JP3033669B2 - Superconducting cable and superconducting coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting cable used for a superconducting magnet or the like and a superconducting coil formed by winding these cables.

[0002]

2. Description of the Related Art A superconducting coil formed of a superconducting conductor has been increasingly used in accelerators for elementary particle experiments and various other measuring instruments in recent years. Also, the use of superconducting coils in experimental generators, bigger magnets, and the like is being studied. Usually, as a superconducting conductor, a collective conductor in the form of a stranded wire is used in addition to a monolithic conductor. Metal superconductors NbTi system such as superconductors, other compounds superconductor Nb ₃ Sn system, etc., Y system, there is a superconductor oxide of Bi system and the like, in particular an oxide superconducting wire or the like, processed In the case of a superconducting wire using a superconductor having poor properties, it is difficult to process the conductor into a stranded form as a collective conductor.

In order to assemble a superconducting coil, a method of winding a superconducting wire, which is a monolithic conductor, into a predetermined coil shape and a method of winding a superconducting twisted wire, which is a collective conductor, are usually employed. As the insulator, for example, an insulating tape or the like containing a semi-cured resin is used, wound around the periphery of a monolithic conductor or a superconducting twisted wire, wound in a coil shape, and then molded, heated and cured in many cases. This method mainly uses Nb
It is applied when assembling a coil with a metal superconducting wire such as Ti. In the case of a compound superconducting wire such as Nb ₃ Sn, the compound is brittle, so that a heat treatment for generating the compound is usually performed after assembling into a coil shape. Since this heat treatment is performed at a high temperature of about 600 ° C. or more, when assembling a coil with a compound superconducting wire such as Nb ₃ Sn, use an insulating material such as glass cloth instead of the above-mentioned insulating tape, and wind the coil. In many cases, the superconducting coil is impregnated with a semi-cured resin, molded, heated and cured. In any case, the reason for generating and heating to cure the semi-cured resin is to maintain the shape of the assembled superconducting coil, improve the line space factor of the superconducting wire, and further suppress the wire movement of the superconducting wire. Is the purpose.

By the way, a method of assembling a superconducting coil by winding a superconducting stranded wire wound with an insulating tape or the like requires a smaller number of turns than a case of winding a monolithic conductor, and is therefore advantageous in assembling the superconducting coil. Also, in order to assemble a superconducting coil using a monolithic conductor, it is necessary to prepare a conductor that is long enough to obtain a predetermined number of turns, but when using a collective conductor, each superconducting twisted wire Since the length of the wire may be relatively short, there is an advantage that a long and large current effect that is difficult to achieve with a monolithic conductor can be obtained industrially. For these reasons, collective conductors are frequently used in assembling superconducting coils.

As the insulator wound around the outer periphery of the above-mentioned superconducting twisted wire, for example, a tape of Kapton or glass cloth (thickness is usually about 25 to 100 μm) coated with a semi-cured resin and impregnated is used. Often. As the method of winding the insulator, wrap winding, half wrap winding, gap winding, a combination thereof, or the like is applied. Gap winding is a winding method in which a gap is intentionally provided to obtain a refrigerant passage.

Here, a brief description of the wire movement will be given. The superconducting coil generates a strong magnetic field during its use, and a strong Lorentz force acts on the superconducting wire forming the coil. When a superconducting coil is used for a rotor of a motor or a generator, centrifugal force due to its rotation also acts. It is known that such an electromagnetic force or inertial force causes a slight displacement of a superconducting wire, and is called a wire movement. Although such a wire movement is usually considered to be minute, it may impair the conduction stability of the superconducting coil or deteriorate the stability of the superconducting wire. Specifically, the displacement movement of the superconducting wire during the operation of the superconducting coil, even if it is a small movement, the magnetic field existing in the superconductor fluctuates rapidly, and the magnetic field disturbs the generated magnetic field, or This is because the electric field is excited to disturb the current. As a result, the magnetic flux fixed in the superconductor moves (referred to as flux flow), and the stability of the superconducting wire is impaired. Also, the sudden displacement of the superconducting wire generates heat due to its friction, which may partially exceed the critical temperature, and in the worst case may lead to quench.

[0007]

As described above, if a superconducting coil is assembled using a superconducting twisted wire (collective conductor), there is an advantage that a long and large current effect that is difficult to achieve with a monolithic conductor can be industrially obtained. is there. In the case of the collective conductor, the current capacity is naturally larger than that of the monolith conductor. However, for example, in the case of a collective conductor composed of seven superconducting wires, a current of about 1/7 of the supplied current flows through each superconducting wire (in the case of direct current). In other words, in order to energize the superconducting coil assembled by winding the collective conductor, a current corresponding to the number of superconducting wires constituting the collective conductor must be supplied to the end.

