JPH08236343A - Method and equipment for manufacturing superconducting coil and permanent current switch - Google Patents

Abstract

PURPOSE: To enable sink marks to be less generated in a resin layer in the vicinity of the center of a coil-wound port and to manufacture a superconducting coil and a permanent current coil where quenching hardly occurs. CONSTITUTION: A superconducting coil 1 in a winding frame 3 is composed of a superconducting wire 2 which is wound in a coil and a thermosetting resin 5. When the resin 5 is cured by heating, a current is applied to a drying oven heater 10 by a temperature controller 8, and also a current is fed to a superconducting wire 2 from a direct current power supply 7. At this point, the set curing temperature of the resin 5a near the center of the resin 5 is set 1 to 10 deg.C higher than that of the peripheral resin 5b. By this setup, the center part 5a of the resin 5 is cured first, and then the peripheral part 5b is gradually cured, so that sink marks are less generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a superconducting coil and a permanent current switch which are solidified and fixed by a thermosetting resin such as an epoxy resin.

[0002]

2. Description of the Related Art A superconducting wire used in a superconducting coil for a magnetic levitation railway or nuclear magnetic resonance imaging (MRI) has a base material made of a metal having a low specific resistance such as Cu or Al, and a superconductor made of Nb-Ti. Those composed of alloys such as Nb ₃ —Sn and compounds such as Nb ₃ —Sn are generally used.

The structure of the superconductor inside the superconducting wire used for the permanent current switch is the same as that of the superconducting coil, but its base material is made of Cu-Ni or the like in order to increase the resistance when the switch is turned off. It is generally composed of a metal having a high specific resistance value. In these superconducting coils, due to some disturbance during energization, the superconducting wires move about several μm to generate thermal energy, which causes local heat generation in the superconducting coils. The temperature rise due to this heat generation is usually suppressed by cooling the surroundings.However, when the amount of heat generation exceeds the cooling capacity and the temperature rise value exceeds the critical temperature of the superconducting wire, the locally heated location is always in the superconducting state. Transfers to the conductive state. This state propagates throughout the superconducting coil,
Loss of characteristics as a superconducting coil is usually called a quench phenomenon.

Even if the superconducting wire does not move, if some kind of thermal energy is generated around the superconducting wire, local heat is generated, and a bud of the normal-conducting transition may occur to cause quenching.

In particular, since the superconducting wire used in the persistent current switch is a base material of a metal having a high specific resistance that does not contribute to stabilization, the superconducting wire having a low specific resistance as a base material leads to quenching. easy.

In the case of a superconducting coil, a high magnetic field is generated due to its characteristics, so that a hoop force that spreads to the outer periphery when energized acts to move the superconducting wire toward the outer periphery of the coil.

In order to suppress the movement of the superconducting wire due to any disturbance or hoop force as described above as much as possible, the superconducting coil and the persistent current switch are wound with high tension,
Alternatively, a method of impregnating or casting an epoxy resin or the like after winding and solidifying and fixing is mainly used. However, superconducting coils and permanent current switches for magnetic levitation railways
Strong vibrations from outside during driving.

Therefore, if the coil is wound with only a high tension, there is a risk of friction between the wires and a large deviation of the wire material, which may lead to quenching. Therefore, it is generally fixed and fixed by a thermosetting resin such as an epoxy resin.

In addition, a coil using a compound superconductor such as Nb ₃ -Sn is heated to form a compound after winding. However, before compounding, the coil is soft and easily damaged, so that winding with high tension is possible. Is not possible, and since it becomes a hard and brittle wire after compounding, it is necessary to solidify and fix with an epoxy resin or the like.

A method of manufacturing an impregnated coil which needs to be solidified and fixed with such an epoxy resin will be described by taking a superconducting coil used in a magnetic levitation railway as an example.

FIG. 15 is an explanatory view of the winding method of this coil. In this figure, 1 is attached to the metal winding form 3.
The maximum experience magnetic field of the flat superconducting wire 2 is about 5T.
In order to generate (Tesla), about 1000 turns are wound by the winding machine 16.

