DE3032399A1 - SUPRAL-CONDUCTING - Google Patents

Abstract

1. Method for manufacturing a superconductive winding in which several thousand fibres, which are provided with a superconductive layer and with a highly conductive metal layer, are combined to form a bundle and this bundle is surrounded by an insulation layer, characterised in that the bundle is saturated in synthetic material, wound in a former (5, 6, 7) into a coil (1) and the synthetic material is hardened in this former.

Description

BROWN, BOVERI & CIE AKTIENGESELLSCHAFT

Mannheim Aug 26, 1980

Mp.no. 60 ^ / 80 ZFK / P2-Sz / Br

Superconducting Windings The invention relates to superconducting windings.

It is known to produce coils from superconducting wires. The superconducting wires consist of superconducting ones Filaments from bsw. NbTi or Nb-Sn, which are in a matrix of highly conductive material, bsw. Copper or aluminum are embedded. The wires are made using metallurgical processes. Here is a good intermetallic Connection between the superconducting filaments and the matrix material for the functionality of the superconducting wire is crucial.

Up to a current strength given by the current carrying capacity of the superconductor, the coils can consist of individual superconducting Wires are wound. For higher currents

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. 602/80 - ^ - 08/26/1980

several wires are combined into ropes and connected to one common insulation layer surrounded. These ropes are wound into reels and have to be used in order to ensure functional reliability Such coils ensure that the ropes are carefully layered next to one another and voids are avoided. The superconducting wires or ropes as well as the insulation are in their position by impregnation with Har2 fixed.

The metallurgical manufacturing processes for superconducting wires are very complex, especially for Nb_Sn superconductors. In the case of the latter, a diffusion annealing must be carried out at BSW to form the superconducting material. 700 ^e C for approx. 60 hours. If this annealing is carried out before the winding process, there is a risk of damage to the very brittle Nb ₃ Sn ~ material during winding, which can only be checked on the finished coil. If the annealing is carried out after the winding process, the entire coil including the insulation must be annealed, which places special demands on the insulation and the structural and contacting materials used in terms of temperature resistance.

It is the object of the invention to produce superconducting coils and windings to avoid the disadvantages of using filament ladders to manufacture.

According to the invention, this object is achieved in that the superconducting windings made of fiber conductors, which from with a finer superconducting layer are made of fibers.

It is already known to use carbon fibers with a thin Schi ch i; a niobium compound of the general formula NbC N " around. to provide an outer, highly conductive metal layer.

602/80 - / ί - 08/26/1980

Such superconducting niobium carbonitrite layers can be produced continuously, for example. Metallic niobium can be deposited on the carbon fibers (carbon filaments) from vaporous niobium chloride in a hydrogen atmosphere at about 600 ^{° C.} This metallic niobium is then converted into the superconducting niobium carbonitrite compound in an ammonia and methane atmosphere at about 1000 ^° C. (DE-AS 28 56 885).

So far, superconductors have been used as filament conductors in wire form and known as the Paserleiter. In the following, the term "filaments" is used for those firmly embedded in a metallic matrix superconducting threads from bsw. NbTi or Nb., Sn is used and the term "fibers" applies to non-braided and unbonded threads of any material, e.g., C-fibers, boron fibers, steel fibers.

It is particularly useful to produce a winding according to the invention so that several thousand with one superconducting layer and provided with a highly conductive metal layer and with a conductive metal layer Fibers are combined into a bundle, and that this bundle surrounded with an insulating layer and that this bundle is soaked in plastic, in a shape to a Coil is wound and the plastic is cured in this form. After hardening, the winding is so stable, that the mold can be removed and a bobbin is not required. Because the claimed for the bobbin If space for turns is available, in addition to saving material, the space available is better exploited. The insulation layer surrounding each bundle can bsw. wrapping with foil or wrapping or braiding of glass fibers.

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Before the plastic hardens, the winding is pressed into the mold. By suitable coordination of the plastic content and pressing force can, according to further features of the invention, e.g. for direct current coils, a good contact of Fiber to fiber of a bundle is achieved and thus the transverse resistance can be reduced, while for pulsed magnetic coils a higher transverse resistance between the individual fibers due to a higher proportion of plastic and / or a less pressing force is achieved, so that current displacement effects are considerably reduced.

