Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Patent
1996-11-25
1998-12-22
Aftergut, Jeff H.
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
156295, 310204, 310214, 310215, H02K 348, H02K 340
Patent
active
058513400
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for fastening conductive bars, in particular, high-voltage windings used in electrical equipment, in the slots of the bundles of laminations, preferably provided with core ducts. The conductive bars are glued with an electro-conductive cross-linked polymer, while the polymer, which is not cross-linked, is laid into the slot in the form of soft material, the conductive bar is imbedded into the polymer which is not cross-linked, the polymer is supplemented at the bar side pointing towards the slot opening, and the conductive bar is fixed until the polymer is cross-linked.
2. Background of the Invention and Related Art
A similar process is known from AT-PS 386,705. In practice, it has been proven that this process guarantees an effective method of fastening conductive bars. It has, however, a certain disadvantage in that the polymer material flows into the core ducts as a result of introducing an uncontrolled polymer material. A reduction of the cooling cross-section is the consequence, which may result in unacceptable heat build-up.
For the sake of order, however, it must be pointed out that this method of fastening does not replace a corona grading. As is generally known, an effective corona grading presupposes that the protective sleeve at the surface is completely wetted. Otherwise, partial discharges would occur in fault positions. To prevent this, the corona grading layer, for example, a silicone rubber, must be applied without gaps together with a carrier material during production prior to inserting the bar into the sleeve.
The aforementioned fastening method of the conductive bar cannot replace the corona grading by any means due to the characteristics of the method of fastening.
A corona grading configuration is also known from DE-PS 1164562 in which a rather costly imbedding of the conductive bar into a rigid filling material between two separating foils is used as a method of fastening. This enables the bar to perform a sliding motion in the axial direction.
SUMMARY OF THE INVENTION
Further, a device is know from U.S. Pat. No. 4,068,691, by means of which, with the winding being inserted, an elastomer may be introduced to the core duct. The wetting of the elastomer takes place laterally between the top of the bar and the slot wall. This form of attachment may result in loosening in the wedge area.
In view of the foregoing, it is an object of the present invention to provide a process of the aforementioned type by means of which the winding is fastened permanently and securely or to prevent said winding from dropping when used in vertically mounted machines.
The inventive process is characterized by the fact that an electro-conductive elastomer is used as polymer, and that the elastomer is introduced approximately in the middle of the partial bundle of laminations at the bottom of the slot and/or on the top of the bar and/or on the intermediate piece, while the elastomer is distributed by pressing in the conductive bar and/or the intermediate bar and/or, if necessary, the slot wedge, so that a predominantly enclosed elastomer layer is produced at the bottom of the slot or at the parallel surface of the bottom of the slot, and the elastomer layer expands at the slot flanks.
It thus becomes possible for the first time to glue the winding to the bundle of laminations in an elastic and stress-free manner. Further, an improved heat dissipation--compared with the conventional wedging out method--from the conductive bar to the bundle of laminations is provided.
The main advantage, however, is that the dosed introduction of elastomer does not reduce the core ducts nor their cross-section.
Exact dosages can be determined mathematically. However, results were also recorded by applying the empirical method to a sampling. There was no indication of elastomer penetrating the core duct.
For the sake of order, the inventive process steps are listed:
The elastomer is introduced into the slot by means of a dosing device wh
REFERENCES:
patent: 3444407 (1969-05-01), Yates et al.
patent: 4068691 (1978-01-01), Lonseth et al.
patent: 4095627 (1978-06-01), Lonseth et al.
patent: 4110900 (1978-09-01), Lonseth et al.
patent: 4112041 (1978-09-01), Lonseth et al.
patent: 4369389 (1983-01-01), Lambrecht
Muller Franz
Mussbacher Gunther
Aftergut Jeff H.
Elin Energieversorgung GmbH
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