JPH08298208A - High temperature superconductor winding - Google Patents

Abstract

PURPOSE: To suppress generation of shearing stress at the crossover part by setting the distance between first and second pancake parts, the angle between the longitudinal center line at the crossover part and the center line of superconducting wire at each pancake part, and the inside diameter at each pancake part, respectively, in specified ranges. CONSTITUTION: A double pancake coil 1, where the distance (d) between coil parts 4, 6 is 0.1mm and the inside diameter at the coil parts 4, 6 is 15mm, is formed using a superconducting wire (wire material) having width W. The angle θ between the longitudinal center line at a crossover part 5 and the center line of the wire material 2 forming the first and second coil parts 4, 6 is set at 30 deg. or less. Since the diameter of a bobbin 3 for winding the wire material 2 is set at 10mm or above and the distance (d) between the first and second coil parts 4, 6 is set longer than 0.1mm but shorter than the width W, generation of shearing stress which may cause lowering of critical current density can be suppressed at the crossover part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature superconducting conductor winding, and more particularly to improving the characteristics of such high-temperature superconducting wires, especially the critical current characteristics.

[0002]

2. Description of the Related Art A high-temperature superconducting material known as a ceramics-based superconductor is subjected to composition processing in a state where it is covered with a metal, and is strongly processed into a thin tape shape. It has been found that a high critical current density can be obtained by combining and.

[0003]

In order to apply the above-mentioned tape-shaped high-temperature superconducting wire to, for example, a coil, it must be wound. Especially when the high-temperature superconducting wire is in the form of a tape, it is suitable to wind it in the form of a double pancake coil.

However, in the case of the double pancake coil,
Since one coil of high-temperature superconducting wire forms two coil portions, 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, it is always twisted at this crossing portion, so that a shear stress is applied to it and thereby the critical current density is lowered.

Therefore, as described above, the object of the present invention is to prevent the generation of shear stress in the transition portion which leads to a decrease in the critical current density when a tape-shaped high temperature superconducting wire is used. To provide a high temperature superconducting conductor winding wound in the form of.

[0006]

The present invention is directed to a high-temperature superconducting conductor winding in which a tape-shaped high-temperature superconducting wire covered with a metal sheath is wound in the shape of a double pancake coil. It should be noted that the length of the transition has an important relationship with the above-mentioned shear stress, and thus with the critical current density. When the length of the transition portion is L, it is defined by L = (W + d) / sin θ.

Here, W is the width of the superconducting wire, and d is the first and second
Is the distance between the pancake portions, and θ is the angle between the centerline of the crossover portion in the vertical direction and the centerline of the superconducting wire of each pancake portion.

That is, in the present invention, in order to solve the above-mentioned technical problem, θ is 30 ° or less and d is 0.1 m.
It is characterized in that m or more and W or less and the inner diameter of each pancake portion is selected to be 10 mm or more.

The high-temperature superconducting wire may be wound on a bobbin having a diameter of 10 mm or more. Further, in the high-temperature superconducting wire according to the present invention, the high-temperature superconducting wire is coated with an inorganic material such as mica or glass fiber, or an insulating material made of an organic material such as tetrafluoroethylene, polyimide resin, or formal resin. Good.

[0010]

According to the present invention, θ is 30.
By setting d below 0.1 ° and d below 0.1 mm and below W, and the inside diameter of each pancake portion above 10 mm, it is possible to suppress the generation of shear stress in the transition area and thereby prevent the decrease of the critical current density. You can

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

[0012]

1 and 2 show a high temperature superconducting conductor winding 1 according to an embodiment of the present invention. Here first
The figure 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 covered with a metal sheath on a cylindrical bobbin 3 so as to form a double pancake coil. It

More specifically, one piece of tape-shaped high-temperature superconducting wire 2 has a top pancake, that is, a first coil portion 4.
Which is wound from the inner peripheral side on the bobbin 3 so as to form
The coiled portion 4 of the coil portion 4 is connected to the winding portion 5 so as to extend obliquely downward on the bobbin, and the same high-temperature superconducting wire 2 forms the lower pancake, that is, the second coil portion, On the outer peripheral surface of 3, the coil is wound from the inner peripheral side in a direction opposite to that of the first coil portion 4.

