrence becomes impermissibly higher Overvoltages at this point of contact avoided by the varistor connected in parallel.
  • the resistance body 3 is made up of partial bodies 30 to 35 and 30 'to 34' and 36 and 37, each with two sections running parallel to the connection electrodes and at least one of the two Sections connecting and the contact point, e.g. 60, 61, built part. Between the two sections of the partial body, e.g. 31, 31 'or 36 is one of the varistors, e.g. 41, arranged.
  • the partial bodies 30 to 35 are each designed as a U and are joined to one another in such a way that the resistance body 3 forms a meander.
  • this meander two successive U's in pairs in the meander are rotated against each other by 180 ° and pushed into one another such that one of the legs of one of the U is located between the legs of the other U.
  • the varistors can then be contacted with the resistance body 3 by simply pushing them into the U without additional spacing means.
  • a particularly good mechanical strength of the resistance body 3 is obtained if, as can be seen from the embodiment according to FIG. 5, at least one of the U, for example the partial body 31 ', in each case one of the varistors, for example 41, and one leg each between the two sections two U, for example the partial bodies 30 'and 32', which are adjacent to one another in the resistance body and are only spaced apart by the varistor, are arranged. If, in addition, the mutually facing inner surfaces of the superimposed legs of the U, for example the partial bodies 31 'and 32' or 30 'and 31', are beveled in a wedge shape, the resistance body 3 can be produced particularly easily by wedging the individual Us against one another. In addition, the U produced by injection molding can then be easily removed from the injection mold.
  • the successive varistors 40 to 45 or 40 to 44 in the resistance body 3 can additionally be bent by U-shaped intermediate pieces 701, 702 (for reasons of clarity, only two such parts are dashed in FIG. 3) indicated) are connected.
  • this results in a particularly low-resistance series connection of the varistors and, on the other hand, the heat generated by the varistors when leakage currents occur is conducted away from the interior of the resistor.
  • FIGS. 4 and 11 show embodiments of the resistor according to the invention, in which the resistor body is made in one piece. Since the contact resistance between the individual partial bodies is eliminated in these embodiments, the resistance body 3 is distinguished by a particularly low ohmic resistance. At the same time, the resistance body can be produced in one casting process and the resistance can then be produced in a particularly simple and cost-saving manner by subsequently plugging in the varistors and the optionally provided intermediate pieces 70 to 73 or 70, 71. In the case of a disk-shaped design of the varistors, the resistance body 3 then has pockets of semicircular cross section which are open towards the front and closed towards the rear and into which the individual varistors are inserted during the manufacture of the resistor.
  • the resistance body 3 can be designed as follows: as a U with a curved (FIGS. 1 to 5) or straight connecting section, as a double U with curved connecting sections (FIG. 2 with dashed lines) or straight connecting sections, as a screw line (FIG. 10) as Double or multiple screw line (Fig. 10 with dashed lines), as a meander ( Figures 3 to 5), as a double meander ( Figures 6 and 11) or garland or double garland (stacking of several partial bodies, which according to the partial body according to Fig. 10 are trained).
  • the resistance body is designed as a double U, double screw line, double meander or double garland, it can have, in addition to the contact point 60, an additional contact point 60 'connected in parallel thereto (FIGS. 2, 6, 10 and 11).
  • a resistor provided with such a resistance body 3 is characterized by great strength, greater current carrying capacity and ease of manufacture. At the same time, thermal and mechanical forces occurring during the PTC transition are evenly distributed throughout the resistance.
  • the part containing the contact point 60 or the part of the U or the double U containing the contact points 60, 60 ', 61,... Is bent, then when executing of the PTC transition, mechanical force generated by strong local heating of the resistance body in the area of the response points is reduced due to the spring action of the legs of the U or double U to the part of the resistance body containing the varistors. If the response points are guided in predominantly horizontally guided areas of the connecting parts of the U or double U, practically no counterforce weakening the vertically acting contact force of the resistor is generated.
  • the resistor can be designed to be particularly space-saving.
  • the resistance body 3 is designed as a screw line, garland or double or multiple garland, particularly good cooling of the resistance is achieved, since ambient air is then guided along the spiral line-shaped resistance body 3 into the interior of the resistance.
  • the response points 60, 60 ' are molded into a predominantly horizontally guided part of the resistance body.
  • the resistance body can also have other, but topologically similar shapes, which are possibly adapted to the topology of the varistor or varistors.
  • the varistor can take virtually any cross-sectional shape and can be round, rectangular or oval, for example.
  • FIG. 2 The mode of operation of a resistor designed according to the invention can be seen from FIG.
  • This resistor is designed in accordance with the embodiment shown in FIG. 2.
  • the U-shape of the resistance body 3 was produced by warm bending a plate made of PTC material with 90 mm ⁇ 40 mm ⁇ 1.5 mm around a 6 mm thick rod.
  • the curved resistance body 3 had a constant cross section over the entire U and had an ohmic resistance of 160 m ⁇ .
  • a prospective short-circuit current of 12 kA was supplied to the resistor in a load circuit. This current was evidently limited to a current peak of 1.2 kA and was already less than 200 A after 1 ms.
  • the resistance was able to hold the recurring voltage without problems for at least 100 ms, ie over 5 periods.
  • the current peak was even limited to 1 kA with a suitably designed resistor, but with a reduced cross-section due to through holes or material constriction.
  • the ohmic resistance of this element was somewhat larger at 250 m ⁇ .

Abstract

The resistance has a pair of parallel terminal electrodes (1,2) in flat contact with a resistance body (3) which has a positive temperature coefficient characteristic. A varistor (40) lies in electrical contact with the resistance body which has 2 contact surfaces (50,51). The response point (60) of the resistance body is connected in parallel with the varistor through the surfaces. A number of series connected varistors (41,42,43,44) may contact respective meanders of a zigzag resistance body between the parallel terminal electrodes via respective contact surfaces (52,53).

Description

TECHNISCHES GEBIETTECHNICAL AREA

Bei der Erfindung wird ausgegangen von einem elektrischen Widerstand nach dem Oberbegriff von Patentanspruch 1. Ein derartiger Widerstand erkennt und begrenzt in einem Lastkreis fliessende Kurzschluss- oder Überströme. Erst danach unterbricht ein im Lastkreis vorgesehener Schalter den begrenzten Strom. Der Schalter kann daher auf eine gegenüber der Kurzschlussleistung geringe Abschaltleistung ausgelegt sein.The invention is based on an electrical resistor according to the preamble of claim 1. Such a resistor detects and limits short-circuit or overcurrents flowing in a load circuit. Only then does a switch in the load circuit interrupt the limited current. The switch can therefore be designed for a low breaking power compared to the short-circuit power.

STAND DER TECHNIKSTATE OF THE ART

Ein strombegrenzender Widerstand der zuvor genannten Art ist beispielsweise in US 5,313,184 A beschrieben. Ein solcher Widerstand enthält zwei Anschlusselektroden zwischen denen zueinander parallel geschaltet ein PTC-Verhalten aufweisender Widerstandskörper sowie ein Varistor angeordnet sind. Der Widerstandskörper und der Varistor kontaktieren einander über die gesamte Isolationsstrecke zwischen den beiden Anschlusselektroden. Hierdurch werden lokale Überspannungen im Widerstandskörper und damit unzulässig hohe lokale thermische Belastungen des Widerstandskörpers vermieden.A current-limiting resistor of the aforementioned type is described for example in US 5,313,184 A. Such a resistor contains two connection electrodes between which a resistor body exhibiting PTC behavior and a varistor are arranged in parallel with one another. The resistance body and the varistor contact each other over the entire insulation distance between the two connection electrodes. As a result, local overvoltages in the resistance body and thus impermissibly high local thermal loads on the resistance body are avoided.

