JPH08162318A - Permanent current switch - Google Patents

Abstract

PURPOSE: To restrict the occurrence of quench by surrounding and fixing a superconducting coil portion with an insulating fiber material and a highly flexible nonmagnetic conductive material and also by impregnating and hardening with a thermosetting resin. CONSTITUTION: A bobbin 10 is constituted with a bent frame 5 providing a bent pin 4 for noninductive winding of a superconducting wire at one end portion of a core 2 and also a grooved frame 8 providing a lead wire 7 for turning a lead wire 6 of the superconducting wire at another end portion. A heater wire 11 and a superconducting wire 12 are turned around a recessed portion of a winding on the bobbin 10 thereby forming a superconducting coil 13. The superconducting coil 13 fixed by turning an insulating fiber material 16a capable of impregnating a resin; its outer peripheral portion is surrounded by a flexible nonmagnetic conductive material (a thin lead sheet material 17 with a film thickness of larger than 20μm; and moreover insulating fiber material 16b is turned around the thin lead sheet material 17 for fixation. This is then impregnated with a thermosetting resin (epoxy resin) and formed in one united body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent current switch used in an exciting circuit of a superconducting magnet used in a power storage device, a magnetic levitation train, or the like, and more particularly to a superconducting coil of a superconducting coil cooled to a cryogenic temperature. The present invention relates to a persistent current switch for switching between a normal state and a normal conducting state.

[0002]

2. Description of the Related Art Conventionally, a persistent current switch is used by supplying a persistent current to a superconducting coil, for example, a power storage device,
It is used in the excitation circuit of superconducting magnets such as magnetic levitation trains.

A superconducting wire used in a persistent current switch has a superconducting filament embedded in a high resistance metal matrix such as cupro-nickel in order to increase the electric resistance when it is turned off. Therefore, this type of superconducting wire has extremely low stability, and there is a problem that quenching occurs even if a slight disturbance (magnetic field) is applied to the superconducting wire.

Various proposals have hitherto been made as a method for preventing such quenching of a superconducting wire used for a persistent current switch and stably using it. As one example thereof, in Japanese Patent Laid-Open No. 53-99794, the wound superconducting wire portion is impregnated with a synthetic resin to prevent mechanical movement of the superconducting wire which causes disturbance. Also, JP-A-61-24
In Japanese Patent No. 7081, the winding portion of a solenoid-type permanent current switch impregnated with resin is spread from the inside to apply tension to the superconducting wire to prevent movement of the superconducting wire. Furthermore, in Japanese Patent Laid-Open No. 60-22383, the lead portion of the superconducting wire is fixed with a metal material having excellent thermal diffusivity, such as a copper material, and local heat generation caused by friction between the lead wire and the lead wire retainer is generated. The suppression is stopped.

[0005]

In the above-mentioned prior art, the consideration of the difference in the coefficient of thermal expansion between the superconducting wire and the winding frame around which the superconducting wire is wound or the resin impregnating the superconducting wire has been insufficient.

Generally, the superconducting coil is impregnated and fixed with an epoxy resin in order to suppress the movement of the superconducting wire forming the superconducting coil, but the coefficient of thermal expansion of the epoxy resin is several times or more that of a metal material. When cooled, a large strain occurs due to the difference in the coefficient of thermal expansion of the superconducting wire,
Cracks occur in the resin layer. There is a problem that the persistent current switch is quenched by the movement of the superconducting wire when the crack occurs.

An object of the present invention is to provide a persistent current switch which suppresses such quenching and operates stably.

[0008]

The summary of the present invention for achieving the above object is as follows.

(1) A winding comprising a winding core, a bending frame having a non-inductive bending pin at one end of the winding core, and a grooved frame having a lead groove for winding the lead wire of a superconducting wire. In the frame,
A permanent current switch that includes a superconducting coil formed by winding a heater wire and a superconducting wire, and switches a superconducting coil cooled to a cryogenic temperature between a superconducting state and a normal conducting state. At least the heater wire and the superconducting wire are superposed coils. The permanent current switch is characterized in that the part is surrounded and fixed by an insulating fiber material and a highly flexible non-magnetic conductive material, and is impregnated and hardened with a thermosetting resin.

