JP2988062B2 - Insulation structure of primary conductor of zero-phase current transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulation structure for a primary conductor that passes through a zero-phase current transformer of a relatively large earth leakage circuit breaker.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show a conventional example of an insulation structure between primary conductors of each phase which penetrates a zero-phase current transformer. In FIG. 5, reference numeral 2 denotes a zero-phase current transformer, which is not shown in the drawing. The secondary winding is wound around a ring-shaped iron core and then housed in a ring-shaped outer case. Donut shape. Reference numerals 3, 4, and 5 denote R-phase, S-phase, and T-phase primary conductors, respectively, and cover the respective phase primary conductors with insulating tubes 6, 7, 6 made of a crosslinked thermoplastic resin, for example, a crosslinked polyethylene. After being heated and shrunk to penetrate the zero-phase current transformer 2, as shown in FIG. 6, it is screwed into a case 1 (hereinafter also referred to as a circuit breaker case or simply a case) of an earth leakage breaker 1. Fix it. At this time, insulation between the primary conductors is maintained by the insulating tubes 6, 7, 6. Insulating tape may be used in place of the insulating tubes 6, 7, 6.

[0003]

As described above, in the insulating structure in which the primary conductors are insulated from each other using the insulating tube, the length of the circumference of the terminal portion of the primary conductor is such that the screw passes through the terminal portion. Because it is necessary to form a hole, to secure the same cross-sectional area,
Since the length of the insulation tube is longer than the circumference of the zero-phase current transformer penetration part, if the insulation tube diameter is selected so that the terminal part can easily pass, even if the insulation tube is completely thermally contracted, it does not adhere to the primary conductor,
There was a problem that the tube was cut when passing through the zero-phase current transformer. In order to avoid this, if the bending of both phases (R phase and T phase) of the primary conductor is made smaller and closer to a straight line, the interval between the primary conductor terminals of each phase is determined by the distance between the phases of the main body of the earth leakage breaker. Therefore, there is a problem that the length of the primary conductor becomes long before and after, and it is impossible to make the earth leakage breaker compact. This is the same also when using an insulating tape instead of an insulating tube.

As one method of solving this problem, the same applicant as the present application has proposed a primary conductor structure shown in FIGS. 7 and 8 (Japanese Utility Model Application No. 2-65836). According to this, a bare conductor is used as a primary conductor, and the two parts are divided at a penetrating portion of a zero-phase current transformer. The recombination of the surfaces forms the entire primary conductor.

With such a structure of the primary conductor, the conductor from the terminal to the entrance of the zero-phase current transformer can be perpendicular to the through-hole, so that the zero-phase current transformer and the primary conductor The front-rear direction of the electric leakage detection unit can be made the minimum dimension. However, in the case of such a primary conductor structure, the insulation between the primary conductors of each phase is only air insulation, and as shown in FIG. If the spacing between conductors is small, when fixing the primary conductor to the circuit breaker case,
There has been a problem that the screw hole of the next conductor terminal portion and the screw are fixed with a gap therebetween, and a sufficient insulation interval is not necessarily ensured.

An object of the present invention is to provide an insulation structure for a zero-phase current transformer primary conductor in which the insulation between the primary conductors of each phase can be ensured and the size of the leakage detecting section can be reduced. .

[0007]

In order to solve the above-mentioned problems, according to the present invention, a bare conductor is used as a primary conductor passing through a through hole of a zero-phase current transformer, and a zero-phase current of each phase bare conductor is used. In the insulating structure of the zero-phase current transformer primary conductor, wherein the current transformer penetration portion is isolated from each other by an insulating partition wall made of a cast resin molded product, the primary conductor is formed using a plate material, The insulating partition includes a shielding plate having a portion wider than the through hole at one end, and the insulating partition is disposed in the through hole of the zero-phase current transformer into which the primary conductor is inserted, and the other end of the insulating partition is provided. And an insulating cover having a portion wider than the through hole. in this case,
It is preferable that the shield plate of the insulating partition is formed at the end on the load side and has a size that covers the entire through hole.

Further, the zero-phase current transformer penetration portion of each phase bare conductor has a flat rectangular cross section, and the insulating partition wall for isolating the zero phase current transformer penetration portion of each phase bare conductor from each other has a cross-sectional shape. The two phases in the zero-phase current transformer penetrating part of each phase bare conductor run parallel to the central partition with the partition at the central part of the character interposed therebetween, and the remaining one phase is opposed to both sides of the character. It is more preferable that each phase bare conductor is arranged so as to run parallel to the opposite surface on either one of the sides.

