JP4696665B2 - Earth leakage breaker - Google Patents

Description

  The present invention relates to an earth leakage circuit breaker applied to a low voltage distribution system, and more particularly, to a structure of a mold case in which its components are incorporated.

As is well known, the earth leakage breaker described above includes a fixed / movable contact corresponding to each phase of the main circuit, an arc extinguishing device, an open / close mechanism for opening / closing the movable contact, an overcurrent trip device, and a zero phase. FIG. 5 and FIG. 6 show a conventional assembly structure (three-phase leakage breaker) having a configuration in which a current transformer is incorporated in a mold case (see, for example, Patent Document 1).
In the figure, reference numeral 1 denotes a mold case having a divided structure composed of a case body 2 and a cover 3, 4 and 5 are main circuit terminals on the power supply side and load side, 6 is a stationary contact integral with a terminal conductor on the power supply side, and 7 is movable. Contact, 8 is a holder of the movable contact 7, 9 is an arc extinguishing device (arc extinguishing grid), 10 is a toggle type opening / closing mechanism that drives the movable contact to an open / close position, 11 is an opening / closing operation handle, and 12 is a trip cross. Bar, 13 is an overcurrent trip device (bimetal type), 14 is a zero-phase current transformer for detecting leakage, 15 is a primary conductor of the zero-phase current transformer 14, and is inserted into the core of the zero-phase current transformer, It is a main circuit conductor of each phase (R, S, T phase) wired between the side terminal 5 and the overcurrent tripping device 13.
Here, the inside of the molded case 1 and so as to partition the phases provided interphase walls along between the power source side pin and the load side pin, interphase wall of the body case 2 in FIG. 6 2a is shown. Although not shown, the cover 3 is also provided with a phase interval wall similar to that described above. Further, the phase interval wall 2a lacks a part in the longitudinal direction (between the load side terminal portion and the overcurrent trip device) and stores the zero-phase current transformer 14 across the phases. (See FIG. 6).

  The switching operation of the earth leakage circuit breaker is well known (also described in detail in Patent Document 1), and the description thereof is omitted here. However, when an overcurrent such as a short-circuit current is interrupted, between the fixed / movable contacts of the main circuit The melt of metal (contact material, etc.) evaporated by the heat of the arc generated in the air scatters around the arc gas and adheres to the structure inside the case, which reduces the insulation strength between the phases and causes a short circuit accident. May cause. In particular, since the zero-phase current transformer 14 is notched in part of the phase interval wall 2a as described above and is housed in the mold case 1 across each phase, arc gas is generated in this part. The R, S, and T phase main circuit conductors 15 that are easy to wrap around between the phases and that are collectively inserted into the iron core as the primary conductors of the zero-phase current transformer 14 are bent as shown in FIG. Since the conductors are wired so as to be close to each other, there is a problem in that the metal melt adheres to and accumulates on the conductor surface and easily causes an interphase short circuit accident.

Therefore, as a countermeasure against the above-mentioned problem, the contact portion and the arc extinguishing device are surrounded for each phase so as to prevent the metal melt generated in the contact portion from being scattered around when the overcurrent is interrupted. There is a known configuration in which an arc chamber container is accommodated as a unit and incorporated in a mold case to prevent diffusion of arc gas and metal melt accompanying current interruption into the mold case (for example, Patent Documents). 2).
Japanese Patent Laid-Open No. 5-250976 Japanese National Patent Publication No. 2001-411168

By the way, the conventional circuit breaker described above has the following problems. That is, in the assembly structure disclosed in Patent Document 2, an arc-extinguishing chamber container is prepared for each phase and mounted on the mold case, which increases the number of assembly parts and the number of assembly steps, resulting in high costs. It becomes.
The present invention has been made in view of the above points, and by adding a simple wall part to the mold case, the arc gas generated between the fixed / movable contacts when the current is interrupted is stored between phases and zero-phase current transformers. An object of the present invention is to provide an earth leakage circuit breaker which is improved so as to prevent the entry into the space and to improve the dielectric strength and reliability.

