JPH10189326A - Electromagnet device and current supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnet device which can be operated safely even when the temperature of a superconducting coil rises due to the stoppage, etc., of a refrigerating machine and, at the same time, to prevent the burning, etc., of current leads which connect a power source in a high-temperature section to electric equipment in a low-temperature section. SOLUTION: An electromagnet device is provided with a superconducting coil 4, a means 10 (a radiation shield which surrounds and cools the coil 4 and a means which actively cools the radiation shield) which actively cools the coil 4, a means 40 which discriminates the stoppage of the cooling means 10, and means 42 and 44 which reduce the current value of the coil 4, and the device is further constituted to reduce the current value of the coil 4 when the cooling means 10 stops. A current supplying device is provided with current leads, a means which actively cools the leads, a means which discriminates the stoppage of the cooling means, and a means which reduces the current values of the leads, and the device is constituted to reduce the current values of the leads when the cooling means stops.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electromagnet device and a current supply device, and more particularly to protection of an electromagnet and a current lead.

[0002]

2. Description of the Related Art A superconducting electromagnet apparatus is used for various purposes such as a study of physical properties by using a generated strong magnetic field. The superconducting coil actually generates the magnetic field, and a superconducting coil having a high current density is used to generate a strong magnetic field. To maintain the superconducting coil in a superconducting state, it is necessary to cool the superconducting coil to about 10K or less. Conventionally, immersion cooling with liquid helium has been employed to cool the superconducting coil. However, with the recent progress in refrigerators, conduction cooled electromagnet devices have been put to practical use. The conduction cooling type electromagnet apparatus actively cools an electromagnet directly by a refrigerator without using liquid helium.

FIG. 13 shows a configuration of a conventional electromagnet apparatus of this type described in, for example, FIG. 6 of JP-A-8-78737. In the figure, 2 is a superconducting electromagnet device, 4 is a superconducting coil, 6 is a radiation shield, and 8 is a vacuum chamber. 10
Is a means for actively cooling the superconducting coil 4, and is generally a refrigerator. 12 is a low-temperature stage of the refrigerator,
14 is a high-temperature side stage of the refrigerator, 16 is a heat conducting member, 1
8 is a flexible heat conductive member, and 20 is a coil support.

In order to reduce thermal radiation, a radiation shield 6
Surround the superconducting coil 4. The radiation shield 6 is generally made of a copper plate, and is generally maintained at a temperature of about 20K to 80K. Furthermore, these superconducting coils 4
The radiation shield 6 is maintained in a vacuum in order to suppress heat conduction. The vacuum chamber 8 maintains this vacuum space, and the superconducting coil 4 and the radiation shield 6 are mechanically held by the coil support 20 from the vacuum chamber 8.

[0005] The refrigerator 10 generates refrigeration. The refrigerator has two stages 12 and 14 of a low temperature side and a high temperature side, and the radiation shield 6 is cooled by the high temperature side stage 14 from about 20K to about 80K. Low temperature stage 12 is 10K
Generates the following low temperatures: In the example of FIG.
The superconducting coil 4 is not directly cooled. The low-temperature side stage 12 of the refrigerator is connected to the heat conducting member 16 and the flexible heat conducting member 18, and cools the superconducting coil 4 via the heat conducting member 16 and the flexible heat conducting member 18. The flexible heat conductive member 18 can be deformed by a combination of a copper wire net and the like, thereby preventing the vibration of the refrigerator 10 from being transmitted to the superconducting coil 4.

When the superconducting electromagnet apparatus is not operated in the permanent current mode, the superconducting coil 4 is connected to a power source via a current lead. FIG. 14 shows this state, and FIG. 14 is obtained by adding a current supply device including a power supply 32 and a current lead 30 to FIG. The superconducting coil 4 is excited from the power supply 32 via the current lead 30. In addition,
In recent years, the current lead 30 is often made of a high-temperature superconductor in order to reduce heat generation due to current-carrying resistance.

