JPS6318606A - Winding method for superconducting coil - Google Patents

Abstract

PURPOSE:To detect insulating defect between the turn layers with change in electric resistance of both ends by connecting one end of a circuit conductor to the distal end of the surperconducting wire of the lowermost layer of the supply drum and connecting the other end to the beginning end of the superconducting wire of the winding portion respectively through slide contact electrodes. CONSTITUTION:A lead 12 of a constant-current power supply 11 is connected to the distal end of a superconducting wire 3 of the lowermost layer of a supply drum 1 and to the distal end of the superconducting wire 3 drawn out from a bobbin 7 respectively through slide contact electrodes 14 and 15. When the superconducting wire 3 is energized from the constant-current power supply 11, the electric resistance of the entire length of the conductor 3 is indicated 13 by a voltage value. If there is a short circuit in the turn layers of the wire 3 to be wound up on the bobbin 7, the indicated voltage falls. Defective portions are detected in the winding and repaired, so the productivity substantially improves.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for winding a superconducting coil that can detect electrical insulation defects between adjacent turn layers during winding of a superconducting wire.

[Conventional technology and its problems]

There are two well-known methods for winding superconducting coils: one is to wind a wire with an electrical insulating layer formed on the surface of the coil while being supplied from a supply drum, and the other is to wind the wire into a coil while supplying a wire with an electrical insulating layer formed on the surface of the wire from a supply drum. There are two ways to wind the coil while covering it with an insulator just before winding it in alignment. This invention is a technique for making the former method more practical and reliable.

The superconducting coil generates heat and quenches when the wound superconducting wire moves during the i11 period. Therefore, superconducting wires are usually tightly wound so that there is no room for movement. However, when superconducting wires are tightly wound, electrical insulation failure occurs between adjacent turn layers when there is a defect in the electrical insulator on the surface or an abnormal local element occurs.

Therefore, conventional methods have been to measure the electrical resistance between the ends of the coil after winding and compare it with the resistance value calculated from the length of the wound conductor, or to measure the inductance at the end of the coil and compare it with the calculated value. The presence or absence of electrical contact abnormalities between turns is being investigated.

However, with these methods, inspection cannot be performed until after the coil is completed, so it is not possible to prevent the occurrence of defective products. In addition, even during post-completion inspections, it is impossible to know in which part the abnormality has occurred, so it is necessary to re-insulate and wind the abnormal coil from the beginning, which increases productivity. Therefore, it is a big bottleneck.

Note that quenching of the superconducting coil may also occur due to other factors, such as poor cooling. Therefore, at the time of quenching, which rapidly changes from a superconducting state to a normal conducting state, as shown in FIG.
The energy stored in the superconducting coil 22 is rapidly consumed by passing current excessively through the superconducting coil 22 to protect the coil 22. However, when a large current flows through the resistor 21, an instantaneous high voltage is generated at both ends of the coil. If a voltage is generated and there is a weak electrical insulation within the coil, sparks will occur in that area and dielectric breakdown will occur. Therefore, testing for defects in electrical insulation is an indispensable item for evaluating the reliability of completed coils, and it is impossible to improve productivity by omitting this test.

The present invention aims to provide a method for detecting insulation defects between turn layers during winding, in order to efficiently produce high-quality superconducting coils without any work loss.

[Means for solving problems]

The method of the present invention is a superconducting coil winding method in which a superconducting wire having an electrically insulating layer on its surface is supplied from a supply drum and wound to form a coil, in which one end of a circuit conductor is placed in the lowest layer of the supply drum. A superconducting wire resistance measuring circuit is provided at the terminal end of a certain superconducting wire, and the other end of the conductor is electrically connected to the starting end of the superconducting wire supplied to the winding section through sliding contact electrodes. The electrical resistance between both ends of the superconducting wire is monitored, and electrical insulation defects between adjacent turn layers during winding are detected from changes in the monitored resistance.

[Effect]

When a current is applied from the power supply of the measurement circuit to the superconducting wire between the supply section and the winding section, and the resistance value between both ends of the superconducting wire is monitored with a resistance measuring device, the difference between the wire being wound and the already wound wire is measured. If there is a short circuit in the mutual contact portion, the conductor resistance of the superconducting wire is reduced by the amount due to the short circuit.

An electrical insulation defect between the turn layers can be immediately detected from this decrease in resistance value, and the location of the insulation defect can also be identified as a winding point. can be partially repaired.

Moreover, this makes it possible to eliminate losses in winding work and occurrence of defects in completed coils.

〔Example〕

An embodiment of the method of the present invention will be explained based on FIGS. 1 to 4. 1 in Fig. 1 is the supply drum supported by the sub-reiskund 2, and the superconducting wire 3 wound around this drum.
is wound into a coil through a tension controller 4 on a bobbin 7 placed on a winding table 6 of an S wire machine 5. The superconducting wire 3 is a wire with an electrically insulating layer provided on the surface of the conductor. Reference numeral 8 denotes a drive motor for the winding machine, and the bobbin 6 is rotated by this motor. 9 is a control device for the winding machine.

