Earth leakage detection unit and earth leakage breaker

Abstract

To provide an earth leakage detection unit capable of sufficiently securing electric insulation between adjacent through conductor units, and improving detection performance of an unbalanced current and flexibility of a product structure.SOLUTION: An earth leakage detection unit includes: a zero phase current transformer 10 having a through-hole 10a; through conductor units 11Ra,11Sa,11Ta of a plurality of primary conductors passing through the through-hole; and a through hole insulating member 12 inserted into the through hole. First insulating units 18, 19 protruding radially inward from an inner circumferential surface of the through hole and extending in an axial direction of the through hole and second insulating units 27, 30 protruding radially outward from the through hole insulating member and connected to the first insulating unit are formed between the through conductor units 11Ra, 11Ta adjacent to each other in the through hole are formed. The first insulating unit and the second insulating unit electrically insulate the adjacent through conductor units from each other.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a leakage circuit breaker including a leakage detection unit and a leakage detection unit.

Background Art

[0002] The leakage detection unit includes an annular zero-phase current transformer and primary conductors of each phase of the main circuit that penetrate a penetrating conductor portion through a through-hole of the zero-phase current transformer. The leakage circuit breaker provided with this leakage detection unit is a device that determines that the load side is in a leakage state and shuts off the main circuit when the leakage detection unit detects an unbalanced current in the main circuit.

[0003] In the leakage detection unit, the electrical insulation between adjacent primary conductors has been a problem. Conventionally, adjacent primary conductors have been electrically insulated by taping an insulating tape to the primary conductors or attaching an insulating tube to the primary conductors. However, since the taping work of the primary conductors and the attachment of the insulating tubes are time-consuming and the workability is poor, in recent years, a device has been developed that inserts a primary conductor insulating member into the through-hole of the zero-phase current transformer and performs electrical insulation of adjacent penetrating conductor portions only with the primary conductor insulating member (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the leakage detection unit of Patent Document 1 has a structure that secures the insulation performance between adjacent penetrating conductor portions by arranging a primary conductor insulating member in the limited space of the through-hole of the zero-phase current transformer, it is necessary to make the primary conductor smaller in shape or increase the diameter of the through-hole of the zero-phase current transformer. Therefore, there are problems in terms of a decrease in the detection performance of the unbalanced current and a decrease in the degree of freedom of the product structure.

[0006] Therefore, an object of the present invention is to provide a leakage detection unit and a leakage circuit breaker that can sufficiently ensure electrical insulation between adjacent through-conductor portions and can improve the detection performance of unbalanced current and the degree of freedom of product structure.

Means for Solving the Problems

[0007] In order to achieve the above object, a leakage detection unit according to the present invention includes a zero-phase current transformer having a through-hole, a through-conductor portion of a plurality of primary conductors penetrating through the through-hole, and a through-hole insulating member inserted into the through-hole. Between adjacent through-conductor portions in the through-hole, a first insulating portion protruding radially inward from the inner peripheral surface of the through-hole and extending in the axial direction of the through-hole, and a second insulating portion protruding radially outward from the through-hole insulating member and connecting to the first insulating portion are formed, and the first insulating portion and the second insulating portion electrically insulate adjacent through-conductor portions.

[0008] Further, a leakage circuit breaker according to the present invention is equipped with an opening / closing mechanism for opening and closing a main circuit contact, an overcurrent tripping device, and a leakage tripping device. The leakage tripping device includes the above-described leakage detection unit that detects an unbalanced current in the main circuit, and a trip coil unit that sets the main circuit contact in an open state when the leakage detection unit detects an unbalanced current.

Effects of the Invention

[0009] According to the leakage detection unit and the leakage circuit breaker of the present invention, electrical insulation between adjacent through-conductor portions can be sufficiently ensured, and the detection performance of unbalanced current and the degree of freedom of product structure can be improved.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Embodiments for Carrying Out the Invention

[0011] Next, with reference to the drawings, the first and second embodiments according to the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thicknesses of the respective layers, etc. are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Also, it goes without saying that there are portions where the dimensional relationships and ratios are different between the drawings.

[0012] Further, the first and second embodiments according to the present invention shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the material, shape, structure, arrangement, etc. of the components as follows. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims. In addition, the terms indicating directions such as "up", "down", "bottom", "front", "rear", "longitudinal direction", "lateral direction", etc. described in the following description are used with reference to the directions of the attached drawings.

