JPH01220805A - Compound superconducting field winding - Google Patents

Abstract

PURPOSE:To provide a field winding capable of generating magnetic field highly uniformly by removably mounting ribs on the surface of a torque tube for defining parallel grooves extending in the axial direction, and disposing a compound superconductor winding in the grooves. CONSTITUTION:Rib pairs 11 and 12, 21 and 22,...81 and 82 are provided on a torque tube 90 having projections extended longitudinally and spaced circumferentially by 90 deg.. These ribs are attached to the torque tube 90 by mechanically bolting the same, by welding or by means of a binder, so that a groove is formed therebetween. Winding is previously heat-treated by diffusion having the same configurations as those of the grooves in which the winding is to be disposed. The winding may be impregnated with epoxy resin if required. The winding contains a compound superconducting body. In order to arrange the winding on the torque tube 90, the winding is first disposed on the projections extending in the direction X and then the ribs 41 and 42 are fixed. The winding is disposed on the opposite side of the tube and the ribs 51 and 52 are fixed. In the same way, disposition of the winding and fixation of the ribs are repeated also in the direction Y. Finally, the winding is disposed and the ribs 11 and 12, 81 and 82 with wedge-like profile are fixed to complete a field winding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a superconducting field winding using a compound superconducting wire.

[Conventional technology]

Superconducting power generators are being developed in hopes of improving power generation efficiency and reducing mechanical dimensions. Although it is desirable to have a so-called fully superconducting machine in which both the rotor and stator are superconducting, at present, making only the field winding of the rotor superconducting is being considered.

The field winding is formed by placing a superconducting coil on a cryogenic cylindrical torque tube and fixing it to withstand high-speed rotation. The conventional field winding uses NbT4 alloy superconducting wire, and as shown in Figure 3, the torque tube (4) has a slot (
5), and a superconducting winding (6) is arranged in the slot (5) and fixed with a wedge (7). Another example is the torque tube (
8) Superconducting winding made of keystone-shaped wire on top (9)
It has a structure in which the outside is tightened with a binder (3). - On the other hand, in order to generate an even higher magnetic field and improve efficiency, the use of compound superconducting wire with a higher critical magnetic field in the field winding is being considered. However, since compound superconducting wires are extremely brittle with an allowable strain rate of usually 0.3% or less, the structure of the field winding is difficult to achieve as shown in Fig. 2(a).
As shown in b), a pair of racetrack-shaped superconducting windings (2) with excellent curvature within the allowable total are laminated, supported by a torque tube (1), and tightened on the outside with a binder (3). be.

[Problem to be solved by the invention]

Good uniformity of the magnetic field is essential for generator design, and the structures shown in Figures 3 and 4 applied to alloy superconducting wires have better uniformity of the magnetic field than the structure shown in Figure 2. Excellent in However, since the tolerance of compound superconductors is small, in order to adopt the structure shown in FIG. It was necessary to form a compound superconductor in the composite wire by pre-rolling and then heating at a necessary high temperature for a necessary period of time. However, when the field winding is manufactured by such a method, there is a problem that the strength of the torque tube material that also serves as the winding frame decreases due to heating, and it becomes unable to withstand high-speed rotation. Therefore, compound superconducting wires are used at the expense of magnetic field uniformity, and the advantages of compound superconductors' high critical temperature and high magnetic field and high current density cannot be fully utilized in generators. The invention has been made in view of the above points, and its object is to provide a compound superconducting field winding that generates a highly uniform magnetic field.

(Means for Solving the Problems and Their Effects) In order to achieve the above object, according to the present invention, a compound superconducting winding formed from a compound superconducting wire is arranged in a compound superconducting field magnet arranged on a torque tube. In the winding, the torque tube has a groove on its surface parallel to the axial direction of the torque tube formed by ribs to be attached and detached, and the compound superconducting winding is arranged in the liquid groove. A superconducting field winding is provided.

To create a compound superconducting field winding with the above structure, first, the compound superconducting winding is molded in advance according to the shape of the groove, and then,
It is manufactured by arranging the compound superconducting winding on a torque tube, then attaching ribs to the torque tube to form grooves, and fixing the compound superconducting winding. Therefore, the compound superconducting wire itself is not adversely affected by strain because the compound superconducting wire is molded and heat-treated before being attached to the torque tube. Furthermore, by designing the grooves formed on the torque tube in consideration of the generated magnetic field, a highly uniform magnetic field can be obtained.

