Inductor devices – With supporting and/or spacing means between coil and core – Coil clamps or wedges
Patent
1992-12-23
1994-07-05
Kozma, Thomas J.
Inductor devices
With supporting and/or spacing means between coil and core
Coil clamps or wedges
296021, H01F 2730
Patent
active
053271130
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a transformer, in particular a substation transformer, having a compression beam and a winding compression ring closing off the winding, where expanding spring elements disposed concentrically around the winding core are disposed between the compression beam and the winding compression ring, where the compression beam has a support surface extending horizontally in respect to its axis of symmetry which is provided with a bore on the side facing the winding compression ring and has a further support surface or a shoulder on its upper end, and where each spring element consists of a bushing which receives the spring and is closed off with a compression piston which limits the spring path.
The windings of transformers are greatly stressed mechanically during operation, particularly when short-circuits appear. A loosening of the coils can occur because of dynamic short-circuit forces, which inevitably results in the destruction of the transformer.
This fact is already taken into consideration during calculation, design and construction. Besides technical and technological steps during production, the windings are subjected to large pre-compression loads by the producer of the transformer.
The support of the winding is customarily provided by means of rigid elements, such as layered wood pieces or the like, disposed between the compression beam and the winding compression ring.
These measures are not sufficient in the case of transformers which are particularly stressed by frequent short-circuits, such as transformers in the catenary network of railroad companies, so-called substation transformers.
A winding compression for transformers and inductance coils having an expanding spring of the previously mentioned type is known from U.S. Pat. No. 3,772,627.
Furthermore, a transformer is known from DE-OS 22 60 399 where disk springs are employed in its compression construction. The
The retroactive compression of the windings of transformers which do not have such known spring elements is extremely costly.
It is therefore the object of the invention to produce a transformer of the previously described type where a retroactive winding compression is possible and where therefore loosening of the winding by dynamic short-circuit forces is prevented.
The transformer in accordance with the invention is distinguished in that for the post-installation of the spring elements provided with disk springs the winding can be precompressed by means of hydraulic cylinders which can be inserted between the compression beam and the winding compression ring and that the bore has a support ring or a threaded bore for adjustment screws, where the adjustment screws act on the compression piston of the insertable pre-stressed spring elements and the bushing of the spring elements has a stop for the compression piston holding the pre-stressed disk springs, which can also be removed after removal of the hydraulic cylinders.
With this invention it is possible for the first time to perform post-installation as well as simple regulation of the tension. In addition, controlled compression is possible by means of the invention. A defined compression can also be provided in the course of inspection.
During post-installation of the invention the spring assembly is pre-stressed and inserted while being pre-stressed. It is therefore possible to attain the pre-defined compression on the winding by means of the adjustment screws.
If the hydraulic cylinder is to be installed at the same time, it is then possible, for example by means of a connection to the outside, to regulate the tension at any time. The winding compression required for the operational reliability of the transformer must be maintained over the remainder of service life of the transformer.
In accordance with a further particular characteristic of the invention at least one adjusting screw seated in the compression beam is provided, which acts on the compression piston. By means of this the possible compression regulation of the winding becomes possible without
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patent: 4009461 (1977-02-01), Usry
patent: 4464644 (1984-08-01), Fukatsu
patent: 4631509 (1986-12-01), Arii
patent: 4754250 (1988-06-01), Duin
Elin Energieversorgung GmbH
Kozma Thomas J.
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