On the other hand, in order to energize the superconducting coil assembled by winding the monolithic conductor, it is sufficient to supply a current for energizing one superconducting wire at the end. At this time, the loop through which the current flows becomes longer than when the collective conductor is used. However, in the case of a superconducting wire, there is no problem of current decay due to electric resistance ideally. Therefore, the supply current is small when energizing,
In addition, since the power supply equipment can be smaller, it is advantageous in terms of operation costs and equipment costs.

For the above reasons, a superconducting coil assembled by winding a collective conductor is advantageous in that a long and large current effect can be obtained industrially and that the number of coil assembling steps is smaller than when a monolith conductor is used. However, it is disadvantageous in terms of operating costs and equipment costs. Therefore, as a method of supplying electricity with a small amount of current while using a collective conductor such as a superconducting stranded wire, the direction of the current flowing through each superconducting wire is insulated by insulating each superconducting wire (strand) forming the superconducting stranded wire. A method of energizing by connecting in series so as to match each other is conceivable. According to this method, although current decay corresponding to the connection resistance of each superconducting wire cannot be avoided, ideally, a current corresponding to the number of superconducting wires forming the superconducting twisted wire may be supplied. However, when manufacturing a superconducting stranded wire or a superconducting molded stranded wire, even if each superconducting wire is insulated before processing, the insulating coating layer is partially broken due to compressive force or shear force received during stranded wire processing. It often happens. Even more so in the case of molded stranded wires undergoing compression molding. If the insulating coating layer is broken, even if it is partial, the superconducting wires connected in series will be short-circuited, causing a problem that a predetermined current will not flow. Therefore, in the case of a coil using a superconducting stranded wire, a large amount of supply current is required for energization, and this is disadvantageous in terms of operating costs and equipment costs.

Therefore, in the case where a superconducting coil is assembled using a superconducting cable which is a collective conductor, and in the case where current is supplied with a small amount of current supply as in the case of a superconducting coil assembled using a monolithic conductor, such a superconducting coil is used. It has been desired that the insulating coating of each superconducting wire constituting the conductor is reliable.

[0011] Further, in the case where a superconducting coil is assembled using a superconducting cable which is a collective conductor, there is no need to supply electricity with a small current supply as in the case of a superconducting coil assembled using a monolithic conductor. However, the conventional superconducting cable has the following problems. For example, in the case of a superconducting wire having extremely poor workability, such as an oxide-based superconducting wire, it is practically difficult to use a collective conductor in the form of a stranded wire because the stranded wire is difficult to process.

When used in an AC application, a Cr plating layer is formed on the strand for the purpose of reducing the coupling loss (one of the AC losses) between the superconducting wires (strands) constituting the superconducting stranded wire. May oxidize the surface. However, there is a problem that the thus formed high resistance layer is partially broken by a shearing force or the like during the stranded wire processing. In this case, the reduction of the coupling loss becomes insufficient. Therefore, a superconducting cable which can be suitably applied to a superconducting wire in which stranded wire processing is difficult is desired, and a high resistance layer for reducing coupling loss is formed on the outer periphery of each superconducting wire constituting the superconducting cable. In such a case, there has been a demand for a superconducting cable capable of reducing the damage of the high resistance layer and effectively reducing the coupling loss.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. That is, the first superconducting cable according to the present invention is a superconducting cable in which a plurality of superconducting wires are arranged in parallel, and thin wires are laterally added and integrated.

A second superconducting cable according to the present invention is a superconducting cable in which a plurality of superconducting wires coated with insulation are arranged in parallel, and thin wires are laterally added and integrated.

Furthermore, as a third superconducting cable of the present invention, there is provided a superconducting cable in which at least two or more superconducting wires having different cross-sectional shapes are arranged in parallel in a substantially wedge shape, and thin wires are laterally added and integrated. .

The first to third superconducting coils of the present invention using the superconducting cable of the present invention are the first to third coils of the present invention.
The superconducting cable according to any one of the above, wherein the thin wire is a semi-cured wire, and after winding it into a predetermined shape, the super-conducting wire is cured by heating to a temperature equal to or higher than the curing temperature of the semi-cured wire. Provide coils.
Further, as the second superconducting coil of the present invention, the first to third superconducting cables of the present invention are wound into a predetermined shape, and then heated to cure the insulating material wound around the superconducting cable. Provide a superconducting coil.