FIG. 15 further simplifies FIG. 14 and shows only a basic configuration. In FIG. 15, 3
8 is a heat conduction member. 13 and 14, the heat conducting member 1
6 and the flexible heat conducting member 18 are shown in FIG.
In the above, these are combined and represented by the heat conducting member 38.

[0008]

The conventional electromagnet apparatus is constructed as described above, and the superconducting coil 4 is connected to the refrigerator 1
However, if the refrigerator 10 stops due to a failure or a power failure, the superconducting coil 4 is not cooled, heat enters from the coil support 20 shown in FIG. 13, and the temperature of the superconducting coil 4 rises. I do. Since the electromagnet continues to be excited, the temperature of superconducting coil 4 becomes higher than the critical temperature of the superconducting wire, and superconducting coil 4 transitions to the normal conducting state. That is, quench occurs. Further, when the quench occurs, an excessive voltage is generated inside the superconducting coil 4, and in the worst case, the coil may be broken down. In particular, in the electromagnet apparatus of the present system having no liquid helium tank, there is a problem that there is little time margin from the stop of the refrigerator to the quench.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. Even when the refrigerator stops for some reason, the stored energy in the superconducting coil can be safely reduced and the safe operation can be performed. The purpose is to provide a system.

[0010]

[Means for Solving the Problems]

An electromagnet device according to a first configuration of the present invention comprises:
A superconducting coil, means for actively cooling the superconducting coil, means for determining the stop of the cooling means, and means for reducing the current value of the superconducting coil; This is to reduce the current value.

An electromagnet device according to a second configuration of the present invention comprises:
A superconducting coil, a radiation shield surrounding the superconducting coil and cooling the superconducting coil by radiation, a means for actively cooling the radiation shield, a means for determining whether to stop the cooling means, and a current for the superconducting coil. Means for reducing the current value of the superconducting coil when the cooling means is stopped.

An electromagnet device according to a third configuration of the present invention comprises:
A superconducting coil, means for measuring the temperature of the superconducting coil, and means for reducing the current value of the superconducting coil, wherein the current value of the superconducting coil is reduced based on the temperature measurement result.

An electromagnet device according to a fourth configuration of the present invention comprises:
A permanent current switch for switching the superconducting coil to a permanent current mode, and opening the permanent current switch based on a temperature measurement result when the cooling means for the superconducting coil or the radiation shield is stopped or for reducing the current value of the superconducting coil. Is to be connected to.

An electromagnet device according to a fifth configuration of the present invention comprises:
A plurality of cooling means are provided, and it is determined whether the current value of the superconducting coil needs to be reduced based on the total cooling capacity of the stopped cooling means.

An electromagnet device according to a sixth configuration of the present invention comprises:
The current value of the superconducting coil is reduced after a lapse of a predetermined time from the stop of the cooling means.

According to a seventh aspect of the present invention, there is provided a current supply device for connecting a power supply in a high-temperature section to an electric device in a low-temperature section, means for actively cooling the current lead, and means for cooling the current lead. Means for judging a stop and means for reducing the current value of the current lead are provided, and the current value of the current lead is reduced when the cooling means is stopped.

According to an eighth aspect of the present invention, there is provided a current supply device for connecting a power supply in a high-temperature section to an electric device in a low-temperature section, means for measuring the temperature of the current lead, Means for reducing the current value of the current lead based on the temperature measurement result.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 1 of the present invention. In the figure, 2 is a superconducting electromagnet device, 4 is a superconducting coil, and 8 is a vacuum chamber. Numeral 10 is a means for actively cooling the superconducting coil 4, and is generally a refrigerator. 12 is a low-temperature stage of the refrigerator, 38 is a heat-conducting member, 40 is stop determination means of the refrigerator, and 42 is a switch. Reference numeral 44 denotes a current value reducing unit, which is a resistor in the example shown in FIG. Although not shown, the vacuum chamber 8 is similar to the conventional one shown in FIGS.
There is a case where a radiation shield is provided between the superconducting coil 4 and the superconducting coil 4, and the high-temperature side stage of the refrigerator 10 is thermally connected to the radiation shield. The same is true for