(2) A winding comprising a winding core, a bending frame having a non-inductive bending pin at one end of the winding core, and a grooved frame having a groove for winding the lead wire of a superconducting wire. In the frame,
A permanent current switch that includes a superconducting coil wound with a heater wire and a superconducting wire and switches between a superconducting state and a normal conducting state of a superconducting coil cooled to an extremely low temperature.The outer periphery of the permanent current switch is surrounded by an insulating fiber material. The permanent current switch is characterized in that it is housed in a highly flexible non-magnetic conductive material case and is filled with a thermosetting resin.

In the above, lead is most preferable as the highly flexible non-magnetic conductive material for the reason described below. It should be noted that the object of the present invention can be achieved by using a non-magnetic conductive material having high flexibility like lead. The highly flexible non-magnetic conductive material preferably has a film thickness of 20 μm or more.

As the insulating fiber material, one or more of glass fiber, carbon fiber and organic polymer fiber are used.

Further, an epoxy resin or a phenol resin in which the thermosetting resin is usually used is preferable. From the viewpoint of handleability, it is preferably liquid at room temperature. The resin may be mixed with a known curing agent, a filler, and the like.

[0014]

[Function] A permanent current switch in which the outer circumference of the superconducting coil is wrapped and wrapped with an insulating fiber material, and further covered with a thin lead sheet material which is a highly flexible non-magnetic conductive material and integrally molded with a thermosetting resin, is provided. It is resistant to electromagnetic waves and shocks and hard to quench because the thin lead sheet material, which is a highly flexible non-magnetic conductive material, follows the deformation of the composite of insulating fiber material and resin even in the heat cycle by heating and cooling. It is thought that this is because it can be deformed to suppress the occurrence of cracks and the like. Particularly, since lead becomes a superconducting conductor in a cryogenic cooling medium, it has an action of preventing a magnetic field from entering from the outside by a diamagnetic action peculiar to the superconducting conductor.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] FIG. 1 is a partially cutaway perspective view of a permanent current switch according to an embodiment of the present invention. A winding core 2 made of stainless steel (SUS), which is a non-magnetic metal material, is coated with a mica insulating material 3 on the periphery thereof, and one end of the winding core 2 has a bending pin 4 for non-inductively winding a superconducting wire. The bending frame 5 provided with is fixed, and the other end is fixed with a grooved frame 8 having a lead-out groove 7 for winding the lead wire 6 of the superconducting wire, and a winding recess 9 for forming a superconducting coil is formed. The reel 10 is formed.

A heater wire 11 is provided in the winding recess 9 of the winding frame 10.
(Manganin or nickel chrome) and superconducting wire 12
(NbTi alloy wire using CuNi as a stabilizing material) was wound to form the superconducting coil 13. At this time, the heater wire 11 wound inside the superconducting coil 13 becomes a heater wire for normal conduction transition. The heater terminal wire 14 connected to the heater wire 11 is drawn out from a heater wire through hole 15 provided separately from the lead-out groove 7.

The above-mentioned superconducting coil 13 is wound and fixed with an insulating fiber material 16a which can be impregnated with a resin, and its outer peripheral portion is made of a flexible non-magnetic conductive material (a thin lead sheet material 17 having a thickness of about 20 μm). The coating was surrounded and further wound and fixed on the thin lead sheet material 17 with an insulating fiber material 16b. This was impregnated with a thermosetting resin (epoxy resin) and integrally molded.

At this time, the non-induction winding groove 19 for arranging the superconducting wire from the bending pin 4 for non-induction winding, the lead-out groove 7 of the lead-out wire 6 and the fixing band 20 for fixing the lead-out wire 6 are made of the same thermosetting resin ( The permanent current switch 1 was manufactured by fixing with an epoxy resin) and integrally molding.