In order to achieve the above object, according to the present invention, a phase interval wall for partitioning each phase is provided in a mold case having a divided structure including a case body and a cover , and a stationary contact and a movable contact are provided in each phase of the mold case. and children, and extinguishing apparatus, with incorporation of the overcurrent tripping device, in the molded case, an opening and closing mechanism, will configure incorporating the zero-phase current transformer of each phase of the main circuit conductor is inserted, the ZCT is disposed so as to straddle each phase behind the overcurrent tripping device, each phase within said phase interval walls of the molded case except housing portion of the zero-phase current transformer In the earth leakage circuit breaker divided into
Inside the molded case, partitions between the housing portion of the overcurrent tripping device and interposed to each phase and the zero-phase current transformer inside the molded case between the zero-phase current transformer on which it is provided a screen-like shield wall, the main circuit conductors of each phase that penetrates the shielding walls inserted in the zero-phase current transformer constructed by connecting the overcurrent tripping device (claim 1 ), And the shielding wall is configured in a specific manner as described below.
(1) The shielding wall is fitted and arranged in the mold case with the wall surface abutting with the notched end of the phase interval wall.
(2) The shielding wall has a divided structure in which the upper wall and the lower wall are butted up and down, and a groove through which the main circuit conductor of each phase is passed is formed in the butted portion.

According to the above configuration, the arc gas and the metal melt generated in the current interrupting part due to the overcurrent interruption are additionally provided by installing the shielding wall having a simple structure inside the mold case composed of the case body and the cover. The main circuit that is blocked by the shielding wall and wraps around between the phases or moves to the zero-phase current transformer located behind the shielding wall, thereby reducing the insulation between the phases and passing through the zero-phase current transformer. The short circuit of the conductor is prevented and the circuit breaker's breaking performance and reliability are improved.
In addition, since the shielding wall has a vertically divided structure and a slot for passing the main circuit conductor is formed at the abutting portion, the shielding wall can be easily assembled into the mold case and the main circuit conductor can be assembled.

Hereinafter, the embodiment of the present invention will be described based on the examples shown in FIGS. 1 to 4 by taking a three-phase earth leakage breaker as an example. The earth leakage breaker of the illustrated embodiment has basically the same structure as the earth leakage breaker shown in FIGS. 5 and 6, and the interior of the mold case 1 is partitioned into three phases by phase interval walls. The fixed contact 6, the movable contact 7, the arc extinguishing device 8, and the overcurrent tripping device 13 are connected to the movable contact holder 8 and above the opening / closing mechanism 10, the operation handle 11, and the trip cross bar 12. Further, a zero-phase current transformer 14 is disposed behind the overcurrent tripping device 13 across the phases.
With respect to the above assembly structure, the mold case 1 of the illustrated embodiment is installed between the overcurrent tripping device 13 and the zero-phase current transformer 14 arranged behind it, so that the space inside the case is on the power supply side. And a screen-like shielding wall 16 (resin molded product) for partitioning to the load side, and the main circuit conductor of each phase passing through the shielding wall 16 and between the load-side terminal 5 and the overcurrent tripping device 13. 15R, 15S, and 15T are wired through the iron core of the zero-phase current transformer 14.

    Here, the outer shape of the shielding wall 16 corresponds to the cross-sectional shape and size of the mold case 1, and is divided into an upper wall 16a and a lower wall 16b as shown in FIG. Slots 16c through which the main circuit conductors 15R, 15S, and 15T (see FIG. 2) pass are formed to be cut out at the abutting ends of 16a and the lower wall 16b. When the shielding wall 16 is incorporated into the mold case 1, as shown in FIGS. 2 and 4, the shielding wall 16 is placed on the power supply side notch end of the phase interval wall 2a so that the wall surface overlaps the case body 2 of the mold case 1. In this state, the inner space of the mold case 1 is separated into the power supply side and the load side with the shielding wall 16 as a boundary. 4 shows a state in which the lower wall 16 is inserted into the case body 2 and is held in a predetermined position. In an actual assembly process, the upper wall 16a is attached to the cover 3 of the mold case 1 (see FIG. 1). The inner wall is inserted and set, and after the parts of the circuit breaker are assembled to the case body 1, the case body 2 is covered with the cover 3, so that the upper wall 16a and the lower wall 16b are brought into contact with each other, and at the same time, the slot 16c The main circuit conductors 15R, 15S, 15T of each phase are passed through.