Next, the operation will be described. When the refrigerator 10 stops, the refrigerator stop determination means 40 detects this. As the determination means 40, for example, it is possible to use a contact output for monitoring when the refrigerator is stopped, which is output from the refrigerator, and to use an AC line monitor because the power is not used when the refrigerator is stopped. Next, after detecting the stop of the refrigerator 10, the current value of the superconducting coil 4 may be reduced by any method. In the example shown in the figure, the method of opening the switch 42 to cut off the power supply 32 and diverting the current of the superconducting coil 4 to the resistor 44 to reduce the current value of the superconducting coil 4 is shown. The electromagnetic energy stored in the superconducting coil 4 is consumed by energizing the resistor 44, and the current value is reduced. That is, the energy stored in the superconducting coil 4 is released as heat generated by the resistor 44. As a result, even when the temperature exceeds the critical temperature, the current of the superconducting coil 4 is already almost zero, so that even if the electromagnet is quenched, no large voltage is generated. That is, in the electromagnet device of the conduction cooling type, safe operation can be performed even when the refrigerator stops.

Embodiment 2 FIG. FIG. 2 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 2 of the present invention. In FIG. 1, the resistor 44 is used to reduce the current value of the power supply. In the example of FIG.
Is used. After the stop determination means 40 determines that the refrigerator 10 is stopped, the power supply 32 is turned off. When the power supply 32 is turned off, the current flowing through the superconducting coil 4
It is commutated to 6. Since a voltage is applied to both ends of the diode 46, all the stored energy stored in the superconducting coil 4 is consumed by the diode 46, the current of the superconducting coil 4 decreases, the magnetic field also decreases, and finally the current becomes zero. Become. In this case, even when the temperature exceeds the critical temperature, the current of the superconducting coil 4 is already zero, so that a large voltage does not occur even when quenched. That is, in the electromagnet device of the conduction cooling type, safe operation becomes possible even when the refrigerator 10 stops. In order to release the energy of the superconducting coil 4, a resistor 44 or a diode 4
A thyristor or the like may be used instead of 6.

Embodiment 3 FIG. In each of the above embodiments, the resistor 44 and the diode 46 are used as the current value reducing means, but an excitation power supply may be used. This example is shown in FIG. In the figure, reference numeral 48 denotes control means for the power supply 32.
That is, when the refrigerator 10 is stopped, the current value of the superconducting coil 4 is reduced by controlling the power supply 32 to demagnetize.
In this case, the power supply 32 reduces the current value to a value near zero while generating a negative voltage (that is, reducing the current value flowing through the superconducting coil 4). As a result, the current value of superconducting coil 4 becomes zero after refrigerator 10 stops, so that superconducting coil 4 does not generate a large voltage even if it is quenched. Note that the current value of the superconducting coil 4 does not necessarily need to be zero. Even if a little current flows,
Even when the temperature rises and quench occurs, the current value may be reduced to a value that does not damage the superconducting coil 4, that is, a current value at which the generated voltage does not cause dielectric breakdown of the coil. In this case, since the current of the superconducting coil 4 is not reduced to zero, the current value is controlled by the control means 48.

Embodiment 4 FIG. 4 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 4 of the present invention. In the figure, reference numeral 50 denotes current value reducing means, but also energy recovery means. Here, the energy recovery means 50 is a power energy converter composed of a thyristor or the like. In the first and second embodiments, the energy of the superconducting coil 4 is released by the energy of the diode 46 or the like. In the example of FIG. 4, for example, the superconducting coil 4 has a superconducting power storage (S
A MES) coil is assumed.

Here, superconducting power storage will be described first. The superconducting power storage (SMES) coil 4 is connected to AC power via a power energy converter 50.
Generally, in the case of superconducting power storage, when energy is stored, the thyristor of the power energy converter 50 is controlled, and power is supplied from AC power. On the other hand, when power is to be taken out, the operation is reversed.

