JP3246117B2 - Primary conductor of earth leakage breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leakage current passing through a zero-phase current transformer having a rectangular cross section perpendicular to the circumferential direction of a ring-shaped storage space for storing a secondary winding wound around a ring-shaped iron core. More particularly, the present invention relates to a structure of a primary conductor of a large earth leakage breaker having a rated current on the order of 800 A as a primary conductor of the circuit breaker.

[0002]

2. Description of the Related Art As a primary conductor for a large-sized earth leakage circuit breaker of this type, a structure having a structure shown in FIG. 3 is conventionally known, and after a zero-phase current transformer 1 is passed through as shown in FIG. It is connected to the load side of the device to form an earth leakage breaker. The three primary conductors 2, 3, and 4 are manufactured by forging, and have a shape that can penetrate the inside of the annular zero-phase current transformer 1 including the width of the terminal portion. In addition, each of the three primary conductors 2, 3, and 4 is wound with an insulating tape so that the primary conductors 1 and 2 are separated from each other and 1
Insulation is provided between the secondary conductor and the zero-phase current transformer.

[0003]

In particular, in the case of a large earth leakage circuit breaker with a large current rating, the absolute value of the size reduction at the time of downsizing is large and its ripple effect is large, so downsizing is strongly required. There is a strong demand for a reduction in the required space of the primary conductor which takes up space for a small number.
However, if the primary conductor is formed from a large-diameter copper rod having a cross-sectional area commensurate with the rated current as in the conventional case, there is a limit to the size reduction due to the minimum bending radius required for the bent portion. Thus, for example, as shown in FIG. 4, it is conceivable to adopt a structure in which two of the three phases of the primary conductor are formed in a U-shape by using a plate material for the primary conductor (Japanese Patent Application No. 3-2729).
No. 61). In this structure, the power supply side and the load side of the two-phase zero-phase current transformer among the three phases of the primary conductor are provided with plate members 11a, 1
2a and 15a, 16a, and copper blocks 11c, 12c, 15c,
16c, and these blocks 11c, 12c and 15c, 16c are each made of a plate material 11 by brazing or the like.
a, 12a and 15a, 16a are integrated with each other, and the zero-phase current transformer power supply side and the load side are integrally connected using screws 13 to complete a primary conductor. However, in this structure, the number of parts of the primary conductor is large, and since the assembly is performed using screws, it takes time and effort to assemble, and a problem arises in that the cost reduction of the earth leakage breaker is hindered.

An object of the present invention is to provide a relatively small zero-phase current transformer which requires less space in the front-rear direction of the zero-phase current transformer and requires a smaller number of parts for forming a primary conductor. Can also penetrate the primary conductor rated at a relatively large current.
It is to provide a structure of a secondary conductor.

[0005]

In order to solve the above-mentioned problems, according to the present invention, a ring-shaped storage space for storing a secondary winding wound around a ring-shaped iron core has a sectional shape perpendicular to the circumferential direction. The primary conductor of the earth leakage breaker that penetrates the rectangular zero-phase current transformer, and the current-carrying part made of a plate, in which two phases out of the three phases of the primary conductor sandwich the annular surface of the zero-phase current transformer from both sides, are opposed. It has a U-shaped part with both sides, and the U-shaped open side end of at least one of the two sides is a free end to constitute the U-shaped part.
Longitudinal U-shape of the side having the free end of the opposing sides
Near the center side and on both sides or one side in the side plate width direction
The width of the side has an appropriate length in the longitudinal direction of the side.
The notch in the direction perpendicular to the direction is formed from the edge side .

[0006] Then, in the primary conductor is formed in the structure, it is further preferred to as the U-shaped portion is formed using one plate material includes a central side of the U.

When the notch is formed, or when the U-shaped portion is formed of a single plate, the width of the center of the U-shape is preferably smaller than the width of the opposite sides of the U-shape. In the case where the U-shaped portion is formed of a single plate material, of the opposite sides forming the U-shaped portion, the side having the free end has a longitudinal direction from the vicinity of the U-shaped central side to the central side longitudinal direction. It is preferable that the inside of both sides in the plate width direction be cut off or cut away from the edge side to the inside in the plate width direction over the entire length.

[0008]

When the primary conductor is formed in such a structure, the zero-phase current detecting portion composed of the primary conductor and the zero-phase current transformer is connected to the primary conductor from the open side of the U-shape of the U-shaped portion. Fit into the phase transformer,
By rotating so that the center of the U-shape enters the inside of the zero-phase current transformer when the center of the U-shape hits the zero-phase current transformer, the primary conductor becomes zero-phase without using screws as in the past. It becomes a conductor with a U-shaped part with the current-carrying part sandwiching the current transformer from both sides and the opposite side of the U-shape.By connecting the side with the free end of the opposite side of the U-shape with an external fixed terminal by screw connection , Can be easily completed.

Therefore, of the two sides facing each other forming the U-shaped portion, the side having the free end is located near the center in the longitudinal direction of the U-shaped side and inside the both sides or one side in the width direction of the side plate. If a notch in the direction perpendicular to the longitudinal direction of the side is formed from the peripheral side, which has a width at an appropriate length in the longitudinal direction, rotation after fitting into the zero-phase current transformer is possible even with a primary conductor having a larger cross section. The same zero-phase current transformer can be used to constitute a zero-phase current detector with a higher current rating, or the zero-phase detector can be downsized with the same current rating. In addition, when miniaturization is not performed to the limit, it is easy to incorporate the primary conductor. Of course, this notch is formed in only a part of one side of the opposite sides of the U-shape, and affects the temperature rise.
Since it is a very small part of the total volume of the secondary conductor, the temperature rise due to the notch is substantially negligible.