[0017]

In the first superconducting cable according to the present invention, a plurality of superconducting wires are arranged in parallel, and thin wires are laterally added and integrated, so that the first superconducting cable is formed without being subjected to stranded wire processing or the like. It is a collective conductor. Therefore, the present invention can be suitably applied to superconducting wires, such as oxide-based ones, for which stranded wire processing is difficult, but can of course be suitably applied to metal superconducting wires. Further, when a high resistance layer for the purpose of reducing the coupling loss is provided on the outer periphery of the superconducting wire, the damage of the high resistance layer is small, so that the coupling loss can be effectively reduced. Further, in the second and third superconducting cables according to the present invention, each superconducting wire forming the superconducting cable is insulated. The insulating method may follow a conventional method. For example, besides a method of baking and coating a usual organic insulating coating layer such as polyvinyl formal, polyamide imide, polyester and polyester imide, a method of winding these resin tapes around a superconducting wire can be adopted. If the thickness is too small, it is easy to be broken. Therefore, it is preferable that the thickness is 5 μm or more.

According to the second superconducting cable according to the present invention, as shown in FIG. 1, a plurality of insulating coated superconducting wires 30 each having an insulating coating layer 20 formed on the outer periphery of the superconducting wire 10 are arranged in parallel. By being laterally attached and integrated, the respective insulating-coated superconducting wires 30 are mutually restrained,
When a superconducting coil is assembled, it can be wound as a collective conductor. When the fine wire 40 is a semi-cured wire, the wire is wound into a predetermined shape and then cured by heating to a temperature equal to or higher than the curing temperature, so that the restraint of each superconducting wire 10 is further strengthened. There is also an effect. In FIG. 1, the number of the thin lines 40 is drawn in a small number for easy viewing. Further, the superconducting cable 50 in FIG. 1 is an example in which seven insulating superconducting wires 30 are arranged, but the number is of course arbitrary.

Preferably, an insulating material is wound around the outer periphery of the second superconducting cable. This is because, by winding the insulating material, the shape and the shape of the coil and the suppression of the wire movement of the insulated superconducting wire 30 can be more reliably achieved by the forming and heating after the winding. In addition, since the superconducting wires arranged are less likely to collapse by winding the insulating material, it can be expected that the assembly process of the superconducting coil is further facilitated.

When the coil is assembled after the insulating material is wound around the outer periphery of the second superconducting cable, the insulating material mainly contributes to fixing the arranged superconducting wires.
The fixing by the thin line may be simplified. In this case, the thin wire also serves as a temporary fixing until the insulating material is wound, but the thin wire attached between adjacent superconducting wires does not lose the role of restraining the superconducting wires.

Although the superconducting cable 50 shown in FIG. 1 uses the superconducting wire 10 having a round cross section, the superconducting wire 11 having a rectangular cross section as shown in FIG. 2 may be used. Although FIGS. 1 and 2 show an example in which the insulated superconducting wires 30 and 31 are arranged in one row, the insulated superconducting wires 33 may be arranged in a plurality of rows as shown in FIGS. .

The third superconducting cable according to the present invention comprises:
At least two or more types of superconducting wires having different cross-sectional shapes are arranged in parallel in a substantially wedge-shaped shape, and thin wires are laterally added to be integrated. FIG. 5 shows an example in which five types of superconducting wires 14a, 14b, 14c, 14d, and 14e having different radii are used and arranged in the order of their sizes after insulation. By arranging the superconducting cables 54 in such a size order, the approximate cross-sectional shape of the superconducting cable 54 becomes a substantially fan-shaped wedge shape. The cross-sectional shape and the number of superconducting wires to be arranged are arbitrary, and the arrangement may be one or more.

Since the third superconducting cable has a substantially wedge-shaped cross section, it is possible to assemble a coil with a high linear density. In particular, when a high winding density and high winding accuracy are required, such as a superconducting coil for a particle accelerator, and prevention of winding displacement due to electromagnetic force or the like generated during operation is required, the third section having a substantially cross-sectional shape is used. Superconducting cables are preferably used. In the case of this third superconducting cable,
It is desirable that the critical current densities of the respective superconducting wires are substantially equalized.