Zur Erhöhung der dielektrischen Festigkeit dieses Widerstandes können mehrere Widerstände in Reihe geschaltet werden. Eine solche Anordnung ist relativ aufwendig, da sowohl zwischen den einzelnen Widerstandskörpern als auch zwischen den einzelnen Varistoren metallene Elektroden angeordnet sind. Im normalen Betriebszustand des Widerstandes wird der Strom durch eine Reihenschaltung von mehreren PTC-Verhalten aufweisenden Widerstandskörpern, zwischen den jeweils eine metallene Elektrode angeordnet ist, geführt. Der Übergangswiderstand zwischen einer metallenen Elektrode und dem Material des Widerstandskörpers ist im allgemeinen relativ hoch und trägt bei einem für Strombegrenzungsaufgaben typischen Widerstand mit einem Gesamtwiderstand von ca. 50 mΩ ebensoviel wie das Material des Widerstandskörpers zum Gesamtwiderstand bei. Darüber hinaus weisen metallene Elektroden und die üblicherweise als Material für den Widerstandskörper eingesetzten füllstoffgefüllten Polymere unterschiedliche elektrische Leitfähigkeiten und unterschiedliche Wärmeausdehnungskoeffizienten auf. Dadurch können mechanische Spannungen im Inneren des Widerstandes entstehen, welche dessen mechanische und elektrische Eigenschaften gegebenenfalls beeinträchtigen können.To increase the dielectric strength of this resistor, several resistors can be connected in series. Such an arrangement is relatively complex, since both between the individual resistance bodies and between the individual Varistors metal electrodes are arranged. In the normal operating state of the resistor, the current is conducted through a series connection of several resistor bodies with PTC behavior, between which a metal electrode is arranged in each case. The contact resistance between a metal electrode and the material of the resistance body is generally relatively high and, with a resistance typical for current limiting tasks with a total resistance of approximately 50 mΩ, contributes just as much as the material of the resistance body to the overall resistance. In addition, metal electrodes and the filler-filled polymers usually used as material for the resistance body have different electrical conductivities and different coefficients of thermal expansion. This can result in mechanical stresses inside the resistor, which may impair its mechanical and electrical properties.

KURZE DARSTELLUNG DER ERFINDUNGSUMMARY OF THE INVENTION

Der Erfindung, wie sie in Patentanspruch 1 angegeben ist, liegt die Aufgabe zugrunde, einen strombegrenzenden Widerstand mit PTC-Verhalten zu schaffen, welcher in einfacher und kostengünstiger Weise herstellbar ist und sowohl eine hohe Nennstromtragfähigkeit und einen weiten Spannungsbereich als auch eine grosse Betriebssicherheit aufweist.The invention, as specified in claim 1, has for its object to provide a current-limiting resistor with PTC behavior, which can be produced in a simple and inexpensive manner and has both a high nominal current carrying capacity and a wide voltage range as well as great operational reliability.

Beim erfindungsgemässen Widerstand ist der PTC-Verhalten aufweisende Widerstandskörper derart ausgebildet, dass er sowohl den elektrischen Kontakt zu den Anschlusselektroden als auch zum Varistor gewährleistet. Dadurch werden der elektrischen Kontaktierung des Varistors dienende metallene Elektroden eingespart. Zugleich kann der erfindungsgemässe Widerstand äusserst kostengünstig und in einem für eine Serienfertigung besonders geeigneten Verfahren hergestellt werden. Der den Varistor und die Anschlusselektroden haltende und üblicherweise von einem füllstoffgefüllten Polymer gebildete Widerstandskörper kann nämlich äusserst preiswert in einem gängigen Kunststoffverarbeitungsverfahren, wie etwa durch Spritzgiessen, erzeugt werden. Durch Einstecken des Varistors in den Widerstandskörper und Aufbringen der Anschlusselektroden an den Widerstandskörper kann dann in äusserst einfacher Weise der erfindungsgemässe Widerstand fertiggestellt werden. Da sich das als füllstoffgefülltes Polymer ausgeführte Material des Widerstandskörpers besonders gut an den im allgemeinen aus einer Metalloxidkeramik bestehenden Körper des Varistors anpasst, kann zudem eine beim Varistor normalerweise vorgesehene flächenhafte Kontaktmetallisierung gegebenenfalls entfallen. Ein weiterer Vorteil ist darin zu sehen, dass die parallel zum Varistor geschaltete und einen PTC-Übergang ausführende Ansprechstelle durch geeignete Ausbildung des Widerstandskörpers in einem Abstand zum Varistor angeordnet werden kann, in dem eine thermische Rückkoppelung zwischen der beim PTC-Übergang erwärmten Ansprechstelle und dem Varistor nicht zu befürchten ist.In the resistor according to the invention, the resistor body exhibiting PTC behavior is designed in such a way that it ensures both the electrical contact to the connection electrodes and to the varistor. This saves metal electrodes serving for electrical contacting of the varistor. At the same time, the resistor according to the invention can be produced extremely inexpensively and in a method which is particularly suitable for series production. The one holding the varistor and the connection electrodes and usually one Resistive bodies formed of filler-filled polymer can namely be produced very inexpensively in a common plastic processing method, such as by injection molding. By inserting the varistor into the resistor body and applying the connection electrodes to the resistor body, the resistor according to the invention can then be completed in an extremely simple manner. Since the material of the resistance body, designed as a filler-filled polymer, adapts particularly well to the body of the varistor, which body generally consists of a metal oxide ceramic, it is also possible, if appropriate, to dispense with a planar contact metallization which is normally provided in the varistor. Another advantage can be seen in the fact that the response point connected in parallel to the varistor and executing a PTC transition can be arranged at a distance from the varistor by suitable formation of the resistance body, in which a thermal feedback between the response point heated during the PTC transition and the Varistor is not to be feared.

Weist der erfindungsgemässe Widerstand mehr als zwei in Reihe geschaltete Varistoren auf, so entfallen metallene Elektroden zwischen den einzelnen Varistoren und zwischen PTC-Verhalten aufweisenden Teilkörpern des Widerstandskörpers, welche ebenso wie die Varistoren in Reihe geschaltet sind. Der Kaltwiderstand des Widerstands wird so ganz wesentlich herabgesetzt und entsprechend die Nennstromtragfähigkeit des strombegrenzenden Widerstands nach der Erfindung erheblich verbessert. Eine besonders hohe Nennstromtragfähigkeit wird erreicht, wenn der Widerstandskörpers einstückig ausgebildet wird. Der sonst zwischen den einzelnen Teilkörpern vorhandene geringe Übergangswiderstand entfällt dann vollständig. Zudem kann der Widerstand dann in besonders kostengünstiger Weise gefertigt werden.If the resistor according to the invention has more than two varistors connected in series, there are no metal electrodes between the individual varistors and between partial bodies of the resistance body which exhibit PTC behavior and which, like the varistors, are connected in series. The cold resistance of the resistor is thus significantly reduced and, accordingly, the nominal current carrying capacity of the current-limiting resistor according to the invention is considerably improved. A particularly high rated current carrying capacity is achieved if the resistance body is made in one piece. The low contact resistance otherwise present between the individual sub-bodies is then completely eliminated. In addition, the resistor can then be manufactured in a particularly cost-effective manner.

KURZE BESCHREIBUNG DER ZEICHNUNGENBRIEF DESCRIPTION OF THE DRAWINGS

Bevorzugte Ausführungsbeispiele der Erfindung und die damit erzielbaren weiteren Vorteile werden nachfolgend anhand von Zeichnungen näher erläutert.Preferred exemplary embodiments of the invention and the further advantages achievable therewith are explained in more detail below with reference to drawings.

