EP0928011B1 - Process for producing transformers encapsulated in cast resin and transformer - Google Patents
Process for producing transformers encapsulated in cast resin and transformer Download PDFInfo
- Publication number
- EP0928011B1 EP0928011B1 EP98124700A EP98124700A EP0928011B1 EP 0928011 B1 EP0928011 B1 EP 0928011B1 EP 98124700 A EP98124700 A EP 98124700A EP 98124700 A EP98124700 A EP 98124700A EP 0928011 B1 EP0928011 B1 EP 0928011B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- resin
- cast
- phenolic resin
- resin layer
- phenolic
- 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.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/32—Insulating of coils, windings, or parts thereof
- H01F27/327—Encapsulating or impregnating
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
- H01F41/12—Insulating of windings
Definitions
- the invention relates to a method for producing transformers, in which the windings are cast in casting molds with a thermosetting cast resin mixture. This creates moisture-proof, tropicalized insulation, which also provides a high level of mechanical protection for the windings. Because of their good mechanical and electrical properties, epoxy resin hardener systems known per se are the preferred casting resins. Resins based on bismaleimide-triazine or epoxy-isocyanate are also used for this (Jürgen Bednarz; "Plastics in Electrical Engineering and Electronics", Verlag W. Kohlhammer, (1988), pp. 70-73).
- an appropriate amount of mineral fillers is added to the resin mixture to increase thermal conductivity, reduce shrinkage, and to adjust the coefficient of expansion of the resin mixture to that of the winding metals.
- the windings are cast in metal molds using either a vacuum casting or pressure gelation process with such a casting resin mixture and the mixture is then cured in this mold.
- problems with regard to flame resistance and in particular the development of flue gas in the event of a fire or an external fire In order to achieve the required flame resistance of the cast body, fillers and additives are added to the cast resin mixtures, which impair the flammability of the resin systems.
- the preferred substance added is aluminum oxide hydrate. As a result, however, both the mechanical (bending tensile strength, crack initiation strength) and the electrical properties in the long-term behavior of the castings are deteriorated.
- Resins made transformers consist in that their outer surfaces with a Phenolic resin layer can be provided by such as a phenolic resin paint or Phenolic resin laminate would be applied to the outer surface.
- the cast resin transformers are preferred directly provided with a phenolic resin layer during manufacture. This can be done in that the inner walls of the metal mold entirely or only to the extent that they are Relate outer surfaces of the cast resin molded body, provided with a phenolic resin layer be, this phenolic resin layer is a new form in which the Cast resin mixture is filled and after the hardening of the cast resin molded body remains on this.
- This phenolic resin layer can be a phenolic resin lacquer layer known per se or a filled phenolic resin compound evenly applied in a thin layer. In both In some cases, the phenolic resin is not yet fully cross-linked, but will be after Casting process hardened together with the casting resin.
- the phenolic resin layer preferably consists of a sheet material impregnated with phenolic resin, which can be uncrosslinked, pre-crosslinked or fully cured. Examples of this are uncrosslinked or hardened phenolic resin-impregnated papers, nonwoven fabrics or fabrics, which may have been preformed before curing.
- Filament Winding - manufactured wound pipe sections which serve in particular as the outer shell of the transformers.
- a particular embodiment of the present invention is that the Casting mold consists of a preformed laminate and after the casting and Hardening process remains as a lost mold on the cast resin molded body. This The process variant places higher demands on those made from phenolic resin Material prefabricated mold, however, the effort involved compensated that the expensive manufacture of metal molds can be avoided.
- this process variant has the further advantage that the production of Cast resin transformers are not tied to cycle times within which the Metal molds must be made available again for a new casting. Because of this No time pressure, cast resin systems can be used for a very long time Curing times and therefore very low temperature peaks during curing exhibit. The cast resin moldings produced in this way are therefore largely free of internal tensions.
- a further simplification of the method according to the invention is that lost forms from tubes based on phenolic resins with different Manufacture diameters. That are vacuum-tight on their top and bottom sides be sealed.
- the molds produced in this way can also be produced without complex Vacuum chamber evacuated and filled with casting resin using the vacuum casting process.
- phenolic resins for the phenolic resin layers produced according to the invention all commercially available condensation products from aldehydes and phenolic Products. The most favorable properties in terms of fire however achieved when using phenol-formaldehyde resins. Be used both alkaline condensed resoles, which are self-curing, and acidic condensed novolaks in a manner known per se with a hardening agent be used. Preferred curing agents for novolaks are resols and / or Hexamethylenetetramine (Hexa). Because novolak-hexa mixtures only at temperatures harden above those that occur during the hardening of the casting resins Temperature peaks are, such systems are only used when as Forms of hardened laminates or pipes can be used.
