JPS60100487A - Permanent current switch - Google Patents

Abstract

PURPOSE:To obtain a stable permanent current switch which has high current flowing performance by separating between layers on which an electromagnetic force is acted in a direction for repelling between adjacent layers of a superconductive winding for forming the switch without bonding with resin. CONSTITUTION:Spacers 4 made of a separating material such as a Teflon sheet are disposed between the second and the third layers and between the fourth and the fifth layers. Accordingly, they are separated therebetween, and even if an electromagnetic force of tensile direction is acted, tensile stress is hardly acted on the immersed resin, and a microcrack is hardly generated. Thus, a crack of the immersed resin which causes a factor of a quenching can be prevented, thereby improving and stabilizing the current flowing performance of the switch.

Description

[Detailed description of the invention] [Summary of the invention] The present invention relates to improving the current carrying performance of a persistent current switch.

[Prior art]

Figure 1 shows the 6-wire structure of a conventional non-inductive solenoid wound persistent current switch. In the figure, (la).

(lb) is a 4-winding superconductor wire, for example, a superfine multifilamentary wire with a NbTi filament embedded in a base material with high resistivity such as CuNi, or a wire made only of NbTi, which is wound with a high-resistance superconducting wire used in streetcars, etc. For example, (la) indicates the outgoing current line, and (lb) indicates the return line, and is wound without induction. 12) is, for example, G
This is a thermal insulation layer made of FRP or the like. Also, (8a)
(8b) shows the lead line, (8a) shows the outgoing line of the first flow, [3b] shows the return line, and the arrow along the line shows the direction of the electrician. Further, the arrow Bt/'i indicates the magnetic flux density that intersects with the winding of the current switch.

The winding fi+ and the thermal insulation layer (2) are integrally impregnated with something like epoxy resin, for example.

Furthermore, FIG. 2 shows the direction of the ridges of the 11 springs from the axial direction of the permanent current switch, the direction of the field B, and the direction of the electromagnetic force f acting between the current and the field.

As can be seen from Figure 2, due to the non-inductive winding, the winding has the repulsive force between the currents in the adjacent layers and the external magnetic field (the composite electromagnetic force of the electromagnetic force due to the alternating magnetic flux density B). There is a compressive force i between the 3rd layer, 8th layer and 4th layer, and 5th layer and 6th layer.
! The tensile force between the 2nd and 8th layers, and the 4th and 5th layers is 141! I<. Since these forces cancel each other out, the magnitude of the electromagnetic force that acts is small.However, impregnating agents such as epoxy resins are strong in the compression direction, but even a small force causes a force in the tension direction. If this occurs, microcracks will occur. At this time, a slight amount of heat is generated. The superconductor #I wire used in permanent current switches is usually made entirely of non-copper-stabilized wire due to the need to increase its constant resistance.
These values are inherently very unstable and often lead to C quench due to minute disturbances. Therefore, the application of the electromagnetic force in the tensile direction described above causes microcracks in the impregnated resin, and the persistent current switch is very likely to be quenched due to the heat generated in the first system.

Furthermore, since these electromagnetic forces are approximately proportional to the product of magnetic flux density and current, the larger the current applied, the larger the electromagnetic force becomes.

However, which force of reaction generates enough heat to quench the persistent current switch depends on 66 conditions such as the state of immersion and the degree of close contact between the windings.

As mentioned above, conventional persistent current switches have a serious drawback of low current carrying performance and large variations in current carrying performance.

[Summary of the invention]

The present invention was made in view of this drawback, and an object of the present invention is to provide a persistent current switch that has high current carrying performance and is stable.

[Embodiments of the invention]

Hereinafter, an explanation will be given according to an embodiment of the present invention shown in FIG.

In the third factor, (4) is a spacer made of lv++ profile material such as a Teflon sheet, which is installed between the second and eighth layers and between the fourth and fifth layers. Therefore, there is a distance t2 between the second layer and the eighth layer, and between the fourth layer and the fifth eyelet, and the electromagnetic force in the above-mentioned tensile direction is 1! l) Even if J, the tensile stress of the impregnated resin VC acts <<, therefore,
Microcracks are also less likely to occur.

In this way, by performing mold release treatment between the layers of the winding where tensile force acts, the occurrence of cranking of @ soaked resin, which is the cause of quenching, is completely prevented, and the current carrying performance of the persistent current switch is improved and stabilized. The release material between the layers can be a Teflon sheet or a metal plate that has been subjected to release treatment such as 7/Recon baking, but
Anything else that can achieve the purpose of mold release may be used.

In the case of a thermal persistent current switch, the heating heater (5) is covered with a Teflon sheet (
If you sandwich it between 41 and serve as electrical insulation for the heater,
It is possible to reduce the thickness of the insulator between the tracks,
Effective in improving heating and cooling responsiveness.

〔Effect of the invention〕

As mentioned above, with this invention, v′,! It is possible to provide a water-input current switch km with high current carrying performance and stable and powerful operation.

[Brief explanation of drawings]

Fig. 1 is a structural diagram showing the @ wire structure of a conventional persistent current switch, Fig. 2 is an explanatory diagram showing the direction of electromagnetic force C acting on the winding,
FIG. 8 is a structural diagram showing an example of the present invention, and FIG. 4 is a structural diagram showing another embodiment of the present invention. In the figure, (ia) T (lb) is a super* conducting wire, (2)
are 82 marginal layers, (8a) and (3b) are lead lines, (4
1 interlayer female section, (5) is a heater. In the figures, the same reference numerals indicate the same or corresponding parts, respectively. Agent Masuo Oiwa 21'4

Claims (1)

[Claims] fi+ A superconducting wire with a high resistance value in a normal I&C conductor coil is wound non-inductively in a solenoid shape, impregnated with resin and hardened, and is operated by a persistent current in parallel with an ilm conductor coil. In a persistent current switch that is connected to utilize the SR transition phenomenon of the superconducting wire, the direction of the magnetic field that intersects in the axial direction of the persistent current switch and the direction of the persistent current flowing through the persistent current switch are always the same. The current direction of the superconducting coil is determined such that the current flow direction is such that the current flow direction is determined such that the current flow direction of the superconducting coil is determined, and in that current flow direction, the interlayers in which electromagnetic force acts in a direction in which adjacent layers of the superconducting winding forming the persistent current switch 1r repel each other are separated. A persistent current switch characterized by being separated from its shape so that it will not be glued during pilgrimage. (2) The persistent current switch according to claim 1, wherein a Teflon sheet spacer is interposed between the layers on which repulsive force acts to release the mold. (3) The persistent current switch is a thermal persistent current switch, and the Teflon sheet also serves as electrical insulation for the heater of the persistent current switch. Persistent current switch 0 according to claim 1, characterized in that a spacer made of a metal plate subjected to a process such as silicone baking is used for the persistent current switch 〇+419 type.