JPS6119113A - Current transformer - Google Patents

Abstract

PURPOSE:To enable to thin off the plate thickness of a core sheet, to enable to improve the sensitivity of detection and to prevent the deformation of blade parts by a method wherein a sheet of the pectinated blade part, formed at the end part of the half part of a core, is formed by a plurality of core plates. CONSTITUTION:Half parts of cores 31 and 51 are constituted by laminating relatively thin core plates 30 and 50. One end part of these core plates 30 and 50 is formed into long-leg parts 30a and 50a, and the other end part is formed into short-leg parts 30b and 50b which are shorter than the long-leg parts 30a and 50a. A plurality of these core plates 30 and 50, two sheets, for example, are superposed in such a manner that the long-led parts 39a and 50a and the short- leg parts 30b and 50b are corresponded each other, and said two-sheet superposed core plates 30 and 50 are laminated in such a manner that their front and back sides are reversed alternately. Accordingly, when the half parts of the main body are assembled with each other, the half parts 31 and 51 are coupled by engaging the pectinated blade parts 32 and 52 located at both end parts of the core half parts 31 and 51. As a result, the thickness of the blade part is not excessively thinned off even when the plate thickness of the core plate is reduced, thereby enabling to prevent the deformation of the blade part.

Description

[Detailed Description of the Invention] Generally, current transformers such as earth leakage detectors are composed of an annular iron core placed around an electric wire such as a power line and a coil placed around a part of this iron core. The iron core and coil detect the magnetic field generated around the wire when an unbalance occurs in the current flowing through the wire due to electrical leakage or the like.

Incidentally, in such a current transformer, the above-mentioned iron core needs to be constructed so that the above-mentioned iron core can be freely divided so that the current transformer can be attached and detached after the above-mentioned electric wire is installed. However, if the core is freely splittable in this way, the loss will be large at the joining portion of the split core halves, resulting in a problem that the detection sensitivity will be reduced.

In order to prevent such problems, for example, a plurality of semi-circular arc-shaped iron core plates are laminated to form the core half, and
The ends of these iron core plates are alternately shifted to form comb-tooth-like blades at the ends of these core halves, and the comb-tooth-like blades are engaged with each other to produce iron.

It was constructed to join the core halves and reduce losses at the joint of the core halves.

By the way, if this iron core is made by laminating a large number of thin iron core plates, the loss will be reduced, the detection sensitivity will be increased, and this iron core can be made more compact. However, when the thickness of the core plates is reduced in this way, the comb-tooth-shaped blades at the ends of the core plates, that is, the ends of the core halves, become easily deformed, and the comb-tooth-shaped blades This may cause problems such as difficulty in meshing the parts. For this reason, the thickness of this iron core plate cannot be made very thin, and there is a limit to the improvement of detection sensitivity and miniaturization of the iron core.

The present invention has been made based on the above circumstances, and its purpose is to provide a current transformer in which the thickness of the iron core plate can be reduced, detection sensitivity can be improved, and the iron core can be made smaller. There is a particular thing.

That is, the present invention provides an annular iron core configured by joining a pair of iron core halves and arranged around an electric wire, and a coil placed around a part of this iron core. The part is constructed by laminating a plurality of core plates, and a plurality of these core plates are stacked one on top of the other to form a plurality of blade parts protruding from the end of the core half at predetermined intervals, and these blade parts are The core halves are joined together by meshing with each other. Therefore, one piece of the comb-tooth-shaped blade part formed at the end of this core half is formed by a plurality of iron core plates, and even if the plate thickness of these iron core plates is made thinner, the blade part of one piece is made thinner. The thickness will not become excessively thin. Therefore, this blade portion will not be deformed. In addition, the thickness of these blade parts is not excessively thin as mentioned above, and there are some gaps between the plurality of iron core plates that make up one blade part, so the blade parts can mesh. At the same time, these gaps are reduced and the thickness of the blade portion is somewhat reduced, making it easier for the comb-toothed blade portions to engage. Therefore, the thickness of these iron core plates can be made sufficiently thin, and the loss of this iron core can be reduced.
The detection sensitivity can be improved and the iron core can also be made smaller.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. This embodiment is a relatively small current transformer for detecting leakage in a power supply system.