After the winding is finished, as shown in the sectional view of FIG. 16 (a), the winding die 3 is housed in the impregnation tank 6, and after impregnated with the resin 5, the impregnation tank 6 and the impregnation tank 6 are carried into the drying furnace 9. . Then, after being cured by hot air from the heater of the drying oven 9 at about 80 to 100 ° C. for several tens of hours, the winding form 3 is taken out from the resin 5 on the outer peripheral portion thereof, and the winding form 3 is disassembled. As a result, FIG.
The superconducting coil 1 as shown in (c) is completed.

As another method, after winding, as shown in FIG.
As shown in (b), there is also a method in which the winding wire 3 is provided with a heater wire 12. That is, after injecting the resin 5 from the impregnation port 4, the winding heater 12 cures the resin at about 100 ° C. for several hours, and then the winding die 3 is disassembled. As a result, the superconducting coil 1 as shown in FIG. 16C is formed.

[0014]

As described above, the method for curing the resin after impregnating or injecting the thermosetting resin such as epoxy into the coil is the method using the drying oven or the winding mold (or the mold for molding). Although the method of using a heater) is generally used, in both cases, the heat of the drying furnace and the heater is gradually transferred from the surface of the coil to the inside of the coil when the resin is cured.
Therefore, the resin around the coil tends to cure first, and the resin near the center of the coil tends to cure last.

In the case of such curing, the resin around the coil is cured before the resin near the center of the coil, so that the resin near the center of the coil is attracted to the outer periphery, and a nest as shown in FIG. 17 may occur.

The superconducting coil 1 is cooled to a cryogenic temperature during its operation and is externally energized until it has a predetermined magnetomotive force. However, when the sink mark 17 as described above exists, a crack caused by the sink mark 17 occurs,
Since the heat energy at that time is transmitted to the superconducting wire 2, there is a risk of causing local heat generation and quenching.

When the sink mark 17 is adjacent to the superconducting wire 2, the superconducting wire 2 causes local heat generation due to the generation of thermal energy due to the displacement of the superconducting wire 2 on the sink mark 17 side, and the quenching also occurs. There is a risk that In this case, since the curing shrinkage force of the resin 5 increases in proportion to the cross-sectional area of the superconducting coil 1, it is considered that the probability that the sink mark 17 is generated and the amount thereof are also increased in accordance with the cross-sectional area.

The present invention has been made in view of the above circumstances, and it is possible to reduce the occurrence of sink marks in the resin layer near the center of the coil-shaped winding portion, and manufacture a superconducting coil and a persistent current switch in which quenching does not easily occur. It is an object of the present invention to provide a method and a device capable of

[0019]

As a means for solving the above-mentioned problems, the present invention impregnates or casts a thermosetting resin into a winding mold in which a superconducting wire is wound in a coil shape and then heats it. When curing this thermosetting resin by
The heating is performed such that the resin layer temperature near the center of the coil-shaped winding portion in the cross-sectional direction of the superconducting wire is higher than the resin layer temperature around the coil-shaped winding portion by a predetermined temperature. It is a thing.

[0020]

[Function] When the winding mold after impregnation or casting is put in a drying oven to cure the resin, the resin around the coiled winding portion inevitably cures first, and then the resin near the center of the coiled winding portion. Will be cured. That is, the curing time of the resin near the center of the coiled winding portion is long.

On the other hand, the thermosetting resin has a characteristic that the curing time becomes shorter as the curing temperature becomes higher. Therefore, in the above structure, the resin layer near the center of the coiled winding portion starts to be cured first, and then the resin layer around the coiled winding portion is cured. Therefore, the occurrence of sink marks can be reduced.

[0022]

1 is a block diagram of an apparatus according to a first embodiment of the present invention. In this figure, a superconducting coil 1 formed by winding a superconducting wire 2 in a coil shape is housed in a winding die 3 together with a thermosetting resin 5 such as epoxy. Where 5a
Indicates the resin near the center of the coil-shaped winding portion, and 5b indicates the resin around the coil-shaped winding portion.

The winding form 3 is immersed in an impregnation tank 6 filled with a resin 5, and the impregnation tank 6 is placed in a drying furnace 9. A winding start lead wire 2a and a winding end lead wire 2b of the superconducting wire 2 are connected to a DC power supply 7. Also, the drying oven 9
A drying furnace heater 10 is provided in the lower part of the.

Thermocouples 20a and 20b for detecting respective temperatures are provided on the resins 5a and 5b. The temperature controller 8 controls the currents of the DC power supply 7 and the drying furnace heater 10 based on the detection of the thermocouples 20a and 20b, and controls the temperatures of the resins 5a and 5b.