- test rods With the dimensions 100 x 15 x 10 mm are produced. These test rods are clamped vertically in accordance with UL 94 and exposed to flame for 2 x 10 s. The smoke density is observed during this flame treatment. The afterburn time is then determined.
- the same epoxy resin hardener system diglycidyl ether based on bisphenol A and methyl tetrahydrophthalic anhydride is used in all experiments. The individual variants and the results are given in the following list:
- Epoxy resin with 65% quartz powder is poured into a metal mold, the Inner walls are lined with a hardened phenolic resin glass laminate. The Outer surfaces of the resulting test rod are reinforced with a Phenolic resin layer.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Insulating Of Coils (AREA)
Description
Die Erfindung betrifft ein Verfahren zur Herstellung von Transformatoren, bei denen
die Wicklungen in Gießformen mit einer duroplastischen Gießharzmischung vergossen
werden. Dadurch entsteht eine feuchtesichere, tropengeeignete Isolierung, die
gleichzeitig einen hohen mechanischen Schutz der Wicklungen darstellt.
Aufgrund ihrer guten mechanischen und elektrischen Eigenschaften sind an sich
bekannte Epoxidharz- Härter-Systeme die bevorzugten Gießharze. Aber auch Harze
auf Bismaleinimid-Triazin- oder Epoxid-Isocyanat-Basis werden hierfür eingesetzt
(Jürgen Bednarz; "Kunststoffe in der Elektrotechnik und Elektronik", Verlag
W.Kohlhammer, (1988), S. 70-73).The invention relates to a method for producing transformers, in which the windings are cast in casting molds with a thermosetting cast resin mixture. This creates moisture-proof, tropicalized insulation, which also provides a high level of mechanical protection for the windings.
Because of their good mechanical and electrical properties, epoxy resin hardener systems known per se are the preferred casting resins. Resins based on bismaleimide-triazine or epoxy-isocyanate are also used for this (Jürgen Bednarz; "Plastics in Electrical Engineering and Electronics", Verlag W. Kohlhammer, (1988), pp. 70-73).
Im bevorzugten Gießverfahren wird der Harzmischung eine geeignete Menge
mineralischer Füllstoffe zugegeben, um die Wärmeleitfähigkeit zu erhöhen, den
Schwund zu verringern und den Ausdehnungskoeffizienten der Gießharzmischung an
den der Wicklungsmetalle anzugleichen.
Die Wicklungen werden in Gießformen aus Metall entweder im Vakuumgieß- oder im
Druckgelierverfahren mit einer derartigen Gießharzmischung vergossen und die
Mischung dann in dieser Form ausgehärtet.
Bei allen dieser eingesetzten Gießharzsysteme bestehen aber Probleme hinsichtlich der
Flammfestigkeit und insbesondere der Rauchgasentwicklung im Falle eines Brandes
oder einer äußeren Brandeinwirkung.
Um die geforderte Flammfestigkeit der Gießkörper zu erzielen, werden den
Gießharzmischungen Füll- und Zusatzstoffe beigegeben, die die Brennbarkeit der
Harzsysteme verschlechtern. Der bevorzugt zugegebene Stoff ist
Aluminiumoxyid-hydrat. Dadurch werden aber sowohl die mechanischen
(Biegezugfestigkeit, Rißeinleitfestigkeit) als auch die elektrischen Eigenschaften im
Langzeitverhalten der Gießlinge verschlechtert.In the preferred casting process, an appropriate amount of mineral fillers is added to the resin mixture to increase thermal conductivity, reduce shrinkage, and to adjust the coefficient of expansion of the resin mixture to that of the winding metals.
The windings are cast in metal molds using either a vacuum casting or pressure gelation process with such a casting resin mixture and the mixture is then cured in this mold.
With all of these cast resin systems used, however, there are problems with regard to flame resistance and in particular the development of flue gas in the event of a fire or an external fire.
In order to achieve the required flame resistance of the cast body, fillers and additives are added to the cast resin mixtures, which impair the flammability of the resin systems. The preferred substance added is aluminum oxide hydrate. As a result, however, both the mechanical (bending tensile strength, crack initiation strength) and the electrical properties in the long-term behavior of the castings are deteriorated.