This current transformer is composed of a pair of main body halves 1, 2. are configured to be assembled and fixed to each other by an embedded nut 7 and an assembly bolt 9. A pair of mounting legs 4 are provided protruding from one main body half 1. These mounting holes 5 and 6 are formed in the leg portion 4, respectively, and one of the mounting holes 5 is formed in a potbell shape, so that the current transformer can be fixed by a hook. And these main body halves 1.2
Core half assemblies 11 and 12 are provided therein, respectively.

Hereinafter, the structure of one of the main body halves 1 will be explained with reference to FIGS. 3 to 6. In the figure, reference numeral 21 denotes a case of the main body half 1, which is made of a synthetic resin material, and the above-mentioned mounting legs 4 are integrally protruded from the lower part of the case. Also,
A lead wire lead-out portion 22 is formed on the lower side surface of this case 21, and the lead wire connected to the coil of the core half assembly 11 is connected to the lead wire 3 within this case 21. is configured to be led out of the case 21 from this lead wire lead-out portion 22. Inside this case 21 is a substantially U-shaped core half assembly 1.
1 is housed, and this core half assembly 11 and case 21
An adhesive or the like is filled between the case 21 and the case 21 to fix the core half assembly 11 and to ensure waterproofness to prevent water from entering the case 21. A semicircular holding member 23 is bonded to the center of the case 21, and is configured to fix the core half assembly 11 and form the wire insertion hole 10 described above.

The above-mentioned core half assembly 11 is constructed as shown in FIG. In the figure, reference numeral 31 denotes an iron core half, and this iron core half 31 has a substantially U-shape and is constructed by laminating a plurality of iron core plates 30.

A plurality of blade portions 32 are provided at both ends of this core half portion 31.
are each protruding in the shape of a comb. Further, positioning step portions 33 are formed at the lower portions of both ends of the core half portion 31.

Coils 35 are arranged at both ends of the core half 31 so as to surround these ends.

This coil 35 is wound around a rectangular cylindrical bobbin 35a. Further, a pair of shield members 34 are arranged surrounding the core half 31 and the coil 35. These shield members 34 are formed from a plate material of a magnetic material such as a steel plate, and have mouth-shaped coil shield portions 34a at both ends thereof.
is formed.

When these shield members 34 are laterally abutted against each other, these coil shield portions 34a surround the coil 35 and serve as a magnetic shield for the coil 35. Note that the outer peripheral portion of the shield member 34 is open, and a positioning step portion 34b is formed at the lower part of the coil shield portion 34.

Further, the core half 31, the end of the shield member 34, and the coil 35 are housed in a coil cap 36. This coil cap 36 is made of a synthetic resin material, has a double cylindrical shape, and has a housing portion 36b formed inside thereof. A core insertion hole 36c is formed in the center of the coil cap 36, and a positioning step 36a is formed in the lower part of the outer periphery thereof. The coil shield portion 34a of the shield member 34 is brought into close contact with the outer periphery of the coil 35, and the coil 35 and the coil shield portion 34a are housed in the accommodating portion 36b of the coil cap 36. , these coils 35 and shield member 34 are held in a predetermined positional relationship. Further, both ends of the core half portion 31 are inserted into core insertion holes 36c of the coil cap 36. The positioning step 33 of the core half 31 comes into contact with the lower end of the coil cap 36, so that the core half 31 and the coil cap 36 are positioned in the vertical direction.

Then, the core half assembly 11 assembled in this manner is positioned in the horizontal direction by fitting the outer peripheral surface of the positioning step portion 36a of the coil cap 36 to the inner peripheral surface of the case 21. , and the positioning section 34 of the shield member 34
b is the positioning step portion 24 formed in the case 2'i described above.
The structure is such that vertical positioning is performed by abutting on each other.

Next, the structure of the other main body half 2 described above will be explained with reference to FIGS. 7 and 8. 7 and 8 show a state in which the main body half 2 is turned upside down. That is, 41 in the figure is a case of this main body half 2, which is made of synthetic resin material like the case 21 of the main body half 1 described above, and has the same structure as the case 21 of this main body half 1. ing.

However, this case 41 is not provided with mounting legs. Note that 8 is a through hole for inserting an assembly bolt. The core half assembly 12 is housed in the case 41, and is filled with an adhesive or the like and fixed therein, and also prevents water from entering the gap to ensure waterproofness.