Further, the zero-phase current transformer penetrating portions of each phase bare conductor have fan-shaped cross sections, and insulating partition walls for isolating the phase bare conductor penetrating portions from each other are formed in an inverted Y-shaped cross section. An insulating structure may be used. In the above insulation structure,
Each phase bare conductor penetrating the zero-phase current transformer is divided into two parts before and after the zero-phase current transformer, and each of the two-phase bare conductors is combined with the zero-phase current transformer and then screwed. It is more preferable to combine them.

[0010]

When the insulating structure of the primary conductor of the zero-phase current transformer is formed in this way, the thickness of the insulating partition wall made of the cast resin molded product is reduced to 1
mm or so, regardless of the cross-sectional shape or cross-sectional area of the zero-phase current transformer penetration part of the primary conductor, there is a misalignment with the breaker case at the primary conductor terminal. Also, the insulation between the primary conductors can be reliably ensured. Also, since the insulating partition wall is structurally inserted after penetrating three phases of the primary conductor into the zero-phase current transformer, the cross-sectional shape of the zero-phase current transformer penetrating part of the primary conductor is, for example, a flat rectangular shape. ,
In addition, by giving an appropriate shape to the primary conductor, for example, by rounding the terminal portion, the large phase in the zero-phase current transformer after the insertion of the R-phase conductor having a large bend as the first phase is used. It is possible to easily insert a T-phase conductor having a large bend as the second phase, and it is possible to reduce the size of the leakage detection unit including the zero-phase current transformer and the primary conductor before and after. In addition, since the insulating partition is inserted last, a primary conductor molding method in which the primary conductor is inserted into the zero-phase current transformer without bending and bent at a right angle using an appropriate jig is also possible. .

In this case, when the shielding plate of the insulating partition is formed at the end on the load side and is formed to have a size to cover the entire through hole, the shielding plate is inserted into the groove of the circuit breaker case to position the insulating partition. Is fixed so that the relative position with the primary conductor does not shift due to vibrations during transportation of the earth leakage breaker, and also connects the load side conductor to the load side terminal of the primary conductor at the place where the earth leakage breaker is used. At the time of work, entry of foreign matter into the insulation space between the bare conductors of each phase is prevented, and the insulation between the primary conductors is maintained substantially unchanged.

Further, the zero-phase current transformer penetration portion of each phase bare conductor has a flat rectangular cross section, and the insulating partition wall for isolating the zero-phase current transformer penetration portion of each phase bare conductor from each other has a character-shaped cross section. The two phases in the zero-phase current transformer penetrating part of each phase bare conductor run parallel to the central partition with the partition at the central part of the character interposed therebetween, and the remaining one phase is opposed to both sides of the character. If the insulation structure in which the bare conductors of each phase are arranged so as to run in parallel with the opposite surfaces on either one of the sides is adopted, as described above as an example, even a primary conductor having a large bend can be relatively easily zeroed. After passing the phase current transformer or penetrating the primary conductor without bending, the remaining conductor part can be bent at right angles to the penetrating part and the terminal part can be formed. Miniaturization becomes possible easily.

Further, the zero-phase current transformer penetrating portions of each phase bare conductor have fan-shaped cross sections, and insulating partition walls for isolating the phase bare conductor penetrating portions from each other are formed in an inverted Y-shaped cross section. With an insulating structure, the conductor cross section of the penetrating portion can be made large, and it is possible to cope with a leakage breaker having a larger rated current by using the same zero-phase current transformer. In the above insulating structure, each phase bare conductor penetrating the zero-phase current transformer is divided into two parts before and after the zero-phase current transformer, respectively. If combined with screws after assembly, the insulation performance between the primary conductors of each phase is reliable and small, regardless of the cross-sectional shape and cross-sectional area of the zero-phase current transformer penetration of the primary conductor. It is possible to easily obtain a simple leakage detecting unit.