In einem anderen Gießverfahren werden die in der Metallform vorliegenden Wicklungen, Glasmatten, -Vliese und Glasgewebe oder Glasrovings (Stützgewebe) durch Vergießen mit einer nicht gefüllten Harz-Härter-Mischung imprägniert. Eine Flammfestigkeit kann dabei nur durch Einsatz an sich nicht erwünschter brom- oder phosphorhaltiger Harze erreicht werden, wobei hier während einer Flammeinwirkung eine Brennbarkeit mit hoher Rauchgasdichte gegeben wäre. In another casting process, those present in the metal mold Windings, glass mats, nonwovens and glass fabric or glass rovings (support fabric) impregnated by pouring with an unfilled resin-hardener mixture. A Flame resistance can only be achieved by using bromine or Resins containing phosphorus can be achieved, here during exposure to flame flammability with high smoke density would be given.
Es ist daher Aufgabe der Erfindung, ein Verfahren zur Herstellung von Gießharztransformatoren bereitzustellen, mit dem Transformatoren hergestellt werden, bei denen die Flammfestigkeit wesentlich verbessert ist und bei denen insbesondere die Rauchgasdichte während einer Flammeinwirkung wesentlich vermindert ist, ohne daß die mechanischen oder elektrischen Eigenschaften verschlechtert werden.It is therefore an object of the invention to provide a method for producing To provide cast resin transformers used to manufacture transformers, where the flame resistance is significantly improved and where in particular the Flue gas density during a flame exposure is significantly reduced without the mechanical or electrical properties are deteriorated.
Die Lösung der Aufgabe erfolgt durch ein Verfahren gemäß der Ansprüche 1-7, sowie durch entsprechend hergestellte Gießtransformatoren, deren Außenflächen oder gesamten Oberflächen mit einer Phenolharzschicht versehen sind gemäß Anspruch 8.The problem is solved by a method according to claims 1-7, and by appropriately manufactured casting transformers, their outer surfaces or entire surfaces are provided with a phenolic resin layer according to claim 8.
Es wurde gefunden, daß die Brandeigenschaften von Gießharztransformatoren wesentlich verbessert werden können, ohne daß die elektrischen und die mechanischen Eigenschaften verschlechtert werden, wenn die Außenflächen oder die gesamten Oberflächen der Gießharzformkörper mit einer verstärkten oder unverstärkten Phenolharzschicht versehen werden. Im Falle einer Brandeinwirkung pyrolysiert das Phenolharz. Flüchtige Zersetzungsprodukte verbrennen, wobei allerdings die Rauchgasdichte gering ist. Zurück bleibt eine Kohlenstoffmatrix, die schwer entflammbar ist und die das darunterliegende Harz thermisch und gegen Zutritt von Sauerstoff isoliert. Nach Beendigung einer äußeren Flammeinwirkung sind die entsprechend hergestellten Gießharztransformatoren selbstverlöschend.It has been found that the fire properties of cast resin transformers can be significantly improved without the electrical and mechanical Properties deteriorate when the exterior surfaces or the whole Surfaces of the cast resin molded body with a reinforced or unreinforced Phenolic resin layer can be provided. In the event of fire, this will pyrolyze Phenolic resin. Burn volatile decomposition products, although the Flue gas density is low. What remains is a carbon matrix that is heavy is flammable and which the underlying resin is thermally and against access of Oxygen isolated. After the end of an external flame exposure, the correspondingly manufactured cast resin transformers self-extinguishing.
Im einfachsten Fall könnte eine Nachrüstung von bereits mit einem der genannten Harze hergestellten Transformatoren darin bestehen, daß deren Außenflächen mit einer Phenolharzschicht versehen werden, indem etwa ein Phenolharzlack oder ein Phenolharz-Laminat auf die Außenfläche aufgebracht würde.In the simplest case, it could be retrofitted with one of the above Resins made transformers consist in that their outer surfaces with a Phenolic resin layer can be provided by such as a phenolic resin paint or Phenolic resin laminate would be applied to the outer surface.
Erfindungsgemäß bevorzugt werden jedoch die Gießharztransformatoren direkt bei der Herstellung mit einer Phenolharzschicht versehen. Dies kann dadurch erfolgen, daß die Innenwände der metallenen Gießform ganz oder nur insoweit, als sie die Außenflächen der Gießharzformkörper betreffen, mit einer Phenolharzschicht versehen werden, wobei diese Phenolharzschicht eine neue Form darstellt, in die die Gießharzmischung gefüllt wird und die nach dem Aushärten des Gießharzformkörpers auf diesem verbleibt.According to the invention, however, the cast resin transformers are preferred directly provided with a phenolic resin layer during manufacture. This can be done in that the inner walls of the metal mold entirely or only to the extent that they are Relate outer surfaces of the cast resin molded body, provided with a phenolic resin layer be, this phenolic resin layer is a new form in which the Cast resin mixture is filled and after the hardening of the cast resin molded body remains on this.
