JP3309390B2 - High-temperature superconducting conductor winding - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a high-temperature superconducting conductor winding, and more particularly to an improvement in characteristics of such a high-temperature superconducting conductor winding, especially in a critical current characteristic.

[Prior art] A high-temperature superconducting material known as a ceramic-based superconductor is subjected to plastic working in a state of being coated with a metal to form a thin tape shape. It has been found that a high critical current density can be obtained by combining with heat treatment.

[Problems to be Solved by the Invention] In order to apply the tape-like high-temperature superconducting wire as described above to, for example, a coil, it must be wound. In particular, when the high-temperature superconducting wire is in the form of a tape,
It is appropriate to wind this in the form of a double pancake coil.

However, in the case of a double pancake coil, two coil portions are formed by one high-temperature superconducting wire, so that a transition portion extending from one coil portion to the other coil portion is required. However, it was found that when a tape-shaped high-temperature superconducting wire is used, since it is twisted at the transition, it is subjected to a shearing stress, thereby lowering the critical current density.

Therefore, as described above, an object of the present invention is to form a double pancake coil that can suppress the occurrence of shear stress in a transition portion that leads to a decrease in critical current density when a tape-shaped high-temperature superconducting wire is used. The object is to provide a wound high-temperature superconducting conductor winding.

Means for Solving the Problems The present invention is directed to a high-temperature superconducting conductor winding in which a tape-shaped high-temperature superconducting wire composited with a metal is wound in the form of a double pancake coil. It is noted that the length of the crossover portion has an important relationship with the above-mentioned shear stress, and thus the critical current density.

That is, in order to solve the above-mentioned technical problem, the present invention is characterized in that the length of the transition between the pancakes is selected to be at least four times the width of the tape-shaped high-temperature superconducting wire.

In the high-temperature superconducting conductor winding according to the present invention, the high-temperature superconducting wire is covered with an insulating material made of an inorganic substance such as mica, glass fiber, quartz fiber, or an organic substance such as ethylene tetrafluoride, polyimide resin, or formal resin. May be done.

Preferably, the high-temperature superconducting conductor winding is impregnated with epoxy, and more preferably, the epoxy contains fibers and / or powder.

Further, the high-temperature superconductor included in the high-temperature superconducting wire may be divided into multiple cores.

According to the present invention, by setting the length of the transition portion to be at least four times the width of the tape-shaped high-temperature superconducting wire, it is possible to suppress the occurrence of shear stress at the transition portion, Accordingly, it is possible to prevent the critical current density from decreasing due to shear stress.

In the present invention, when the high-temperature superconducting wire is coated with the insulation, the high-temperature superconducting wire can be wound as it is without using a special insulating material.

Further, when the high-temperature superconducting conductor winding according to the present invention is impregnated with epoxy, it becomes strong against the stress received when such a winding is manufactured or when it is excited,
If the epoxy contains fibers and / or powder, it will be more resistant to the stresses described above.

In addition, when the high-temperature superconductor contained in the high-temperature superconductor is divided into multiple cores, the strain resistance becomes excellent, and even after the high-temperature superconductor is sintered, it can be wound without any problem. Can be.

Embodiment FIG. 1 and FIG. 2 show a high-temperature superconducting conductor winding 1 according to an embodiment of the present invention. Here, FIG.
FIG. 2 is a front view, and FIG. 2 is a top view.

The high-temperature superconducting conductor winding 1 is formed by winding a tape-shaped high-temperature superconducting wire 2 composited with metal on a cylindrical bobbin 3 so as to form a double pancake coil. You.

More specifically, one tape-shaped high-temperature superconducting wire 2 is
It is wound on the bobbin 3 from the inner peripheral side to form the upper pancake, that is, the first coil portion 4. The crossover portion 5 continuing to the winding start end of the first coil portion 4 is guided so as to extend diagonally downward on the bobbin 3, and the same high-temperature superconducting wire 2
Is formed on the outer peripheral surface of the bobbin 3 from the inner peripheral side so as to form the lower pancake, that is, the second coil portion 6.
Is wound in the direction opposite to the coil portion 4 of the first coil.

In the winding state of the tape-shaped high-temperature superconducting wire 2 as described above, a gap is formed in both the first coil portion 4 and the second coil portion 6 as a result of the formation of the crossover portion 5. , These gaps are, respectively, spacers 7
And 8 are absorbed.