Hierbei zeigen die Figuren 1 bis 6, 10 und 11 jeweils in der Seitenansicht bevorzugte Ausführungsformen des strombegrenzenden Widerstands nach der Erfindung mit zwei zueinander parallel liegenden Anschlusselektroden, einem zwischen den Anschlusselektroden angeordneten Widerstandskörper mit PTC-Verhalten und einem oder mehreren mit dem Widerstandskörper kontaktierten Varistoren.1 to 6, 10 and 11 each show a side view of preferred embodiments of the current-limiting resistor according to the invention with two connection electrodes lying parallel to one another, a resistor body with PTC behavior arranged between the connection electrodes and one or more varistors contacted with the resistor body.

Die Figuren 7 bis 9 zeigen in einer Seitenansicht von rechts ein als Ansprechstelle ausgebildetes Teil des gemäss den Figuren 1 und 2 ausgeführten Widerstands.FIGS. 7 to 9 show a side view from the right of a part of the resistor designed according to FIGS. 1 and 2 designed as a contact point.

Die Figur 12 schliesslich zeigt ein Diagramm, in dem der zeitliche Verlauf von elektrischen Grössen dargestellt ist, die beim Begrenzen eines Kurzschlussstroms für das Verhalten des gemäss Fig.2 ausgeführten Widerstands typisch sind, wie die am Widerstandskörper anliegende Spannung UPTC sowie der im Widerstandskörper geführte Strom IPTC und der im Varistor geführte Strom IVaristor.Finally, FIG. 12 shows a diagram in which the time profile of electrical variables is shown, which are typical for the behavior of the resistor designed according to FIG. 2 when a short-circuit current is limited, such as the voltage U PTC applied to the resistor body and the one conducted in the resistor body Current I PTC and the current I varistor carried in the varistor.

WEGE ZUR AUSFÜHRUNG DER ERFINDUNGWAYS OF CARRYING OUT THE INVENTION

In den Figuren bezeichnen gleiche Bezugszeichen gleichwirkende Teile. Die in den Figuren 1 bis 6, 10 und 11 dargestellten strombegrenzenden Widerstände enthalten jeweils einen zwischen zwei parallel zueinander ausgerichteten metallenen Anschlusselektroden 1, 2 angeordneten und flächenhaft kontaktierten Widerstandskörper 3 sowie einen Varistor 40 oder mehrere Varistoren 40, 41, 42, 43, 44, 45.In the figures, the same reference symbols denote parts with the same effect. The current-limiting resistors shown in FIGS. 1 to 6, 10 and 11 each contain a resistance body 3, which is arranged between two metal connecting electrodes 1, 2 aligned parallel to one another and are in surface contact, and a varistor 40 or more varistors 40, 41, 42, 43, 44, 45.

Die Varistoren 40 - 45 sind vorzugsweise aus einer dotierten Keramik auf der Basis eines Metalloxids, wie etwa ZnO, oder eines Titanates, wie etwa SrTiO3 oder BaTiO3, oder eines Carbides, wie etwa SiC, gebildet. Der in den Ausführungsformen gemäss den Figuren 1, 2 und 10 vorgesehene Varistor 40 weist eine Durchbruchspannung auf, die oberhalb der Nennspannung des elektrischen Systems liegt, in der der Widerstand eingesetzt wird. Bei den Ausführungsformen gemäss den Figuren 3, 4, 5, 6 und 11 hingegen sind mehrere Varistoren, z.B. die Varistoren 40, 41, 42, 43, 44 und 45, in einem Stapel angeordnet in Reihe geschaltet. Dieser Varistorstapel weist eine Durchbruchspannung auf, die ebenfalls oberhalb der Nennspannung des den strombegrenzenden Widerstand enthaltenden elektrischen Systems liegt.The varistors 40-45 are preferably formed from a doped ceramic based on a metal oxide, such as ZnO, or a titanate, such as SrTiO 3 or BaTiO 3 , or a carbide, such as SiC. The varistor 40 provided in the embodiments according to FIGS. 1, 2 and 10 has a breakdown voltage which is above the nominal voltage of the electrical system in which the resistor is used. In the embodiments according to FIGS. 3, 4, 5, 6 and 11, on the other hand, a plurality of varistors, for example the varistors 40, 41, 42, 43, 44 and 45, are arranged in series in a stack. This varistor stack has a breakdown voltage which is also above the nominal voltage of the electrical system containing the current-limiting resistor.

Der Widerstandskörper 3 besteht aus einem PTC-Verhalten aufweisendem Material und kann von einem mit einem elektrisch leitenden Füllstoff, wie beispielsweise Leitfähigkeitsruss, TiC oder TiB2, gefüllten, insbesondere thermo- oder duroplastischen, Polymer gebildet sein.The resistance body 3 consists of a material exhibiting PTC behavior and can be formed from a polymer, in particular thermoplastic or thermosetting, filled with an electrically conductive filler, such as, for example, conductive carbon black, TiC or TiB 2 .

Die erfindungsgemässen Widerstände können in einfacher Weise wie folgt hergestellt werden:
Zunächst werden nach einem in der Varistortechnik üblichen Verfahren, wie etwa durch Pressen oder Giessen und nachfolgendes Sintern einer mit verschiedenen Metalloxiden dotierten keramischen Grundsubstanz, wie etwa ZnO, Varistoren 40 bis 45 hergestellt. Diese Varistoren sind plattenförmig ausgebildet und weisen eine Dicke von beispielsweise 2 mm auf. Auf ihren flächigen Seiten können die Varistoren zur Verbesserung des Stromübergangs metallisiert sein. Mit einem Schermischer wird aus einem thermoplastischen Polymer, wie etwa einem Polyäthylen, und einem elektrisch leitfähigen, pulverförmigen Füllstoff, wie beispielsweise TiC, PTC-Material hergestellt. Aus dem PTC-Material wird etwa durch Spritzgiessen der Widerstandskörper 3 gefertigt. Je nach Ausbildung des Widerstandskörpers wird der Varistor 40 oder werden zwei oder mehrere der Varistoren 40 bis 45 in den Widerstandskörper 3 eingebaut. Sodann werden die Anschlusselektroden 1, 2 auf den Widerstandskörper gebracht und unter Ausübung von Kontaktdruck festgesetzt. Da der Widerstandskörper 3 aus kompressiblem Material hergestellt ist und zugleich in Druckrichtung elastisch verbiegbar ausgebildet ist, setzt der Kontaktdruck zugleich auch den Varistor oder die Varistoren im Widerstandskörper 3 fest.The resistors according to the invention can be produced in a simple manner as follows:
First of all, varistors 40 to 45 are produced using a process customary in varistor technology, such as by pressing or casting and subsequent sintering of a ceramic base substance doped with various metal oxides, such as ZnO. These varistors are plate-shaped and have a thickness of, for example, 2 mm. The varistors can be metallized on their flat sides to improve the current transfer. A shear mixer is used to produce PTC material from a thermoplastic polymer, such as a polyethylene, and an electrically conductive, powdery filler, such as, for example, TiC. The resistance body 3 is produced from the PTC material, for example by injection molding. Depending on the design of the resistance body, the varistor 40 or two or more of the varistors 40 to 45 are installed in the resistance body 3. Then the connection electrodes 1, 2 brought to the resistance body and fixed by exerting contact pressure. Since the resistance body 3 is made of compressible material and at the same time is designed to be elastically bendable in the pressure direction, the contact pressure also fixes the varistor or the varistors in the resistance body 3.

In allen Ausführungsformen weist der Widerstandskörper 3 zwei Kontaktflächen 50, 51 auf sowie eine Ansprechstelle 60, welche über die zwei Kontaktflächen 50, 51 parallel zum Varistor 40 geschaltet ist. Die Ansprechstelle 60 ist derart bemessen, dass sie einen PTC-Übergang ausführt, wenn ein im Widerstand geführter Strom einen vorgegebenen Schwellwert überschreitet.In all embodiments, the resistance body 3 has two contact surfaces 50, 51 and a response point 60 which is connected in parallel with the varistor 40 via the two contact surfaces 50, 51. The response point 60 is dimensioned such that it carries out a PTC transition if a current carried in the resistor exceeds a predetermined threshold value.