Diese Phenolharzschicht kann eine an sich bekannte Phenolharz-Lackschicht sein oder eine in dünner Schicht gleichmäßig aufgebrachte gefüllte Phenolharz-Masse. In beiden Fällen ist das Phenolharz noch nicht vollständig vernetzt, sondern wird nach dem Gießvorgang zusammen mit dem Gießharz gehärtet.This phenolic resin layer can be a phenolic resin lacquer layer known per se or a filled phenolic resin compound evenly applied in a thin layer. In both In some cases, the phenolic resin is not yet fully cross-linked, but will be after Casting process hardened together with the casting resin.
Bevorzugt aber besteht die Phenolharzschicht aus einem mit Phenolharz imprägnierten
flächigen Material, das unvernetzt, vorvernetzt oder vollständig ausgehärtet sein kann.
Beispiele hierfür sind unvernetzte oder gehärtete phenolharzimprägnierte Papiere,
Faservliese oder Gewebe, die gegebenenfalls vor der Härtung schon vorgeformt sind.
Bevorzugt eingesetzt werden vorgeformte, d.h., der äußeren Form des
Gießharzkörpers entsprechende, Phenolharzpapiere oder phenolharzimprägnierte
Prepregs aus bevorzugt Glasfaservliesen, die ein- oder mehrlagig verwendet werden
können, aus derartigen Prepregs hergestellte, der äußeren Form des Gießharzkörpers
entsprechend vorgeformte und gehärtete Laminate, die ebenfalls ein- oder mehrlagig
sein können oder mittels Laminiertechnologie wie z. B. im Filament Winding -
Verfahren hergestellte gewickelte Rohrabschnitte, die insbesondere als Außenhülle der
Transformatoren dienen.However, the phenolic resin layer preferably consists of a sheet material impregnated with phenolic resin, which can be uncrosslinked, pre-crosslinked or fully cured.
Examples of this are uncrosslinked or hardened phenolic resin-impregnated papers, nonwoven fabrics or fabrics, which may have been preformed before curing. Preformed, ie, phenolic resin papers or phenolic resin-impregnated prepregs made of preferably glass fiber nonwovens, which can be used in one or more layers, made from such prepregs and preformed and hardened according to the outer shape of the cast resin body, which are likewise a preformed and hardened laminate, are preferably used - Can be multi-layer or by means of laminating technology such. B. Filament Winding - manufactured wound pipe sections, which serve in particular as the outer shell of the transformers.
Die entsprechend mit einer Phenolharzschicht versehenen Metallformen werden dann in an sich bekannter Weise mit den Wicklungen bestückt und in an sich bekannter Weise entweder in Vakuumkammern nach Vakuumgießverfahren oder in entsprechenden Druckvorrichtungen nach dem Druckgeliervervahren oder mit kombinierten Vakuum-Druck-Verfahren mit dem duroplastischen Gießharz-Härter-Gemisch gefüllt und dann einer für das jeweilige Gießharz-Härter-System notwendigen thermischen Behandlung unterworfen, bei der das Gießharz härtet. Nach dem Entformen bilden der Gießharzformkörper und die Phenolharzschicht eine feste Einheit.The correspondingly provided with a phenolic resin layer metal molds equipped with the windings in a manner known per se and in a manner known per se Way either in vacuum chambers after vacuum casting or in appropriate printing devices after the Druckgeliervervahren or with combined vacuum pressure process with the thermosetting Cast resin-hardener mixture filled and then one for each Cast resin hardener system subjected to the necessary thermal treatment at the the resin hardens. After demolding, the cast resin molded body and the Phenolic resin layer a solid unit.
Eine besondere Ausführungsform der vorliegenden Erfindung besteht darin, daß die Gießform aus einem vorgeformten Laminat besteht und nach dem Gieß- und Härtungsvorgang als verlorene Form auf dem Gießharzformkörper verbleibt. Diese Verfahrensvariante stellt zwar höhere Anforderungen an die aus phenolharzhaltigem Material vorgefertigte Gießform, jedoch wird der damit verbundene Aufwand dadurch ausgeglichen, daß die teure Herstellung von Metallformen unterbleiben kann.A particular embodiment of the present invention is that the Casting mold consists of a preformed laminate and after the casting and Hardening process remains as a lost mold on the cast resin molded body. This The process variant places higher demands on those made from phenolic resin Material prefabricated mold, however, the effort involved compensated that the expensive manufacture of metal molds can be avoided.