Next, the operation of FIG. 1 will be described. First,
As shown in FIG. 2, resins 5a and 5b are injected into the winding die 3. After that, this is immersed in the impregnation tank 6, and as shown in FIG. 1, the impregnation tank 6 is placed in the drying furnace 9. Then, the temperature controller 8 energizes the drying oven heater 10 to raise the temperature in the oven, and further causes the DC power source 7 to energize the superconducting wire 2 to heat and cure the resins 5a and 5b. In this case, the curing temperature of the resin 5a is set to be 10 ° C. higher than the curing temperature of the resin 5b.

FIG. 3 is an example of a characteristic diagram showing the relationship between the curing temperature of an impregnating epoxy resin and the time until gelation (resin solidification). According to this figure, it is understood that the gelling time becomes shorter as the curing temperature becomes higher. For example, at a curing temperature of 90 ° C and 100 ° C, 10
At 0 ° C., gelation occurs about 1 hour faster.

Therefore, assuming that the setting temperature of the resin 5a is 100 ° C. and the setting temperature of the resin 5b is 90 ° C., the resin 5a starts to be cured first.
It takes 1 hour after the resin 5a is cured to cure the resin 5b.

In this way, the curing temperature of the resin 5a is set to the resin 5
When the temperature is higher than the curing temperature of b by 10 ° C., the resin 5b does not start to cure first as in the conventional case, so that the occurrence of sink marks can be reduced. Further, in the configuration of FIG. 1, since the temperature can be finely adjusted using the thermocouples 20a and 20b, the difference in curing shrinkage between the resins 5a and 5b can be controlled in advance, and the difference in residual stress due to the difference in shrinkage can be reduced. It can be made as small as possible.

By the way, when the impregnated resin such as epoxy resin is cured, since the curing shrinkage is remarkable when the main curing temperature is set from the beginning, it is semi-cured (primary curing) at a temperature lower by about 20 ° C. to 40 ° C. It is common to completely cure (secondary cure) at the main curing temperature.

Therefore, in this embodiment also, such a curing method is adopted. FIG. 4 shows an example of a curing pattern in that case. For the resin 5a, the curing temperature of the primary curing region and the secondary curing region is 80 ° C., 10 ° C.
The temperature is set to 0 ° C., and the curing temperature of each region of the resin 5b is set to 70 ° C. and 90 ° C.

Since the thermocouples 20a and 20b are no longer needed after the heat curing is completed, they can be cut at appropriate places. Further, in the manufacturing line, the thermocouples 20a and 20b need not be used for manufacturing all superconducting coils. That is, one or more superconducting coils are heated and cured by using the thermocouples 20a and 20b, and when the heating control pattern is grasped, thereafter, for the superconducting coils having the same specifications, the thermocouple 20a, 20
It is possible to perform the temperature control based on the grasped control pattern without performing the control based on the temperature detection of b.

Further, when performing the above-mentioned heat curing, the inside of the drying furnace 9 is filled with nitrogen gas or the like, and the internal pressure is adjusted to 10 to 10.
If pressure is applied to about 30 kg / cm 2, the sink marks generated on the resins 5a and 5b can be further reduced.

Further, although the above-mentioned embodiment is intended for the superconducting coil, it is of course applicable to a permanent current switch having a similar structure.

FIG. 5 is a block diagram of an apparatus according to the second embodiment of the present invention. As shown in FIG. 6, in the superconducting coil 1,
In many cases, voltage measurement lines 11a, 11b, 11c, 11d for measuring the internal voltage during energization and quench are attached. In the present embodiment, the lead wires 2a and 2b of the superconducting coil 1 and the measuring wires 11a to 11d are used together to energize the superconducting wire 2. In addition,
In FIG. 5, description of the reference numerals that are the same as those in FIG. 1 is omitted.

In FIG. 5, the resin 5a near the center is heated by energization of the superconducting wire 2 sandwiched between the measurement lines 11b and 11c, and the left resin 5c and the right resin 5d are respectively connected to the lead wire 2a. And the measurement line 11a, and between the measurement line 11d and the lead wire 2b are heated by energization of the superconducting wire 2.

