JPH04276602A - Interlayer insulation method for water-cooled magnet coils - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for interlayer insulation of water-cooled magnet coils.

0002

2. Description of the Related Art An apparatus for generating a strong magnetic field of 10 T or more is constructed by disposing a superconducting magnet coil 2 concentrically outside a water-cooled magnet coil 1, as shown in FIG. At the center 3 of the magnetic field of the water-cooled magnet coil 1, the sum of the magnetic fields generated by both the magnet coils 1 and 2 becomes maximum, and a strong magnetic field of, for example, 30 T or more can be generated. This water-cooled magnet coil has polyhelix type, bitter type, and monohelix type.

[0003] A water-cooled magnet is supplied with several MW of power and generates an enormous amount of heat of several MJ, so it is cooled with pure water (deionized water) having a resistivity of 1 MΩcm or more for electrical insulation. ing.

0004

[Problems to be Solved by the Invention] Such a water-cooled magnetic coil is shown in FIG. 6 using a polyhelical coil as an example, and the interlayer insulation 5 inserted between the helically wound conductors 4 is Due to the interaction of the heat due to Joule loss generated during operation, the pure water that boils due to the heat, and the weak current flowing through the interlayer insulation, a moth-eaten hole forms in the interlayer insulation in a relatively short period of time, resulting in an interlayer short circuit. This may lead to the inconvenience that the magnet no longer functions properly. In view of these circumstances, the present invention aims to provide a water-cooled magnet coil in which interlayer short circuits are less likely to occur. [Structure of the invention]

[0005]

[Means for Solving the Problems] As shown in the cross-sectional view in FIG. A prepreg sheet 9 is obtained by disposing a base material 7 and impregnating this base material with a thermosetting resin 8 having excellent heat resistance, water resistance, and electrical insulation properties to bring it into a semi-cured state. As shown in FIG. 2, a method for interlayer insulation of water-cooled magnet coils comprises inserting this prepreg sheet 9 between conductors 4, heating the conductors while pressing them, and curing the thermosetting resin in the prepreg sheet. It is.

Polymer films with excellent heat resistance, water resistance, and electrical insulation properties include polyimide (PI) film, polyether ether ketone (PEEK) film, polyether sulfone (PES) film, and polyphenylene sulfide ( PPS) film, aramid film, polytetrafluoroethylene (PTFE) film, etc. Further, examples of thermosetting resins having excellent heat resistance, water resistance, and electrical insulation include polyimide resins, bismaleimide triazine (BT) resins, and epoxy resins. Both sides of the polymer film are processed by mechanical methods such as sandblasting, corona discharge, chemical methods, etc.
It is good to rough up the face.

[0007] Glass woven fabrics also include methacrylate chromic chloride, vinyltrichlorosilane, γ-aminopropyltriethocine, N-β-N vinylbenzylamino-γ-aminopropyltrimethoxysilane monohydrodiene chloride, γ-N phenylamino It is desirable to perform surface treatment with a surfactant such as propyltrimethoxysilane.

[0008]

[Operation] In the present invention, the thermosetting resin in the prepreg sheet is cured by heating while pressing between the conductors. By adhering and integrating the conductors, the mechanical strength as a magnet is increased. This is to preserve it.

[0009] Also, the reason why we used materials with excellent heat resistance, water resistance, and electrical insulation properties for the thermosetting resin and polymer film is that the heat generated by the Joule loss generated during operation of the water-cooled magnet, This is to prevent the interlayer insulation from deteriorating due to the interaction of the boiling pure water and the weak current flowing through the interlayer insulation, causing holes in the interlayer insulation to become moth-eaten, resulting in an interlayer short circuit.

[0010] In particular, polymer films have a higher dielectric breakdown strength per unit thickness than GERP (glass fiber reinforced plastic), and have the characteristics that it is difficult for electric current to flow through them. Since the film generally has poor adhesive strength, it is placed in the center of the prepreg sheet so that it does not come into direct contact with the conductor. The reason why it is preferable to roughen both sides of the film is to improve adhesion at the interface between the GFRP and the polymer film formed after curing, and to create a structure that is difficult for water to penetrate. In addition, it is recommended to surface-treat the glass fibers with a surfactant such as a silane coupling agent to improve wetting of the interface between the thermosetting resin and the glass fibers, improve adhesion, and create a structure that is difficult for water to penetrate. This is to make it happen.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. First, as polymer films with excellent heat resistance, water resistance, and electrical insulation, we used a 25 μm thick polyimide film (product name Kapton, manufactured by DuPont Toray) and polyether ether ketone (PEEK) film (product name TALPA-). 2000C (manufactured by Mitsui Toatsusha) is prepared. On both sides of this film, 30 μm thick γ
-N phenylaminopropyltrimethoxysilane treated glass fabric is placed and bismaleimidotriazine (B
T) Resin (product name BTA-300: manufactured by Mitsubishi Gas Chemical Co., Ltd.)
and epoxy resin (trade name E-23A, manufactured by Arisawa Seisakusho Co., Ltd.) and dried at 110°C for 10 minutes to produce a semi-cured prepreg sheet with a resin content of approximately 83% by weight in the glass woven fabric portion. did.

[0012] For comparison, the thickness was 100 μm.
glass woven fabric (product name #30.1: manufactured by Arisawa Seisakusho Co., Ltd.)
was impregnated with BTA-300 and dried at 110°C for 10 minutes to produce a semi-cured prepreg sheet with a resin content of about 45% by weight.