Further, current-carrying terminals 9 and 10 are attached to each end of the wound high-temperature superconducting wire 2.

Although the winding frame 3 is shown in a simple cylindrical shape, generally, flanges (not shown) are formed at both ends thereof.

In this specification, "the length of the transition portion" is referred to as the center of the portion where the transition portion 5 shown in FIG. 1 is exposed from the first coil portion 4 and the second coil portion 6. It refers to the length of the line.

Hereinafter, more specific examples performed to confirm the effects of the present invention will be described.

Example 1 Bi: Pb: Sr: Ca: Cu = 1.82: 0.43: 2.01: 2.22: 3.03 An oxide or a carbonate containing each element was mixed so as to have a composition, and Bi: Pb: A powder comprising a 2212 phase having a composition of Sr: Ca: Cu of about 2: 2: 1: 2 and a non-superconducting phase was prepared. This was subjected to a degassing treatment at 700 ° C. for 3 hours in a reduced pressure atmosphere of 2 Torr.

The powder thus obtained was filled in a silver pipe. The 1296 silver pipes were loaded into a large silver pipe having an outer diameter of 12 mm and an inner diameter of 10 mm, wire-drawn until the outer diameter became 1 mm, and then rolled to a thickness of 0.18 mm.

The tape-shaped wire obtained in this way is heated at 840 ° C for 5 minutes.
The sheet was heat-treated for 0 hour, and then rolled into a tape-shaped wire having a width of 4 mm and a thickness of 0.15 mm. Next, this tape-shaped wire was heat-treated at 840 ° C. for 50 hours.

Next, this tape-shaped wire is covered with a 0.1 mm thick formal resin, and wound on a bobbin having an outer diameter of 15 mm.
For each pancake, a 10-turn double pancake coil was prepared. At this time, several samples with different lengths of the transition part were prepared, and in each case, Jc, coi
l / Jco (= critical current density in the form of a coil / critical current density as it is) was measured.

 The results are shown in Table 1 below.

As is clear from Table 1, when the length of the crossover is set to four times or more the width of the tape-shaped wire, the improvement of the characteristics is remarkable.

Example 2 A tape-shaped wire having a width of 4.3 mm and a thickness of 0.14 mm was prepared in the same manner as in Example 1, and was covered with a polyimide resin instead of formal resin. A cake coil was prepared. In Example 2, this coil was impregnated with an epoxy resin containing glass fibers.

Table 2 shows the evaluation results of the obtained samples.

Table 2 shows that impregnation with an epoxy resin further increases the effect.

Example 3 A single-core wire was manufactured through the same steps as in Example 1. This was rolled to a thickness of 0.18 mm, covered with quartz fiber, formed into a double pancake coil, and then heat-treated at 840 ° C. for 50 hours.

Also in this case, when the crossover length is four times or more the width of the wire, the critical current density in the form of a coil is as excellent as 90% or more of the critical current density of the wire as it is. Was.

[Brief description of the drawings]

FIG. 1 is a front view showing a high-temperature superconducting conductor winding 1 according to an embodiment of the present invention. FIG. 2 is a top view showing the high-temperature superconducting conductor winding 1 shown in FIG. In the figure, 1 is a high-temperature superconducting conductor winding, 2 is a high-temperature superconducting wire, 4 is a first coil portion, 5 is a bridge portion, and 6 is a second coil portion.
Of the coil.

Claims (5)

(57) [Claims] 1. A high-temperature superconducting conductor winding in which a tape-shaped high-temperature superconducting wire composited with a metal is wound in the form of a double pancake coil, wherein the length of the transition between the pancakes is tape-shaped. A high-temperature superconducting conductor winding, wherein the width is at least four times the width of the high-temperature superconducting wire. 2. The high-temperature superconducting wire is insulated and coated.
The high-temperature superconducting conductor winding according to claim 1. 3. The high-temperature superconducting conductor winding according to claim 1, which is impregnated with epoxy. 4. The high-temperature superconducting conductor winding according to claim 3, wherein the epoxy contains fibers and / or powder. 5. The high-temperature superconductor winding according to claim 1, wherein the high-temperature superconductor contained in the high-temperature superconducting wire is divided into multiple cores.