Bei den Ausführungsformen gemäss den Figuren 1 und 2 ist der Widerstandskörper im wesentlichen jeweils U-förmig ausgebildet. Die Kontaktflächen 50 und 51 sind jeweils auf den Innenflächen der Schenkel des U angeordnet. Hierdurch wird erreicht, dass der Varistor 40 ohne zusätzliche metallene Kontakte über den Widerstandskörper 3 in elektrisch leitender Weise mit den Anschlusselektroden 1, 2 verbunden ist. Bei der Ausführungsform gemäss Fig.2 ist zusätzlich ein aus Metall oder leitfähigem Polymer bestehendes Zwischenstück 70 vorgesehen, welches zwischen einer Kontaktfläche des Varistors 40 und der Kontaktfläche 51 der Widerstandskörpers 3 angeordnet ist. Dieses Zwischenstück ermöglicht zum einen die Aufweitung des U. Andererseits dient das Zwischenstück 70 der Absorption thermischer Energie aus dem Varistor 40. Eine solche Energie wird erzeugt, wenn aufgrund einer an den Kontaktflächen 50, 51 auftretenden Überspannung ein Ableitstrom durch den Varistor 40 geführt wird.In the embodiments according to FIGS. 1 and 2, the resistance body is essentially U-shaped. The contact surfaces 50 and 51 are each arranged on the inner surfaces of the legs of the U. This ensures that the varistor 40 is connected in an electrically conductive manner to the connection electrodes 1, 2 via the resistance body 3 without additional metal contacts. In the embodiment according to FIG. 2, an intermediate piece 70 made of metal or conductive polymer is additionally provided, which is arranged between a contact surface of the varistor 40 and the contact surface 51 of the resistance body 3. On the one hand, this intermediate piece enables the U to be widened. On the other hand, the intermediate piece 70 serves to absorb thermal energy from the varistor 40. Such energy is generated when a leakage current is passed through the varistor 40 due to an overvoltage occurring at the contact surfaces 50, 51.

Bei beiden Ausführungsformen befindet sich die Ansprechstelle 60 im gebogenen Verbindungsteil des U. Durch diese Verlagerung der Ansprechstelle nach aussen wird zum einem der Varistor 40 vor thermischer Aufheizung bei einem PTC-Übergang geschützt und wird zum anderen beim PTC-Übergang der Aufbau unerwünschter mechanischer Spannungen im Widerstandskörper 3 weitgehend vermieden.In both embodiments, the response point 60 is located in the curved connecting part of the U. This shifting of the response point to the outside protects the varistor 40 from thermal heating during a PTC transition and, on the other hand, the build-up of undesirable mechanical stresses in the PTC transition Resistor body 3 largely avoided.

Die Ansprechstelle kann den gleichen Querschnitt wie der Widerstandskörper 3 im Bereich der beiden Kontaktflächen 50, 51 aufweisen, da durch die Biegung des U bereits eine lokale Erhöhung des Widerstands gewährleistet ist. Im allgemeinen wird die Ansprechstelle jedoch als Materialeinformung ausgebildet sein, welche den Querschnitt des U im Bereich seiner Biegung verringert. In jedem Fall sollte der Querschnitt des Widerstandskörpers 3 im Bereich der Ansprechstelle 60 kleiner sein als jede der beiden Kontaktflächen zwischen dem Widerstandskörper und den beiden Anschlusselektroden 1, 2, da nur dann der PTC-Übergang zur Ansprechstelle 60 hin verlagert werden kann.The response point can have the same cross-section as the resistance body 3 in the region of the two contact surfaces 50, 51, since a local increase in the resistance is already ensured by the bending of the U. In general, however, the contact point will be designed as a material indentation which reduces the cross section of the U in the area of its bend. In any case, the cross section of the resistance body 3 in the area of the response point 60 should be smaller than each of the two contact surfaces between the resistance body and the two connection electrodes 1, 2, since only then can the PTC transition to the response point 60 be shifted.

Konstruktive Ausbildungen der Ansprechstelle 60 sind aus den Figuren 7, 8 und 9 ersichtlich und können durch Taillierung des Querschnitts des U quer zur Zeichenebene (Fig.7) oder in Richtung der Schenkel des U in der Zeichenebene (Fig.8 in Zusammenhang mit den Figuren 1 und 2), durch Anordnung von in Richtung der Enden des U geführten und im wesentlichen zueinander parallel verlaufenden Schlitzen 601 (Fig.9) oder in besonders einfacher Weise durch runde Durchgangslöcher erreicht werden. Insbesondere die geschlitzte Ausführungsform der Ansprechstelle 60 zeichnet sich dadurch aus, dass der Strom nicht nur gleichmässig über den eingeengten Querschnitt verteilt geführt wird, sondern dass beim Ausführen des PTC-Überganges das Material der Ansprechstelle sich in praktisch alle Richtungen bewegen kann, wodurch unerwünschte mechanische Spannungen im Widerstandskörper 3 in besonders starken Masse vermieden werden.Structural designs of the contact point 60 can be seen from FIGS. 7, 8 and 9 and can be made by fitting the cross section of the U transversely to the plane of the drawing (FIG. 7) or in the direction of the legs of the U in the plane of the drawing (FIG. 8 in connection with the figures) 1 and 2), by arranging slots 601 (FIG. 9) which are guided in the direction of the ends of the U and run essentially parallel to one another, or in a particularly simple manner through round through holes. In particular, the slotted embodiment of the contact point 60 is characterized in that the current is not only distributed uniformly over the narrowed cross section, but that when the PTC transition is carried out, the material of the contact point can move in practically all directions, thereby causing undesirable mechanical stresses can be avoided in the resistor body 3 in a particularly strong mass.

Bei Nennstrombetrieb des beispielsweise in einem Lastkreis als Strombegrenzer eingebauten Widerstands fliesst der über die Anschlusselektrode 1 eingespeiste Strom über den als U ausgebildeten Widerstandskörper 3 zur Anschlusselektrode 2. Tritt im Lastkreis ein Kurzschlussstrom oder ein unzulässig hoher Überstrom auf, so führt die an der Ansprechstelle 60 besonders hohe Stromdichte zu einem PTC-Übergang. Beim PTC-Übergang erhöht sich der ohmsche Widerstand des Widerstandskörpers 3 im Bereich der Ansprechstelle 60 sehr rasch um mehrere Grössenordnungen und wird so der durch den Widerstand fliessende Strom schnell begrenzt. Nach der Begrenzung des Stromes an den Anschlusselektroden 1, 2 auftretende Überspannungen werden durch Ableitströme abgebaut. Da der Varistor 40 hierbei Energie aufnimmt und erheblich aufgeheizt wird, ist es besonders vorteilhaft, dass die durch den PTC-Übergang ebenfalls stark aufgeheizte Ansprechstelle 60 vom Varistor 40 räumlich getrennt angeordnet ist.During nominal current operation of the resistor installed as a current limiter in a load circuit, for example, the current fed in via the connection electrode 1 flows via the resistance body 3 designed as U to the connection electrode 2. If a short-circuit current or an impermissibly high overcurrent occurs in the load circuit, this leads particularly to the response point 60 high current density to a PTC transition. During the PTC transition, the ohmic resistance of the resistance body 3 increases very rapidly by several orders of magnitude in the region of the contact point 60 the current flowing through the resistor is quickly limited. After the current is limited at the connection electrodes 1, 2, overvoltages that occur are dissipated by leakage currents. Since the varistor 40 in this case absorbs energy and is heated up considerably, it is particularly advantageous that the response point 60, which is also strongly heated by the PTC transition, is arranged spatially separated from the varistor 40.