Next, the operation when the refrigerator 10 is stopped will be described.
After the refrigerator 10 stops, the temperature of the superconducting coil 4 rises, so it is necessary to reduce the energy stored in the superconducting coil 4. When lowering the stored energy of the superconducting coil 4, the same operation as that for extracting the electric power may be performed.
That is. The energy stored in the superconducting coil 4 may be converted into AC power using a thyristor or the like, and power may be supplied to a load or a power system. Thereby, the energy of the superconducting coil 4 is automatically extracted to the outside, and the current value of the superconducting coil 4 decreases. In this case, the stored energy of the superconducting coil 4 does not necessarily need to be reduced to zero.
The energy may be reduced to an energy at which the superconducting coil 4 is not damaged even if it is quenched.

Embodiment 5 FIG. 5 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 5 of the present invention. In this embodiment, an example of a superconducting coil in a permanent current mode is shown. In the figure, reference numeral 60 denotes a permanent current switch, 62 denotes a heater for a permanent current switch, 64 denotes a heater power supply, and 66 denotes a heater power switch. The permanent current switch heater 62, the heater power supply 64, and the heater power switch 66 are permanently used. It constitutes a current switch open means. Reference numeral 68 denotes a heater current lead.

Here, the permanent current mode will be described. The permanent current switch 60 is constituted by a superconducting wire. A permanent current switch heater 62 is arranged around the permanent current switch 60. When exciting the electromagnet, the heater 62 for the permanent current switch is energized by the switch 66 for the heater power supply and the power supply 64 for the heater. In this case, the superconducting wire of the permanent current switch 60 is in a normal conducting state and has a resistance. This state is viewed from the power supply 32,
It becomes a normal LR circuit (L is the superconducting coil 4 and R is the permanent current switch 60), and when the power supply 32 supplies a current, a current flows through the superconducting coil 4. Thereafter, when the power supply 64 of the permanent current switch heater 62 is turned off, the superconducting wire of the permanent current switch 60 enters a superconducting state. In this case, even if the current of the power supply 32 is reduced, the permanent current switch 60 and the coil 4 form a closed circuit, and the current continues to flow. Further, the power supplies 32 and 64 can be separated.

When the refrigerator 10 stops in this state, the temperature of the superconducting coil 4 rises. In order to reduce the energy stored in the superconducting coil 4, the permanent current switch 60 may be opened. That is, the heater power switch 66 is set to O
It is sufficient to set the current permanent current switch 60 to the normal conduction state by setting the current permanent current switch 60 to N and energizing the permanent current switch heater 62. In this case, a voltage is generated across the persistent current switch 60, the diode 46 is turned on, and as described in the second embodiment,
It is possible to release stored energy.

Normally, after the excitation, the current lead 30 and the heater current lead 68 are pulled out to reduce heat penetration. In this case, a protection diode may be provided inside the electromagnet circuit in parallel with the permanent current switch 60.

Although the permanent current switch 60 is of a thermal type, it may be a magnetic type or a mechanical type. In the case of a mechanical type, the means for opening the permanent current switch is a mechanical force, and the magnetic type switch is a heater 6.
In place of 2, a current is passed through the coil to generate a magnetic field to make the superconducting wire a normal conductor. In this case, the permanent current switch open means 67 includes a coil for applying a magnetic field to the magnetic permanent current switch and a power supply for the coil. Furthermore,
Although the diode 46 is used in the drawing, the present invention is not limited to this, and a resistor 44 similar to that of FIG. 1 may be used.

Embodiment 6 FIG. FIG. 6 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 6 of the present invention. In each of the above embodiments, the refrigerator 10 is provided with the superconducting coil 4.
Had cooled. However, the refrigerator 10 has the superconducting coil 4
Is not cooled, and only the radiation shield 6 is cooled. Also in this case, when the refrigerator 10 stops, the temperature of the radiation shield 6 increases, and further, the temperature of the superconducting coil 4 increases, and the superconducting coil 4 may be quenched.
Therefore, even when the refrigerator 10 cools only the radiation shield 6, it is necessary to reduce the current value of the superconducting coil 4. The method of reducing the current value of the superconducting coil 4 is the same as in each of the above embodiments.

