DE1956307A1 - Process for making connections between stabilized superconductors - Google Patents

Description

Maschinenfabrik Oerlikon, Zurich-Oerlikon (Switzerland)

Process for making connections between stabilized n

Superconductors.

The present invention relates to a method for Establishing connections between stabilized superconductors and the connections themselves made using this process »

Stabilized superconductors already belong to the state of the art, which consist of superconducting wires which are plated with a normally conductive material, preferably copper or aluminum or embedded therein by means of cold deformation. Today's technical facilities limit the length of stabilized Superconductors depending on the weight per unit length of 50 to 300 m. However, since superconducting windings are often considerable are longer (2000 m and more) it is necessary to be superconducting. Putting pieces together. This occurs both electrical and mechanical problems. For example, the contact resistance of the connection points between the superconductors must be of the order of magnitude of 10 Ω. In addition, tensile forces of approx. J5000 kp to record. In the case of larger contact resistances, local Warming occurs, which would result in an increased consumption of the expensive coolant. If the mechanical strength is too low the winding could not withstand the electromagnetic forces occurring during operation. It should also be noted that the Manufacture of the connection points between the superconductors these

ObJ. 52921

00 9832/1274

must not be heated above 450 C, otherwise the critical one Current, above which the superconducting properties are lost, sinks.

It is the object of the invention, between stabilized superconductors Establish connections which meet the aforementioned requirements in both electrical and mechanical terms.

The solution to this problem is that the to be connected Graduated ends of the superconductors, which are made oxide-free in the longitudinal direction of the ladder / running step surfaces, which are transverse to the longitudinal direction The stepped surfaces lying on the superconductor are etched, the stepped ends mechanically overlapping with one another connected and the column of the connection points are electron beam welded.

The connections obtained in this way are characterized by high mechanical strength and very low contact resistances the end.

In the drawing, exemplary embodiments of the subject matter of the invention are shown in simplified form.

It shows

1 shows the ends of two superconductors to be connected to one another, FIG. 2 shows the overlap of two stepped conductor ends, FIG. 5 shows a finished connection.

In Fig. 1, 1 denotes the end of a first, and I ¹ denotes the end of a second stabilized superconductor. Superconducting wires 3.3 'are embedded in the copper 2.2 *. In order to connect the superconductors to one another, first in a predetermined

3292X 009832/1274

■ - 3 -

Distance from the ends 1.1 'slots 4.4' attached, which are about Extend over half the width of the ladder. After that the hatched Parts removed, for example by milling.

According to Fig. 2 are the stepped ends of the two superconductors arranged overlapped. First are those running in the longitudinal direction To free step surfaces from oxides. This can be done mechanically, chemically or by ultrasound. Farther the step surfaces lying transversely to the longitudinal direction are etched, e.g. with hydrofluoric acid, so that the superconducting wires are at the points 5.5 'removed. Finally, additional, superconducting Deposits 6, for example made of niobium-tin, may be provided.

According to Fig.] 5, rivets 7 * are used in corresponding openings are used for the mechanical connection of the superconductors. With knowledge of the electromagnetic forces to be expected, Easily determine the number of rivets required, and this in turn determines the length of the gradation. Electron beam welds 8 close the remaining gaps. The already described etching out of the superconductors is used to create a to avoid poorly conductive alloy, which would otherwise be produced during welding. The gaps in the length of the ladder are also closed by electron beam welding in order to keep the connection point free of oxides and water.

009832/12 7.4

Claims (1)

Claim ^ '' ° ■ ^D ° ^u / Process for the production of connections between stable superconductors, characterized in that the ends (1, 1 ^f ) of the superconductors (2, 3; 2 ', 3 ^f ) to be connected, which extend in the longitudinal direction of the conductors (2, 3 ; 2 ', 3') are made oxide-free, the step surfaces lying transversely to the longitudinal direction of the superconductors (2 ^{, 3; 2 f} , y) are etched and the stepped ends are mechanically connected to one another in an overlapping arrangement. Jbi: Method according to claim X, characterized in that slots (4, V) are first made at a predetermined distance from the conductor ends (1, I ¹ ) and the conductor material is removed according to the slot depth up to the conductor ends (l, l ^f) will. ^ 1
ή. Method according to claim -ί-, characterized in that the step surfaces of the superconductors (2, 3; 2 ', 3 ^f ) running in the longitudinal direction are freed of oxide layers mechanically, chemically or by means of ultrasound. ■. ■ 1 ■ ■ 'The method according to claim J., characterized in that the ^{step surfaces lying transversely to the longitudinal direction of the superconductors (2, 3; 2 f} , 2') are etched with hydrofluoric acid. Method according to claim i ^ characterized in that the stepped ends of the superconductors (2,3 * 2 ', 3') overlapped and be connected to each other by rivets. 009832/127 4 O- ♦ Connections between stabilized superconductors established according to the method according to claim £ ·, C connections according to patent claim ü-, characterized in that superconducting inserts (6) are arranged between the step surfaces of the superconductors (2, 3j2 ^{f 3 ') running in the longitudinal direction.} MACHINE FACTORY OERLIKOU & μ + α * K / V 0Q9832 / 127 Blank page