Further, if the U-shaped portion of the primary conductor is formed using a single plate including the central side of the U-shape, it is possible to reduce the cost of the primary conductor itself. Also,
When forming a notch in the vicinity of the center of the U-shape of the side having the free end of the U-shape opposite sides constituting the U-shape, or when forming the U-shape with a single plate material, When the width of the U-shape central side is formed smaller than the width of the U-shape opposite sides, or when the U-shape portion is formed of one sheet of material, the free end of the opposing sides forming the U-shape portion is By forming a conductor structure in which the inside of both sides in the sheet width direction is shaved or cut off from the side of the edge to the inside in the sheet width direction from the vicinity of the central side in the longitudinal direction of the side having the U-shape to the entire length in the center side longitudinal direction, Incorporation into a phase current transformer becomes extremely easy.

[0011]

1 and 2 show one embodiment of the present invention.
The two phases (R phase, T phase) on both sides in the three phases of the primary conductor have U-shaped portions 5a and 7a having current-carrying portions sandwiching the zero-phase current transformer 1 from both sides and having two opposite sides of a U shape. In this embodiment, the U-shaped portion is formed of a single plate including the center of the U-shape. A notch 8 is formed at one end in the width direction on one side on the near side of the two opposing sides of the U-shaped portion 7a of the T-phase primary conductor 7.
In the phase primary conductor 5, notches 8 are formed at both ends in the width direction. The two conductors are assembled into the zero-phase current transformer 1 by first fitting the U-shaped portion 7a into the zero-phase current transformer 1 from the open side of the U-shape of the T-phase primary conductor 7 having only one notch 8. When the center of the U-shape hits the zero-phase current transformer 1, the U-shaped part is rotated so that the center of the U-shape comes to the inner diameter 1 a (FIG. 2) of the zero-phase current transformer 1. The phase primary conductor 5 is similarly incorporated into the zero-phase current transformer 1. The space inside the zero-phase current transformer that can be used for rotation when the R-phase primary conductor is incorporated is small, but notches are formed on both sides in the width direction on one side near the middle of the U-shape. Rotation becomes possible. The center-phase (S-phase) flat primary conductor is then inserted into the zero-phase current transformer 1.

[0012]

According to the present invention, the primary conductor of the earth leakage breaker penetrating the annular zero-phase current transformer having a rectangular cross section perpendicular to the circumferential direction of the ring-shaped storage space for storing the secondary winding is provided. With such a configuration, the following effects can be obtained. In the primary conductor according to the first aspect, it is not necessary to use a screw to perform the assembly into the zero-phase current transformer as in the related art, so that the assembly work is reduced, the assembly man-hour is reduced, and the zero-phase current detection unit is reduced. The cost required for the configuration is reduced. Also, the U-shaped part
The notch formed on the free end side allows the zero-phase current transformer
It is easy to assemble, and for a zero-phase current transformer of the same size,
A primary conductor with a large cross section can be assembled, and a large current
Rated earth leakage breaker can be formed without enlargement
it can.

[0013] In primary conductor of claim 2, reduced to the cost of the primary conductor itself.

According to the primary conductor structure of the third and fourth aspects, it is extremely easy to incorporate the primary conductor structure into the zero-phase current transformer, which contributes to the cost reduction of the earth leakage breaker.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a primary conductor structure of an earth leakage circuit breaker according to the present invention in a state where a zero-phase current detecting portion is formed through a zero-phase current transformer.

FIG. 2 is an explanatory diagram showing a method of incorporating a primary conductor having the structure shown in FIG. 1 into a zero-phase current transformer.

FIG. 3 is a front view showing an example of a conventional earth leakage breaker primary conductor structure with a zero-phase current transformer penetrated.

4 shows an example of a conventional primary conductor structure in which the required space in the front-rear direction of the zero-phase current transformer is smaller than that in FIG. 3; FIG. 4 (a) is a front view, and FIG. Bottom view, (c) is a perspective view

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Zero-phase current transformer 5 Primary conductor 5a U-shaped part 6 Primary conductor 7 Primary conductor 7a U-shaped part 8 Notch

Claims (4)

(57) [Claims] A primary conductor of an earth leakage breaker penetrating a zero-phase current transformer having a rectangular cross section perpendicular to the circumferential direction of a ring-shaped storage space for storing a secondary winding wound around a ring-shaped iron core. Wherein two of the three phases of the primary conductor have a U-shaped portion sandwiching the annular surface of the zero-phase current transformer from both sides and having a current-carrying portion made of a plate facing both sides, and at least one of the two sides. The open end of the U-shape is a free end, and the pair forming the U-shaped portion
In the longitudinal U-shape of the side having the free end
Near the central side and on either side or one side in the width direction of the side plate
The side has a width at an appropriate length in the longitudinal direction of the side, the longitudinal direction of the side
And a notch in a direction perpendicular to the edge of the primary conductor of the earth leakage breaker. 2. The primary conductor of an earth leakage circuit breaker according to claim 1 , wherein the U-shaped portion is formed using a single plate including the center side of the U-shape. . 3. A primary conductor according to claim 1 or 2, primary conductor fault interrupter, characterized in that the width of the U-center side is formed smaller than the width of the U-facing sides. 4. The primary conductor according to claim 2, wherein, of the opposing sides constituting the U-shaped portion, the side having the free end has a U-shaped central portion extending from the vicinity of the central portion in the longitudinal direction to the entire length of the central side in the longitudinal direction. A primary conductor of an earth leakage breaker, characterized in that the inside on both sides in the board width direction is shaved off or cut off from the edge side to the inside in the board width direction.