It is also useful if the fiber material is placed on the already existing carrier body (e.g. generator shaft) is matched so that the thermal shrinkage behavior the superconducting winding is adapted to the thermal shrinkage behavior of the carrier body.

According to a further feature of the invention, cooling tubes can be integrated into the fiber conductor winding at any point will. The mechanical strength is not influenced by these cooling tubes.

Fig. 1 shows an embodiment of the invention Coil, while in Fig. 2 the winding form is shown, which is only used for the production of the winding and can be divided appropriately. The winding form consists of the core 5 and the two side parts or end plates 6 and 7. The outer diameter of the core 5 corresponds to the inner diameter Di of the coil. The diameter of the end caps 6 and 7 - must be larger than the outer diameter Da of the coil. As can be seen from Fig. 2, a with insulation provided bundle 8, which consists of several fibers and is impregnated with plastic, on the core 5 of the Coil shape wound on which several turns 9 have already been applied became. The cooling tubes 2 shown in FIG. 1

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. after the first layer has been applied, bundles can be rolled up or pushed on. The bundle 8 can then be wound further into the coil shape until the required number of turns is reached. At the ends 3 and 4 of the cooling tube 2, when the coil is in operation, a cooling medium can be supplied or removed. The length of the coil is indicated by L ₄ The coil part 1 consists of the fiber conductors and the plastic with which the bundle was soaked and which is cured after winding the coil, so that the core 5 and the end disks 6 and 7 of the winding form are removed körtneh.

Since the space otherwise required for the coil body can be fully wound, the coil according to the invention a larger number of turns can be accommodated in a certain space. Before hardening, a suitable Pressing tool, the winding is pressed into the desired shape, through a suitable choice of pressing force and plastic content the coil can be adapted to the desired operating conditions. When using DC coils is a strong compression and / or a smaller proportion of plastic is useful to get a Strands to achieve good contact, so that there is a low cross resistance. With pulsed magnet coils on the other hand, it is more appropriate to compress the coil less with a larger proportion of plastic, as this results in it the current displacement effect is favorably influenced when the current rises sharply.

It is useful to adapt the thermal dilation of the winding to that of a carrier body. If e.g. If a generator shaft is made of steel, it will pull itself down to the operating temperature when it cools down from room temperature of 4.5 ° K together. To adapt the winding to this shrinkage of the generator shaft, it is useful to as the fiber base material for such a winding steel or another material with similar thermal dilation to use.

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Claims (8)

Mp.no. 602/80 Aug 26, 1980 ZFE / P2-Sz / Br Expectations Superconducting windings, characterized in that they are made from fiber conductors which consist of fibers provided with a superconducting layer. 2. Superconducting winding according to claim 1, characterized in that several thousand with a superconducting Layer and with a highly conductive metal layer arrange fibers to be combined into a bundle (8) and that this bundle is surrounded by an insulating layer, and that this bundle is soaked in plastic, in one Form (5, 6, 7) wound into a coil (1) and the plastic is cured in this form. 3. Superconducting winding according to claim 2, characterized in that the insulation layer consists of a wrapping with foil or wrapping or braiding with glass fibers. 4. Superconducting winding according to claim 2, characterized in that the winding (1) before curing in the coil shape is pressed. 5. Superconducting winding according to claim 2 for a direct current coil, characterized in that the plastic portion and the pressing force are matched to one another in such a way that there is good fiber conductor to fiber conductor contact within the fiber conductor strand (low transverse resistance).
35 Original . 602/80 - 2 - August 26, 1980 6. Superconducting winding according to claim 2 for pulsed magnetic coils, characterized in that the plastic component and the pressing force are matched to one another in such a way that a high transverse resistance between the fiber conductors of a Line is present (avoidance of a current displacement effect) . 7. Superconducting winding according to claim 2, characterized in that one or more cooling tubes (2) with the Fiber conductor strand (8) are wound into the coil form (5, 6, 7). 8. superconductive winding according to one or more of claims 1 to 7, characterized in that at one given carrier body (e.g. generator shaft) a fiber material is used whose thermal shrinkage behavior and thus the shrinkage behavior of the superconducting winding is adapted to the shrinkage behavior of the carrier body.