KR101326981B1 - Electrode for vacuum interrupter - Google Patents

Abstract

The present invention relates to an electrode for a vacuum interrupter. The electrode for a vacuum interrupter according to a preferred embodiment of the present invention comprises: a plurality of main slits that is arranged at equal intervals while each extending from the surface of an end of a contact carrier towards the surface of the other end of the contact carrier to form a predetermined slope with a contact end plate; and at least one axial magnetic field inducing unit that is formed between two neighboring main slits of the main slits; wherein the axial magnetic field inducing unit induces an axial magnetic field parallel to a longitudinal direction of the contact carrier by forming a current path up and down in the circumferential direction of the contact carrier.

Description

Electrode for vacuum interrupter {ELECTRODE FOR VACUUM INTERRUPTER}

The present invention relates to a vacuum interrupter electrode, and more particularly, to a vacuum interrupter electrode having excellent arc control performance by a seed field induction part and an improved mechanical strength by a slit reinforcing member.

The Vacuum Circuit Breaker (VCB) is responsible for protecting critical equipment in the power system and system by quickly and automatically breaking fault currents using vacuum as the insulating medium. The vacuum interrupter (VI), a current interrupter in the vacuum breaker, rapidly diffuses the arc plasma generated in the gap of the electrode into the vacuum, thereby minimizing the arc energy injected to the electrode surface quickly. An arc structure for arc extinguishing, which is a key part of a vacuum circuit breaker. In addition, the vacuum circuit breaker has excellent breaking performance, safety and reliability compared to other types of circuit breakers, and has a merit of small size and light weight.

Recently, due to the rapid development of the industry, the power demand is increasing due to the increase in the power demand and the rapid increase in the system load. Therefore, there is a need for research and development for increasing the current breaking capacity of the circuit breaker and improving various performances.

In order to improve the performance of the vacuum circuit breaker, it is necessary to increase the current blocking capacity by using a technique for effectively controlling the arc in the vacuum interrupter.

Since the vacuum breaker has the purpose of blocking the fault current, the high current breaking performance is a very important factor in the design of the vacuum interrupter. In order to increase the large current blocking capacity, a method of controlling the arc plasma generated in the electrode gap using a magnetic field is very effective. Although a variety of methods have been developed and used, the seed-type vacuum interrupter designed to generate an axial magnetic field (AMF) parallel to the arc formed in the electrode gap of the vacuum interrupter to distribute the arc energy evenly on the contact surface has a large current. It is very advantageous for increasing the breaking capacity and miniaturization.

Hereinafter, a seed field type electrode according to the prior art will be described with reference to FIGS. 1 and 2. 1 shows a front view of an electrode for a vacuum interrupter of the seed field method according to the prior art. 2 shows a cross-sectional view of the electrode of FIG. 1.

Referring to FIG. 1, the electrode 1 includes a plurality of first slits 11 and a plurality of second slits 12 on the side of the contact table 10. The current in the circumferential direction is induced by the current path between the first slit 11, the first slit 11 and the second slit 12, and the second slit 12. The seed field B parallel to the arc is formed by the induced circumferential current i. In this structure, the mechanical strength is reinforced by the region 13 in which no slit is formed between the first slit 11 and the second slit 12.

2, a predetermined interval is spaced apart from the contact table 10, and a cylindrical reinforcing member 14 is installed. By the reinforcing member 14, the mechanical strength of the contact table 10 is reinforced.

However, in the electrode 1 as described above, the current i1 in the opposite direction to the current i forming the seed field B is generated significantly. As a result, since the seed field B is attenuated, there is a problem that the arc control performance of the circuit breaker is lowered.

In addition, since the electrode 1 has a space in which three or more slits are located between the upper end and the lower end of the contact, there is a problem that the mechanical strength of the contact with respect to the impact during the breaker trip is very weak.

In addition, there is a problem that the mechanical strength reinforced by the region 13 in which no slit is formed between the first slit 11 and the second slit 12 is very weak.

Korean Registered Patent No. 0496659 (Keishisha Meidensha) 2005.06.13

Accordingly, an object of the present invention is to provide an electrode for a vacuum interrupter capable of minimizing the generation of current in the opposite direction to the current forming the seed field and maximizing the induced seed field in the seed field method having a slit structure. .

In addition, an object of the present invention is to provide an electrode for a vacuum interrupter that can improve the strength of the contact zone while maximizing the induction of the seed field.

Moreover, an object of this invention is to provide the electrode for the vacuum interrupter which is easy to manufacture, maximizing seed field induction.