〔Example〕

The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 is a cross-sectional view of the winding frame used in this example,
A pair of ribs (11, 12) on a torque tube (90) having protrusions in the longitudinal direction at intervals of 90@ on the circumference;
(21, 22), ... (81, 82) are formed. The ribs are formed by precision machining,
The torque tube (90) can be mechanically bolted,
Attached by welding or binder. The ribs formed in this way and the ribs and torque tube (
90) The groove between the protrusions on the top is formed with good dimensional accuracy a
The t' wire is previously subjected to diffusion heat treatment in a mold of the same type as the groove in which it is placed, impregnated with epoxy resin if necessary, and contains a compound superconductor.

The winding produced in this way is a torque tube (90
), but first, after placing the winding on the protrusion in the X direction, the ribs (41) and (42) are fixed, and after placing the winding on the opposite side, the rib (51), (52) is fixed. Thereafter, the winding arrangement and rib fixation are repeated in the Y direction, and finally the ribs (21), (22) and rib (7
After fixing 1) and (72), the winding is arranged and the ribs (11), (12) and (81), (82) each having a wedge-shaped cross section are fixed to complete the field winding. Finally, if necessary, further impregnation with epoxy resin can be performed.

The winding used in this example was 1ffI which was not heat treated.
It is a two-turn winding formed from I11×5ffIIl Nb5Sn compound composite wire (the outside of the wire is insulated with 250-glass), and after heat-treating this winding and placing it on the torque tube. , the ribs were bolted together to form the field winding, and finally the whole was vacuum impregnated with epoxy resin. The inner diameter of the torque tube in this case is 25
mm, medium diameter is 34mm, outer diameter is 45+nm, minimum bending diameter of winding is 10IIIfi, straight part length is 800m.
It was a+. For comparison, N was subjected to similar heat treatment.
b. A Sn compound composite wire was wound in a conventional manner as shown in FIG. 3 and impregnated with epoxy resin. Table 1 shows the results of various tests conducted on these windings.

The Ic of the straight section is measured by attaching a voltage terminal to the center 50mm of the 80oIIIIIIl long straight section.
The c measurement was carried out by attaching a voltage terminal to the transition point from the curved part of the ribs (11, 12), which is the minimum radius of curvature, to the straight part. In the comparative example, the curved portion did not exhibit a superconducting state and Ic was set to zero, but this is thought to be because the compound superconductor in this portion was discontinuous due to bending.

The following comparative experiment was conducted to evaluate the uniformity of the magnetic field. As a comparative example (C), 1 f without heat treatment
After insulating the fIIX 5 tra Nb, Sn compound composite wire with glass tape of about 250μ, we prepared four sets of racetrack coils with two turns each as shown in Fig. 2(b), and after heat treatment, each coil was Epoxy impregnated, second [
The field winding was completed with the arrangement shown in ff1(a).

In comparative example (C), the Ic characteristics of the curved portion were not deteriorated, but
The uniformity of the magnetic field (relative value with Example (A) as 1) is poor.

〔Effect of the invention〕

As explained above, according to the present invention, the torque tube has a groove on its surface that is parallel to the axial direction of the torque tube and is formed by ribs that can be attached and detached, and the compound superconducting winding is disposed in the liquid groove. Because of this, a highly uniform high magnetic field can be obtained.
This has the excellent effect of maintaining the mechanical strength of the torque tube.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the frame portion of an embodiment of the present invention, and FIG. 2 (
a) is a cross-sectional view of a conventional compound superconducting field winding; FIG. 2(b) is a perspective view of the compound superconducting winding used therein;
Figure 3 is a cross-sectional view of a conventional alloy superconducting field winding, Figure 4 (a) is a cross-sectional view of another conventional alloy superconducting field winding, and Figure 4 (b) is a perspective view thereof. be. 1.4, 8.90...torque tube, 2.6゜9...superconducting winding, 3...binder, 5...
・Slot, 7...Wedge, 10...Spacer, ■1゜12.21.22.31.32.41.
42.51.52.61.62゜71, 72.81.8
2...Rib. Patent applicant Furukawa Electric Co., Ltd. (a)
(b) Figure 2

Claims (1)

[Claims] Compound superconducting winding formed from compound superconducting wire,
In a compound superconducting field winding arranged on a torque tube, the torque tube has a groove on its surface parallel to the axial direction of the torque tube formed by a rib to be attached and detached, and the compound superconducting field winding is placed on the torque tube. A compound superconducting field winding characterized in that it is arranged in a groove.