[0014]

1 to 3 show an embodiment of a zero-phase current transformer primary conductor insulation structure according to the present invention. In these figures, the same or corresponding members as in FIGS. 5 to 8 are denoted by the same reference numerals. In this embodiment, the primary conductor is formed using a rectangular plate material having a flat cross section in all three phases, and among these primary conductors, the R phase and the T phase are two-phase as shown in FIG.
One split and each conductor 3A is inserted from the front and back of the zero-phase current transformer 2 to the zero-phase current transformer, butt abutting portion 3A _1, 3B ₁ of 3B, with aligning tighten both abutting portion by screws ing. After the three phases of the primary conductor have been passed through the zero-phase current transformer in this way, the insulating partition 15 formed as a cast resin molded product is inserted as shown in FIG. 1 (b). When the insulating cover 16 is fitted to the insulating partition 15 by pressing the shielding plate 15a formed integrally with the partition 15, the insulating partition 1
The projections 15b of the fifth and the holes 16b of the insulating cover 16 are engaged with each other, and the leakage detecting section is completed as a single unit.

The insulating partition wall 15 is formed in a cross section in the shape of a character.
The insulation between the primary conductors of each phase is ensured by the penetration breakdown strength due to the thickness of the partition walls and the creeping breakdown strength due to the long creeping insulation distance. In this embodiment, the R-phase and T-phase primary conductors are divided into two. However, since the cross-sectional shape of the primary conductor is a flat square, for example, the terminal portion is rounded so as to be divided into two. It is also possible to pass through the zero-phase current transformer without using the following.

FIG. 3 shows a state in which the leakage detecting unit thus completed is incorporated in the case 1 of the leakage breaker. Here, the shielding plate 15a of the insulating partition 15 is fitted into the groove of the circuit breaker case 1, and the relative positions of the insulating partition 15 and the primary conductors 3, 4, and 5 are fixed immovably. It can be seen that the earth leakage breaker is much smaller than the conventional one (FIG. 6). On the other hand, when the earth leakage breaker is downsized in this way, the space for mounting printed circuit boards, electronic circuit components, and the like to be incorporated in the earth leakage breaker is reduced, and the inside of the circuit breaker case is mounted so that these can be mounted. It is undeniable that the shape tends to be complicated. However, since the insulating partition wall 15 can be easily formed into a complicated shape as a cast resin molded product, it is easy to make the shape of the shielding plate 15a and the insulating cover 16 into a shape that matches the internal shape of the circuit breaker case. Yes,
Furthermore, a structure that also serves as a mounting member for a printed board or an electronic circuit component is possible, and the presence of an insulating partition or an insulating cover does not prevent the circuit breaker from being downsized. FIG. 4 shows a modification of the embodiment shown in FIGS. The cross section of the zero-phase current transformer of each phase primary conductor is formed in a fan shape with a cross section of about 120 °, so that the maximum possible cross-sectional area can be obtained for the given inner diameter of the zero-phase current transformer. ing. In this case, naturally, both the R-phase and T-phase primary conductors are divided into two parts, inserted into the zero-phase current transformer from both sides, and tightened with screws. Further, the insulating partition 17 is formed in an inverted Y shape, and
It is inserted into the opposing gap of the next conductor and is integrated with the insulating cover 18. Also in this case, the insulation between the primary conductors of each phase is ensured by the penetration breakdown strength by the thickness of the insulating partition wall 17 and the creeping breakdown strength by the creeping insulation distance.

[0017]

As described above, according to the present invention, the bare conductor is used as the primary conductor penetrating the through-hole of the zero-phase current transformer, and the zero-phase current transformer penetrating portion of each phase bare conductor is formed. In the insulating structure of the zero-phase current transformer primary conductor, which is separated from each other by an insulating partition made of a cast resin molded product, the primary conductor is formed by using a plate material, and the insulating partition is provided at one end. A shielding plate having a portion wider than the through hole;
The insulating partition is arranged in the through-hole of the zero-phase current transformer in which the secondary conductor is inserted, and an insulating cover having a portion wider than the through-hole is attached to the other end of the insulating partition. Insulation between conductors is ensured by the penetration breakdown strength and creepage breakdown strength of the insulating bulkhead without being affected by play between the hole of the primary conductor terminal and the screw, improving insulation reliability, By appropriately providing the cross-sectional shape of the primary conductor through-hole of the zero-phase current transformer, or by dividing the primary conductor into two, the insulating partition is further inserted last into the zero-phase current transformer. Therefore, a method of forming a primary conductor in which both phases of the primary conductor are inserted in a straight line into the zero-phase current transformer and then bent at a right angle is also possible, and the miniaturization of the earth leakage breaker can be achieved together.