It is also an object of the present invention to provide an electrode for a vacuum interrupter in which a temperature increase can be minimized while maximizing seed field induction.

Other objects of the present invention will be readily understood through the following description of the embodiments.

A vacuum interrupter electrode according to a preferred embodiment of the present invention for achieving the above object, extending from the one end surface of the contact table toward the other end surface of the contact table in a predetermined inclination with the contact end plate. A plurality of main slits arranged at intervals; And at least one seed field inducing portion formed between neighboring main slits among the plurality of main slits, wherein the seed field inducing portion forms a current path in the circumferential direction of the contact table to the top and the bottom thereof. Inducing a seed system parallel to the.

Here, the seed field induction part may be spaced apart from the upper and lower ends of the neighboring main slit and the contact.

The seed field induction part may be spaced apart at the same azimuth angle on the contact table.

In addition, the seed field induction part may be formed of at least one of a hole type and a slit type.

In addition, the seed field induction part may be formed on an area where only one main slit is located between the upper end and the lower end of the contact table.

In addition, the seed field induction part may be formed in a hole type only, and may be formed on an area in which only one main slit is formed between an upper end and a lower end of the contact table.

In addition, the seed field induction part is formed in a slit type, one end of the seed field induction part toward the first main slit of the neighboring main slit, the other end toward the second main slit of the neighboring main slit, A circumferential current path between the neighboring main slits may be formed.

The seed field induction part may be formed of at least one slit type, and the slit type seed field induction part may have at least one region having an inclination angle formed with the contact end plate smaller than an inclination angle formed by the main slit and the contact end plate. It may include.

In addition, the main reinforcing member spaced apart from the inner peripheral surface of the contact by a predetermined interval; And a slit reinforcing member installed between the inner circumferential surface of the contact and the main reinforcing member to reinforce the mechanical strength of the contact with respect to the axial direction of the contact.

In addition, one surface of the slit reinforcing member may be fixed in close contact with the inner peripheral surface of the contact.

In addition, the slit reinforcing member may have a lower conductivity than the contact table.

As described above, the present invention can minimize the generation of current in the opposite direction to the current forming the seed field by the seed field induction unit formed between the neighboring main slits, and maximize the seed field induced.

In addition, according to the present invention, since the seed field induction part is formed on an area where only one main slit is located between the upper end and the lower end of the contact point, the decrease in strength of the contact point caused by the main slit and the seed field induction part can be minimized.

In addition, the present invention can maximize the induction of the seed system and improve the strength of the contact table by the slit reinforcing member that is tightly fixed to the side of the contact table. Moreover, in this invention, when making a seed field guide part into a hole type, a seed field guide part can be formed easily by forming a hole with a drill.

In addition, the present invention can widen the distance between the seed field induction and the main slit when the seed field induction part is a hole type, it is possible to minimize the temperature increase due to the resistance between the seed field induction part and the main slit and to reduce the mechanical strength of the contact It can be minimized.

1 shows a front view of an electrode for a vacuum interrupter of the seed field method according to the prior art.
2 shows a cross-sectional view of the electrode of FIG. 1.
3 is a front view of an electrode for a vacuum interrupter according to a preferred embodiment of the present invention.
4 is a cross-sectional view of the vacuum interrupter electrode of FIG. 3.
5 is a plan view in a state where a contact is removed from the electrode of FIG. 3.
6 is a front view of an electrode for a vacuum interrupter according to another embodiment of the present invention.
7 is a plan view of an electrode for a vacuum interrupter in a state where a contact is removed according to another embodiment of the present invention.
8 is a front view of an electrode for a vacuum interrupter according to another embodiment of the present invention.
9 is an arc control characteristic measurement result of the electrode of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The present invention forms a seed field guide between a plurality of main slits arranged at equal intervals. And the seed field induction part induces the seed field parallel to the axial direction of a contact stand by forming a current path to the upper part and the lower part in the circumferential direction of a contact stand. The seed field induction part may be formed of at least one of a slit type and a hole type. The seed field induction part may be alternately formed with the slit type and the hole type in the circumferential direction of the contact table.

Hereinafter, an electrode according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3 to 5. First, the case where the seed field induction part is of the slit type will be described. 3 is a front view of an electrode for a vacuum interrupter according to a preferred embodiment of the present invention. 4 shows a cross-sectional view of the electrode of FIG. 3. 5 is a plan view in a state where a contact is removed from the electrode of FIG. 3.