Bei den gemäss den Figuren 3, 4, 5, 6 und 11 ausgeführten Widerständen ist neben dem Varistor 40 noch mindestens ein weiterer mit diesem Varistor in Reihe geschalteter Varistor 41 bis 45 vorgesehen. Dementsprechend weist der Widerstandskörper 3 weitere Kontaktflächen auf, von denen aus Gründen der Übersichtlichkeit nur die den Varistor 41 auf Potential führenden Kontaktflächen 52 und 53 bezeichnet sind. Über zwei der weiteren Kontaktflächen, wie z. B. 52, 53, jeweils parallel zu einem, wie z.B. 41, der weiteren Varistoren 41 bis 45 sind weitere Ansprechstellen geschaltet, von denen aus Gründen der Übersichtlichkeit nur die Ansprechstelle 61 dargestellt ist. Entsprechend der Ansprechstelle 60 sind auch diese weiteren Ansprechstellen, wie die Ansprechstelle 61, von den Varistoren lokal entkoppelt in den Widerstandskörper 3 eingeformt und führen entsprechend der Ansprechstelle 60 einen PTC-Übergang aus, wenn der im Widerstand geführte Strom den vorgegebenen Schwellwert überschreitet.In the resistors designed according to FIGS. 3, 4, 5, 6 and 11, at least one further varistor 41 to 45 connected in series with this varistor is provided in addition to the varistor 40. Accordingly, the resistance body 3 has further contact surfaces, of which, for reasons of clarity, only the contact surfaces 52 and 53 which carry the varistor 41 at potential are designated. About two of the other contact areas, such as. B. 52, 53, each parallel to one, e.g. 41, the other varistors 41 to 45, further contact points are connected, of which only the contact point 61 is shown for reasons of clarity. Corresponding to the contact point 60, these further contact points, like the contact point 61, are formed locally decoupled from the varistors in the resistance body 3 and, in accordance with the contact point 60, carry out a PTC transition if the current carried in the resistor exceeds the predetermined threshold value.

Die mindestens zwei in Reihe geschaltete Varistoren 40, 41 enthaltenden Ausführungsformen des erfindungsgemässen Widerstands sind zum Einsatz in Lastkreisen mit hohen Spannungen vorgesehen. Beim Auftreten eines grossen Stroms führen die in Reihe geschalteten Ansprechstellen 60, 61 den PTC-Übergang aus und wird so der durch den Widerstand fliessende Strom schnell begrenzt. Nach der Begrenzung des Stromes an den Anschlusselektroden 1, 2 auftretende Überspannungen werden durch Ableitströme abgebaut, welche in den in Reihe geschalteten Varistoren 40, 41 geführt werden. Spricht eine der Ansprechstellen, beispielsweise die Ansprechstelle 61, an bevor die anderen Ansprechstellen angesprochen haben, so wird das Auftreten unzulässig hoher Überspannungen an dieser Ansprechstelle durch den parallel geschalteten Varistor vermieden.The embodiments of the resistor according to the invention containing at least two varistors 40, 41 connected in series are provided for use in load circuits with high voltages. If a large current occurs, the response points 60, 61 connected in series carry out the PTC transition and the current flowing through the resistor is thus quickly limited. After the current at the connection electrodes 1, 2 has been limited, overvoltages which occur are dissipated by leakage currents which are conducted in the varistors 40, 41 connected in series. If one of the contact points, for example the contact point 61, speaks before the other contact points have responded, the occurrence becomes impermissibly higher Overvoltages at this point of contact avoided by the varistor connected in parallel.

Wie aus den Figuren 3 bzw. 5 bzw. 6 entnommen werden kann, ist der Widerstandskörper 3 aus Teilkörpern 30 bis 35 bzw. 30' bis 34' bzw. 36 und 37 mit jeweils zwei parallel zu den Anschlusselektroden verlaufenden Abschnitten und mindestens einem die beiden Abschnitte verbindenden und die Ansprechstelle, z.B. 60, 61, enthaltendem Teil aufgebaut. Zwischen den beiden Abschnitten der Teilkörper, z.B. 31, 31' oder 36, ist jeweils einer der Varistoren, z.B. 41, angeordnet.As can be seen from FIGS. 3 and 5 and 6, the resistance body 3 is made up of partial bodies 30 to 35 and 30 'to 34' and 36 and 37, each with two sections running parallel to the connection electrodes and at least one of the two Sections connecting and the contact point, e.g. 60, 61, built part. Between the two sections of the partial body, e.g. 31, 31 'or 36 is one of the varistors, e.g. 41, arranged.

Bei den Ausführungsform gemäss den Figuren 3 und 5 sind die Teilkörper 30 bis 35 jeweils als U ausgebildet und sind derart aneinandergefügt, dass der Widerstandskörper 3 ein Mäander bildet. Bei diesem Mäander sind je zwei im Mäander paarweise aufeinanderfolgende U gegeneinander um 180° gedreht und derart inandergeschoben, dass sich jeweils einer der Schenkel eines der U zwischen den Schenkeln des anderen U befindet. Die Varistoren können dann ohne zusätzliche Abstandsmittel durch einfaches Einschieben in die U mit dem Widerstandskörper 3 kontaktiert werden.In the embodiment according to FIGS. 3 and 5, the partial bodies 30 to 35 are each designed as a U and are joined to one another in such a way that the resistance body 3 forms a meander. In this meander, two successive U's in pairs in the meander are rotated against each other by 180 ° and pushed into one another such that one of the legs of one of the U is located between the legs of the other U. The varistors can then be contacted with the resistance body 3 by simply pushing them into the U without additional spacing means.

Eine besonders gute mechanische Festigkeit des Widerstandskörpers 3 wird erhalten, wenn wie aus der Ausführungsform gemäss Fig.5 ersichtlich ist, zwischen den beiden Abschnitten mindestens eines der U, z.B. der Teilkörper 31', jeweils einer der Varistoren, z.B. 41, und je ein Schenkel zweier im Widerstandskörper benachbarter und lediglich durch den Varistor voneinander beabstandeter U, z.B. die Teilkörper 30' und 32', angeordnet sind. Sind zusätzlich die einander zugewandten Innenflächen der aufeinanderliegenden Schenkel der U, z.B. der Teilkörper 31' und 32' bzw. 30' und 31', keilförmig abgeschrägt ausgebildet, dann kann der Widerstandskörper 3 durch gegenseitiges Verkeilen der einzelnen U besonders einfach hergestellt werden. Zudem können die durch Spritzgiessen hergestellten U dann problemlos aus der Spritzgussform entfernt werden.A particularly good mechanical strength of the resistance body 3 is obtained if, as can be seen from the embodiment according to FIG. 5, at least one of the U, for example the partial body 31 ', in each case one of the varistors, for example 41, and one leg each between the two sections two U, for example the partial bodies 30 'and 32', which are adjacent to one another in the resistance body and are only spaced apart by the varistor, are arranged. If, in addition, the mutually facing inner surfaces of the superimposed legs of the U, for example the partial bodies 31 'and 32' or 30 'and 31', are beveled in a wedge shape, the resistance body 3 can be produced particularly easily by wedging the individual Us against one another. In addition, the U produced by injection molding can then be easily removed from the injection mold.

Bei den Ausführungsformen nach den Figuren 3 und 5 können die im Widerstandskörper 3 aufeinanderfolgenden Varistoren 40 bis 45 bzw. 40 bis 44 zusätzlich durch U-förmig gebogene Zwischenstücke 701, 702 (aus Gründen der Übersichtlichkeit sind nur in der Fig.3 zwei derartige Teile gestrichelt angedeutet) verbunden werden. Hierdurch wird zum einen eine besonders niederohmige Reihenschaltung der Varistoren erreicht und zum anderen wird die von den Varistoren beim Auftreten von Ableitströmen erzeugte Wärme aus dem Inneren des Widerstands weggeführt.In the embodiments according to FIGS. 3 and 5, the successive varistors 40 to 45 or 40 to 44 in the resistance body 3 can additionally be bent by U-shaped intermediate pieces 701, 702 (for reasons of clarity, only two such parts are dashed in FIG. 3) indicated) are connected. On the one hand, this results in a particularly low-resistance series connection of the varistors and, on the other hand, the heat generated by the varistors when leakage currents occur is conducted away from the interior of the resistor.