In the above-mentioned permanent current switch 1, the superconducting coil 13 is covered and surrounded by the insulating fiber material 16a, the thin lead sheet material 17, and the insulating fiber material 16b in this order, and is strongly protected by the insulating layer of the composite structure impregnated with the epoxy resin. Therefore, it is excellent against electromagnetic vibration and shock. Further, since the thin lead sheet material 17 is excellent in flexibility, even if the insulating layer is deformed by electromagnetic vibration, impact, etc., it is possible to prevent the occurrence of cracks and the like by following the deformation, resulting in the cracks and the like. Since it is possible to prevent the occurrence of quench due to thermal agitation, it is possible to provide a highly reliable persistent current switch.

Further, since the thin lead sheet material 17 covering and surrounding the superconducting coil 13 prevents the magnetic field from entering from the periphery,
A permanent current switch having a magnetic field shielding structure can be obtained.

In the present embodiment, a lead thin sheet material was used as the non-magnetic conductive material, but a permanent current switch having a magnetic field shielding structure was produced by changing this to a copper sheet material, and a heat cycle test for heating and cooling. I went. As a result, it was confirmed that peeling and resin cracking were less likely to occur when a thin lead sheet material was used. It is considered that this is because the thin lead sheet material adapts to the heat shrinkage due to the heat cycle and is deformed due to its material flexibility.

[Embodiment 2] FIG. 2 is a partially cutaway perspective view of a permanent current switch according to another embodiment of the present invention. An insulating bending frame 21 made of a glass fiber material is provided on one of the cores 2 coated with a mica insulating material 3 made of a non-magnetic metal material (SUS).
Is fixed to the other side by a frame 22 with a glass fiber insulating groove,
A shield winding frame 24 provided with a shield winding recess 23 was formed, and a heater wire 11 and a superconducting wire 12 were wound around the shield winding recess 23 to form a superconducting coil 13 for switching between a superconducting state and a normal conducting state. The heater terminal wire 14 of the heater wire 11 and the lead wire 6 of the superconducting wire 12 are arranged in the heater wire passage hole 15 and the lead groove 7, respectively.

The outer circumferences of the insulating bending frame 21, the insulating grooved frame 22 and the superconducting coil 13 are wound and covered with an insulating fiber material 16a which can be impregnated with resin, and a lead thin sheet material 17 is covered and surrounded on the insulating fiber material 16a. The whole was covered and wound with the insulating fiber material 16b, impregnated with an epoxy resin, and integrally molded to fabricate a permanent current switch 1.

As described above, similarly to the first embodiment, it is possible to obtain a highly reliable permanent current switch that is resistant to electromagnetic vibrations and shocks, excellent in stability against a magnetic field.

Since the shield coating is applied to the portion other than the superconducting coil 13, it is possible to obtain a permanent current switch which is more stable against a magnetic field.

[Embodiment 3] FIG. 3 is a partially cutaway perspective view of a permanent current switch according to another embodiment of the present invention. In the first and second embodiments, the superconducting coil 13 wound with the heater wire 11 and the superconducting wire 12 or the superconducting coil 13 and the winding frame are covered and wrapped with the insulating fiber materials 16a and 16b and the lead thin sheet material 17. It was impregnated and molded with an epoxy resin.

Non-magnetic core 25 coated with mica insulating material 3
An insulating winding frame 2 in which an insulating fiber bending frame 26 is fixed to one side and an insulating fiber grooved frame 27 is fixed to the other side to have a winding recess 29
8 is formed, and the heater wire 11 and the superconducting wire 1 are formed in the winding recess 29.
The unwound permanent current switch 30 having the superconducting coil 13 formed by winding 2 was constructed.

The core through hole 31 of the non-magnetic core 25, the heater wire through hole 32 of the heater wire 11, the outlet hole (not shown) of the superconducting coil 13 and the resin injection port 33 of the impregnated resin are provided. The unwinding permanent current switch 30 was housed in the housing case 34 made of a non-magnetic metal material provided, and epoxy resin was injected from the resin injection port 33 for impregnation molding.

