Electricity: circuit makers and breakers – Multiple circuit control – Pivoted contact
Patent
1994-09-27
1996-05-14
Scott, J. R.
Electricity: circuit makers and breakers
Multiple circuit control
Pivoted contact
323340, 323341, 336150, H01F 2904, H01H 1508, H01H 1954, H01H 2162
Patent
active
055169929
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application is the U.S. national phase of PCT application PCT/EP93/01114 filed 6 May 1993 with a claim to the priorities of German applications P 42 16 034.0 filed 15 May 1992 and P 42 37 242.9 filed 4 Nov. 1992.
FIELD OF THE INVENTION
The present invention relates to a step switch of the type connectable with a single- or polyphase step transformer where the taps of the step winding are externally accessible. Such a step switch is particularly usable with cast-resin transformers.
BACKGROUND OF THE INVENTION
Cast-resin transformers of the described type are for example known from the product literature "Technische Information Giessharz-Transformatoren" of Starkstrom-Geratebau GmbH of Regensburg (1985). Such dry transformers are increasingly popular, in particular in the region up to about 600A due to their simpler construction and not the least because of the environmental advantage with respect to clophene- or oil-insulated transformers.
With these transformers the connector conductors and with them the taps of an existing step winding lead to connector tabs on the output coil rails or directly on the core sleeve of the cast-resin winding and there are connected by connection lines with the step switch.
German patent 3,630,415 describes using a conventional oil-filled step switch which is mounted on a support laterally adjacent the transformer and which is connected electrically by connection lines.
Swiss patent 391,088 further describes an arrangement where the connections are extended out of the transformer to contacts which are arranged like a collar around the periphery of a cylindrical housing in which the step switch is recessed so that same is connectable by respective contacts on the outside of the step-switch housing electrically with the collar of contacts and therethrough with the transformer.
Another built-on step switch of the load-selector type for oil transformers is known from German published application 2,712,484 which has a grid that fixes and guides the connection lines between the step contacts and the respective transformer.
Finally a cast-resin transformer is known from Japanese utility model Sho-62-10,973 wherein the connections of the step winding are extended to a cast-in-place contact plate whence they are extended by electrical connector lines to a step switch.
All these known arrangement have substantial disadvantages.
First in every case there are a plurality of electrical connections on the step switch with the respective taps of the transformer by means of numerous electrical lines. This is expensive, requires special means for mechanically fixing these conductors and for avoiding electrical interaction, and does not in addition allow for a change of connectors for example during assembly or repair. It is further disadvantageous that the adjacent step switch must be fixed near the transformer by means of special holders, traverses, struts, or the like that are not normally provided on or needed by the transformer. This means further that the respective step switch must not only be matched in every case to the electrical characteristics of the transformer, its number of steps, and so on, but also to the respective mechanical and constructive circumstances, such as size, type, style, and position of the electrical connections and of the mechanical mounting means and so on.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a built-on step switch which is simply electrically connected to and mechanically mounted on step transformers, in particular on cast-resin insulated step transformers of different types and construction.
SUMMARY OF THE INVENTION
A cast-resin transformer has a transformer housing, a plurality of windings each having a plurality of taps, respective contacts connected to the taps and mounted on the housing in respective arrays which are all identical, and respective identical mounting elements on the housing at each of the contact arrays. Respective identical step switches each serve
REFERENCES:
patent: 1985927 (1935-01-01), Jansen
patent: 2036305 (1936-04-01), Snyder
patent: 3177307 (1965-04-01), Weber et al.
patent: 3192328 (1965-06-01), Wilson, Jr.
patent: 3581188 (1971-05-01), Watanabe
patent: 3628128 (1971-12-01), Buhler
patent: 4504811 (1985-03-01), Stunzi
patent: 4562316 (1985-12-01), Kranich, II
patent: 4644112 (1987-02-01), Kranich, II
"Ofentransformatoren zum Speisen von Lichtbogenofen mit Ofenschalter im Zwischenkreis" by R. Brehler, published in Siemens Periodical 50 (1976), vol. 1, pp. 9-17.
Dohnal Dieter
Neumeyer Josef
Dubno Herbert
Maschinenfabrik Reinhausen GmbH
Scott J. R.
Wilford Andrew
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