Aus den Figuren 4 und 11 sind Ausführungsformen des erfindungsgemässen Widerstandes ersichtlich, bei denen der Widerstandskörper einstückig ausgebildet ist. Da bei diesen Ausführungsformen der Übergangswiderstand zwischen den einzelnen Teilkörpern entfällt, zeichnet sich der Widerstandskörper 3 durch einen besonders geringen ohmschen Widerstand aus. Zugleich kann der Widerstandskörper in einem Giessvorgang hergestellt werden und kann dann der Widerstand durch nachfolgendes Einstecken der Varistoren und der gegebenenfalls vorgesehenen Zwischenstücke 70 bis 73 bzw. 70, 71 in besonders einfacher und kostensparender Weise hergestellt werden. Bei scheibenförmiger Ausbildung der Varistoren weist der Widerstanskörper 3 dann nach vorne geöffnete und nach hinten geschlossene Taschen von halbrundem Querschnitt auf, in die bei der Fertigung des Widerstands die einzelnen Varistoren eingeschoben werden.FIGS. 4 and 11 show embodiments of the resistor according to the invention, in which the resistor body is made in one piece. Since the contact resistance between the individual partial bodies is eliminated in these embodiments, the resistance body 3 is distinguished by a particularly low ohmic resistance. At the same time, the resistance body can be produced in one casting process and the resistance can then be produced in a particularly simple and cost-saving manner by subsequently plugging in the varistors and the optionally provided intermediate pieces 70 to 73 or 70, 71. In the case of a disk-shaped design of the varistors, the resistance body 3 then has pockets of semicircular cross section which are open towards the front and closed towards the rear and into which the individual varistors are inserted during the manufacture of the resistor.

Der Widerstandskörper 3 kann wie folgt ausgebildet sein: als U mit gebogenem (Figuren 1 bis 5) oder geradem Verbindungsabschnitt, als Doppel-U mit gebogenen Verbindungsabschnitten (Fig.2 mit Strichelung) oder geraden Verbindungsabschnitten, als Schneckenlinie (Fig.10), als Doppel- oder Mehrfachschneckenlinie (Fig.10 mit Strichelung), als Mäander (Figuren 3 bis 5), als Doppelmäander (Figuren 6 und 11) oder Girlande bzw. Doppelgirlande (Übereinanderstapeln von mehreren Teilkörpern, welche gemäss dem Teil-körper nach Fig.10 ausgebildet sind).The resistance body 3 can be designed as follows: as a U with a curved (FIGS. 1 to 5) or straight connecting section, as a double U with curved connecting sections (FIG. 2 with dashed lines) or straight connecting sections, as a screw line (FIG. 10) as Double or multiple screw line (Fig. 10 with dashed lines), as a meander (Figures 3 to 5), as a double meander (Figures 6 and 11) or garland or double garland (stacking of several partial bodies, which according to the partial body according to Fig. 10 are trained).

Ist der Widerstandskörper als Doppel-U, Doppelschneckenlinie, Doppelmäander oder Doppelgirlande ausgebildet, so kann er neben der Ansprechstelle 60 eine dazu parallel geschaltete zusätzliche Ansprechstelle 60' aufweisen (Figuren 2, 6, 10 und 11). Ein mit einem derartigen Widerstandskörper 3 versehener Widerstand zeichnet sich durch grosse Festigkeit, grössere Stromtragfähigkeit und einfache Herstellbarkeit aus. Zugleich werden beim PTC-Übergang auftretende thermische und mechanische Kräfte gleichmässig im ganzen Widerstand verteilt.If the resistance body is designed as a double U, double screw line, double meander or double garland, it can have, in addition to the contact point 60, an additional contact point 60 'connected in parallel thereto (FIGS. 2, 6, 10 and 11). A resistor provided with such a resistance body 3 is characterized by great strength, greater current carrying capacity and ease of manufacture. At the same time, thermal and mechanical forces occurring during the PTC transition are evenly distributed throughout the resistance.

Verläuft bzw. verlaufen wie bei den Ausführungsformen gemäss den Figuren 1 bis 6 das die Ansprechstelle 60 enthaltende Teil bzw. die die Ansprechstellen 60, 60', 61,...enthaltenden Teile des U oder des Doppel-U gebogen, so wird beim Ausführen des PTC-Über-gangs durch starkes lokales Erwärmen des Widerstandskörpers im Bereich der Ansprechstellen erzeugte mechanische Kraft aufgrund der Federwirkung der Schenkel des U bzw. Doppel-U abgeschwächt auf den die Varistoren enthaltenden Teil des Widerstandskörpers übertragen. Werden die Ansprechstellen in überwiegend horizontal geführte Bereiche der Verbindungsteile des U bzw. Doppel-U geführt, so wird praktisch keine die vertikal wirkende Kontaktkraft des Widerstands schwächende Gegenkraft erzeugt.If, as in the embodiments according to FIGS. 1 to 6, the part containing the contact point 60 or the part of the U or the double U containing the contact points 60, 60 ', 61,... Is bent, then when executing of the PTC transition, mechanical force generated by strong local heating of the resistance body in the area of the response points is reduced due to the spring action of the legs of the U or double U to the part of the resistance body containing the varistors. If the response points are guided in predominantly horizontally guided areas of the connecting parts of the U or double U, practically no counterforce weakening the vertically acting contact force of the resistor is generated.

Verläuft ein eine Ansprechstelle 60 enthaltendes Teil des U oder Doppel-U senkrecht zu den Schenkeln des U oder Doppel-U (Fig.11), so kann der Widerstand besonders platzsparend ausgebildet werden.If a part of the U or double U containing a contact point 60 extends perpendicular to the legs of the U or double U (FIG. 11), the resistor can be designed to be particularly space-saving.

Ist der Widerstandskörper 3 als Schneckenlinie, Girlande oder Doppel- oder Mehrfachgirlande ausgebildet, so wird eine besonders gute Kühlung des Widerstands erreicht, da dann Umgebungsluft längs des schneckenlinienförmigen aufgebauten Widerstandskörpers 3 ins Innere des Widerstandes geführt wird. Zugleich sind die Ansprechstellen 60, 60' in einen überwiegend horizontal geführten Teil des Widerstandskörpers eingeformt. Beim Ausführen des PTC-Übergangs durch starkes lokales Erwärmen des Widerstandskörpers im Bereich der Ansprechstellen erzeugte mechanische Kraft wirkt dann überwiegend in horizontaler Richtung, so dass keine die vertikal wirkende Kontaktkraft des Widerstands schwächende Gegenkraft erzeugt wird.If the resistance body 3 is designed as a screw line, garland or double or multiple garland, particularly good cooling of the resistance is achieved, since ambient air is then guided along the spiral line-shaped resistance body 3 into the interior of the resistance. At the same time, the response points 60, 60 'are molded into a predominantly horizontally guided part of the resistance body. When performing the PTC transition generated by strong local heating of the resistance body in the area of the response points Mechanical force then acts predominantly in the horizontal direction, so that no counterforce weakening the vertically acting contact force of the resistor is generated.

Der Widerstandskörper kann auch andere, jedoch topologisch ähnliche Formen aufweisen, welche gegebenenfalls an die Topologie des Varistors bzw. der Varistoren angepasst sind. Der Varistor kann praktisch beliebige Querschnittsformen annehmen und beispielsweise rund, rechteckig oder oval ausgebildet sein.The resistance body can also have other, but topologically similar shapes, which are possibly adapted to the topology of the varistor or varistors. The varistor can take virtually any cross-sectional shape and can be round, rectangular or oval, for example.