Embodiment 7 FIG. 7 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 7 of the present invention. In the figure, 70 is the first cooling means, that is, the refrigerator 1,
Reference numeral 72 denotes second cooling means, that is, the refrigerators 2 and 74, the stop determination means 1, 76, the stop determination means 2, and 78, a refrigeration capacity determination means.

In the case of a large electromagnet apparatus, the capacity of the refrigerator is insufficient, so that a single refrigerator may not be able to cool the electromagnet and may use a plurality of electromagnets. In each of the above embodiments, the current value of superconducting coil 4 was immediately reduced when the refrigerator stopped. By the way, in the case of a system having a plurality of refrigerators 70 and 72, in many cases, the configuration is such that the temperature of the superconducting coil 4 is not increased even if one refrigerator stops. In this case, even if one refrigerator stops, it is not necessary to cut off the power supply 32 or reduce the current value of the superconducting coil 4. Further, not all refrigerators have the same capacity, and refrigerators having different refrigerating capacities may be used. When a refrigerator having a small refrigerating capacity breaks down, it is considered that the temperature of the superconducting coil does not rise so much. If the number of refrigerators is stopped at the same time, it may be known in advance whether the temperature starts to rise or quench. Therefore, by determining the number and type of the stopped refrigerators, it is possible to determine whether to keep the current value of the superconducting coil as it is, or to cut off the power supply or reduce the current value. This determination is made by the refrigeration capacity determination means 7
8 Further, only when the refrigeration capacity determination means 78 determines that the temperature of the superconducting coil 4 has risen and is likely to quench, the power supply 32 is cut off or the current value is reduced.
Thus, even if some of the plurality of refrigerators are stopped, the superconducting coil 4 can continue to be excited, and the operation efficiency can be improved.

In the embodiment shown in FIG.
The case of the table (chiller 1 and refrigerator 2) is shown. In the example shown in the figure, an AND circuit is used as the refrigerating capacity determination means 78. When either one of the refrigerators 70, 72 is stopped, the power supply 32 is not shut off, and when both the refrigerators 70, 72 are stopped. , The power supply 32 is shut off.

When a plurality of refrigerators are provided, since the refrigerating capacity of each refrigerator is known in advance, the total refrigerating capacity of the failed refrigerator is used to calculate the total refrigerating capacity of the remaining normally operating refrigerators. We understand ability. The stopped chiller may be monitored, the remaining refrigeration capacity may be calculated from this, and if the remaining refrigeration capacity falls below a certain value, the power supply may be shut off or the current value may be reduced.

Embodiment 8 FIG. FIG. 8 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 8 of the present invention. In the figure, 79 is a time measuring means, that is, a timer. Even if the refrigerator 10 stops, the temperature does not immediately rise, but the temperature starts to rise after a certain period of time has elapsed according to the heat capacity of the superconducting coil 4. If the repair of the refrigerator 10 is completed during this time, the current of the superconducting coil 4 does not need to be reduced. Therefore, as in the present embodiment, the timer 79 may be inserted so that the energy stored in the superconducting coil 4 is reduced after a certain time has elapsed after the refrigerator 10 is stopped. Thereby, even when the refrigerator 10 is stopped, the excitation of the superconducting coil 4 can be maintained, which helps to improve the operation rate.

Embodiment 9 FIG. 9 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 9 of the present invention. In the figure, reference numeral 80 denotes a temperature measuring means, that is, a temperature sensor. 82 is a temperature determination means. In each of the above embodiments, the stop of the refrigerator is detected. Embodiment 8 has described that the temperature of the coil does not immediately rise when the refrigerator stops. Also, even if the refrigerator stops,
There are cases where it is desirable to maintain the excitation as much as possible. In this case, it may be better to monitor the temperature of the superconducting coil directly instead of monitoring the stop of the refrigerator. Therefore, the temperature of the superconducting coil 4 is monitored by the temperature sensor 80. When this temperature approaches the critical temperature of the superconducting wire, the power supply 32 is cut off and the current value of the superconducting coil 4 is reduced by the resistor 44, for example, as in the first embodiment. This determination is made by the temperature determining means 82.