FIG. 7 is a characteristic diagram showing an example of the curing pattern of this embodiment. As shown in this figure, in the primary curing region, the thermosetting temperature is set to 90 ° C. for the resin 5a, 85 ° C. for the resins 5c and 5d, and 80 ° C. for the resin 5b. Then, in the secondary curing region, the resin 5a is 120 ° C.,
The thermosetting temperature of each of the resins 5c and 5d is set to 110 ° C.

Also in this embodiment, if the resin having the characteristics shown in FIG. 3 is used, the time difference between the gelation (solidification of the resin) at 80 ° C. and 90 ° C. is 2 hours. From the 5a side to the resin 5b side, it is possible to gradually gelate over 2 hours.

FIG. 8 is a block diagram of an apparatus according to the third embodiment of the present invention. In this embodiment, the embedded heater 12 is embedded inside the winding form 3, and the temperature controller 8 includes the embedded heater 12.
It is designed to control the current flowing through. In this embodiment, since the embedded heater 12 comes close to the resin 5b to facilitate temperature control, better temperature characteristics can be obtained.

By the way, Cl, Al or Cu-Ni
A value obtained by dividing the area of the base material such as by the area of the superconductor such as Nb-Ti or Nb ₃ -Sn is called a base material matrix ratio. As shown in the cross-sectional view of FIG.
The cross-sectional area of the resin is kept constant, and becomes smaller as it approaches the resin 5a near the center. Note that the configuration in which the matrix ratio is changed in this way can of course be applied to other embodiments.

By changing the matrix ratio as described above, an effective temperature difference can be provided as compared with the case where the matrix ratio is constant. That is, since the superconductor has a resistance higher than that of the base material in the normal conducting state (normal temperature), almost all the current flows in the base material when the current is applied at room temperature. On the other hand, when the cross-sectional area of the superconducting wire is constant, the smaller the matrix ratio is, the smaller the area of the base material is, and the higher the resistance at room temperature is.

In such superconducting coil 1, since the matrix ratio of the superconducting wire 2e at the central portion is small, the superconducting wire 2d around it is medium, and the superconducting wire 2c near the surface is large. , The temperature gradually increases from the surface side to the center side.

Although it is ideal to change the matrix ratio in the vertical and horizontal directions as shown in FIG. 10, the winding work becomes considerably difficult. Therefore, as shown in FIG. 11, the matrix ratio may be changed only in the vertical direction, that is, only from the inner and outer circumference sides to the center side.

FIG. 12 is a block diagram of an apparatus according to the fourth embodiment of the present invention. In this embodiment, a switch circuit 1 for putting a superconducting wire 2 wound in a coil into a short circuit state or an open state.
6 and an induction coil 13 installed near the winding form 3 and energized by an AC power supply 17.

When the superconducting wire 2 is short-circuited and an alternating current is passed through the induction coil 13, the induced current flows through the coil-shaped superconducting wire 2 and the temperatures of the resins 5a and 5b rise. In order to suppress the temperature rise, the switching circuit 16 may be turned off and put into an open state. The temperature controller 8 performs such temperature control.

The superconducting wire 2 of the third embodiment has a different matrix ratio, but in the fourth embodiment, as shown in FIG.
As shown in FIG. 3, the cross-sectional area is changed.
In such a configuration, the inner and outer peripheral superconducting wires 2f
Has a large cross-sectional area and thus has a small resistance, and the central superconducting wire 2g has a small cross-sectional area and thus has a large resistance. Therefore, the temperature on the center side can be made higher than that on the inner peripheral side and the outer peripheral side, and the temperature difference can be effectively provided.

In the fourth embodiment, an example in which the cross-sectional area is changed only in the vertical direction is shown, but it is ideal if the cross-sectional area is changed not only in the vertical direction but also in the horizontal direction.

FIG. 14 is a block diagram of an apparatus according to the fifth embodiment of the present invention. However, this fifth embodiment is intended only for the permanent current switch.

Most of the permanent current switches currently used are of the so-called thermal switching type, which switches between the superconducting state and the normal conducting state by turning the heater on and off during operation. FIG. 14 shows such a thermal-type open / close type permanent current switch 14, which is a superconducting wire 2
A permanent current switch heater 15 is mounted between the two.
Then, by energizing the heater 15 from the direct current power supply 7 through the lead wires 15a and 15b, it is possible to make a temperature difference between the resin 5a (not shown) near the center and the resin 5b around the center.