Furthermore, it is not necessary to insulate the primary conductor of each phase, and the man-hour for assembling the leakage detector is reduced, so that the total cost of the leakage breaker is reduced. In addition, since the insulation partition walls can be easily formed as a cast resin molded product with a complicated shape, the cross-sectional shape of the primary conductor, particularly the cross-sectional shape of the zero-phase current transformer penetration part, can be designed relatively freely, It is possible to cope with a case where it is desired to partially increase the wall thickness by taking measures against rising or the like, and it is possible to immediately design a more balanced primary conductor and change specifications of an ordered product.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a zero-phase current transformer primary conductor insulation structure according to the present invention, wherein FIG. 1 (a) is a front view and FIG.
2A is a cross-sectional view taken along the line AA in FIG. 2A, FIG. 2C is a perspective view showing the structure of an insulating partition used in the present embodiment, and FIG.
Is a perspective view showing the structure of an insulating cover integrated with the insulating partition shown in FIG.

FIG. 2 is a perspective view showing the structure of an R-phase conductor (reference numeral 3) in the embodiment of FIG.

3 has a primary conductor insulation structure shown in the embodiment of FIG. 1,
Front view showing a state in which a leakage detector comprising a zero-phase current transformer and a primary conductor is incorporated in a case of a leakage breaker.

FIG. 4 is a view showing a modification of the embodiment of the zero-phase current transformer primary conductor insulation structure shown in FIG. 1, wherein FIG. 4 (a) is a front view and FIG.
(b) is a sectional view taken along the line BB in FIG.

FIG. 5 is a front view showing an example of a conventional zero-phase current transformer primary conductor insulation structure.

6 has a primary conductor insulating structure shown in the conventional example of FIG. 5,
Front view showing a state in which a leakage detector comprising a zero-phase current transformer and a primary conductor is incorporated in a case of a leakage breaker.

FIG. 7 is a diagram showing a structure proposed by the applicant of the present application of a conventional earth leakage detector comprising a zero-phase current transformer and a primary conductor,
(A) is a front view, and (b) is a bottom view.

FIG. 8 is a perspective view showing a primary conductor structure of a ground fault detecting unit whose structure is shown in FIG. 7;

[Explanation of symbols]

 2 Zero-phase current transformer 3 Primary conductor 4 Primary conductor 5 Primary conductor 15 Insulating partition 15a Shielding plate 17 Insulating partition 17a Shielding plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01F 27 / 32,38 / 28 H01H 83/02

Claims (5)

(57) [Claims] 1. A bare conductor is used as a primary conductor passing through a through-hole of a zero-phase current transformer, and the zero-phase current transformer penetration of each phase bare conductor is formed by an insulating partition made of a cast resin molded product. In the insulating structure of the primary conductor of the zero-phase current transformer, the primary conductor is formed using a plate material, and the insulating partition has at one end a portion wider than the through hole. Wherein the insulating partition is disposed in a through hole of the zero-phase current transformer in which the primary conductor is inserted, and an insulating cover having a portion wider than the through hole is attached to the other end of the insulating partition. An insulation structure for a primary conductor of a zero-phase current transformer. 2. The insulating structure according to claim 1, wherein the shielding plate of the insulating partition is formed at an end on the load side and has a size to cover the entire through hole. Insulation structure of the primary conductor of the flow device. 3. The insulating structure according to claim 1, wherein the through-passage of the zero-phase current transformer of each bare conductor has a flat rectangular cross section and the through-passage of the zero-phase current transformer of each bare conductor. An insulating partition wall that is isolated from each other is formed in the shape of a cross section, and two phases in the zero-phase current transformer penetrating portion of each phase bare conductor are parallel to the center partition wall with the partition wall at the center of the character being interposed therebetween. Characterized in that the bare conductors of each phase are arranged so that the remaining one phase runs parallel to the opposing surfaces on either one of the opposite sides of the construction. Insulation structure. 4. The insulating structure according to claim 1, wherein each of the zero-phase current transformer penetrating portions of each phase bare conductor has a fan-shaped cross section, and separates each phase bare conductor penetrating portion from each other. Is formed in an inverted Y-shape in cross section. 5. The insulation structure according to claim 1, wherein each of the bare conductors passing through the zero-phase current transformer is divided into two parts before and after the zero-phase current transformer, respectively. An insulating structure for a primary conductor of a zero-phase current transformer, wherein each of the two divided bare conductors is combined with a zero-phase current transformer and then screwed together.