Aus Figur 12 ist die Wirkungsweise eines erfindungsgemäss ausgebildeten Widerstands zu entnehmen. Dieser Widerstand ist entsprechend der Ausführungsform gemäss Fig.2 ausgebildet. Die U-Form des Widerstandskörpers 3 wurde durch Warmbiegen einer mit 90 mm x 40 mm x 1,5 mm bemessenen Platte aus PTC-Material um einen 6 mm dicken Stab erzeugt. Der gebogene Widerstandskörper 3 hatte über das ganze U konstanten Querschnitt und wies einen ohmschen Widerstand von 160 mΩ auf. In einem Lastkreis wurde dem Widerstand ein prospektiver Kurzschlussstrom von 12 kA zugeführt. Dieser Strom wurde ersichtlich auf eine Stromspitze von 1,2 kA begrenzt und war nach 1 ms bereits kleiner 200 A. Der Widerstand konnte die wiederkehrenden Spannung mindestens 100 ms, d.h. über 5 Perioden, problemlos halten. Mit einem entsprechend ausgebildeten Widerstand, bei dem jedoch die Biegung aufgrund von Durchgangsbohrungen bzw. einer Materialeinschnürung einen verringerten Querschnitt aufwies, wurde die Stromspitze sogar auf 1 kA begrenzt. Der ohmsche Widerstand dieses Elementes war jedoch mit 250 mΩ etwas grösser.The mode of operation of a resistor designed according to the invention can be seen from FIG. This resistor is designed in accordance with the embodiment shown in FIG. 2. The U-shape of the resistance body 3 was produced by warm bending a plate made of PTC material with 90 mm × 40 mm × 1.5 mm around a 6 mm thick rod. The curved resistance body 3 had a constant cross section over the entire U and had an ohmic resistance of 160 mΩ. A prospective short-circuit current of 12 kA was supplied to the resistor in a load circuit. This current was evidently limited to a current peak of 1.2 kA and was already less than 200 A after 1 ms. The resistance was able to hold the recurring voltage without problems for at least 100 ms, ie over 5 periods. The current peak was even limited to 1 kA with a suitably designed resistor, but with a reduced cross-section due to through holes or material constriction. However, the ohmic resistance of this element was somewhat larger at 250 mΩ.

BezugszeichenlisteReference list

1, 21, 2
AnschlusselektrodenConnection electrodes
33rd
WiderstandskörperResistance body
30, 31, 32, 33, 34, 35, 30', 31', 32', 33', 34'30, 31, 32, 33, 34, 35, 30 ', 31', 32 ', 33', 34 '
TeilkörperPartial body
40, 41, 42, 43, 44, 4540, 41, 42, 43, 44, 45
VaristorenVaristors
50, 51, 52, 5350, 51, 52, 53
KontaktflächenContact areas
60, 60', 61, 61'60, 60 ', 61, 61'
AnsprechstellenContact points
601601
SchlitzeSlits
70, 71, 72, 73, 701, 70270, 71, 72, 73, 701, 702
ZwischenstückeSpacers

Claims (15)

Strombegrenzender Widerstand mit zwei parallel zueinander angeordneten Anschlusselektroden (1, 2), mit einem von den Anschlusselektroden (1, 2) flächenhaft kontaktierten und PTC-Verhalten aufweisenden Widerstandskörper (3) und mit einem mit dem Widerstandskörper (3) in elektrisch leitendem Kontakt befindlichen ersten Varistor (40), dadurch gekennzeichnet, dass der Widerstandskörper (3) zwei erste Kontaktflächen (50, 51) enthält sowie eine erste Ansprechstelle (60), welche über die zwei ersten Kontaktflächen (50, 51) parallel zum ersten Varistor (40) geschaltet ist und oberhalb eines Schwellwertes eines durch den Widerstand fliessenden Stroms einen PTC-Übergang ausführt.Current-limiting resistor with two connection electrodes (1, 2) arranged in parallel to one another, with a resistance body (3) which is in area contact with the connection electrodes (1, 2) and exhibits PTC behavior, and with a first one which is in electrically conductive contact with the resistance body (3) Varistor (40), characterized in that the resistance body (3) contains two first contact surfaces (50, 51) and a first response point (60) which is connected in parallel with the first varistor (40) via the two first contact surfaces (50, 51) and performs a PTC transition above a threshold value of a current flowing through the resistor. Widerstand nach Anspruch 1 mit mindestens einem mit dem ersten Varistor (40) in Reihe schaltbaren zweiten Varistor (41), dadurch gekennzeichnet, dass der Widerstandskörper (3) zwei zweite Kontaktflächen (52, 53) sowie mindestens eine zweite Ansprechstelle (61) enthält, welche über die zwei zweiten Kontaktflächen (52, 53) parallel zum zweiten Varistor (41) geschaltet ist und welche oberhalb des Schwellwertes den PTC-Übergang ausführt.Resistor according to Claim 1 with at least one second varistor (41) which can be connected in series with the first varistor (40), characterized in that the resistance body (3) contains two second contact surfaces (52, 53) and at least one second response point (61), which is connected in parallel to the second varistor (41) via the two second contact surfaces (52, 53) and which carries out the PTC transition above the threshold value. Widerstand nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, dass eine (50) der zwei ersten Kontaktflächen über ein elektrisch leitendes erstes Zwischenstück (70) mit einer Kontaktfläche des ersten Varistors (40) verbunden ist. (Figuren 2, 4, 6, 10, 11).Resistor according to one of Claims 1 or 2, characterized in that one (50) of the two first contact surfaces is connected to a contact surface of the first varistor (40) via an electrically conductive first intermediate piece (70). (Figures 2, 4, 6, 10, 11). Widerstand nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass im Bereich der ersten (60) und/oder der mindestens einen zweiten Ansprechstelle (61) die Querschnittsfläche des Widerstandskörpers (3) geringer ist als jede der beiden Kontaktflächen zwischen dem Widerstandskörper (3) und den beiden Anschlusselektroden (1, 2).Resistor according to one of Claims 1 to 3, characterized in that in the region of the first (60) and / or the at least one second response point (61) the cross-sectional area of the resistance body (3) is smaller than each of the two contact surfaces between the resistance body (3 ) and the two connection electrodes (1, 2). Widerstand nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass parallel zu den Anschlusselektroden (1, 2) geführte Abschnitte des Widerstandskörpers (3) jeweils eine der beiden ersten (50, 51) oder zweiten Kontaktflächen (52, 53) enthalten, und dass die erste (60) oder die mindestens eine zweite Ansprechstelle (61) in ein zwei benachbarte dieser Abschnitte verbindendes Teil des Widerstandskörpers (3) eingeformt ist.Resistor according to one of Claims 1 to 4, characterized in that sections of the resistance body (3) which are parallel to the connection electrodes (1, 2) each contain one of the two first (50, 51) or second contact surfaces (52, 53), and that the first (60) or the at least one second response point (61) is molded into a part of the resistance body (3) connecting two adjacent of these sections. Widerstand nach Anspruch 5, dadurch gekennzeichnet, dass die erste (60) und/oder die mindestens eine zweite Ansprechstelle (61) in Richtung der Abschnittsenden geführte und im wesentlichen zueinander parallel angeordnete Schlitze (601) oder eine Taillierung enthalten.Resistor according to Claim 5, characterized in that the first (60) and / or the at least one second response point (61) contain slots (601) which are guided in the direction of the section ends and are arranged essentially parallel to one another, or a waist. Widerstand nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass der Widerstandskörper (3) einstückig ausgebildet ist (Figuren 1, 2, 4, 10 und 11).Resistor according to one of claims 1 to 6, characterized in that the resistance body (3) is formed in one piece (Figures 1, 2, 4, 10 and 11). Widerstand nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass der Widerstandskörper (3) aus Teilkörpern (30, 31, ..., 34') mit jeweils zwei parallel zu den Anschlusselektroden (1, 2) verlaufenden Abschnitten und mindestens einem die beiden Abschnitte verbindenden Teil aufgebaut ist.Resistor according to one of claims 1 to 6, characterized in that the resistance body (3) from partial bodies (30, 31, ..., 34 ') each with two sections running parallel to the connection electrodes (1, 2) and at least one part connecting the two sections is constructed. Widerstand nach Anspruch 8, dadurch gekennzeichnet, dass zwischen den beiden Abschnitten mindestens eines Teilkörpers (30) einer der Varistoren (40) und höchstens ein Abschnitt eines im Widerstandskörper (3) benachbarten Teilkörpers (31) angeordnet sind (Fig.3)Resistor according to claim 8, characterized in that between the two sections of at least one partial body (30) one of the varistors (40) and at most one section of a partial body (31) adjacent in the resistance body (3) are arranged (Fig. 3) Widerstand nach Anspruch 9, dadurch gekennzeichnet, dass zwischen den beiden Abschnitten mindestens eines der Teilkörper (31') einer der Varistoren (41) und je ein Abschnitt zweier im Widerstandskörper (3) benachbarter Teilkörper (30', 32') angeordnet sind (Fig.5).Resistor according to claim 9, characterized in that between the two sections at least one of the partial bodies (31 ') one of the varistors (41) and a section of two adjacent in the resistance body (3) Partial bodies (30 ', 32') are arranged (Fig.5). Widerstand nach Anspruch 10, dadurch gekennzeichnet, dass die einander zugewandten Flächen der beiden Abschnitte der Teilkörper (30', 31', ...) keilförmig abgeschrägt ausgebildet sind.Resistor according to claim 10, characterized in that the mutually facing surfaces of the two sections of the partial body (30 ', 31', ...) are beveled in a wedge shape. Widerstand nach einem der Ansprüche 1 bis 11, dadurch gekennzeichnet, dass der Widerstandskörper (3) als U, Schneckenlinie, Doppel-U, Doppel- oder Mehrfachschneckenlinie, Mäander, Girlande, Doppel- oder Mehrfachmäander oder Doppel- oder Mehrfachgirlande ausgebildet ist.Resistor according to one of claims 1 to 11, characterized in that the resistance body (3) is designed as a U, screw line, double U, double or multiple screw line, meander, garland, double or multiple meander or double or multiple garland. Widerstand nach Anspruch 12, dadurch gekennzeichnet, dass bei Ausbildung des Widerstandskörpers als Doppel-U, Doppelschneckenlinie, Doppelmäander oder Doppelgirlande neben der ersten (60) oder der zweiten Ansprechstelle (61) mindestens eine dazu parallel geschaltete zusätzliche Ansprechstelle (60', 61') vorgesehen ist (Figuren 2, 6, 10, 11).Resistor according to Claim 12, characterized in that when the resistance body is designed as a double U, double screw line, double meander or double garland, in addition to the first (60) or the second response point (61), at least one additional response point (60 ', 61') connected in parallel thereto is provided (Figures 2, 6, 10, 11). Widerstand nach einem der Ansprüche 12 oder 13, dadurch gekennzeichnet, dass jedes eine Ansprechstelle (60) enthaltende Teil des U oder Doppel-U senkrecht zu den Schenkeln des U oder Doppel-U verläuft (Fig.11).Resistor according to one of claims 12 or 13, characterized in that each part of the U or double U containing a response point (60) extends perpendicular to the legs of the U or double U (Fig. 11). Widerstand nach einem der Ansprüche 12 oder 13, dadurch gekennzeichnet, dass jedes eine Ansprechstelle (60) enthaltende Teil des U oder Doppel- oder Mehrfach-U gebogen verläuft (Figuren 1-6).Resistor according to one of claims 12 or 13, characterized in that each part of the U or double or multiple U containing a contact point (60) is curved (Figures 1-6).
EP97810116A 1996-03-30 1997-03-03 Current limiting resistor with PTC-behaviour Expired - Lifetime EP0798750B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6259349B1 (en) 1998-07-25 2001-07-10 Abb Research Ltd. Electrical component with a constriction in a PTC polymer element