Also, the third superconducting cable may have an insulating material wound around the outer periphery, as in the case of the above-described second superconducting cable. This insulating material has the effect of strengthening the restraint of each superconducting wire, as in the case of the second superconducting cable. Also, as in the case of the above-described second superconducting cable, when the insulating material is wound around the outer periphery of the superconducting cable, the insulating material mainly contributes to the fixing of the arranged superconducting wires. You can do it. In this case, the thin wire also serves as a temporary fixing until the insulating material is wound, but the thin wire attached between adjacent superconducting wires does not necessarily lose the role of restraining the superconducting wire. , And the second superconducting cable.

Next, a thin line used in the present invention will be described. The usable fine wire is not particularly limited as long as the arranged insulating-coated superconducting wires can be mutually restrained. For example, in addition to organic resin yarns such as polyamide, polyester, polypropylene, polyvinyl chloride and semi-cured epoxy resin, natural fibers such as cotton yarn and hemp yarn, metal fibers such as steel wire, inorganic fibers such as alumina fiber, glass fiber and SiC fiber. Fibers and the like can be used. However, when applied to the superconducting cable according to claim 2, use of a thin metal wire may break the insulating coating layer due to friction or the like. desirable. The thickness of these thin wires is not particularly limited, but if the thickness is too large, the interval between adjacent superconducting wires may be too large, or the flexibility of the thin wires may be reduced, which may cause inconvenience in knitting work. It is desirable that the thickness be several hundred μm or less. When a semi-cured insulating material is wound around the periphery, the insulating material is often hardened by heating after winding into a coil. In this case, however, the thin wire itself does not need to be heat-cured. Of course, the hardening of the fine wire itself further strengthens the constraint of the superconducting wire. Therefore, it is desirable to use a semi-cured fine wire or a cotton thread impregnated with a semi-cured resin.

By the way, a method of knitting a fine wire is a simple method of arranging superconducting wires and knitting using a conventional weaving machine. FIG. 1 shows an example in which two thin wires are woven, and FIG. 2 shows an example in which one thin wire is woven. However, in the present invention, the number of woven wires is arbitrary. In Figs. 1 to 7, the spacing between the fine wires braided is drawn widely for the purpose of making it easier to see, but in practice, the narrower the spacing between the fine wires braided and the more braided, the stronger the superconducting wire Needless to say, it can be restrained.

The superconducting cable according to any one of the first to third aspects of the present invention described above, wherein the thin wire is a semi-cured wire, wound into a predetermined shape, and then heated to form the semi-cured wire. The hardened first superconducting coil of the present invention is more advantageous in process than a case where a monolith conductor is wound and assembled. Further, the wire movement of the superconducting wire constituting the superconducting cable is suppressed by the thin wire. Also, an insulator is wound around the outer periphery of the superconducting cable according to any one of the first to third aspects of the present invention, which is wound into a predetermined shape, and then heated to cure the insulator.
As described above, the superconducting coil described above is more advantageous in process than a case where a monolithic conductor is wound and assembled. Further, the hardening of the insulator makes it possible to more reliably maintain the coil shape, and further suppresses the wire movement of the superconducting wire.

The second and third superconducting cables of the present invention are:
The superconducting wire constituting this is covered with insulation. Since the superconducting cable does not undergo stranded wire processing, the insulating coating layer is hardly damaged. Therefore, the insulation between the superconducting wires is maintained, and the supply current can be saved when the superconducting coil of the present invention formed by winding the second and third superconducting cables of the present invention is energized. This will be described with reference to FIG. When a current is supplied to the superconducting coil formed by winding the superconducting cable 50 of FIG. 1, a current corresponding to seven insulated superconducting wires 30 may be supplied to the entire end thereof.
If currents are connected in series and energized so that the directions of the currents flowing through the respective insulating-coated superconducting wires 30 are aligned, only one current needs to be supplied. In the case of the superconducting cable 50 of the present invention, since the stranded wire processing has not been performed, the insulating coating layer 20 is partially torn, and no short circuit occurs with the adjacent insulating coated superconducting wire 30. Therefore, ideally, a predetermined current can be supplied by supplying one current. Strictly speaking, there is a connection resistance at a portion connecting each of the insulating coated superconducting wires 30 in series, but the other portions are in a superconducting state.
As described above, when the second and third superconducting cables of the present invention are used, it is possible to reduce the supply current as compared with the case where the conventional superconducting twisted wire is energized.