[0013] [First Embodiment] FIG. 1 is a perspective view showing a three-phase (R, S, T) AC leakage circuit breaker 1 according to the first embodiment of the present invention. The leakage circuit breaker 1 of this embodiment includes a main body case 2 made of a molded resin and a cover (not shown) that covers the main body case 2. An opening / closing mechanism 3 for opening and closing main circuit contacts (a fixed contact and a movable contact not shown), an overcurrent tripping device 4, and a leakage tripping device 5 are mounted on the main body case 2. The leakage tripping device 5 includes a leakage detection unit 6 and a trip coil unit 7. When the leakage detection unit 6 detects an unbalanced current in the main circuit, the trip coil unit 7 opens the fixed contact and the movable contact of the main circuit contact to cut off the main circuit.

[0014] As shown in FIGS. 2 and 3, the leakage detection unit 6 includes an annular zero-phase current transformer 10, a primary conductor 11R of the R phase, a primary conductor 11S of the S phase, and a primary conductor 11T of the T phase through which respective through-conductor portions described later penetrate the through-hole 10a of the zero-phase current transformer 10, a first insulating member 12 inserted into the through-hole 10a from one opening of the zero-phase current transformer 10, and a second insulating member 13 disposed at the other opening of the zero-phase current transformer 10 and detachably engaged with the first insulating member 12. Note that the through-hole insulating member according to the present invention corresponds to the first insulating member 12.

[0015] As shown in Fig. 4, the zero-phase current transformer 10 includes an annular case 14 formed of a synthetic resin of an electrical insulating material, an annular core 10b disposed inside the case 14, a coating resin 10c covering the surface of the annular core 10b, and a secondary coil (not shown) wound around the outer surface of the coating resin 10c.

[0016] As shown in Fig. 5, the case 14 includes a case body 15 having a U-shaped cross section and continuous in an annular shape, and an annular lid member 16 that closes the opening of the case body 15 and is integrally fixed to the case body 15. A secondary terminal 17 that is connected to the secondary coil and outputs a secondary current is formed on the outer peripheral surface of the case body 15. Also, as shown in Fig. 5, on the inner peripheral surface 15a of the case body 15, two first through-hole ribs 18 and second through-hole ribs 19 are formed that project from positions spaced apart from each other at a predetermined interval in the circumferential direction toward the center of the through-hole 10a and extend along the axial direction of the through-hole 10a. Note that the first insulating portion according to the present invention corresponds to the first through-hole ribs 18 and the second through-hole ribs 19.

[0017] As shown in Fig. 5, the primary conductor 11R of the R phase is formed by bending a metal strip into a substantially U shape, and includes a flat R-phase through-conductor portion 11Ra and a pair of parallel conductor portions 11Rb and 11Rc that extend in parallel from both ends of the R-phase through-conductor portion 11Ra. An R-phase load-side terminal 11Rd is integrally formed at the end of one of the parallel conductor portions 11Rb, and an R-phase power-source-side terminal 11Re is connected to the end of the other parallel conductor portion 11Rc.

[0018] The primary conductor 11T of the T phase also has a shape symmetrical to the left and right of the primary conductor 11R of the R phase, and as shown in Fig. 5, is formed by bending a metal strip into a substantially U shape, and includes a flat T-phase through-conductor portion 11Ta and a pair of parallel conductor portions 11Tb and 11Tc that extend in parallel from both ends of the T-phase through-conductor portion 11Ta. A T-phase load-side terminal 11Td is integrally formed at the end of one of the parallel conductor portions 11Tb, and a T-phase power-source-side terminal 11Te is connected to the end of the other parallel conductor portion 11Tc.

[0019] As shown in FIG. 5, the primary conductor 11S of the S phase is formed by bending a metal strip into a substantially L shape, and includes an S-phase through conductor portion 11Sa and an orthogonal conductor portion 11Sb extending orthogonally to the S-phase through conductor portion 11Sa. An S-phase load-side terminal 11Sd is integrally formed at an end of the S-phase through conductor portion 11Sa, and an S-phase power-source-side terminal 11Se is connected to an end of the orthogonal conductor portion 11Sb.

[0020] The first insulating member 12 is formed of a synthetic resin of an electrical insulating material, and as shown in FIGS. 5 and 6, includes a first side plate 20 covering one side surface 10d of the zero-phase current transformer 10, a substantially rectangular opening 21 formed below the first side plate 20, a substantially rectangular cylindrical S-phase insulating cylinder portion 22 protruding from the periphery of the opening 21 on the surface covering one side surface 10d of the first side plate 20, and two flat plate-shaped R-phase insulating plate portions 23 and T-phase insulating plate portions 24 standing up in parallel at a distance from each other in the longitudinal direction from the flat upper surface of the S-phase insulating cylinder portion 22.