Embodiment 10 FIG. FIG. 10 is a diagram showing an overall circuit configuration of an electromagnet device according to Embodiment 10 of the present invention. In the figure, 84 is a liquid helium container, and 86 is liquid helium. In the above embodiments, the so-called conduction cooling type electromagnet device in which the superconducting coil 4 is actively cooled by the refrigerator has been described. But, for example,
Even in the case of an electromagnet apparatus of a system immersed in liquid helium 86 as a refrigerant, the entire superconducting coil 4 is
May be used without immersion. In this case, since the upper portion of the superconducting coil 4 is not immersed in the liquid helium 86, the temperature of the liquid helium rises above 4.2K, and quench may occur. In order to prevent a large voltage from being generated when quenching, the temperature of the coil is constantly monitored by the temperature sensor 80, and when the temperature approaches the critical temperature of the superconducting wire, for example, as in the first embodiment, the power supply 32
And the current value of the superconducting coil 4 is reduced by the resistor 44.

Embodiment 11 FIG. FIG. 11 is a diagram showing an overall circuit configuration of an electromagnet device using a current supply device according to Embodiment 11 of the present invention. In the drawing, 88 is a normal temperature or high temperature portion, 89 is a low temperature portion, 90 is a refrigerator as active cooling means for current lead, 92 is a low temperature stage, 94
Is a heat conducting member. Although not shown, the superconducting coil 4 is cooled by another refrigerator or liquid helium.

In each of the above embodiments, mainly the superconducting coil 4
Was quenched. However, the refrigerator 90 may be used for cooling the current lead 30,
When the refrigerator 90 stops, the temperature of the current lead 30 may increase. This case will be described. The current lead 30 shown in FIG.
And the low-temperature section 89 in which the superconducting coil 4 exists, and supplies a current from the power supply 32 on the normal temperature side to the superconducting coil 4 on the low temperature side. By the way, the current lead 3
When 0 is cooled, the temperature of the current lead 30 rapidly rises when the refrigerator 90 stops because the heat capacity of the current lead 30 is small. The current lead 30 is often made of a high-temperature superconductor recently. Therefore, when the temperature of the current lead 30 rises, the current lead 30 may be quenched. Further, even when the current lead 30 is made of copper, copper does not quench, but when it is heated to a high temperature, it burns or breaks the insulating coating. Therefore, when the current lead refrigerator 90 stops, it is necessary to immediately reduce the current value of the superconducting coil 4 and reduce the current of the current lead 30. Thereby, even if the current lead refrigerator 90 is stopped, the current lead 30 can be kept safe.

Embodiment 12 FIG. FIG. 12 is a diagram showing an overall circuit configuration of an electromagnet device using a current supply device according to Embodiment 12 of the present invention. In the figure, reference numeral 102 denotes a temperature sensor for measuring the temperature of the current lead 30. 1
04 is a temperature determination means, and 106 is an OR circuit. Others are the same as those in FIG. In the eleventh embodiment, the refrigerator that cools the current lead 30 is stopped.
In the present embodiment, the temperature of the current lead 30 is directly monitored, and the current value is reduced when there is a possibility of burning. That is, the temperature of the current lead 30 is monitored by the temperature sensor 102, and it is determined whether or not the temperature of the current lead 30 is likely to be burned by the judging means 104. . In the example of FIG.
Since there are two current leads 30, the OR circuit 106
When the temperature of either of the two current leads 30 rises, the power supply 32 is cut off and the current value is reduced by the resistor 44. Thereby, the current lead 30 can be operated safely. Although copper is assumed as the current lead 30 here, a high-temperature superconductor may be used as in the eleventh embodiment. Although the case where the power supply 32 is cut off is shown, the power supply 3 is turned off in the same manner as in the third embodiment.
2 may be controlled to reduce the current value.

