JPH04282512A - Superconducting conductor - Google Patents

Abstract

PURPOSE:To provide a superconducting conductor capable of manufacturing a superconducting coil by improving cooling performance, facilitating coil molding with no habit of the conductor, and easily removing and connecting an insulation coating further providing small connecting space. CONSTITUTION:In the case of a superconducting conductor of strand wire structure winding a superconducting element wire 2 to the peripheral surface of a center core 1, irregularity is provided in the peripheral surfaces of the center core 1 and the superconducting element wire 2, so that a superconducting coil can be manufactured by improving cooling performance of the coil, facilitating coil molding with no habit of the conductor, further facilitating connection work without giving damage to the superconducting conductor and decreasing connecting space.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stranded superconducting conductor used as an electrical conductor.

0002

2. Description of the Related Art When a superconducting wire is subjected to a fluctuating magnetic field, it generates heat due to so-called alternating current loss. AC losses can be broadly classified into 1) hysteresis loss that occurs in the superconducting filament, 2) overcurrent loss that occurs in the stabilizing material, and 3) coupling loss that occurs between the superconducting wire and the stabilizing material. . Of these, the first hysteresis loss can be reduced by making the diameter of the superconducting filament thinner. When comparing the amounts of the second overcurrent loss and the third coupling loss, the coupling loss is generally larger. When the coupling loss is P(W) and the twist pitch of the superconducting wire is IP, there is a relationship of P(W)=IP 2 . Therefore, it is desirable to configure the conductor so that the twist pitch is small. On the other hand, there is a limit to the twist pitch due to the manufacturing of the wire. If the wire diameter is D, then 1
The limit is 0D to 20D. Therefore, for conductors with a large current capacity, many wires with a small diameter are used to create a twisted wire structure.

FIGS. 2 and 3 show a cross-sectional view and a perspective view of a typical conventional superconducting conductor having a stranded wire structure. In the figure, a central core 1 is formed of a reinforcing material such as stainless steel or superconducting wire, and superconducting strands 2 are twisted and wound around the outer peripheral surface of this central core 1. An insulating coating 3 is applied to the outer peripheral surfaces of the central core 1 and the superconducting strands 2 in order to reduce the aforementioned coupling loss. Such a structure is effective when the current capacity is relatively small or when the coupling loss is relatively small, but when the current capacity is further increased or the coupling loss is further reduced, the structure shown in Fig. 2
It is also conceivable to collect a plurality of twisted wire structure conductors shown in FIG. 3 to form a further twisted wire structure.

0004

[Problem to be Solved by the Invention] However, in a superconducting conductor having such a structure, since the superconductor constituting the strands has high rigidity, the twisting direction during processing of the strands is distorted.
Springback is large, making it difficult to form conductors when manufacturing coils. Furthermore, when manufacturing a coil, connections between superconducting conductors and current leads, or between superconducting conductors, always occur. Soldering is a common method for connecting such superconducting conductors. In order to connect by soldering, it is necessary to remove the insulation coating applied to the superconducting wire, and if the core is made of superconducting wire, the insulation coating of the core must also be removed. Dissolve and remove the insulation coating using a coating removal agent. However, even if the stranded wire is immersed in an insulation coating removal solution, it is difficult to remove the insulation coating of the surrounding core, and some of the insulation coating remains unremoved. It was necessary to immerse it in an insulation coating removal solution.

However, it is difficult to untwist a twisted wire conductor or a conductor formed into a rectangular shape once the wires are untwisted, and the volume of the connection part of a superconducting conductor after removing the insulation coating and applying soldering is This makes it difficult to manufacture superconducting coils with small connection spaces. Moreover,
Untwisting or untwisting the wires not only reduces work efficiency, but also may cause damage to the superconducting conductor, such as filament breakage within the superconducting conductor.

The present invention has been made in view of the above circumstances, and its objects are to provide good cooling performance, to make it easy to form a coil without forming a conductor, to make it easy to remove the insulation coating and to make connections, and to save space for connections. The object of the present invention is to provide a superconducting conductor with which a small superconducting coil can be manufactured. [Structure of the invention]

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a superconducting conductor having a stranded wire structure in which superconducting wires are wound around the outer peripheral surface of the central core. It is characterized by providing unevenness on the outer peripheral surface.

[0008]

[Function] According to the superconducting conductor of the present invention, its cooling performance is good, the conductor does not have any curls, it is easy to form a coil, and the insulation coating can be easily removed, making connection work easy. Furthermore, it is possible to provide a superconducting coil with a small connection space without damaging the superconducting conductor.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of one embodiment of the present invention. As shown in the figure, a central core 1 is formed of a reinforcing material such as stainless steel or superconducting wire, and superconducting wires 2 with several grooves 4 provided on the outer surface of the central core 1 are twisted and wound. It's being passed around.

[0011] In the superconducting conductor having such a structure, the surface area of the conductor is increased by the grooves 4 on the outer surface, and the cooling performance is improved. Furthermore, the grooves 4 on the outer circumferential surface release the curls of the strands, eliminating the springback of the conductor, making it easier to form a coil, and reducing the possibility of damaging the superconducting conductor. Also, when connecting superconducting conductors by soldering,
It is only necessary to remove the insulation coating 3 applied to the superconducting wire 2, and even without removing the insulation coating of the core 1, the solder enters the portion of the groove of the core 1 that is not covered by the coating, and the electrical connection is established. It is not necessary to remove the insulation to ensure that the Therefore, when dissolving and removing the insulation coating with a liquid insulation coating removal agent, there is no need to remove the insulation coating of the surrounding core, so the stranded wire can be immersed in the insulation coating removal solution and the insulation coating removed. It becomes possible to find a way to remove this. In addition, since there is no need to untwist the wires and immerse them in insulation removal solution, superconducting This is advantageous when removing the insulation coating of a conductor. Furthermore, since the shape of the soldered end of the superconducting conductor does not change much, the volume of the connection part of the superconducting conductor does not increase, making it possible to manufacture a superconducting coil with a small connection space. Furthermore, since it is not necessary to untwist or untwist the wires, workability is improved and damage to the superconducting conductor is reduced. Furthermore, as the solder gets into the groove,
This allows for a stronger connection. Therefore, it is advantageous when used in coils that are subjected to large electromagnetic forces or coils used in centrifugal force fields such as field coils of superconducting generators.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, but can be implemented with various modifications, such as replacing the grooves with other uneven shapes, without changing the gist thereof.

[0013]

As explained above, according to the superconducting conductor of the present invention, the cooling performance of the superconducting conductor is good, the conductor does not have any peculiarities, making it easy to form coils, and furthermore, the insulation coating can be easily removed, so that connections can be made easily. This method has excellent effects in that it is easy to work with, and superconducting coils can be manufactured with a small connection space.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional stranded wire structure superconducting conductor.

FIG. 3 is a perspective view of a conventional stranded wire structure superconducting conductor.

[Explanation of symbols]

1...Core, 2...Superconducting wire, 3...Insulating coating, 4...Groove.

Claims (1)

[Claims] 1. A superconducting conductor having a stranded wire structure in which superconducting strands are wound around the outer circumferential surface of a central core, characterized in that irregularities are provided on the outer circumferential surface of the central core and the outer circumferential surface of the superconducting strands.