[0021] As shown in FIG. 7, a rib engagement horizontal plate 25 protruding to the left side not facing the T-phase insulating plate portion 24 is fixed to the upper end side of the R-phase insulating plate portion 23 and continuously extends in the depth direction (the front-rear direction of the paper surface in FIG. 7). Further, a rib engagement rising plate 26 is fixed at a distance from the upper end side of the R-phase insulating plate portion 23 in parallel from the upper surface of the rib engagement horizontal plate 25. And a first through-hole rib engagement recess 27 is formed in the space surrounded by the upper end side of the R-phase insulating plate portion 23, the rib engagement horizontal plate 25, and the rib engagement rising plate 26. Further, a rib engagement horizontal plate 28 protruding to the right side not facing the R-phase insulating plate portion 23 is fixed to the upper end side of the T-phase insulating plate portion 24 and continuously extends in the depth direction of the T-phase insulating plate portion 24. Further, a rib engagement rising plate 29 is fixed at a distance from the upper end side of the T-phase insulating plate portion 24 in parallel from the upper surface of the rib engagement horizontal plate 28. And a second through-hole rib engagement recess 30 is formed in the space surrounded by the upper end side of the T-phase insulating plate portion 24, the rib engagement horizontal plate 28, and the rib engagement rising plate 29. Note that the second insulating portion according to the present invention corresponds to the first through-hole rib engagement recess 27 and the second through-hole rib engagement recess 30.

[0022] The second insulating member 13 is formed of a synthetic resin of an electrical insulating material, similar to the first insulating member 12. As shown in FIGS. 5 and 6, it includes a second side plate 31 that covers the through-hole 10a of the zero-phase current transformer 10, engaging pieces 32 and 33 that extend orthogonally to the second side plate 31 from the upper edge of the second side plate 31, and insulating plate engaging recesses 36 and 37 formed by a rectangular protrusion 34 and a pair of flat plates 35a and 35b that protrude on the surface side covering the through-hole 10a of the second side plate 31.

[0023] The primary conductor 11R of the R phase is arranged such that the R-phase through-conductor portion 11Ra is located in the through-hole 10a of the zero-phase current transformer 10, the parallel conductor portion 11Rb and the R-phase load-side terminal 11Rd are located on the other side surface (the lid member 16 side) of the zero-phase current transformer 10, and the parallel conductor portion 11Rc and the R-phase power-source side terminal 11Re are located on one side surface 10d of the zero-phase current transformer 10. Also, the primary conductor 11T of the T phase is arranged such that the T-phase through-conductor portion 11Ta is located in the through-hole 10a of the zero-phase current transformer 10, the parallel conductor portion 11Tb and the T-phase load-side terminal 11Td are located on the other side surface (the lid member 16 side) of the zero-phase current transformer 10, and the parallel conductor portion 11Tc and the T-phase power-source side terminal 11Te are located on one side surface 10d of the zero-phase current transformer 10. As shown in FIG. 4, the R-phase through-conductor portion 11Ra of the primary conductor 11R of the R phase is arranged at a position closer to the left side of the through-hole 10a of the zero-phase current transformer 10, and the T-phase through-conductor portion 11Ta of the primary conductor 11T of the T phase is arranged at a position closer to the right side of the through-hole 10a of the zero-phase current transformer 10.

[0024] The first insulating member 12 is arranged on one side surface 10d side of the zero-phase current transformer 10, and the S-phase insulating cylinder portion 22, the R-phase insulating plate portion 23, and the T-phase insulating plate portion 24 are inserted into the through-hole 10a. At this time, the R-phase through-conductor portion 11Ra is located to the left of the R-phase insulating plate portion 23, and the T-phase through-conductor portion 11Ta is located to the right of the T-phase insulating plate portion 24. Also, the first through-hole rib engaging recess 27 provided at the upper end of the R-phase insulating plate portion 23 fits into the first through-hole rib 18 protruding from the inner peripheral surface 15a of the through-hole 10a of the case 14, and the second through-hole rib engaging recess 30 provided at the upper end of the T-phase insulating plate portion 24 fits into the second through-hole rib 19 protruding from the inner peripheral surface 15a.

[0025] The S-phase primary conductor 11S's S-phase load-side terminal 11Sd and the S-phase through-conductor part 11Sa are inserted through the opening 21 of the first insulating member 12. At this time, the S-phase through-conductor part 11Sa is positioned in the through-hole 10a of the zero-phase current transformer 10 and is arranged within the S-phase insulating cylinder part 22.

[0026] Then, the R-phase insulating plate part 23 and the T-phase insulating plate part 24 of the first insulating member 12 that protrude from the opening of one side surface 10d of the zero-phase current transformer 10 fit into the insulating plate engaging recesses 36, 37 of the second insulating member 13, and the engaging pieces 32, 33 of the second insulating member 13 engage with the rib engaging rising plates 26, 29 of the first insulating member 12, whereby the second insulating member 13 is detachably connected to the first insulating member 12.