Referring to FIG. 3, the electrode 100 may include a contact end plate 120 fixed on the shaft 110 and a contact end 130 fixed on the contact end plate 120. In addition, the contact 140 may be fixed on one end surface 133 of the contact table 130. Here, when the electrode 100 is a fixed electrode, the shaft 110 is a fixed shaft, and when the electrode 100 is a movable electrode, the shaft 110 may be a moving shaft. Here, the contact end plate 120 and the contact table 130 may be integrally formed. In addition, the contact table 130 and the contact 140 may be integrally formed. The present invention does not limit the shape of the contact 140. For example, radial slits may be formed on the contact 140 to minimize the effects of eddy currents. The slit may be radially formed to correspond to the main slit 131 which will be described later.

The contact table 130 may include a main slit 131 and a seed field inducing part 132.

The main slit 131 may extend from one end surface 133 of the contact table 130 toward the other end surface 134. The main slit 131 may be formed in plural. The plurality of main slits 131 may be formed at equal intervals in parallel to each other. Here, the main slit 131 may extend to the other end surface 134. The main slit 131 may form a predetermined inclination angle α with the contact end plate 120. Unlike in FIG. 3, the main slit 131 may have a smooth curved surface or may be formed in a step shape. The present invention does not limit the shape of the main slit 131. The main slit 131 may induce a current i having a predetermined angle of inclination α with the contact end plate 120 between the one end surface 133 of the contact table 130 and the other end surface 134. As long as it is within the scope of the present invention. As is well known, the seed field B can be induced by a current i having a contact end plate 120 and a predetermined angle of inclination α.

The seed field induction part 132 may be formed in a slit type. Here, the term “slit” may mean “a form of a line passing through the side surface of the contact table 130”. Here, “line” may mean at least one of a straight line and a curve. At least one seed field induction part 132 may be formed between neighboring main slits 131. Here, one end of the seed field induction part 132 may face the first main slit among the neighboring main slits, and the other end may face the second main slit among the neighboring main slits. In addition, the seed field induction part 132 may be spaced apart from the adjacent main slit 131 by a predetermined interval so that a current flows between an end portion of the seed field induction part 132 and the main slit 131. In addition, the seed field induction part 132 may be spaced apart from the top and bottom of the contact by a predetermined interval so that the current in the circumferential direction can be guided to the top and bottom. A plurality of seed field guides 132 may be disposed between neighboring main slits 131, and in this case, the plurality of seed field guides 132 may be parallel to each other. In addition, the seed field induction part 132 may not be formed between some neighboring main slits 131. That is, the seed field induction part 132 may be intermittently disposed between the main slits 131. For example, when the first main slit to the sixth main slit are sequentially formed, a seed field guide part is formed between the first main slit and the second main slit, and the seed field guide part is formed between the second main slit and the third main slit. Is not formed, and a seed field induction part is formed between the third main slit and the fourth main slit, and a seed field induction part is not formed between the fourth main slit and the fifth main slit, and between the fifth main slit and the sixth main slit. The seed field guide may be formed and the seed field guide may not be formed between the sixth main slit and the first main slit. Alternatively, the seed field guide may be formed only between the first main slit and the second main slit, and between the fourth main slit and the fifth main slit. Due to the narrow width between the main slit 131 and the end of the seed field guide 132, heat may be generated. Therefore, it is desirable to minimize the number and width of the seed field inducing units 132 in the range of obtaining the desired arc control performance. When the seed field induction part 132 is intermittently disposed, the seed field induction part 132 may be spaced at the same azimuth angle on the contact surface 130 so that a uniform magnetic field is formed on the contact point 140. That is, the seed field guide part 132 may be located at the same angle in the circumferential direction of the contact table 130. The plurality of seed field guides 132 may be formed at positions symmetrical with respect to the axis of the contact table 130. In addition, the inclination angle β formed with the seed field guide part 132 and the contact end plate 120 may be smaller than the inclination angle α between the main slit 131 and the contact end plate 120. That is, the inclination angle β formed with the seed field induction part 132 and the contact end plate 120 may satisfy the following equation (1).