In this embodiment, the unwound permanent current switch 30 not impregnated with resin is housed in the storage case 34 made of a non-magnetic metal material and impregnated with resin. Therefore, the unwound permanent current switch 30 and the storage case 34 are separately provided. Since the workability is good and the insulating fiber material 35 is easily impregnated with the resin by manufacturing, a highly reliable permanent current switch having a stronger resin impregnated structure which is hardly affected by the external magnetic field can be obtained.

[0031]

As described above, according to the present invention, the superconducting coil is surrounded by the insulating fiber material and the highly flexible metal from the outer peripheral portion, impregnated with the thermosetting resin and integrally molded and cured. Therefore, it is possible to provide a permanent current switch that is resistant to electromagnetic vibrations and shocks, stable against external magnetic fields, and highly reliable, with less occurrence of cracks and the like.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a persistent current switch according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of a persistent current switch according to a second embodiment of the present invention.

FIG. 3 is a partially cutaway perspective view of a persistent current switch according to a third embodiment of the present invention.

[Explanation of symbols]

1 ... Permanent current switch, 2 ... Winding core, 3 ... Mica insulating material,
4 ... Bending pin, 5 ... Bending frame, 6 ... Lead wire, 7 ... Lead groove, 8 ... Grooved frame, 9 ... Winding recessed portion, 10 ... Winding reel, 11 ...
Heater wire, 12 ... Superconducting wire, 13 ... Superconducting coil, 14
... Heater terminal wire, 15 ... Heater wire through hole, 16 ... Insulating fiber material, 17 ... Lead thin sheet material, 19 ... Non-induction winding groove, 20 ...
Fixed band, 21 ... Insulated bending frame, 22 ... Insulated grooved frame, 23
... shield winding recess, 24 ... shield winding frame, 25 ... non-magnetic winding core, 26 ... insulating fiber bending frame, 27 ... insulating fiber grooved frame, 28 ... insulating winding frame, 29 ... winding recess, 30 ... unwinding Permanent current switch, 31 ... Core through hole, 32 ... Heater wire through hole, 33 ... Resin injection port, 34 ... Storage case, 35 ... Insulating fiber material.

Claims (7)

[Claims] 1. A winding frame comprising a winding core, a bending frame having a non-inductive bending pin at one end of the winding core, and a grooved frame having a groove for winding a lead wire of a superconducting wire. In a permanent current switch that includes a superconducting coil wound with a heater wire and a superconducting wire and switches the superconducting coil cooled to cryogenic temperature between the superconducting state and the normal conducting state, at least the heater wire and the superconducting wire are wound. A persistent current switch characterized in that a superconducting coil portion is surrounded and fixed by an insulating fiber material and a highly flexible non-magnetic conductive material, and is impregnated and cured with a thermosetting resin. 2. The persistent current switch according to claim 1, wherein the highly flexible non-magnetic conductive material is lead. 3. The non-magnetic conductive material having high flexibility has a film thickness of 2
The persistent current switch according to claim 1, which is a lead foil having a thickness of 0 μm or more. 4. The insulating fiber material comprises one or more of glass fiber, carbon fiber and organic polymer fiber.
Alternatively, the permanent current switch described in 3 above. 5. The permanent current switch according to claim 1, wherein the thermosetting resin is an epoxy resin or a phenol resin. 6. A winding frame comprising a winding core, a bending frame provided with a non-inductive bending pin at one end of the winding core, and a grooved frame having a groove for winding a lead wire of a superconducting wire. In a permanent current switch that includes a superconducting coil wound with a heater wire and a superconducting wire, and switches the superconducting coil cooled to a cryogenic temperature between a superconducting state and a normal conducting state, the outer periphery of the permanent current switch is wound with an insulating fiber material. A persistent current switch characterized in that it is surrounded and housed in a highly flexible non-magnetic conductive material case and is filled with a thermosetting resin. 7. The persistent current switch according to claim 6, wherein the non-magnetic conductive case is lead and the thermosetting resin is an epoxy resin.