[0027] By arranging the leakage detection part 6 with the above configuration adjacent to the trip coil unit 7 within the case 2, it is incorporated as the leakage diversion device 5 of the leakage circuit breaker 1. According to the leakage detection part 6 of the present embodiment, since the S-phase through-conductor part 11Sa is arranged within the S-phase insulating cylinder part 22, sufficient insulation distances from the adjacent R-phase through-conductor part 11Ra and T-phase through-conductor part 11Ta to the S-phase through-conductor part 11Sa are ensured.

[0028] Also, as shown in FIG. 8, between the adjacent R-phase through-conductor portions 11Ra and T-phase through-conductor portions 11Ta, there are provided a first insulating wall formed by a first through-hole rib 18 protruding from the inner peripheral surface 15a of the case 14 and an R-phase insulating plate portion 23, and a second insulating wall formed by a second through-hole rib 19 protruding from the inner peripheral surface 15a of the case 14 and a T-phase insulating plate portion 24. Thus, a sufficient insulation distance between the R-phase through-conductor portion 11Ra and the T-phase through-conductor portion 11Ta is ensured. Moreover, since the first through-hole rib 18 has an inlay structure that fits into the first through-hole rib engaging recess 27 of the R-phase insulating plate portion 23, and the second through-hole rib 19 also has an inlay structure that fits into the second through-hole rib engaging recess 30 of the T-phase insulating plate portion 24, the insulation creepage distance (the shortest distance between conductors along the surface of the insulator) of the R-phase insulating plate portion 23 and the T-phase insulating plate portion 24 is set large. In this way, by setting the insulation creepage distance of the R-phase insulating plate portion 23 and the T-phase insulating plate portion 24 large, the distance between the R-phase through-conductor portion 11Ra and the T-phase through-conductor portion 11Ta can be reduced.

[0029] Therefore, sufficient electrical insulation can be ensured between the S-phase through-conductor portion 11Sa, the R-phase through-conductor portion 11Ra, and the T-phase through-conductor portion 11Ta that penetrate through the through-hole 10a of the zero-phase current transformer 10 of the leakage detection unit 6 of the present embodiment. Also, since it is not necessary to reduce the shapes of the S-phase through-conductor portion 11Sa, the R-phase insulating plate portion 23, and the T-phase insulating plate portion 24, and it is not necessary to enlarge the through-hole 10a of the zero-phase current transformer 10, the detection performance of the unbalanced current and the degree of freedom of the product structure can be improved.

[0030] [Second Embodiment] Next, FIG. 9 is a plan view showing the leakage detection unit 40 of the second embodiment. The leakage detection unit 40 of the present embodiment is a device provided with a P-phase in addition to the R-phase, S-phase, and T-phases. Note that the same reference numerals are given to the same constituent members as those in the first embodiment, and the description thereof is omitted. The leakage current detection unit 40 includes a P-phase primary conductor 41P, an R-phase primary conductor 41R, an S-phase primary conductor 41S, and a T-phase primary conductor 41T through which respective through-conductor portions described later penetrate the through-hole 10a of the zero-phase current transformer 10, a first insulating member 42 disposed on one side surface of the zero-phase current transformer 10 and having first to fourth insulating plate portions 51 to 54 described later inserted into the through-hole 10a, and a second insulating member 43 disposed on the other side surface of the zero-phase current transformer 10 and detachably engaged with the first insulating member 42. Note that the through-hole insulating member according to the present invention corresponds to the first insulating member 42.

[0031] As shown in FIG. 10, the zero-phase current transformer 10 has four first through-hole ribs 44a to 47a formed on the inner peripheral surface 15a of the case 14, protruding from equally spaced positions 90° apart in the circumferential direction toward the center of the through-hole 10a and extending along the axial direction of the through-hole 10a. Further, on one side surface 10d of the case 14, four first side ribs 44b to 47b are formed, continuously extending radially from the four first through-hole ribs 44a to 47a toward the center of the through-hole 10a. Note that the first insulating portion according to the present invention corresponds to the first side ribs 44b to 47b. Also, the third insulating portion according to the present invention corresponds to the first side ribs 44b to 47b.

[0032] As shown in FIG. 11, the P-phase primary conductor 41P includes a P-phase load-side conductor portion 41Pa, a P-phase power-source-side conductor portion 41Pb, a P-phase conductor connecting screw 41Pc, a P-phase conductor connecting nut 41Pd, and a P-phase through-conductor portion 41Pe. At one end of the P-phase load-side conductor portion 41Pa, a screw hole 41Pf through which the P-phase conductor connecting screw 41Pc penetrates is formed, and at the other end, a P-phase load-side terminal 141Pg is integrally formed. In the P-phase power-source-side conductor portion 41Pb, a screw hole 41Ph through which the P-phase conductor connecting screw 41Pc penetrates is formed. The P-phase through-conductor portion 41Pe is a cylindrical metal member into which the P-phase conductor connecting screw 41Pc is inserted. As shown in FIG. 12, a P-phase power-source-side terminal 41Pi is connected to the P-phase power-source-side conductor portion 41Pb.