The current i introduced into the main slit 131 may branch to i1 and i2 in the seed field inducing unit 132. At this time, the inclination angle β formed by the seed field induction part 132 and the contact end plate 120 is smaller than the inclination angle α between the main slit 131 and the contact end plate 120, whereby the main slit 131. ), The current component i1 in the circumferential direction of the contact table 130 can be very large compared with the case of forming only). In this manner, most of the current flowing from the contact 140 to the contact 130 may be induced to the circumferential component. In consideration of the breaking capacity and / or the carrying capacity and / or resistance, the inclination between the main slit 131 and the contact end plate 120, the inclination between the seed field induction part 132 and the contact end plate 120, the main At least one of the number or length of the slits 131 and the seed field inducing part 132, the spacing between the main slits 131, and the spacing between the seed field inducing parts 132 may be adjusted. In FIG. 3, the seed field induction part 132 is formed as one line segment, but the seed field induction part 132 may be formed in a curved line. In this case, it is preferable that some sections of the curve are smaller than the angle of inclination between the contact end plate 120 and the main slit 131 and the contact end plate 120. In addition, the seed field induction part 132 may be formed of a plurality of line segments or a combination of line segments and curved surfaces. As long as the inclination angle formed with the contact end plate 120 includes an area smaller than the inclination angle between the main slit 131 and the contact end plate 120, the seed field induction part 132 of the present invention may correspond. Here, the inclination angle formed by the seed field induction part 132 with the contact end plate 120 may include 0 degrees. The seed field induction part 132 may be formed on an area S in which only one main slit is located between the upper end and the lower end of the contact table. By this, the mechanical strength of the contact zone can be improved.

Referring to FIG. 4, the main reinforcing member 150 may be positioned inside the contact table 130. The main reinforcing member 150 may be spaced apart from the inner peripheral surface of the contact table at predetermined intervals. The main reinforcement member 150 supports the contact 140 between the contact 140 and the contact end plate 120 to support the contact 140 and at the same time reinforce the mechanical strength of the contact 130. Can be. The slit reinforcement member 160 may be installed between the inner circumferential surface of the contact table 130 and the main reinforcement member 150. The slit reinforcing member 160 may be installed to reinforce the mechanical strength of the contact 130 with respect to the axial direction of the contact 130. Here, the main reinforcing member 150 has a main function of supporting the contact 140, the slit reinforcing member 160 by supporting the contact table 130, the main slit 131 and the seed field induction portion ( The main function can be to prevent deformation of 132).

Referring to FIG. 5, the slit reinforcement member 160 may be formed in a hollow cylinder. In addition, both ends of the slit reinforcement member 160 may be opened. In addition, the outer circumferential surface of the slit reinforcing member 160 may have the same radius as the inner circumferential surface of the contact table 130, and the outer circumferential surface of the slit reinforcing member 160 may be fixed to the inner circumferential surface of the contact table 130. One end of the slit reinforcing member 160 may be fixed to the contact 140, and the other end may be fixed to the contact end plate 120. At this time, the seed field generated by the main slit 131 and the seed field inducing unit 132 may be attenuated by the current flowing on the slit reinforcing member 160 when the fault current is blocked. Therefore, it is necessary to minimize the current flowing on the slit reinforcement member 160. To this end, the slit reinforcing member 160 is preferably formed of an insulator. When the slit reinforcing member 160 is conductive, it is preferable that the slit reinforcing member 160 has a lower conductivity than the contact table 130. By the designer, the material of the slit reinforcing member 160 may be appropriately selected in consideration of mechanical strength, arc control performance, and the like.

Hereinafter, an electrode for a vacuum interrupter according to another embodiment of the present invention will be described with reference to FIG. 6. Descriptions overlapping with the above description will be omitted or simplified. 6 is a front view of an electrode for a vacuum interrupter according to another embodiment of the present invention. In FIG. 6, the same reference numerals are given to the same components as those in FIG.

Referring to FIG. 6, at least one seed field inducing unit 232 may be formed between neighboring main silts 131. The seed field induction part 232 may include an area 232b that is horizontal to the area 232a that is inclined with respect to the contact end plate 120. The inclined region 232a and the contact end plate 120 may form a predetermined inclination angle γ. Here, the inclination angle γ between the inclined region 232a and the contact end plate 120 may be greater than 0 degrees and less than 90 degrees. However, it is preferable that the inclination angle γ between the inclined region 232a and the contact end plate 120 is smaller than the inclination angle α between the main slit 131 and the contact end plate 120 so that seed field formation is advantageous. Here, the current i induced between the main slits 131 may be easily branched to the horizontal area 232b by the inclined area 232a. Further, a stronger seed field can be induced by the current easily branched into the horizontal region 232b. 6 is merely an example, and the horizontal region 232b may be formed to have a predetermined inclination angle with the contact end plate 120. In this case, the inclination angle between the horizontal region 232b and the contact end plate 120 is preferably smaller than the inclination angle α between the main slit 131 and the contact end plate 120. As such, the seed field induction part of the present invention is provided so long as the inclination angle formed by the seed field induction part 232 with the contact end plate 120 is smaller than the inclination angle between the main slit 131 and the contact end plate 120. 232). Here, the inclination angle formed by the seed field guide part 232 with the contact end plate 120 may include 0 degrees.