Tape-shaped high temperature superconducting winding 2 as described above
In the winding state of No. 5, as a result of forming the crossover portion 5, a gap is formed in both the first coil portion 4 and the second coil portion 6, and these gaps are formed by the spacer 7 and the spacer 7, respectively. Absorbed by putting 8. In FIG. 1, W is the width of the superconducting wire, d is the distance between the first and second coil portions, and θ is the longitudinal centerline of the crossover portion and the centerline of the superconducting wire of each coil portion. It is an angle.

Conducting terminals 9 and 10 are attached to each end of the wound high temperature superconducting wire 2.

Although the bobbin 3 is illustrated as a simple cylindrical shape, generally flanges (not shown) are formed at both ends thereof. Also, the distance d between both pancakes is shown larger than W, but in reality d is much smaller than W. In this specification, when referring to "the length of the transition portion", the center line in 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 is shown. Shall indicate the length of.

Example 1 Bi: Pb: Sr: Ca: C
u = 1.82: 0.43: 2.01: 2.22: 3.0
The oxides or carbonates containing the respective elements are mixed so as to have a composition of 3, and then heat treated (Bi, Pb): Sr:
221 Ca: Cu having a composition of approximately 2: 2: 1: 2
A powder consisting of two layers and a non-superconducting layer was prepared. This is 2T
Degassing treatment was performed at 700 ° C. for 3 hours in a reduced pressure atmosphere of orr.

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 to an outer diameter of 1 mm, and then rolled to a thickness of 0.18 mm.

The tape-shaped wire thus obtained was heat-treated at 840 ° C. for 50 hours 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, use this tape-shaped wire for a thickness of 0.1 mm.
Of formal resin and wound on a bobbin having an outer diameter of 15 mm to prepare a double pancake coil having 10 turns per pancake.

In this way, the width W of the superconducting wire is 4 mm,
A sample of a double pancake coil having a distance d between pancakes of 0.1 mm and an inner diameter of each pancake coil of 15 mm was prepared.

At this time, several samples with different θ were prepared.
I in each case_{c coil}/ I _co(In the form of a coil
The critical current density / critical current density up to the wire) was measured.
The result is shown in FIG.

As is apparent from FIG. 3, when θ exceeds 30 °, I _{c coil} / I _co sharply decreases.

(Embodiment 2) The angle θ of the crossover portion is 27 °.
Samples of several double pancake coils with different bobbin diameters were prepared in the same manner as in Example 1 except for the above.

I of each obtained sample_{c coil}/ I_coMeasurement result
The result is as shown in FIG. As is clear from FIG.
When the diameter of the bobbin is less than 10 mm, I_{c coil}/ I
_coDecreases. In addition, the distance d between the pancakes is set to the superconducting sea.
If the width W is greater than the width W of the double pancake coil
The ratio of the conductor wire (coil packing factor) is
Always small, the current density through the coil is very small
As a result, the generation of a strong magnetic field, which is a characteristic of superconducting coils,
Not made

[Brief description of 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 a high-temperature superconducting conductor winding 1 shown in FIG.

FIG. 3 is a graph showing the effect of θ on I _{c coil} / I _co in Example 1 of the present invention.

FIG. 4 is a bobbin diameter I according to a second embodiment of the present invention.
It is a graph which shows the effect which it has on _{c coil} / I _co .

[Explanation of symbols]

 1 high temperature superconducting conductor winding 2 high temperature superconducting wire 3 bobbin 4 first coil part 5 crossover part 6 second coil part

Claims (4)

[Claims] 1. A tape-shaped high-temperature superconducting wire covered with a metal sheath is wound in the form of a double pancake coil, and the double pancake coil comprises first and second pancake portions and the first pancake portion. And a crossover portion provided between the second pancake portion, wherein W is the width of the superconducting wire, d is the distance between the first and second pancake portions, θ is an angle formed by the center line in the vertical direction in the crossover portion and the center line of the superconducting wire in each pancake portion, θ is 30 ° or less, d is 0.1 mm or more and W or less, and the inner diameter of each pancake portion Is 10 mm or more, a high temperature superconducting conductor winding. 2. The high-temperature superconducting conductor winding according to claim 1, wherein the high-temperature superconducting wire is wound around a bobbin having a diameter of 10 mm or more. 3. The high temperature superconducting conductor winding according to claim 1, wherein the high temperature superconducting wire is a bismuth copper oxide superconductor coated with a silver sheath. 4. The high-temperature superconducting conductor winding according to claim 3, wherein the high-temperature superconducting wire is insulation-coated.