[0033] The primary conductor 41T of the T-phase includes members that are symmetric about the left and right and have the same shape as the primary conductor 41P of the P-phase shown in FIG. 11, and is shown by replacing a part of the symbol "P" with "T". As shown in FIG. 11, the primary conductor 41R of the R-phase includes an R-phase load-side conductor part 41Ra, an R-phase power-source-side conductor part 41Rb, an R-phase conductor connecting screw 41Rc, an R-phase conductor connecting nut 41Rd, and an R-phase through-conductor part 41Re. A screw hole 41Rf through which the R-phase conductor connecting screw 41Rc passes is formed at one end of the R-phase load-side conductor part 41Ra, and an R-phase load-side terminal 41Rg is integrally formed at the other end. A screw hole 41Rh through which the R-phase conductor connecting screw 41Rc passes is formed in the R-phase power-source-side conductor part 41Rb. The R-phase through-conductor part 41Re is a cylindrical metal member into which the R-phase conductor connecting screw 41Rc is inserted. As shown in FIG. 12, an R-phase power-source-side terminal 41Ri is connected to the R-phase power-source-side conductor part 41Rb.

[0034] Also, the primary conductor 41S of the S-phase includes members that are symmetric about the left and right and have the same shape as the primary conductor 41R of the R-phase shown in FIG. 11, and is shown by replacing a part of the symbol "R" with "S". Note that the continuous conductor part according to the present invention corresponds to the P-phase power-source-side conductor part 41Pb, the R-phase power-source-side conductor part 41Rb, the T-phase power-source-side conductor part 41Tb, and the S-phase power-source-side conductor part 41Sb.

[0035] The first insulating member 42 is formed of a synthetic resin of an electrical insulating material, and as shown in FIG. 13, includes a first side plate 50 that abuts against one side surface 10d of the zero-phase current transformer 10, and first insulating plate parts 51 to 54 that project in a cross shape from one side surface of the first side plate 50. Note that the insulating side plate according to the present invention corresponds to the first side plate 50.

[0036] A pair of rising pieces 55a and 55b that protrude parallel to each other are continuously formed at the upper end of the first insulating plate portion 51 and the upper part of one side surface of the first side plate 50. As a result, a first through-hole rib engaging recess 56a is formed at the upper end of the first insulating plate portion 51, and a first side surface rib engaging recess 56b is formed on the first side plate 50 side. A pair of rising pieces 57a and 57b that protrude parallel to each other are continuously formed at the right end of the second insulating plate portion 52 and the right side of one side surface of the first side plate 50. As a result, a second through-hole rib engaging recess 58a is formed at the right end of the second insulating plate portion 52, and a second side surface rib engaging recess 58b is formed on the first side plate 50. Also, a pair of rising pieces 59a and 59b that protrude parallel to each other are continuously formed at the lower end of the third insulating plate portion 53 and the lower part of one side surface of the first side plate 50. As a result, a third through-hole rib engaging recess 60a is formed at the lower end of the third insulating plate portion 53, and a third side surface rib engaging recess 60b is formed on the first side plate 50 side. Further, a pair of rising pieces 61a and 61b that protrude parallel to each other are continuously formed at the left end of the fourth insulating plate portion 54 and the left side of one side surface of the first side plate 50. As a result, a fourth through-hole rib engaging recess 62a is formed at the left end of the fourth insulating plate portion 54, and a fourth side surface rib engaging recess 62b is formed on the first side plate 50 side. Note that the second insulating portion according to the present invention corresponds to the first through-hole rib engaging recess 56a, the second through-hole rib engaging recess 58a, the third through-hole rib engaging recess 60a, and the fourth through-hole rib engaging recess 62a. Also, the fourth insulating portion according to the present invention corresponds to the first side surface rib engaging recess 56b, the second side surface rib engaging recess 58b, the third side surface rib engaging recess 60b, and the fourth side surface rib engaging recess 62b.

[0037] The second insulating member 43 is formed of a synthetic resin of an electrical insulating material. As shown in FIG. 14, it includes a second side plate 65 that covers the through-hole 10a of the zero-phase current transformer 10, and a cross-shaped engaging recess 67 that protrudes from the second side plate 65 and into which the tips of the first insulating plate portions 44 to 47 of the first insulating member 42 are fitted.