The first embodiment shown in FIGS.
In 1 and 12, although the superconducting coil 4 is connected to the low-temperature section 89, the superconducting coil 4 does not necessarily need to be connected, and other electric devices such as a superconducting motor that uses a relatively large current at a low temperature. Is also effective. Also,
A plurality of refrigerators may be provided. Further, as in the case of the seventh embodiment, the necessity of reducing the current value is determined based on the total cooling capacity of the stopped refrigerators among the plurality of refrigerators. You may. Although the high temperature section 88 is at normal temperature here, it may be liquid nitrogen temperature or the like, and the low temperature section 89 may be liquid helium temperature, but may be liquid hydrogen temperature or the like. As in the case of the coil refrigerator described in the eighth embodiment, there is a method in which a timer is inserted and the power supply 32 is shut off after a predetermined time.

[0043]

As described above, according to the first configuration of the present invention, the superconducting coil, the means for actively cooling the superconducting coil, the means for judging the stop of the cooling means, the above-described superconducting coil, Means for reducing the current value of the coil, and when the cooling means is stopped, the current value of the superconducting coil is reduced, so that even if the cooling means is stopped and the superconducting coil is quenched, a large voltage is not generated and it is safe. Can be operated.

According to the second aspect of the present invention, a superconducting coil, a radiation shield surrounding the superconducting coil and cooling the superconducting coil by radiation, a means for actively cooling the radiation shield, Means for determining the suspension of the means;
Means for reducing the current value of the superconducting coil, and when the cooling means is stopped, the current value of the superconducting coil is reduced, so that even if the cooling means is stopped and the superconducting coil is quenched, a large voltage may be generated. It can be driven safely without.

According to a third aspect of the present invention, there is provided a superconducting coil, means for measuring the temperature of the superconducting coil, and means for reducing the current value of the superconducting coil, based on the temperature measurement result. Since the current value of the superconducting coil is reduced, even if the temperature rises and the superconducting coil is quenched, a large voltage is not generated and the operation can be performed safely.

According to the fourth configuration of the present invention, a permanent current switch for switching the superconducting coil to the permanent current mode is provided, and when the cooling means of the superconducting coil or the radiation shield is stopped or based on the temperature measurement result, the permanent current switch is turned off. Since the current switch is opened and the superconducting coil is connected to the current value reducing means, even if the superconducting coil is quenched when operating in the permanent current mode, a large voltage is not generated and safe operation is possible. .

According to the fifth configuration of the present invention, since a plurality of cooling means are provided, and the necessity of reducing the current value of the superconducting coil is determined based on the total cooling capacity of the stopped cooling means, for example, In some cases, even if such a cooling unit stops, the excitation can be continued without reducing the current value, and the operation rate can be improved.

According to the sixth configuration of the present invention, the current value of the superconducting coil is reduced after a lapse of a predetermined time from the stop of the cooling means, so that the superconducting coil is quenched after the cooling means is stopped. If the cooling means stopped during the period can be restarted, the excitation of the superconducting coil can be continued, so that the operation rate can be improved.

According to the seventh aspect of the present invention, the current lead for connecting the power supply of the high temperature section to the electric equipment of the low temperature section, the means for actively cooling the current lead, and the stop of the cooling means are determined. And a means for reducing the current value of the current lead, and the current value of the current lead is reduced when the cooling means is stopped, so that the current lead can be safely operated without burning.

According to the eighth aspect of the present invention, a current lead for connecting a power supply in a high-temperature section to an electric device in a low-temperature section, means for measuring the temperature of the current lead, and a reduction in the current value of the current lead Means for reducing the current value of the current lead based on the temperature measurement result, so that the current lead can be safely operated without burning out.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall circuit configuration of an electromagnet device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an overall circuit configuration of an electromagnet device according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an overall circuit configuration of an electromagnet device according to a third embodiment of the present invention.

FIG. 4 is a diagram showing an overall circuit configuration of an electromagnet device according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing an overall circuit configuration of an electromagnet device according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing an overall circuit configuration of an electromagnet device according to a sixth embodiment of the present invention.

FIG. 7 is a diagram showing an overall circuit configuration of an electromagnet device according to a seventh embodiment of the present invention.

FIG. 8 is a diagram showing an overall circuit configuration of an electromagnet device according to an eighth embodiment of the present invention.

