SE436949B - KIT FOR MANUFACTURING TENSIONS FOR ELECTRICAL INDUCTION DEVICES - Google Patents

Description

7908081-8 2 Furthermore, it can be read from the text that the straps are produced of fibrous materials impregnated with polymerizable plastic.

In this case, the straps before their assembly are either complete. polymerized or used in non-polymerized stand. The straps are manufactured as endless loops and can be prepared, in that several layers of one with non-polymeric serrated soaked fiberglass strips are wound over each other with tension on a drum. The tension of the straps must be maintained by gluing the superimposed layers in different points. The straps retain sufficient flexibility for can be applied to the winding and tightened between the corresponding shoulders. The polymerization of the loops then takes place after application. the winding under tension. Furthermore, however the loops are completely polymerized before application, i giving them their final form. According to the above writing, there is also the possibility of clamping the winding with non-prefabricated tapes. For this purpose, the winding an initial longitudinal pressing, until it has reached the required league had to. Thereafter, the tapes are wound directly into several other subsequent layers, e.g. around the entire winding block.

After this operation, the ends of the straps are fastened, preferably by gluing on the neighboring layer, and afterwards the it under the required conditions. By means of additives tensioning devices, the belt tension can be regulated. Generally however, prefabricated, fully polymerized are preferred straps, which must be obtained before application to the winding its final form. (DD patent 198 388). These can tested electrically and mechanically before insertion. At the known straps, it is inconvenient that they often have an air inner ~ conclusions and are therefore unusable due to its inadequacy insured electrical strength. A further shortcoming states that they are prefabricated, completely polymerized the straps due to internal stresses after removal the mold or out of the clamping device throws itself and thus often only with difficulty can be built. As before, also gives the risk of strap tears.

The object of the invention is to provide a method 7908081-s 3 for the production of straps made of hardenable plastic soaked insulating material strips or wires, in particular fiberglass strips, which are repeatedly applied to each other, which allows timely utilize the strength of the insulating material as well as that achieve a higher electrical strength by avoiding air inclusions and improved dimensional stability of straps. This object is solved according to the invention by that those of the plastic-soaked, repeatedly applied to each other the insulating material strips or wires formed, still with holes room straps are soaked with insulating liquid under vacuum and then tightened and while maintaining the tensile curing in the insulating liquid bath at elevated temperature.

Preferably, the straps are twisted around themselves before soaking with insulating liquid. Furthermore, it is advantageous to perform the one like endless, elongated loops with two on definite spaced strands.

By means of an exemplary embodiment, the invention will be explained. race closer. The straps are made of a pre-impregnated fiberglass strips with mainly longitudinal fibers. The poly- merisable resin to be used for the impregnation, should have such a consistency at room temperature that it the impregnated fiberglass strip has the necessary flexibility for processing. Of the impregnated fiberglass strip multilayer loops are now attached and the ends are glued to neighboring the layers. The relatively loosely wound loops are then twisted several times about themselves, in that e.g. a point on the loop is held and the rotation takes place approximately on the opposite side of the point, so that the loops become so twisted that approx at 1 m loop length, 3-5 winding turns fall. Then of fiberglass- the belt shall be made elongated loops with two on the tuned spaced strands, are arranged advantageously both the mentioned points on the turning points.

The still loose fiberglass strip in the then state, whose stock is not yet fully glued together with second and partly form cavities, occupy in the following

Claims (4)

7908081-8 4 insulating liquid bath, e.g. an elongate vessel filled with transformer oil, liquid under vacuum. While remaining in the bath, the strap is tensioned, the tensioning elements attacking the turning points of the elongate loop. Because the glass fibers are helically rotated, the strip solidifies through the acting clamping forces. While maintaining the tensile stress, the loops in the insulating liquid bath are cured under elevated temperature. The elongated loops with now rod-shaped shape produced by this procedure are characterized by a very high electrical strength, when voids are excluded, and thus satisfy the highest requirements in the transformer technology. Furthermore, the helical rotation of the glass fibers in the load condition provides a more uniform clamping force distribution over the cross section of the belt, so that the dimensional stability and load-bearing capacity increase and the risk of a clamping strip tear in the built-in condition is avoided. For straps, which are exposed e.g. for minor electrical stresses, there is also the possibility of manufacturing them without soaking with insulating liquid. The wound loops are then tensioned immediately after rotation and are finally cured at elevated temperature while maintaining the tensile stress. Patent claims Methods for the production of clamping baths for electric induction devices of insulating material strips or wires soaked in hardenable plastic, in particular glass fiber strips, which are repeatedly applied to one another, characterized in that the insulating material strips of the plastic soaked The strips formed by the wires or wires are soaked with insulating liquid under vacuum and then tensioned and, while maintaining the tensile stress, finally cures in the insulating liquid bath at elevated temperature. 2. Methods for the production of clamping baths for electric inductors of insulating material strips or wires soaked in hardenable plastic, in particular fiberglass strips, which are repeatedly applied to each other, characterized in that those of the plastic-soaked insulating strips The formed strips of insulating material or threads are superimposed on each other and then tensioned and, while maintaining the tensile stress, shrink at elevated temperature. 3. A method according to claim 1, characterized in that the strips are rotated about themselves before the soaking with insulating liquid. 4. A method according to claims 1 and 2, characterized in that the straps are designed as endless, elongated loops with two sub-strands extending at fixed distances from each other.