[0038] The primary conductor 41P of the P phase arranges the P-phase through-conductor part 41Pe in the through-hole 10a of the zero-phase current transformer 10, inserts the P-phase conductor connecting screw 41Pc in the order of the screw hole 41Ph of the P-phase power supply side conductor part 41Pb, the inside of the P-phase through-conductor part 41Pe, and the screw hole 41Pf of the P-phase load side conductor part 41Pa, and integrates by screwing the P-phase conductor connecting nut 41Pd onto the tip of the P-phase conductor connecting screw 41Pc that has come out of the screw hole 41Pf. The primary conductor 41R of the R phase arranges the R-phase through-conductor part 41Re in the through-hole 10a of the zero-phase current transformer 10, inserts the R-phase conductor connecting screw 41Rc in the order of the screw hole 41Rh of the R-phase power supply side conductor part 41Rb, the inside of the R-phase through-conductor part 41Re, and the screw hole 41Rf of the R-phase load side conductor part 41Ra, and integrates by screwing the R-phase conductor connecting nut 41Rd onto the tip of the R-phase conductor connecting screw 41Rc that has come out of the screw hole 41Rf.

[0039] Also, the primary conductor 41S of the S phase arranges the S-phase through-conductor part 41Se in the through-hole 10a of the zero-phase current transformer 10, inserts the S-phase conductor connecting screw 41Sc in the order of the screw hole 41Sh of the S-phase power supply side conductor part 41Sb, the inside of the S-phase through-conductor part 41Se, and the screw hole 41Sf of the S-phase load side conductor part 41Sa, and integrates by screwing the S-phase conductor connecting nut 41Sd onto the tip of the S-phase conductor connecting screw 41Sc that has come out of the screw hole 41Sf. The primary conductor 41T of the T phase arranges the T-phase through-conductor part 41Te in the through-hole 10a of the zero-phase current transformer 10, inserts the T-phase conductor connecting screw 41Tc in the order of the screw hole 41Th of the T-phase power supply side conductor part 41Tb, the inside of the T-phase through-conductor part 41Te, and the screw hole 41Tf of the T-phase load side conductor part 41Ta, and integrates by screwing the T-phase conductor connecting nut 41Td onto the tip of the T-phase conductor connecting screw 41Tc that has come out of the screw hole 41Tf.

[0040] As shown in Fig. 15, the P-phase through-conductor part 41Pe of the primary conductor 41P of the P phase is arranged at the upper left side of the through-hole 10a of the zero-phase current transformer 10, the R-phase through-conductor part 41Re of the primary conductor 41R of the R phase is arranged at the lower left side of the through-hole 10a, the S-phase through-conductor part 41Se of the primary conductor 41S of the S phase is arranged at the lower right side of the through-hole 10a, and the T-phase through-conductor part 41Te of the primary conductor 41T of the T phase is arranged at the upper right side of the through-hole 10a.

[0041] The first insulating member 42 is disposed on one side surface 10d side of the zero-phase current transformer 10, and the first insulating plate portion 51 to the fourth insulating plate portion 54 are inserted into the through-hole 10a. At this time, as shown in FIG. 15, each of the first insulating plate portion 51 to the fourth insulating plate portion 54 protruding in a cross shape is located between adjacent R-phase through-conductor portions 41Re to T-phase through-conductor portions 41Te. Then, a first through-hole rib 44a protruding from the inner peripheral surface 15a of the through-hole 10a of the case 14 fits into a first through-hole rib engaging recess 56a provided at the tip of the first insulating plate portion 51, and a fourth through-hole rib 47a protruding from the inner peripheral surface 15a fits into a second through-hole rib engaging recess 58a provided at the tip of the second insulating plate portion 52. Further, a third through-hole rib 46a protruding from the inner peripheral surface 15a fits into a third through-hole rib engaging recess 60a provided at the tip of the third insulating plate portion 53, and a second through-hole rib 45a protruding from the inner peripheral surface 15a fits into a fourth through-hole rib engaging recess 62a provided at the tip of the fourth insulating plate portion 54.

[0042] Also, when the first insulating member 42 is inserted into the through-hole 10a of the zero-phase current transformer 10, as shown in FIG. 16, a fourth side rib 47b protruding from one side surface 10d of the case 14 of the zero-phase current transformer 10 fits into the second through-hole rib engaging recess 58a of the first insulating member 42. Although not shown, a second side rib 45b protruding from one side surface 10d of the case 14 also fits into the fourth through-hole rib engaging recess 62a of the first insulating member 42. Further, as shown in FIG. 17, a first side rib 44b protruding from one side surface 10d of the case 14 of the zero-phase current transformer 10 fits into the first side rib engaging recess 56b of the first insulating member 42.

[0043] Then, the tips of the first insulating plate portion 44 to the fourth insulating plate portion 47 of the first insulating member 42 protruding from the opening of one side surface 10d of the zero-phase current transformer 10 fit into the engaging recess 67 of the second insulating member 43, whereby the second insulating member 43 is detachably connected to the first insulating member 42.