As described above, the second and third superconducting cables of the present invention are longer and longer than those using a monolithic conductor.
The advantage of the collective conductor is that the large current effect is obtained industrially and the coil is easy to assemble. Further, the shape of the superconducting coil assembled by the thin wires and the insulator is prevented, and the wire movement of the superconducting wire is suppressed. Further, the superconducting coil using the second and third superconducting cables of the present invention can be operated with a small current supply, and the operating cost and equipment cost can be reduced.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. Invention Example 1 This will be described with reference to FIG. Round cross section (diameter 0.8m
m) An NbTi / Cu-based superconducting wire 10 was coated with an insulating covering layer 20 (average thickness 25 μm) made of polyvinyl formal resin (PVF) by an ordinary method to produce an insulating-coated superconducting wire 30. Next, as shown in the figure, seven insulating-coated superconducting wires 30 are arranged side by side to form a thin wire 40 (polypropylene fiber, diameter of 0.1 mm).
1mm) using a weaving machine to knit the superconducting cable 50.
Was prepared. FIG. 1 shows a thin line 40 for easy viewing.
Are drawn roughly, but they are actually braided so closely that the thin wires 40 come into close contact with each other. The dielectric breakdown voltage between the insulated superconducting wires 30 of the superconducting cable of Example 1 of the present invention thus produced was 5 kV as a result of the measurement, and 5 T
(Tesla), the current carrying capacity at 4.2K (Kelvin) is 55
It was 0A.

An insulator (tape obtained by coating and impregnating a polyimide film with an epoxy resin, thickness: 25 μm) is wound around the outer periphery of the superconducting cable 50 (approximately 1000 m thick) by half-wrap winding, and then a saddle-shaped coil having a bore diameter of 1 m is wound. Assembled. Thereafter, a molding heat treatment was performed at 150 ° C. for 5 hours while applying pressure to cure the insulator.
As the energization of the superconducting coil of the present invention example 1 thus produced, the insulating coated superconducting wires 30 are connected in series so that the directions of the currents flowing through the seven insulating coated superconducting wires 30 are all the same, and 440 A of DC current was supplied. The superconducting coil of Example 1 of the present invention was excellent in energization stability, was able to generate a 4T stable magnetic field without quenching on the way.

Conventional Example 1 A substantially rectangular Rutherford type superconducting cable (formed in the form of the present invention example 1) was formed by using seven superconducting wires 10 (without an insulating coating layer) and forming and twisting the same. Substantially shape: 1.4 mm × 2.05 mm). The current carrying capacity of this superconducting cable was 3850 A at 5T and 4.2K. The superconducting cable of this conventional example 1 (about 1000 m
Insulation (tape coated with epoxy resin on a polyimide film, thickness 0.075 μm) is wound around the outer periphery of the used half-wrap and wound, and then wound to assemble a superconducting coil similar to that of Example 1 of the present invention. Was. Thereafter, a molding heat treatment was performed at 150 ° C. for 5 hours while applying pressure to cure the insulator. The superconducting coil of Conventional Example 1 produced in this way generates a 4T stable magnetic field by 3
This was achieved by passing a DC current of 080 A. However, as compared with Example 1 of the present invention, the supplied current was larger, and a larger supply current was required.

Comparative Example 1 A substantially rectangular Rutherford type superconducting cable (substantially in shape: 1.4 m) was formed by using seven of the same insulated superconducting wires 30 in the case of Inventive Example 1 and forming and twisting them. × 2.
05mmmm). As a result of the measurement, it was confirmed that the insulation between the insulated superconducting wires was broken. This can be presumed to be because the insulating coating layer was partially broken by the shearing force received during the forming stranded wire processing. The current carrying capacity of this superconducting cable is 5T;
It was 3850 A at 2K. An insulator (a tape in which an epoxy resin is applied to a polyimide film, a thickness of 0.0
75 μm) was wound in a half-wrap manner, and then wound, to assemble a superconducting coil similar to that of Example 1 of the present invention. Thereafter, a molding heat treatment was performed at 150 ° C. for 5 hours while applying pressure to cure the insulator. With the superconducting coil of Conventional Example 1 thus manufactured, a current supply of 3080 A direct current was required to generate a 4T stable magnetic field.

Embodiment 2 of the present invention will be described with reference to FIG. Square cross section (0.7 ×
An insulating coating layer 21 (thickness: 20 μm) made of polyamide was formed on the superconducting wire 11 having a thickness of 1.4 mm) to produce an insulating coated superconducting wire 31. Next, seven insulated superconducting wires 31 are arranged, and a thin wire 41 (polypropylene fiber, diameter: 0.1 mm) is knitted by a weaving machine as shown in the drawing to form a superconducting cable 51.
Was prepared. FIG. 2 shows a thin line 41 for easy viewing.
Are drawn roughly, but in the example 2 of the present invention, the fine wires 41 are tightly woven so as to be in close contact with each other. The insulating superconducting wire 3 of the superconducting cable of the present invention example 2 thus produced
As a result, the dielectric breakdown voltage between the two was 10 V, and the current carrying capacity at 5 T (tesla) and 4.2 K (kelvin) was 800 A.