The resistance measuring circuit 10 of the electromotive conducting wire 3 includes a constant current power source 11,
It consists of a monitor lead wire 12 as a circuit conductor connected to both poles of the power supply, and a voltmeter 13 that displays the resistance value, and one of the monitor lead wires 12 extending from the power supply is a superconducting wire 3 located at the bottom layer of the supply drum 1. The terminal end of the superconducting wire 3 is electrically connected to the starting end of the superconducting wire 3 drawn out from the collar of the bobbin 7 via sliding contact electrodes 14 and 15, respectively.

The sliding contact electrodes 14, 15 are provided to enable current to be applied to the wound superconducting wire 3. As shown in FIG. 2, the sliding contact electrode 14 on the supply side is a combination of a cylindrical rotating electrode 14a that rotates integrally with the supply drum and a fixed electrode 14b that is placed in a fixed position and slidably contacts the rotating electrode 14a. , a rotating type f electrically insulated from the bearing with an insulator 16
One end of the superconducting wire 3 is connected to the fixed electrode 14 at the ffi 14a.
Lead wires 12 are electrically connected to the terminals b. The sliding contact electrode 15 on the winding section side is basically the same as the electrode 14, that is, it is attached to the rotating shaft of the winding table 6 in an electrically insulated manner, and the rotating electrode 15 connects the starting end of the superconducting wire 3. 1. A fixed electrode 1 connected to a lead wire 12 that is slidably connected to a fixed electrode 15a at a fixed position.
Consisting of 5b.

The electrical circuit with the above configuration is shown in FIG. is displayed. Then, the wire 3 wound around the bobbin 7
When a short circuit occurs between the turn layers, the voltage displayed on the voltmeter 13 decreases.

In order to confirm the reliability of detection due to this voltage drop, the following experiment was conducted.

First, Nb3Sn with a conductor diameter of 1.2 mm and a length of 500 mm.
A superconducting wire whose surface is coated with a horizontally wound glass yarn with a thickness of approximately 70 μm is prepared, and this is coiled around a bobbin using the method shown in Figure 1, and a 50 mA current is applied between the conductor ends of the wire from a constant current power source. Then, when the glass coating for one turn was removed at the winding part for the bobbin and the four bare bodies were brought into contact with the adjacent turn layer, the voltage was 0.4 mV with respect to the first measured voltage value. There was a voltage drop. This is calculated 1
It was found that short circuits can be detected reliably.

Next, 0.8X1.6+u+”, 500 m long Nb
Approximately 25μmr on the surface of the Ti rectangular conductor! Using a superconducting wire coated with formal i-, a current of 50 mA is passed between the ends of the conductor while winding it in the same manner as above, and at the 10th turn of the coil part, part of the formal is removed and the wire is wound for 11 turns. It made contact with the eye line. As a result, there was a voltage drop of 0.57 mV, indicating that even partial electrical insulation defects could be reliably detected.

Note that the resistance value may be measured with an ammeter instead of a voltmeter, and in this case, the measured current value increases due to a short circuit.

Additionally, although the illustrated method winds a solenoid-type coil, the present invention is also applicable to racetrack-type dipole coils, saddle coils, etc., in which the supply drum is sometimes rotated around the winding portion during winding. It can also be used for winding dipole coils.

In addition, the sliding contact electrodes 14 and 15 are connected to the supply drum and S
The shape, structure, etc. are not particularly limited as long as the superconducting wire and the measurement circuit can be electrically connected while rotating the wire machine.

〔effect〕

As described above, according to the present invention, the electrical resistance between both ends of the superconducting wire is monitored during winding, and insulation defects between adjacent turn layers in the coil section are detected from changes in the monitored resistance. It becomes possible to discover and repair defective parts, which completely eliminates losses caused by redoing the winding work, greatly improving productivity.

In addition, the completed coil will be a good product with no insulation defects, resulting in high long-term reliability without causing sparks during quenching, resulting burnout deterioration, or unnecessary evaporation of cooling agent during operation. .

[Brief explanation of the drawing]

FIG. 1 is a side view showing a specific example of the method of the present invention;
Figure 2 is an enlarged view of the supply section, Figure 3 is an enlarged front view of the S line section, Figure 4 is an electric circuit diagram representing the method in Figure 1, and Figure 5 is when the superconducting coil is quenched. It is a circuit diagram. 1... Supply drum, 2... Supply stand, 3... Superconducting wire, 4...
Tension controller, 5... Winding machine, 6...
... Winding stand, 7 ... Bobbin, 8 ... Drive motor, 9 ... Control device, 10 ...
Resistance measurement circuit, 11... Constant current power supply, 12...
...Monitor lead wire, 13...Voltmeter,
14.15...Sliding contact electrode.

Claims (1)

[Claims] In a superconducting coil winding method in which a superconducting wire with an electrically insulating layer on the surface is supplied from a supply drum and wound to form a coil, the terminal end of the superconducting wire where one end of the circuit conductor is in the lowest layer of the supply drum. A superconducting wire resistance measuring circuit is provided, the other end of which is electrically connected to the starting end of the superconducting wire supplied to the winding section through sliding contact electrodes, and the resistance measurement circuit is installed to measure the resistance between both ends of the superconducting wire in the winding. A method for winding a superconducting coil, the method comprising: monitoring the electrical resistance of the superconducting coil, and detecting electrical insulation defects between adjacent turn layers during winding from changes in the monitored resistance.