As shown in FIG. 2, these prepreg sheets 9 are cut into a C-shape to match the shape of the conductor, and as shown in FIG. 3, cut into pieces slightly larger than the conductor 4. The two prepreg sheets are successively inserted between all the helical conductors in an overlapping state by arranging them so as to overlap each other and sequentially shift their positions in the circumferential direction.

As shown in FIG. 4, the coil 10 with the prepreg sheet inserted between the conductors has a predetermined length H inside and a polytetrafluoroethylene film on the surface for mold release. Insert the copper pipe 12 wrapped with the sheet 11, tighten it using the threaded rod 15 and hexagonal nut 16 via the steel flange 13 and spring washer 14, and heat it in a dryer at 160 °C for 16 hours. As a result, the conductor is cured while pressing the prepreg sheet 9.

[0015] In the above embodiment, the prepreg sheets cut into a C-shape are arranged so that the prepreg sheets are overlapped in half and are sequentially shifted in the circumferential direction. The prepreg sheets can be placed one on top of the other in a continuous manner to form interlayer insulation with an even thickness, and by placing at least one unbroken layer of prepreg sheets between the conductors, weak points can be avoided along the entire length between the conductors. or interlayer insulation can be formed. The reason why the prepreg sheet was cut to be slightly larger than the conductor was to increase the creeping distance between the conductors and make it difficult for current to flow along the creeping surface.

[0016] The reason why a hexagonal nut was used to tighten the spring washer was because when the prepreg sheet was heated, the resin contained in the prepreg sheet became fluid and the conductor was pressed by the force of the spring washer. , the prepreg sheet is deformed until it is stopped by the copper pipe, and eventually hardens and integrates into a predetermined size.

The interlayer insulation using the prepreg sheet in which the polymer film of this example is placed in the center has a dielectric breakdown strength of 88 kV/mm, whereas the comparison with the prepreg sheet using glass woven fabric as the base material shows that the interlayer insulation has a dielectric breakdown strength of 88 kV/mm. The example interlayer insulation is 58
kV/mm, which is about 1.5 times higher.

When these water-cooled magnets with interlayer insulation were operated under the same conditions of power consumption of 7.2 MW and central magnetic field of 19 T, in the case of the comparative example, the operating time was 135 h;
Whereas interlayer short circuit occurred and operation became impossible, in the case of the present example, no abnormality occurred even after operation for 2000 hours or more. Next, other embodiments of the present invention will be described below.

In the above examples, polyimide (PI) was used as a polymer film with excellent heat resistance, water resistance, and electrical insulation properties.
) Film, polyetheretherketone (PEEK)
Although a film was used, polyether ether sulfone (
PES) film, polyphenylene sulfide (PP
S) film, aramid film, and polytetrafluoroethylene (PTFE) film may also be used.

[0020] Bismaleimide triazine (B
T) Although resin and epoxy resin were used, polyimide resin may also be used. Furthermore, although a woven glass fabric was used as the base material in the above embodiments, a non-woven glass fabric may also be used.

[0021]

As explained above, according to the present invention, a base material such as glass woven fabric or non-woven fabric is placed on both sides of a polymer film having excellent heat resistance, water resistance, and electrical insulation.
This base material is impregnated with a thermosetting resin with excellent heat resistance, water resistance, and electrical insulation, and a semi-cured prepreg sheet is inserted between the conductors, heated while pressing between the conductors, and the prepreg sheet is heated. The thermosetting resin is hardened to form the interlayer insulation of the water-cooled magnet, so there is heat due to Joule loss generated while the magnet is operating, pure water that boils due to the heat, and a weak amount that flows through the interlayer insulation. The interlayer insulation becomes moth-eaten and has holes due to deterioration caused by the interaction of electric currents.
Interlayer short circuits are less likely to occur, allowing stable operation over a long period of time.

[Brief explanation of the drawing]

[Fig. 1] A cross-sectional view showing the structure of a prepreg sheet used in an example of the present invention.

[Figure 2] Diagram showing the shape when the prepreg sheet in Figure 1 is cut

[Figure 3] Diagram explaining the relationship between the size of the conductor and prepreg sheet

[Figure 4] Diagram for explaining the method of manufacturing a coil according to the present invention

[Figure 5] Diagram explaining the configuration of a hybrid magnet

[
Figure 6: Diagram showing the configuration of a polyhelical coil

[Explanation of symbols]

1...Water-cooled magnet coil 2...Superconducting magnet coil

Claims (3)

[Claims] Claim 1: A base material such as glass woven fabric or non-woven fabric is placed on both sides of a polymer film with excellent heat resistance, water resistance, and electrical insulation properties, and this base material has heat resistance, water resistance, and electrical insulation properties. A semi-cured prepreg sheet impregnated with an excellent thermosetting resin is inserted between conductors, and heated while pressing between the conductors to harden the thermosetting resin in the prepreg sheet. Water-cooled magnet coil interlayer insulation method. 2. The interlayer insulation method for a water-cooled magnet coil according to claim 1, wherein bismaleimide triazine or epoxy is used as the thermosetting resin. 3. The interlayer insulation method for a water-cooled magnet coil according to claim 1, wherein a polyetheretherketone film or a polyimide film is used as the polymer film.