An insulator (a tape made by coating and impregnating a polyaramid woven fabric with an epoxy resin, having a thickness of 100 μm) is wound around the outer periphery of the superconducting cable 51 (approximately 1000 m thick) by half-wrapping, and then a race track having a bore diameter of 2 m. The mold coil was assembled. Then, pressurize 15
The insulator was cured by performing a molding heat treatment at 0 ° C. for 5 hours. As the energization of the superconducting coil of Example 2 of the present invention thus produced, the insulated superconducting wires 31 were connected in series so that the directions of the currents flowing through the seven insulated covered superconducting wires 31 were all the same, and a 680 A DC current was supplied. The superconducting coil of Example 2 of the present invention was excellent in conduction stability, was able to generate a 4.2 T stable magnetic field without quench.

Embodiment 3 of the present invention will be described with reference to FIG. 5 with round cross section and different diameter
Types of superconducting wires 14a, 14b, 14c, 14d, 14
e (NbTi / Cu system, diameters are 1.0 mm and 0.98, respectively)
mm, 0.96 mm, 0.94 mm, 0.92 mm). The critical current values of these superconducting wires are all 850 A
(At5T, 4.2K). These superconducting wires are coated with an insulating coating layer 24 (average thickness 50 μm) made of polyvinyl formal resin (PVF) by a conventional method, and the insulating coated superconducting wires 34a, 34b, 34c, 34
d and 34e were produced. Next, as shown in the drawing, these insulating-coated superconducting wires were arranged in the order of the diameter, and as shown, the thin wires 44 (polyaramid fiber, diameter 50 mm) were woven using a weaving machine to produce a superconducting cable 54. 5
Although the number of the fine wires 44 is roughly drawn for easy viewing, the fine wires 44 are actually woven so closely that the fine wires 44 are in close contact with each other. The dielectric breakdown voltage between the insulated superconducting wires of the superconducting cable of Inventive Example 3 thus produced was 7 kV as a result of the measurement, and the current carrying capacity at 5 T (tesla) and 4.2 K (kelvin) was 800 A. .

The same insulator (a tape in which a polyimide film is coated with an epoxy resin and impregnated, thickness: 25 μm) is half-wrapped around the outer periphery of the superconducting cable 54 (using about 1000 m). Winding,
Next, a saddle coil having a bore diameter of 1 m was assembled. afterwards,
The above-mentioned insulator was cured by applying a molding heat treatment of maintaining the temperature at 150 ° C. for 5 hours while applying pressure. As the energization of the superconducting coil of Inventive Example 3 thus produced, the superconducting coils were connected in series so that the directions of the currents flowing through the five insulating-coated superconducting wires 34a, 34b, 34c, 34d, and 34e all coincided.
A DC current of 80 A was supplied. The superconducting coil of Example 3 of the present invention has excellent conduction stability, has no quench on the way, and has a 4.2 T
Was able to generate a stable magnetic field.

Inventive Example 4 This will be described with reference to FIG. 5 types of superconducting wires 15a, 15b, 15c, 15d having rectangular cross sections and different sizes
15e (NbTi / Cu system) was prepared. These sizes are 1.4 × 0.7 mm, 1.38 × 0.68 m, respectively.
m, 1.36 × 0.66 mm, 1.34 × 0.64 m
m, 1.32 × 0.62 mm. The critical current value of each of these superconducting wires is 550A (7T, 4.2K). Polyvinyl formal resin (P
VF) is coated with an insulating coating layer 25 (average thickness 20 μm) by an ordinary method, and the insulating coating superconducting wires 35a, 35b,
35c, 35d, and 35e were produced. These insulated superconducting wires are arranged in the order of diameter as shown in the figure, and as shown in the figure, a thin wire 45 (polypropylene fiber, diameter 50 μm
m) was knitted using a weaving machine to produce a superconducting cable 55. In FIG. 6, the number of the fine wires 45 is roughly drawn for easy understanding, but actually, the fine wires 45 are densely woven so that the fine wires 45 are in close contact with each other. The dielectric breakdown voltage between the insulated superconducting wires of the superconducting cable of Inventive Example 4 thus produced was 5 kV as a result of the measurement, and the current carrying capacity at 7 T (tesla) and 4.2 K (kelvin) was 500 A. .