Außerdem hat diese Verfahrensvariante den weiteren Vorteil, daß die Herstellung der Gießharztransformatoren nicht an Taktzeiten gebunden ist, innerhalb deren die Metallformen wieder für einen neuen Guß bereitgestellt werden müssen. Da dieser Zeitdruck entfällt, kann man als Gießharzsysteme solche einsetzen, die sehr lange Härtungszeiten und damit sehr geringe Temperaturspitzen während der Härtung aufweisen. Die dadurch hergestellten Gießharzformkörper sind daher weitgehend frei von inneren Spannungen.In addition, this process variant has the further advantage that the production of Cast resin transformers are not tied to cycle times within which the Metal molds must be made available again for a new casting. Because of this No time pressure, cast resin systems can be used for a very long time Curing times and therefore very low temperature peaks during curing exhibit. The cast resin moldings produced in this way are therefore largely free of internal tensions.
Eine weitere Vereinfachung des erfindungsgemäßen Verfahrens besteht darin, die verlorenen Formen aus Röhren auf Basis von Phenolharzen mit unterschiedlichen Durchmessern herzustellen., die an ihren Ober- und Unterseiten vakuumdicht abgedichtet werden. Die so hergestellten Formen können auch ohne aufwendige Vakuumkammer evakuiert und im Vakuumgießverfahren mit Gießharz gefüllt werden.A further simplification of the method according to the invention is that lost forms from tubes based on phenolic resins with different Manufacture diameters. That are vacuum-tight on their top and bottom sides be sealed. The molds produced in this way can also be produced without complex Vacuum chamber evacuated and filled with casting resin using the vacuum casting process.
Als Phenolharze für die erfindungsgemäß hergestellten Phenolharzschichten können alle handelsüblichen Kondensationsprodukte aus Aldehyden und phenolischen Produkten verwendet werden. Die brandtechnisch günstigsten Eigenschaften werden jedoch bei Verwendung von Phenol-Formaldehyd-Harzen erzielt. Eingesetzt werden sowohl alkalisch kondensierte Resole, die selbsthärtend sind, als auch sauer kondensierte Novolake, die in an sich bekannter Weise mit einem Härtungsmittel eingesetzt werden. Bevorzugte Härtungsmittel für Novolake sind Resole und/oder Hexamethylentetramin (Hexa). Da Novolak-Hexa-Gemische erst bei Temperaturen härten, die oberhalb der bei der Härtung der Gießharze auftretenden Temperaturspitzen liegen, werden derartige Systeme nur dann verwendet, wenn als Formen ausgehärtete Laminate oder Rohre eingesetzt werden. As phenolic resins for the phenolic resin layers produced according to the invention all commercially available condensation products from aldehydes and phenolic Products. The most favorable properties in terms of fire however achieved when using phenol-formaldehyde resins. Be used both alkaline condensed resoles, which are self-curing, and acidic condensed novolaks in a manner known per se with a hardening agent be used. Preferred curing agents for novolaks are resols and / or Hexamethylenetetramine (Hexa). Because novolak-hexa mixtures only at temperatures harden above those that occur during the hardening of the casting resins Temperature peaks are, such systems are only used when as Forms of hardened laminates or pipes can be used.
Durch Gießen von flüssigen Epoxidharz-Härter-Mischungen in eine Metallform und
anschließendes Aushärten bei erhöhter Temperatur werden Prüfstäbe hergestellt mit
den Abmessungen 100 x 15 x 10 mm. Diese Prüfstäbe werden gemäß UL 94 vertikal
eingespannt und 2 x 10 s lang beflämmt. Während dieser Beflammung wird die
Rauchgasdichte beobachtet. Danach wird die Nachbrennzeit ermittelt.
Eingesetzt wird in allen Versuchen das gleiche Epoxidharz-Härter-System
(Diglycidylether auf Basis Bisphenol A und Methyltetrahydrophthalsäureanhydrid).
Die einzelnen Varianten und die Ergebnisse sind in der folgenden Aufstellung
angegeben:By pouring liquid epoxy resin-hardener mixtures into a metal mold and then curing them at elevated temperatures, test rods with the dimensions 100 x 15 x 10 mm are produced. These test rods are clamped vertically in accordance with UL 94 and exposed to flame for 2 x 10 s. The smoke density is observed during this flame treatment. The afterburn time is then determined.