[0044] According to the leakage detection unit 6 of the present embodiment, between the P-phase through-conductor portion 41Pe of the P-phase primary conductor 41P, the R-phase through-conductor portion 41Re of the R-phase primary conductor 41R, the S-phase through-conductor portion 41Se of the S-phase primary conductor 41S, and the T-phase through-conductor portion 41Te of the T-phase primary conductor 41T, which are arranged in the through-hole 10a of the zero-phase current transformer 10 and adjacent to each other, as shown in FIG. 15, the first through-hole ribs 44a to 47a protruding from the inner peripheral surface 15a of the case 14 and the first insulating plate portions 51 to 54 of the first insulating member 42 corresponding to each of them are provided with first to fourth insulating walls. Therefore, the insulation distances of the P-phase through-conductor portion 41Pe, the R-phase through-conductor portion 41Re, the S-phase through-conductor portion 41Se, and the T-phase through-conductor portion 41Te are sufficiently ensured. Moreover, the first through-hole rib 44a has an inlay structure that fits into the first through-hole rib engaging recess 56a of the first insulating plate portion 51, the fourth through-hole rib 47a has an inlay structure that fits into the second through-hole rib engaging recess 58a of the second insulating plate portion 52, the third through-hole rib 46a has an inlay structure that fits into the third through-hole rib engaging recess 60a of the third insulating plate portion 53, and the second through-hole rib 45a has an inlay structure that fits into the fourth through-hole rib engaging recess 62a of the fourth insulating plate portion 54. Thus, the insulation creepage distance between adjacent through-conductor portions (for example, the P-phase through-conductor portion 41Pe and the R-phase through-conductor portion 41Re) can be set large, so that sufficient electrical insulation between adjacent through-conductor portions can be ensured.

[0045] Also, as shown in FIG. 16, between the T-phase power supply side conductor portion 41Tb and the S-phase power supply side conductor portion 41Sb adjacent to each other, the fourth side rib 47b protruding from one side surface 10d of the case 14 of the zero-phase current transformer 10 has an inlay structure that fits into the second through-hole rib engaging recess 58a of the first insulating member 42. Thus, the T-phase power supply side conductor portion 41Tb and the S-phase power supply side conductor portion 41Sb can be arranged close to each other with a large insulation creepage distance set.

[0046] Also, as shown in FIG. 17, between the P-phase load-side conductor portion 41Pa and the T-phase load-side conductor portion 41Ta adjacent to each other, a first side surface rib 44b protruding from one side surface 10d of the case 14 of the zero-phase current transformer 10 is fitted into a first side surface rib engaging recess 56b of the first insulating member 42. With this inlay structure, the P-phase load-side conductor portion 41Pa and the T-phase load-side conductor portion 41Ta can be arranged close to each other with a large insulation creepage distance. In this way, since the conductor portions can be arranged close to each other, there is no need to reduce the shape of the conductor portions, and there is no need to enlarge the through-hole 10a of the zero-phase current transformer 10. Therefore, the detection performance of the unbalanced current and the degree of freedom of the product structure can be improved.