An insulator (tape made by coating and impregnating epoxy resin with epoxy resin, thickness of 100 μm) is wound around the outer periphery of the superconducting cable 55 (approximately 1000 m in length) by half-wrap winding, and then a saddle coil having a bore diameter of 1 m is wound. Assembled. Thereafter, a molding heat treatment of maintaining at 180 ° C. for 3 hours while applying pressure was performed to cure the fine wires 45 and the insulator. The superconducting coil of Example 4 of the present invention thus produced was provided with five insulating-coated superconducting wires 35a, 35b, 35.
They were connected in series so that the directions of the currents flowing through c, 35d, and 35e all coincided, and a DC current of 350 A was passed. The superconducting coil of Example 4 of the present invention was excellent in current-carrying stability, and required only three quench steps on the way to generate a stable magnetic field of 5.6 T.

Inventive Example 5 This will be described with reference to FIG. Three types of superconducting wires 16a, 16b, 16c (NbT
i / Cu system). These sizes are each 1.
4 × 0.7mm, 1.36 × 0.66mm, 1.32 ×
0.62 mm. The critical current value of these superconducting wires is
All are 1000A (5T, 4.2K). Next, an insulating coating layer 26 (average thickness 25 μm) made of semi-cured epoxy resin is coated by a conventional method, and the insulating coated superconducting wire 3 is formed.
6a, 36b and 36c were produced. These insulating coated superconducting wires are arranged three by three in the order of the diameter as shown in the figure, and as shown in the figure, the thin wire 46 (epoxy-impregnated glass fiber,
The superconducting cable 56 was manufactured by knitting with a weaving machine. In FIG. 7, the number of the fine wires 46 is roughly drawn for easy viewing, but actually, the fine wires 46 are densely woven so that the fine wires 46 are in close contact with each other. The insulation breakdown voltage between the insulating coated superconducting wires of the superconducting cable of Example 5 of the present invention thus produced was 5 kV as a result of the measurement, and 5T
(Tesla), conduction capacity at 4.2K (Kelvin) is 90
It was 0A.

An insulator (a tape of E glass cloth tape impregnated with an epoxy resin, a thickness of 100 μm) is half-wrapped and wound around the outer periphery of the superconducting cable 56 (using about 1000 m), and then a saddle having a bore diameter of 1 m is wound. The mold coil was assembled. Then, pressurize at 170 ° C for 3
The insulator was cured by performing a molding heat treatment for holding for a time. As the energization of the superconducting coil of Example 5 of the present invention thus produced, nine insulating-coated superconducting wires 36a, 36b, 3
6c were connected in series so that the directions of the currents flowing through them all matched, and a DC current of 720A was supplied. The superconducting coil of Inventive Example 5 was excellent in conduction stability, was able to generate a 4 T stable magnetic field without quench.

The superconducting cable assembly conductors of Examples 1 to 5 of the present invention described above, so that they are compared with the case of a monolithic conductor.
There is an advantage that the number of assembling steps of the superconducting coil is reduced. And since the superconducting wire constituting the superconducting cable is reliably insulated, when energizing the assembled superconducting coil, by connecting these superconducting wires in series, as in the case of a superconducting coil formed by winding a monolithic conductor, It is also possible to operate with a small current supply.

Inventive Example 6 In place of the insulated superconducting wire 30 of Inventive Example 1, an Nb ₃ Sn superconducting wire of the same size provided with a Cr plating layer (thickness: 5 μm) by electroplating was used. A superconducting cable was produced in the same manner as in Inventive Example 1 except that a thin metal wire (SUS wire, diameter 20 μm) was used. The coupling loss between the superconducting wires of the superconducting cable of Inventive Example 6 thus produced was as low as about 5 mJ / cm ² . This is an effect that unlike the case of the conventional superconducting stranded wire, the Cr plating layer did not fall off during the stranded wire processing.

[0044] Using those conventional similar to the two invention Examples Nb ₃ Sn superconducting wire provided with a Cr plating layer in 6, Rutherford superconducting cable (short for substantially rectangular by processing this seven-molded stranded wire (Shape: 1.4 mm x 2.05 mm). The coupling loss between the superconducting wires of the superconducting cable of Conventional Example 2 was about 15 mJ / cm ² . This is considered to be due to the fact that the Cr plating layer was partially dropped during the forming stranded wire processing, so that the coupling loss was higher than that of Example 6 of the present invention. As described above, the superconducting cable of Example 6 of the present invention is a superconducting cable in which the high-resistance layer for the purpose of reducing the coupling loss is less damaged and the coupling loss can be effectively reduced.