Further, a holding member 42 similar to the above-mentioned holding member 23 is adhered to the center portion of the case 41, and is configured to form an electric wire insertion hole 1o.

This core half assembly 12 is constructed as shown in FIG. Reference numeral 51 in the figure indicates a core half, and this core half 51 has the same configuration as the core half 31 described above, and has comb-tooth-shaped blades 52 formed at both ends thereof. A deciding part 53 is formed. Further, 54 is a shield member, and this shield member 54 has the same structure as the above-mentioned shield member 34, and a trowel-shaped coil shield portion 54a is formed at both ends of the shield member 54. A positioning step portion 54b is formed in the upper portion (lower portion in FIG. 8). The inner surface of the coil shield portion 54a of the shield member 54 is dimensioned to tightly fit onto the outer circumferential surface of the coil cap 36.

Further, core holding members 5 are provided at both ends of the core half portion 51.
5 are arranged respectively. These core holding members 5
5 is made of a synthetic resin material, and has an iron core insertion hole 55a formed in its center, and a positioning protrusion 55b formed in its outer edge.

Both ends of the core half portion 51 are inserted into the core insertion holes 5a of the core holding members 55, and the positioning step portion 53 of the core half portion 51 is brought into contact with the edge of the core insertion hole 55a. The core half portion 51 and the core holding member 55 are positioned in contact with each other. Further, the outer peripheral surface of this core holding member 55 is connected to the coil shield portion 4 of the abutted shield member 54.
The positioning convex portion 55b of the core holding member 55 comes into contact with the positioning step portion 54b of the shield member 54, and positioning is performed. In addition, when the core half assembly 12 is assembled in this way, the dimensions of each part are adjusted so that the coil shield part 54a of the shield member 54 protrudes from the tip of the blade part 52 of the core half part 51, as shown in FIG. is set.

Next, referring to FIGS. 9 and 10, the above iron core half 3
1.51 configuration will be explained. These core halves 31.5
1 is a relatively thin U-shaped iron core plate 30. '
It is constructed by laminating 50 layers. These iron core plates 30.
One end of 50 is formed into long leg portions 30a, 50a,
The other end portions are formed into short leg portions 30b, 50b that are shorter than the long leg portions 30a, 50a. Incidentally, chamfered portions 30c and 50c are formed on both sides of the tips of the long strands 30a and 50a and the short leg portions 30b and 50b, respectively. A plurality of these iron core plates 30.50 are stacked, for example, two at a time, so that the long legs 30a and 50a and the short legs 30b and 50b correspond to each other, and these two stacked iron core plates 30.50 are stacked alternately with the front and back sides reversed. Therefore, this core half 31.
At both ends of 51, long legs 30a, 50a and short legs 30b
, 50b are alternately arranged, and the long leg portions 30a,
Two pieces of the blades 50a protrude to form comb-tooth-shaped blade portions 32.52. When the aforementioned main body halves 1 and 2 are assembled together, the comb tooth-shaped blades 32.52 at both ends of the core halves 31.51 mesh with each other, and these core halves 31.51 are assembled together. 31° and 51 are combined to form an annular iron core.

Next, the operation of this embodiment will be explained. To install this current transformer, first, one of the main body halves 1 is attached by attaching the flap part 4 to a building frame or the like, and then placing electric wires etc. in the electric wire insertion holes 10 of this main body half 1. Then, the other main body half 2 is abutted against this main body half 1, and these main body halves 1 and 2 are assembled and fixed with assembly bolts 9. Therefore, the above-mentioned iron core half parts 31 and 51 are combined to form an annular iron core surrounding the electric wire and the like. When a leakage occurs in the power system and the current flowing through the wire becomes unbalanced, a magnetic field is generated around the wire, and this magnetic field generates a magnetic field within the iron core.
This magnetic field causes a current to flow through the coil 35, and by detecting this current, it is possible to detect a leakage current.