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1168378A1 (en) * 2000-06-19 2002-01-02 Abb Research Ltd. Method of producing a PTC-resistor device
US6411191B1 (en) 2000-10-24 2002-06-25 Eaton Corporation Current-limiting device employing a non-uniform pressure distribution between one or more electrodes and a current-limiting material
DE10058908C1 (en) * 2000-11-21 2002-08-08 Siemens Ag Arrangement for reducing overvoltages with several varistors
DE10144364A1 (en) 2001-09-10 2003-04-03 Epcos Ag Electrical multilayer component
US9034210B2 (en) * 2007-12-05 2015-05-19 Epcos Ag Feedstock and method for preparing the feedstock
US20090145977A1 (en) * 2007-12-05 2009-06-11 Jan Ihle Injection molded nozzle and injector comprising the injection molded nozzle
US20090148657A1 (en) * 2007-12-05 2009-06-11 Jan Ihle Injection Molded PTC-Ceramics
US20090148802A1 (en) * 2007-12-05 2009-06-11 Jan Ihle Process for heating a fluid and an injection molded molding
US20090146042A1 (en) * 2007-12-05 2009-06-11 Jan Ihle Mold comprising a ptc-ceramic
US7973639B2 (en) * 2007-12-05 2011-07-05 Epcos Ag PTC-resistor
CN117393253A (en) 2022-07-04 2024-01-12 国巨电子（中国）有限公司 Surge-resistant resistor and method for manufacturing same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4780598A (en) * 1984-07-10 1988-10-25 Raychem Corporation Composite circuit protection devices
JPH01158702A (en) * 1987-12-15 1989-06-21 Murata Mfg Co Ltd Composite functional electronic component
JPH01310509A (en) * 1988-06-09 1989-12-14 Tdk Corp Circuit protecting element
US5064997A (en) * 1984-07-10 1991-11-12 Raychem Corporation Composite circuit protection devices

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976854A (en) * 1974-07-31 1976-08-24 Matsushita Electric Industrial Co., Ltd. Constant-temperature heater
CH581377A5 (en) * 1975-02-11 1976-10-29 Bbc Brown Boveri & Cie
DE3204207C2 (en) * 1982-02-08 1985-05-23 Siemens AG, 1000 Berlin und 8000 München Electrical resistance with a ceramic PTC body and method for its manufacture
DE4142523A1 (en) * 1991-12-21 1993-06-24 Asea Brown Boveri RESISTANCE WITH PTC BEHAVIOR
DE4221309A1 (en) * 1992-06-29 1994-01-05 Abb Research Ltd Current limiting element
DE4230848C1 (en) * 1992-09-15 1993-12-23 Siemens Matsushita Components Multiple cold conductor for overload protection - has stacked cold conductor discs with U=shaped hoops forming integral disc contacts and contact connections
US5379022A (en) * 1993-05-03 1995-01-03 Fluke Corporation Thermistor device with extended operating range

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4780598A (en) * 1984-07-10 1988-10-25 Raychem Corporation Composite circuit protection devices
US5064997A (en) * 1984-07-10 1991-11-12 Raychem Corporation Composite circuit protection devices
JPH01158702A (en) * 1987-12-15 1989-06-21 Murata Mfg Co Ltd Composite functional electronic component
JPH01310509A (en) * 1988-06-09 1989-12-14 Tdk Corp Circuit protecting element

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 013, no. 429 (E-823), 25. September 1989 & JP 01 158702 A (MURATA MFG CO LTD), 21. Juni 1989 *
PATENT ABSTRACTS OF JAPAN vol. 014, no. 108 (E-0896), 27. Februar 1990 & JP 01 310509 A (TDK CORP), 14. Dezember 1989 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6259349B1 (en) 1998-07-25 2001-07-10 Abb Research Ltd. Electrical component with a constriction in a PTC polymer element

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US5861795A (en) 1999-01-19
EP0798750A3 (en) 1998-12-02

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