The same epoxy resin hardener system (diglycidyl ether based on bisphenol A and methyl tetrahydrophthalic anhydride) is used in all experiments. The individual variants and the results are given in the following list:
Claims (8)
- Method for producing cast-resin transformers by encapsulating the windings with an epoxy resin-based thermosetting resin mixture with or without fillers, characterized in that the outer faces or the entire surfaces of the cast-resin mouldings are provided with a reinforced or unreinforced phenolic resin layer.
- Method according to Claim 1, characterized in that the inner walls of the casting mould are provided completely or partially with a phenolic resin layer, this phenolic resin layer forming a new mould which is filled with the cast-resin mixture and which remains on the cast-resin moulding once the latter has been cured.
- Method according to Claims 1 and 2, characterized in that the phenolic resin layer located in the metallic mould is not completely cured yet, but is completely cured when the cast-resin moulding is cured.
- Method according to Claim 3, characterized in that the phenolic resin layer located in the metallic mould is a premoulded, phenolic resin-impregnated prepreg which corresponds to the outer form of the cast-resin moulding.
- Method according to Claims 1 and 2, characterized in that the phenolic resin layer is completely cured even before casting.
- Method according to Claim 5, characterized in that the phenolic resin layer located in the metallic mould is a premoulded, phenolic resin-containing laminate corresponding to the outer form of the cast-resin moulding.
- Method according to Claim 1, characterized in that the casting mould comprises a premoulded, phenolic resin-containing laminate and remains on the cast-resin moulding as a lost mould following the casting and curing process.
- Cast-resin transformer based on an epoxy resin-based thermosetting resin mixture with or without fillers, characterized in that its outer faces or its entire surfaces are provided with a reinforced or unreinforced phenolic resin layer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19758213A DE19758213A1 (en) | 1997-12-31 | 1997-12-31 | Process for the production of cast resin transformers |
| DE19758213 | 1997-12-31 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0928011A2 EP0928011A2 (en) | 1999-07-07 |
| EP0928011A3 EP0928011A3 (en) | 1999-12-08 |
| EP0928011B1 true EP0928011B1 (en) | 2004-08-11 |
Family
ID=7853573
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP98124700A Expired - Lifetime EP0928011B1 (en) | 1997-12-31 | 1998-12-25 | Process for producing transformers encapsulated in cast resin and transformer |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0928011B1 (en) |
| CN (1) | CN1230757A (en) |
| BR (1) | BR9805694A (en) |
| DE (2) | DE19758213A1 (en) |
| TW (1) | TW590867B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100310150B1 (en) | 1999-07-26 | 2001-09-29 | 윤종용 | Resin molding method for a coil used in a transformer of a microwave oven |
| CA2721358C (en) | 2008-04-14 | 2016-12-20 | Aker Engineering & Technology As | Rotary transformer |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1141405A (en) * | 1965-09-27 | 1969-01-29 | Matsushita Electric Ind Co Ltd | Insulating method for electrical machinery and apparatus |
| JPS5616514A (en) * | 1979-07-20 | 1981-02-17 | Matsushita Electric Works Ltd | Thermosetting resin varnish |
| JPS62132615A (en) * | 1985-12-06 | 1987-06-15 | Toho Shiitofureemu Kk | Manufacture of fire resistant panel based on composite metal source |
-
1997
- 1997-12-31 DE DE19758213A patent/DE19758213A1/en not_active Withdrawn
-
1998
- 1998-12-25 DE DE59811791T patent/DE59811791D1/en not_active Expired - Lifetime
- 1998-12-25 EP EP98124700A patent/EP0928011B1/en not_active Expired - Lifetime
- 1998-12-30 BR BR9805694-8A patent/BR9805694A/en not_active Application Discontinuation
- 1998-12-30 CN CN98111663A patent/CN1230757A/en active Pending
-
1999
- 1999-01-11 TW TW087121887A patent/TW590867B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| TW590867B (en) | 2004-06-11 |
| BR9805694A (en) | 2000-03-28 |
| DE19758213A1 (en) | 1999-07-01 |
| DE59811791D1 (en) | 2004-09-16 |
| EP0928011A2 (en) | 1999-07-07 |
| CN1230757A (en) | 1999-10-06 |
| EP0928011A3 (en) | 1999-12-08 |
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