Then, when assembling the main body halves 1 and 2 together,
Since the coil shield portion 54a of the core half assembly 12 of the other main body half 2 protrudes from the blade portion 52 of the core half 51, this blade portion 52 is connected to the blade portion 32 of the one core half 31.
This coil shield portion 54a fits into the outer peripheral surface of the coil cap 36 of one core half assembly 11, and the blade portions 32.52 of these core halves 31 and 51 mesh accurately. The position is determined as follows. therefore,
These blades 32,52 are guided so that they mesh easily, and such blades 52 are prevented from being deformed by hitting other objects.

Moreover, since these blade parts 32, 52 are formed by stacking a plurality of, for example, two iron core plates 30.50, even if these iron core plates 30.50 are thin, these blade parts 3
2.52 does not become excessively thin, and these blade portions 32, 52 do not deform or become difficult to mesh. Moreover, this blade part 32.52 is 2
Since the core plates 30.50 are stacked, a slight gap is formed between the core plates 30.50, and this gap decreases when the blades 32.52 mesh with each other. As a result, the thickness of these blade portions 32, 52 is slightly reduced, making it easier for these blade portions 32, 52 to mesh and to mesh closely with each other. Therefore, the iron core plate 30.degree. 50 can be formed sufficiently thin, the loss of the iron core can be reduced, the detection sensitivity can be improved, and the iron core can be made smaller.

In addition, in this example, a coil is provided in the divided part of the iron core, and this coil is provided in one half of the main body, so the terminal processing of the lead wires of these coils is done inside the case of this half of the main body. can be processed in a mold. Therefore, water does not enter the terminal processing portion, and waterproofness is improved. Furthermore, since the above-mentioned coil can also be molded integrally with the case of this main body half, complete waterproofness can be obtained even in this coil portion. Although the inside of the above-mentioned iron core cannot be completely waterproof, this iron core is generally made of permalloy and has corrosion resistance, so even if some water enters the inside of this iron core, no problem will occur.

Note that the present invention is not limited to the above embodiments.

For example, in the above embodiment, two core plates are stacked to form one blade, but three or more core plates may be stacked to form one blade.

Further, the structure of the shield member and other components is not necessarily limited to the above embodiment.

As described above, the present invention includes an annular iron core formed by joining a pair of iron core halves and arranged surrounding an electric wire, and a coil arranged surrounding a part of this iron core.
The core half is constructed by laminating a plurality of core plates, and a plurality of these core plates are stacked one on top of the other to form a plurality of blades protruding from the end of the core half at predetermined intervals. The core halves are joined by interlocking the blades with each other. Therefore, one piece of the comb-tooth-shaped blade part formed at the end of this core half is formed by a plurality of iron core plates, and even if the plate thickness of these iron core plates is made thinner, the blade part of one piece is made thinner. The thickness will not become excessively thin. Therefore, this blade portion will not be deformed. In addition, the thickness of these blade parts is not excessively thin as mentioned above, and there are some gaps between the plurality of iron core plates that make up one blade part, so the blade parts can mesh. At the same time, these gaps are reduced and the thickness of the blade portion is somewhat reduced, making it easier for the comb-toothed blade portions to engage. Therefore, the plate thickness of these iron core plates can be made sufficiently thin, the loss of this iron core can be reduced, detection sensitivity can be improved, and this iron core can also be made smaller. is large.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, and FIG. 1 is an overall perspective view;
Fig. 2 is a perspective view of the main body half divided, Fig. 3 is a plan view partially shown in cross section, Fig. 4 is a front view partially shown in cross section, and Fig. 5 is one half of the main body. FIG. 6 is an exploded perspective view of one core half assembly, FIG. 7 is a perspective view of the other main body half, FIG. 8 is an exploded perspective view of the other main body half, and FIG. The figure is a perspective view of the end of the core half, and FIG. 10 is a side view of the end of the core half. 1.2... Main body half, 11.12... Iron core half assembly, 30.50... Iron core plate, 31.51... Iron core half, 32.52... Blade part, 34.54...Shield member. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 3 J Figure 4 Figure 5 Figure 7 Figure 9 Figure 10

Claims (1)

[Claims] In an annular core configured by joining a pair of core halves and arranged around an electric wire, and a coil arranged surrounding a part of the core, the core half has a plurality of core halves. A plurality of core plates are stacked one on top of the other to form a plurality of blades protruding from the ends of the core halves at predetermined intervals, and these blades are engaged with each other to produce the above-mentioned structure. A current transformer characterized by joining halves of an iron core.