Explanation of Signs

[0047] 1 Earth leakage circuit breaker 2 Main body case 3 Opening and closing mechanism 4 Overcurrent tripping device 5 Earth leakage tripping device 6 Earth leakage detection section 7 Trip coil unit 10 Zero-phase current transformer 10a Through-hole 10b Annular core 10c Coating resin 10d One side surface 11R Primary conductor of R phase 11Ra R-phase through-conductor portion 11Rb, 11Rc Parallel conductor portions 11Rd R-phase load-side terminal 11Re R-phase power supply-side terminal 11S Primary conductor of S phase 11Sa S-phase through-conductor portion 11Sb Orthogonal conductor portion 11Sd S-phase load-side terminal 11Se S-phase power supply-side terminal 11T Primary conductor of T phase 11Ta T-phase through-conductor portion 11Tb, 11Tc Parallel conductor portions 11Td T-phase load-side terminal 11Te T-phase power supply-side terminal 12 First insulating member 13 Second insulating member 14 Case 15 Case body 15a Inner peripheral surface of the case 16 Cover member 17 Secondary terminal 18 First through-hole rib 19 Second through-hole rib 20 First side panel 21 Opening 22 S-phase insulating cylinder part 23 R-phase insulating plate part 24 T-phase insulating plate part 25 Rib engaging horizontal plate 26 Rib engaging rising plate 27 First through-hole rib engaging recess 28 Rib engaging horizontal plate 29 Rib engaging rising plate 30 Second through-hole rib engaging recess 31 Second side panel 32, 33 Engaging pieces 34 Rectangular protrusion 35a, 35b Pair of flat plates 36, 37 Insulating plate engaging recesses 40 Leakage detection part 40 41P Primary conductor of P phase 41Pa P-phase load side conductor part 41Pb P-phase power source side conductor part 41Pc P-phase conductor connecting screw 41Pd P-phase conductor connecting nut 41Pe P-phase through conductor part 41Pf Screw hole 11Pg P-phase load side terminal 41Ph Screw hole 41Pi P-phase power source side terminal 41R Primary conductor of R phase 41Ra R-phase load side conductor part 41Rb R-phase power source side conductor part 41Rc R-phase conductor connecting screw 41Rd R-phase conductor connecting nut 41Re R-phase through conductor part 41Rf Screw hole 11Rg R-phase load side terminal 41Rh Threaded hole 41Ri R-phase power supply side terminal 41S Primary conductor of S-phase 41Sa S-phase load side conductor part 41Sb S-phase power supply side conductor part 41Sc S-phase conductor connecting screw 41Sd S-phase conductor connecting nut 41Se S-phase through conductor part 41Sf Threaded hole 11Sg S-phase load side terminal 41Sh Threaded hole 41Si S-phase power supply side terminal 41T Primary conductor of T-phase 41Ta T-phase load side conductor part 41Tb T-phase power supply side conductor part 41Tc T-phase conductor connecting screw 41Td T-phase conductor connecting nut 41Te T-phase through conductor part 41Tf Threaded hole 11Tg T-phase load side terminal 41Th Threaded hole 41Ti T-phase power supply side terminal 42 First insulating member 43 Second insulating member 44a~47a First through-hole rib~Fourth through-hole rib 44b~Rib 47b First side rib~Fourth side rib 50 First side panel 51~54 First insulating board part~Fourth insulating board part 55a,55b Upright pieces 56a First through-hole rib engaging recess 56b First side rib engaging recess 57a,57b Upright pieces 58a Second through-hole rib engaging recess 58b Second side rib engaging recess 59a,59b Upright pieces 60a Third through-hole rib engaging recess 60b Third side rib engaging recess 61a,61b Upright pieces 62a Fourth through-hole rib engagement recess 62b Fourth side rib engagement recess 65 Second side panel 67 Engagement recess

Claims

1. A zero-phase current transformer having a through-hole, a through-conductor portion of a plurality of primary conductors passing through the through-hole, and a through-hole insulating member inserted into the through-hole, wherein between the adjacent through-conductor portions in the through-hole, a first insulating portion protruding radially inward from the inner peripheral surface of the through-hole and extending in the axial direction of the through-hole, and a second insulating portion protruding radially outward from the through-hole insulating member and connected to the first insulating portion are arranged, and the adjacent through-conductor portions are electrically insulated by the first insulating portion and the second insulating portion. A leakage detection unit characterized by this.

2. One of the tip portions of the first insulating portion and the tip portions of the second insulating portion is a convex portion, and the other is a concave portion, and the first insulating portion and the second insulating portion are connected by an inlay structure in which the convex portion and the concave portion fit together. The leakage detection unit according to Claim 1, characterized by this.

3. A convex portion formed of a plate-like rib is formed on the first insulating portion, and a concave portion into which the rib fits is formed at the tip of the second insulating portion. The leakage detection unit according to Claim 2, characterized by this.

4. The plurality of primary conductors include continuous conductor portions extending along one side surface of the zero-phase current transformer from the through-conductor portions, the through-hole insulating member includes an insulating side plate covering one side surface of the zero-phase current transformer together with the plurality of continuous conductor portions, between the adjacent continuous conductor portions on one side surface of the zero-phase current transformer, a third insulating portion protruding from the one side surface and a fourth insulating portion protruding from the insulating side plate and connected to the third insulating portion are formed, and the adjacent continuous conductor portions are electrically insulated by the third insulating portion and the fourth insulating portion. The leakage detection unit according to Claim 1 or 2, characterized by this.

5. One of the tip portions of the third insulating portion and the tip portions of the fourth insulating portion is a convex portion, and the other is a concave portion, and the third insulating portion and the fourth insulating portion are connected by an inlay structure in which the convex portion and the concave portion fit together. The leakage detection unit according to Claim 4, characterized by this.

6. The third insulating portion is a convex portion formed of a plate-like rib protruding from the one side surface, and the fourth insulating portion is a concave portion protruding from the insulating side plate and into which the rib fits. The leakage detection unit according to Claim 5, characterized by this.

7. An opening / closing mechanism for opening and closing the main circuit contact, an overcurrent tripping device, and a leakage tripping device are mounted. The leakage tripping device includes a leakage detection unit according to any one of claims 1 to 3 that detects an unbalanced current in the main circuit, and a trip coil unit that sets the main circuit contact to an open state when the leakage detection unit detects an unbalanced current. A leakage circuit breaker characterized by comprising the above.

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