FIG. 9 is a diagram showing an overall circuit configuration of an electromagnet device according to a ninth embodiment of the present invention.

FIG. 10 is a diagram showing an overall circuit configuration of an electromagnet device according to a tenth embodiment of the present invention.

FIG. 11 is a diagram showing an overall circuit configuration of an electromagnet device using a current supply device according to an eleventh embodiment of the present invention.

FIG. 12 is a diagram showing an overall circuit configuration of an electromagnet device using a current supply device according to a twelfth embodiment of the present invention.

FIG. 13 is a cross-sectional view illustrating a configuration of a conventional electromagnet device.

FIG. 14 is a cross-sectional view showing the entire configuration of a conventional electromagnet device.

FIG. 15 is a diagram showing an overall circuit configuration of a conventional electromagnet device.

[Explanation of symbols]

4 superconducting coil, 6 radiation shield, 8 vacuum chamber, 10, 70, 72, 90 refrigerator, 30, 68
Current leads, 32, 64 power supplies, 40, 74, 7
6 Stop determination means, 42, 66 switch, 44
Resistance, 46 diode, 48 power control means,
Reference Signs List 50 power energy converter, 60 permanent current switch, 62 heater for permanent current switch, 67 permanent current switch open means, 78 refrigeration capacity determination means, 79 time measurement means, 80,102 temperature sensor, 82,104 temperature determination means, 84 Liquid helium container, 86 liquid helium, 88 high temperature part,
89 low temperature section, 106 OR circuit.

Claims (11)

[Claims] 1. A superconducting coil, means for actively cooling the superconducting coil, means for judging stop of the cooling means, means for reducing the current value of the superconducting coil, An electromagnet device characterized in that the current value of the superconducting coil is sometimes reduced. 2. A superconducting coil, a radiation shield surrounding the superconducting coil and cooling the superconducting coil by radiation,
Means for actively cooling the radiation shield, means for determining stop of the cooling means, and means for reducing the current value of the superconducting coil, wherein the current value of the superconducting coil is reduced when the cooling means is stopped. An electromagnet device, characterized in that the electromagnet device is configured to: 3. A superconducting coil, means for measuring the temperature of the superconducting coil, and means for reducing the current value of the superconducting coil, wherein the current value of the superconducting coil is reduced based on the temperature measurement result. An electromagnet device characterized by having such a configuration. 4. A superconducting coil, comprising: a permanent current switch for switching a superconducting coil to a permanent current mode, wherein said superconducting coil is opened when said cooling means of said superconducting coil or radiation shield is stopped or based on a temperature measurement result. 4. The electromagnet device according to claim 1, wherein the electromagnet device is configured to be connected to a current value reducing means. 5. The superconducting coil according to claim 5, wherein
5. The electromagnet device according to claim 1, wherein the electromagnet device is a resistor, a diode, or a thyristor. 6. The superconducting coil according to claim 6, wherein:
The electromagnet device according to any one of claims 1 to 4, which is a power supply for controlling a current value of the superconducting coil. 7. The superconducting coil according to claim 7, wherein:
The electromagnet device according to any one of claims 1 to 4, wherein the electromagnet device is a power energy converter that recovers stored energy of the superconducting coil. 8. The electromagnet apparatus according to claim 1, wherein a plurality of cooling means are provided, and the necessity of reducing the current value of the superconducting coil is determined based on the total cooling capacity of the stopped cooling means. 9. The electromagnet device according to claim 1, wherein the current value of the superconducting coil is reduced after a predetermined time has elapsed since the cooling means was stopped. 10. A current lead for connecting a power supply in a high-temperature section to an electric device in a low-temperature section, means for actively cooling the current lead, means for determining whether to stop the cooling means, and a current for the current lead. Means for reducing the current value of the current lead when the cooling means is stopped. 11. A temperature measuring device comprising: a current lead for connecting a power supply in a high-temperature section to an electric device in a low-temperature section; a means for measuring the temperature of the current lead; and a means for reducing a current value of the current lead. A current supply device configured to reduce a current value of the current lead based on a result.