With the above configuration, in the assembled state shown in FIG. 1, the inner space of the mold case 1 is divided into the power source side and the load side where the zero-phase current transformer 14 is arranged with the shielding wall 16 as a boundary. The space is isolated by the phase interval wall 2 a and the shielding wall 16.
As a result, the arc gas generated between the fixed / movable contacts when the overcurrent is interrupted does not flow into the phase or flow into the storage space of the zero-phase current transformer 14, and the arc extinguishing of the arc extinguishing device 9 is all performed. It flows between the grids and is discharged to the outside through a gas discharge port that opens at the end face of the case.
Therefore, the arc gas does not enter between the phases inside the mold case and does not enter the storage area of the zero-phase current transformer 14, so that the metal melt generated by the arc heat enters the iron core of the zero-phase current transformer 14. It is possible to prevent adhesion to the main circuit conductors 15R, 15S, and 15T of the respective phases that are collectively inserted, and to ensure high interruption performance and reliability.

  In addition, the shielding wall 16 has a vertically divided structure of an upper wall 16a and a lower wall 16b, and a groove hole 16c through which the main circuit conductors 15R, 15S, and 15T pass is formed at the abutting end portion thereof. By fitting and mounting inside, it is possible to reliably prevent arc gas and metal melt from entering the storage space of the zero-phase current transformer, and to easily assemble the main circuit conductor parts. Even when the earth leakage circuit breaker is manufactured by adding the zero-phase current transformer to the main part of the circuit breaker for wiring and the mold case as a common part, it is easy to assemble the shielding wall 16 inside the mold case. Yes.

Sectional drawing showing the assembly structure of the earth-leakage circuit breaker by the Example of this invention 1 is a bird's-eye view showing a state in which a shielding wall and main circuit conductor are incorporated in the case body in FIG. FIG. 2 is a structural diagram of a shielding wall in FIG. 1, (a) and (b) are external perspective views of an upper wall and a lower wall that are divided into two parts 1 is a bird's-eye view showing a state in which a shielding wall is inserted and held in the case main body in FIG. Cross-sectional view of a conventional earth leakage circuit breaker FIG. 5 is an overhead view with the cover of FIG. 5 removed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold case 2 Main body case 2a Phase space | interval wall 3 Cover 6 Fixed contact 7 Movable contact 9 Arc-extinguishing device 10 Opening-and-closing mechanism 11 Handle 13 Overcurrent tripping device 14 Zero-phase current transformer 15 Main circuit conductor 16 Shielding wall 16a Upper wall 16b Lower wall 16c Slot through which conductor passes

Claims (3)

The interphase walls partitioning the respective phases provided in the molded case of the divided structure composed of the case body and the cover, and the fixed contacts and the movable contact in each phase of the molded case, the arc extinguishing device, the overcurrent tripping device In addition, the open / close mechanism and a zero-phase current transformer into which the main circuit conductor of each phase is inserted are incorporated in the mold case, and the zero-phase current transformer is located behind the overcurrent trip device. a is disposed so as to straddle the respective phases, the earth leakage breaker interior of the molded case except housing portion of the zero-phase current transformer is divided into phases in the phase interval wall,
Inside the molded case, partitions between the housing portion of the overcurrent tripping device and interposed to each phase and the zero-phase current transformer inside the molded case between the zero-phase current transformer on which it is provided a screen-like shield wall, leakage breaker, characterized in that the main circuit conductors of each phase that penetrates the shielding walls inserted in the zero-phase current transformer connected to said overcurrent tripping device vessel. In earth leakage breaker according to claim 1, wherein the shielding wall, earth leakage breaker, characterized in that the wall was fitted disposed inside the molded case against the notch edge of the phase interval wall. The earth leakage circuit breaker according to claim 1, wherein the shielding wall has a divided structure in which an upper wall and a lower wall are butted up and down, and a groove hole through which a main circuit conductor of each phase passes is formed in the butted portion. A ground fault circuit breaker.

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