Invention Example 7 Five types of Bi-based oxide superconducting wires having a round cross section and different diameters (diameters of 1.0 mm, 0.98 mm, 0.96 mm,
0.94 mm, 0.92 mm). These are arranged one by one in the order of diameter in the same manner as in Example 3 of the present invention (the superconducting wires 14a to 14e in FIG. 5 are replaced with Bi-based oxide superconducting wires having the above diameter, and the insulating coating layer 24 is formed. (Not shown), and a superconducting cable was produced by braiding using a thin metal wire (SUS wire, diameter 30 μm) instead of the thin wire 44 in FIG. The current carrying capacity of this superconducting cable is 5T (tesla),
It was 1000A at 4.2K (Kelvin). Using this superconducting cable, a cylindrical solenoid coil having a bore diameter of 1 m was produced. This coil was able to generate a central magnetic field of 1T. The superconducting cable of Example 7 of the present invention is not subjected to stranded wire processing, and can be suitably applied to superconducting wires having poor workability, such as oxide-based superconducting wires. Further, since the superconducting cable of Example 7 of the present invention has a substantially fan-shaped cross section, it is convenient when assembling a coil.

[0046]

As described above, the present invention relates to a case where a superconducting coil is assembled using a superconducting cable, and is similar to a case of a superconducting coil assembled using a monolithic conductor.
In the case where current is supplied with a small amount of current supply, the superconducting wires constituting the collective conductor are surely coated with insulation and can be supplied with a small amount of current supply. In addition, when used for AC applications, when a high-resistance layer is formed around the superconducting wires constituting the superconducting cable to reduce coupling loss, the high-resistance layer is less damaged, It is possible to reduce the coupling loss. Further, the superconducting cable and the superconducting coil of the present invention can be suitably applied to a superconducting wire having extremely poor workability, such as an oxide-based superconducting wire. As described above, the present invention has a remarkable industrial contribution.

[Brief description of the drawings]

FIG. 1 is a partially sectional perspective view of a superconducting cable according to the present invention.

FIG. 2 is a partially sectional perspective view of a superconducting cable according to the present invention.

FIG. 3 is a partially sectional perspective view of a superconducting cable according to the present invention.

FIG. 4 is a partially sectional perspective view of a superconducting cable according to the present invention.

FIG. 5 is a partially sectional perspective view of a superconducting cable according to the present invention.

FIG. 6 is a partially sectional perspective view of a superconducting cable according to the present invention.

FIG. 7 is a partially sectional perspective view of a superconducting cable according to the present invention.

[Explanation of symbols]

10, 11, 12, 13 superconducting wires 14a, 14b, 14c, 14d, 14e superconducting wires 15a, 15b, 15c, 15d, 15e superconducting wires 16a, 16b, 16c superconducting wires 20, 21, 22, 23, 24, 25, 26 Insulation coating layer 30, 31, 32, 33 Insulation coating superconducting wire 34a, 34b, 34c, 34d, 34e Insulation coating superconducting wire 35a, 35b, 35c, 35d, 35e Insulation coating superconducting wire 36a, 36b, 36c Insulation coating superconducting wire 40, 41, 42, 43, 44, 45, 46 Fine wire 50, 51, 52, 53, 54, 55, 56 Superconducting cable

Claims (5)

(57) [Claims] 1. A superconducting cable in which a plurality of superconducting wires are arranged in parallel, and thin wires are laterally attached and integrated. 2. A superconducting cable in which a plurality of insulated superconducting wires are arranged in parallel, and thin wires are laterally attached and integrated. 3. A superconducting cable in which at least two or more superconducting wires having different cross-sectional shapes are arranged in parallel in a substantially wedge shape, and thin wires are laterally added and integrated. 4. The method according to claim 1, wherein the fine wire is a semi-cured wire.
4. A superconducting coil obtained by winding the superconducting cable according to any one of claims 3 to 3 into a predetermined shape, and then heating the cable to a temperature equal to or higher than the curing temperature of the semi-cured wire. 5. A superconducting coil obtained by winding the superconducting cable according to any one of claims 1 to 3 into a predetermined shape, and then heating and curing an insulating material wound around the superconducting cable.