According to each of the above-mentioned embodiments, when manufacturing the superconducting coil and the impregnated coil of the persistent current switch,
When the resin is cured, the resin can be gradually cured from the inside of the impregnated coil, so that it is possible to reduce the occurrence of internal sink marks as compared with the conventional case.

Therefore, during operation of the superconducting coil and the persistent current switch, quenching due to local heat generation of the superconducting wire due to crack generation due to internal sink portion and quenching due to local heat generation due to movement of the superconducting wire into the sink portion It is possible to manufacture a superconducting coil and an impregnated coil for a persistent current switch that can be reduced in number and have higher stability than before.

Further, since a fine temperature distribution is possible by controlling the internal temperature of the impregnated coil and the ambient temperature with a controller or the like, there is little variation in production and less variation in performance. Can be obtained.

Although various modes have been introduced in the above-mentioned embodiments, these modes can be freely combined without departing from the spirit of the present invention.

[0053]

As described above, according to the present invention, the temperature of the resin layer in the vicinity of the center of the coil-shaped winding portion in the cross-sectional direction of the superconducting wire is a predetermined temperature higher than the temperature of the resin layer around the coil-shaped winding portion. Since the heating is performed so as to raise the temperature, it is possible to reduce the occurrence of sink marks in the resin layer near the center of the coil-shaped winding portion, and to manufacture a superconducting coil and a persistent current switch in which quenching is less likely to occur.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an apparatus according to a first embodiment of the present invention.

2 is an explanatory view of the structure of the superconducting coil in FIG.

FIG. 3 is a characteristic diagram regarding gelation of a resin in the first embodiment.

FIG. 4 is a characteristic diagram of a resin curing pattern in the first embodiment.

FIG. 5 is a configuration diagram of an apparatus according to a second embodiment of the present invention.

6 is an explanatory view of the structure of the superconducting coil in FIG.

FIG. 7 is a characteristic diagram of a resin curing pattern in the second embodiment.

FIG. 8 is a configuration diagram of an apparatus according to a third embodiment of the present invention.

FIG. 9 is a perspective view showing the shape of a superconducting coil according to a third embodiment.

10 is a cross-sectional view taken along line XX of FIG.

11 is a cross-sectional view showing a modified example of FIG.

FIG. 12 is a configuration diagram of an apparatus according to a fourth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a changed state of the cross-sectional area of the superconducting wire in the fourth embodiment.

FIG. 14 is a configuration diagram of an apparatus according to a fifth embodiment of the present invention.

FIG. 15 is an explanatory diagram of how to wind a superconducting wire.

FIG. 16 is an explanatory diagram of a conventional manufacturing method.

FIG. 17 is an explanatory diagram of a problem of the conventional manufacturing method.

[Explanation of symbols]

 1 superconducting coil 2 superconducting wire 3 winding type 5 epoxy resin (thermosetting resin) 5a resin near the center of the coiled winding portion 5b resin around the coiled winding portion 7 DC power supply 8 temperature controller 9 drying oven 10 drying oven Heater 11a-11d Voltage measurement line 12 Embedded heater 13 Induction coil 14 Permanent current switch 15 Permanent current switch heater 17 AC power supply 20a, 20b Temperature detection means (thermocouple)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tatsumi Yamane, Inventor 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu factory, Toshiba Corp. (72) Hisayuki Hirai 2, 4-Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa Address inside Toshiba Keihin office

Claims (16)