Hereinafter, an electrode for a vacuum interrupter according to still another embodiment of the present invention will be described with reference to FIG. 7. Descriptions overlapping with the above description will be omitted or simplified. 7 is a plan view of an electrode for a vacuum interrupter in a state where a contact is removed according to another embodiment of the present invention. In FIG. 7, the same reference numerals are given to the same components as those in FIG. The structure of the slit reinforcing member of FIG. 7 to be described later may be applied to the electrodes of FIGS. 3 and 6.

Referring to FIG. 7, a plurality of slit reinforcing members 360 may be spaced apart from each other. In addition, the plurality of slit reinforcing members 360 may be fixed to the inner circumferential surface of the contact table 130. In addition, the plurality of slit reinforcing members 360 may be spaced apart at the same azimuth angle θ. In this case, in order to minimize deformation of the main slit 131 and the seed field inducing unit 132 (see FIG. 3), the plurality of slit reinforcing members 360 may be disposed to correspond to an area where the main slit 131 starts. desirable. By adopting the structure as shown in FIG. 7, the slit reinforcing member 360 can be easily manufactured, and the manufacturing cost thereof can be reduced. The present invention does not limit the shape of the slit reinforcing member 360. For example, the slit reinforcement member 360 may be formed in a rod type. In addition, a plurality may be disposed for each area to be reinforced. The slit reinforcing member 360 may be fixed on the contact table 130 by welding.

Hereinafter, an electrode for a vacuum interrupter according to still another embodiment of the present invention will be described with reference to FIG. 8. 8 is a front view of an electrode for a vacuum interrupter according to another embodiment of the present invention. Descriptions overlapping with the above description will be omitted or simplified. In FIG. 8, the same reference numerals are given to the same components as those in FIG.

Referring to FIG. 8, the seed field inducing unit 432 may be formed in a hole type. As described above, when the seed field induction part is formed in the slit type, since the cutting operation is performed by an end mill when the seed field induction part is formed, there is a high possibility that a deviation occurs between the seed field induction parts. That is, the position of the seed field guide cannot be made uniform. When the seed field induction part is formed by the cutting operation by the end mill, the inclination angle between the seed field induction part and the contact end plate may not be uniform. In addition, when the seed field induction part 432 is precisely processed, there is a problem that the electrode production process is delayed. In addition, when the seed field guide part is a slit type, there may be a limit in reducing the width of the seed field guide part. That is, the distance between the seed field guidance view and the main slit may be narrowed. If the spacing between the seed field guide and the main slit becomes narrow, the resistance between the seed field guide and the main slit increases, which can cause the temperature of the electrode to rise very much and attenuate the seed field by preventing the current flow from the top to the bottom of the main slit. You can also

However, when the seed field induction part 432 is a hole type, as shown in FIG. 8, the seed field induction part 432 may be simply formed by using only a drill. When the hole is precisely formed by only the position of the hole, the seed field inducing part 432 is formed, and thus the seed field inducing part 432 may be uniformly formed. And the hole type can be processed very easily, and can shorten an electrode manufacturing process.

The hole type may have a very small width compared to the slit type. Therefore, the interval (in other words, the energization area) between the hole type seed field induction part 432 and the main slit 131 is the interval (in other words, the energization area) between the slit type seed field induction part and the main slit 131. Can be larger than As a result, the resistance between the hole type seed field induction part 432 and the main slit 131 may be smaller than the resistance between the slit type seed field induction part and the main slit 131 and the temperature rise may be less. Even if the diameter of the hole type seed field induction part 432 is smaller than that of the slit type, as described above, the resistance between the hole type seed field induction part 432 and the main slit is small, so that more current may flow between the main slit. As a result, the circumferential currents i1 and i2 induced in the upper and lower portions of the hole type seed field inducing unit 432 may be larger than those of the slit type. Therefore, the hole type can induce a seed field comparable to the slit type while solving the above-described various problems of the slit type. That is, the arc control characteristic of the hole type may be equivalent to the arc control characteristic of the slit type. In addition, the hole type has a wider spacing between the seed field inducing portion 432 and the main slit 131 than the slit type, thereby improving the mechanical strength of the contact zone. When the seed field guide portion 432 is a hole type, the diameter of the hole may be appropriately selected by the designer in consideration of mechanical strength, temperature, arc control performance, and the like. As described above, the hole type seed field induction part 432 may be spaced apart from the upper and lower ends of the main slit and the contact table by a predetermined distance. In addition, the hole type seed field induction part 432 may be formed intermittently between neighboring main slits, and the intermittently formed seed field induction part may be spaced apart at the same azimuth angle. In addition, the hole type seed field induction part 432 may be formed on an area S in which only one main slit is located between the upper end and the lower end of the contact table. 8 illustrates a case in which the cross section of the hole is circular, but the hole may be an ellipse, a triangle, a rectangle, a rhombus, or the like. That is, the present invention does not limit the shape of the hole as long as it penetrates the side of the contact table.

The E model (slit type) and the F model (hole type) were made of the same material and the arc control characteristics of the model were tested at the same breaking current. In the experiment, when the fixed electrode and the movable electrode were separated by a certain distance, the magnetic flux density at each point was measured based on the center of the intermediate point of the fixed electrode and the movable electrode. Experimental results are shown in FIG. 9. 9 is an arc control characteristic measurement result of the electrode of the present invention. In Fig. 9, the horizontal axis represents the distance from the center of the middle of the fixed electrode and the movable electrode, and the vertical axis represents the magnetic flux density.

As shown in FIG. 9, it can be seen that the arc control characteristics are equivalent to the E model (slit type) and the F model (hole type). And, through the results of Figure 9, the breaking performance of 84kV / 31.5kA rating for both the E model (slit type) and F model (hole type) was confirmed. And, as seen above, it can be seen that the hole type is superior to the slit type in terms of heat, mechanical strength, processing precision, removal of deviations between seed field induction parts, and manufacturing process speed.

3 to 8 illustrate only the case where the seed field induction part is formed of any one type selected from the slit type and the hole type, but the seed field induction part may be alternately formed in the slit type and the hole type in the circumferential direction of the contact table. Alternatively, both the slit type and the hole type seed field guide may be included between neighboring main slits.

It will be apparent to those skilled in the relevant art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. The appended claims are to be considered as falling within the scope of the following claims.

1: electrode
10: contact table
11: first slit
12: second slit
13: reinforcing member
100, 200, 300, 400: electrode
110: axis
120: contact end plate
130: contact table
131: main slit
132, 232: seed field induction part
140: contact
150: main reinforcing member
160: slit reinforcing member

Claims (11)

In the electrode for vacuum interrupter,
A plurality of main slits arranged at equal intervals extending from the one end surface of the contact table toward the other end surface of the contact table in a predetermined inclination with the contact end plate;
At least one seed field inducing part formed between neighboring main slits among the plurality of main slits-The seed field inducing part is formed in the axial direction of the contact table by forming a current path in the circumferential direction of the contact table to the top and the bottom thereof. Inducing parallel seed fields,
The seed field induction part is formed in at least one of a hole type or a slit type electrode. The method of claim 1,
The seed field induction part is characterized in that the adjacent main slit and spaced apart from the top and bottom of the contact by a predetermined interval. The method of claim 1,
And the seed field induction part is spaced apart from each other at the same azimuth angle. delete The method of claim 1,
The seed field induction part,
And an electrode formed on an area where only one main slit is located between an upper end and a lower end of the contact. The method of claim 1,
The seed field induction part is formed only in the hole type, characterized in that formed on the region where only one main slit is formed between the upper end and the lower end of the contact. The method of claim 1,
The seed field induction part is formed of a slit type,
One end of the seed field induction part faces a first main slit among the neighboring main slits, and the other end faces a second main slit among the neighboring main slits, thereby circumferentially contacting the neighboring main slits. And an electrode forming a current path. The method of claim 1,
The seed field guide portion is formed of at least one slit type, and the seed field guide portion of the slit type includes at least one region having an inclination angle formed with the contact end plate smaller than an inclination angle formed by the main slit and the contact end plate. An electrode, characterized in that. The method of claim 1,
A main reinforcement member spaced apart from the inner circumferential surface of the contact portion by a predetermined interval; And
And a slit reinforcing member installed between the inner circumferential surface of the contact and the main reinforcing member to reinforce the mechanical strength of the contact in the axial direction of the contact. The method of claim 9,
One surface of the slit reinforcing member is in close contact with the inner peripheral surface of the contact. 11. The method of claim 10,
The slit reinforcing member is characterized in that the conductivity is lower than the contact.

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