[Claims] 1. A method for manufacturing a superconducting coil and a permanent current switch, wherein a thermosetting resin is impregnated or cast into a winding die in which a superconducting wire is wound in a coil shape, and then the thermosetting resin is cured by heating thereafter. In the above, the heating is performed such that the resin layer temperature in the vicinity of the center of the coil-shaped winding portion in the cross-sectional direction of the superconducting wire becomes higher than the resin layer temperature around the coil-shaped winding portion by a predetermined temperature. And a method for manufacturing a superconducting coil and a persistent current switch. 2. The manufacturing method according to claim 1, wherein the predetermined temperature has a value of 1 ° C. to 10 ° C. 3. The manufacturing method according to claim 1, wherein temperature detecting means is provided in the vicinity of the center of the coil-shaped winding portion and around the coil-shaped winding portion, and based on the detection of each temperature detecting means. Controlling the temperature of each resin layer. 4. The manufacturing method according to claim 1, wherein the temperature of the resin layer near the center of the coil-shaped winding portion has a different value depending on the position in the cross-sectional direction. A manufacturing method characterized by: 5. The manufacturing method according to claim 1, wherein the curing pattern of the thermosetting resin based on the heating is a primary curing region having a predetermined curing temperature, and curing of the primary curing region. And a secondary curing region having a curing temperature higher than the temperature. 6. The manufacturing method according to any one of claims 1 to 5, wherein the superconducting wire is formed so that the matrix ratio of the base material gradually decreases from the peripheral side to the center side of the coiled winding portion. A manufacturing method characterized by being formed. 7. The manufacturing method according to claim 1, wherein the matrix ratio of the base material near the inner circumference side and the outer circumference side of the coiled winding portion is large, and the inner circumference side and the outer circumference side are large. The superconducting wire is formed such that the matrix ratio of the base material to the side is small. 8. The manufacturing method according to claim 1, wherein the superconducting wire is formed so that the cross-sectional area gradually decreases from the peripheral side to the center side of the coiled winding portion. A manufacturing method characterized by the following. 9. The manufacturing method according to claim 1, wherein the coiled winding portion has a large cross-sectional area in the vicinity of the inner peripheral side and the outer peripheral side, and the inner peripheral side and the outer peripheral side. The superconducting wire is formed such that the cross-sectional area between the two is small. 10. The manufacturing method according to claim 1, wherein the heating is performed while applying a predetermined pressure to the winding mold after the impregnation or casting. . 11. A manufacturing device of a superconducting coil and a permanent current switch, wherein a thermosetting resin is impregnated or cast into a winding die in which a superconducting wire is wound in a coil shape, and the thermosetting resin is cured by heating thereafter. In the above, a DC power source connected to the lead wire of the superconducting wire wound in a coil shape, and energizing the superconducting wire, and a first resin near the center of the coiled winding portion in the cross-sectional direction of the superconducting wire. At least two or more temperature detecting means for respectively detecting the layer temperature and the second resin layer temperature around the coiled winding portion, and controlling the output of the DC power source based on the detection values from the temperature detecting means. And a temperature control means for controlling the temperature so that the first resin layer temperature becomes higher than the second resin layer temperature by a predetermined temperature, and a superconducting coil and a persistent current switch. Manufacturing equipment. 12. The manufacturing apparatus according to claim 11, wherein the temperature control means also controls energization of a heater of a drying furnace that houses the winding mold after the impregnation or casting. Manufacturing equipment. 13. The manufacturing apparatus according to claim 11 or 12, wherein the DC power source energizes the superconducting wire by using together with the lead wire, a voltage measuring wire for measuring an internal voltage. , A manufacturing apparatus characterized by the above. 14. The manufacturing apparatus according to claim 11, wherein the winding die has an embedded heater, and the temperature control means also controls energization of the embedded heater. apparatus. 15. The manufacturing apparatus according to claim 11, further comprising a switch circuit for placing the coil-shaped superconducting wire in a short-circuited state or an open state, instead of the DC power source, and outputting AC power. An alternating current power supply, and an induction coil for generating an induced current in the superconducting wire in the short-circuited state by energization from the alternating current power supply, and the temperature control means, the detection value from each of the temperature detection means. Based on this, on / off control of the switch circuit is performed, thereby performing temperature control such that the first resin layer temperature is higher than the second resin layer temperature by a predetermined temperature. apparatus. 16. A winding form in which a superconducting wire is wound in a coil shape, and a heater for switching from a superconducting state to a normal conducting state is mounted between the superconducting wires.
In a manufacturing apparatus of a permanent current switch in which a thermosetting resin is impregnated or cast, and then the thermosetting resin is cured by heating, a DC power supply for energizing the heater, and a coil in the cross-sectional direction of the superconducting wire. At least two temperature detecting means for respectively detecting the first resin layer temperature near the center of the coil-shaped winding portion and the second resin layer temperature around the coil-shaped winding portion, and the detection from each of the temperature detecting means Temperature control means for controlling the output of the DC power supply based on the value, and thereby controlling the temperature so that the first resin layer temperature becomes higher than the second resin layer temperature by a predetermined temperature. An apparatus for manufacturing a persistent current switch, which is characterized in that