Patent Description:
In general, an air circuit breaker (ACB) is installed in a low voltage distribution line and performs transmission, switching, switching, and stop of low voltage system power in a planned manner, and uses air as extinguishing medium to break a circuit in an event of abnormalities such as overcurrent, short circuit and ground fault and thus protect people and a load.

More specifically, a direct-current air circuit breaker according to a prior art includes an extinguishing part and an electrical conducting part inside the circuit breaker. When abnormal current occurs due to overcurrent, short circuit, or ground fault of a line, a mechanical part operates via a relay such that a fixed contact and a movable contact are removed from each other.

Further, an arc is generated when the fixed contact and the movable contact are removed from each other. Accordingly, the arc as generated travels from the fixed contact and the movable contact to a cooling plate via a Lorentz force (an arc magnetic field-based driving force) generated orthogonally by arc current and a magnetic flux density and is cooled and extinguished by the cooling plate.

Further, an arc guide is coupled to an arc chute assay, and the arc guide serves to guide the arc to a center of the cooling plate so that arc extinguishing occurs quickly.

However, in an event of interruption of a small current based on IEC <NUM>-<NUM> ANNEX D standard, a very small magnetic field-based driving force is generated from the arc due to the small current and magnetic field. Further, arc stagnation occurs between the fixed contact and the movable contact.

Further, high temperature arc stagnation causes serious structural and electrical damage to the extinguishing part and the conducting part, and thus causes deterioration of performance of the breaker and equipment accidents.

Prior art document <CIT> discloses the features of the preamble of claim <NUM>. Document <CIT> discloses an orientation of magnets according to claim <NUM>.

One aspect of the present disclosure has a purpose to provide an arc-extinguishing structure for a direct-current air circuit breaker that generates an arc magnetic field-based driving force using a magnetic field of a magnet, and quickly discharges the arc to an extinguishing unit.

Another aspect of the present disclosure has a purpose to provide an arc-extinguishing structure for a direct-current air circuit breaker in which upper and lower portions of a magnet have different poles in a vertical direction in which the arc guide is positioned below a grid in an arc chute assay, thereby preventing reverse flow of the arc.

Another aspect of the present disclosure has a purpose to provide an arc-extinguishing structure for a direct-current air circuit breaker that may maximize a magnetic field magnitude of the magnet inserted into the arc guide to maximize an arc magnetic field-based driving force.

Another aspect of the present disclosure has a purpose to provide an arc-extinguishing structure for a direct-current air circuit breaker that may secure small current interruption performance while shortening an arc duration.

An arc-extinguishing structure for a direct-current air circuit breaker according to one embodiment of the present disclosure includes a plurality of grids; both opposing side plates respectively coupled to both opposing sides of each of the plurality of grids so that the plurality of the grids are stacked and spaced from each other; a discharge cover positioned on tops of the side plates and the plurality of grids; each arc guide coupled to each of the side plates such that the guide is positioned below the plurality of grids; and each magnet coupled to each arc guide, wherein the magnet had upper and lower portions in a vertical arrangement of the plurality of grids and the arc guide, wherein the upper and lower portions have different poles.

In one implementation of the arc-extinguishing structure, each magnet receiving groove is defined in the arc guide, wherein the magnet is received in the groove, wherein the magnet extends in the arrangement direction of the grids, wherein the magnet receiving groove extends in the arrangement direction of the grids.

In one implementation of the arc-extinguishing structure, side plate fixing means is defined in the arc guide in an area of the magnet receiving groove, wherein arc guide fixing means corresponding to the side plate fixing means is defined in the side plate.

In one implementation of the arc-extinguishing structure, each of the side plate fixing means and the arc guide fixing means is embodied as a through-hole.

In one implementation of the arc-extinguishing structure, the magnet extends in a longitudinal direction of the arc guide, and a mounting hole corresponding to the through-hole is defined in the magnet, wherein a fastener fastens the arc guide fixing means, the mounting hole, and the side plate fixing means to each other, wherein the fastener fastens the arc guide to the side plate while the magnet is received in the magnet receiving groove.

In one implementation of the arc-extinguishing structure, an upper portion of the magnet is magnetized as a S pole and a lower portion thereof is magnetized as an N pole.

In one implementation of the arc-extinguishing structure, the guide plate of the arc guide in which the magnet receiving groove is defined is formed such that a dimension of one side of the guide plate is larger than a dimension of an opposite side thereof, wherein a dimension of one side ofthe magnet receiving groove is larger than a dimension of an opposite side thereof, wherein a dimension of one side of the magnet coupled to the magnet receiving hole is larger than a dimension of an opposite side thereof.

In one implementation of the arc-extinguishing structure not according to the invention, the magnet includes a plurality of magnets, wherein the arc guide has a plurality of magnet receiving grooves for receiving the plurality of the magnets, wherein side plate fixing means is defined in the arc guide in an area of each of the magnet receiving grooves, wherein arc guide fixing means corresponding to the side plate fixing means is defined in the side plate.

In one implementation of the arc-extinguishing structure, each ofthe side plate fixing means and the arc guide fixing means is embodied as a through-hole.

In one implementation ofthe arc-extinguishing structure,
a fastener fastens the arc guide fixing means and the side plate fixing means to each other, wherein the fastener fastens the arc guide to the side plate while the magnet is received in the magnet receiving groove.

In one implementation of the arc-extinguishing structure, an upper portion of each magnet is magnetized as a S pole and a lower portion thereof is magnetized as an N pole.

In one implementation of the arc-extinguishing structure not according to the invention, the arc guide extends in a longitudinal direction from one side to an opposite side thereof and, further, extends downwards from one side, wherein the magnet receiving groove includes a first magnet receiving groove extending downwards from one side of the arc guide, and a second magnet receiving groove extending from one side of the arc guide to the opposite side thereof, wherein the magnet includes a first magnet extending downwards in a corresponding manner to the first magnet receiving groove, and a second magnet extending in the longitudinal direction in a corresponding manner to the second magnet receiving groove.

In one implementation ofthe arc-extinguishing structure, the grid has a downwardly-inclined portion at a bottom of the grid, wherein the downwardly-inclined portion has an inner side face inclined outwardly as the portion extends from a center toward each ofboth opposing ends, wherein the arc guide further includes a guide plate having an upwardly-inclined portion facing toward the downwardly-inclined portion.

Independent claim <NUM> defines the invention. Dependent claims <NUM> to <NUM> state various embodiments of the invention.

According to the present disclosure, the arc magnetic field-based driving force is generated by the magnetic field of the magnet, and thus, the arc may be quickly discharged to the extinguishing structure. According to another aspect of the present disclosure, the upper and lower portions of the magnet have different poles in a vertical direction in which the arc guide is positioned below a grid in an arc chute assay, thereby preventing reverse flow of the arc. Further, the arc-extinguishing structure may maximize a magnetic field magnitude of the magnet inserted into the arc guide to maximize the arc magnetic field-based driving force. Further, the arc-extinguishing structure may secure small current interruption performance while shortening an arc duration.

<FIG> is a configuration diagram schematically showing an arc-extinguishing structure for a direct-current air circuit breaker according to a first embodiment of the present disclosure. <FIG> is a schematic diagram showing an arc guide in the arc-extinguishing structure shown in <FIG>. <FIG> is a schematic diagram showing a magnet in the arc-extinguishing structure shown in <FIG>.

An arc-extinguishing structure <NUM> may allow a direct-current air circuit breaker used in various direct-current interruption facilities including solar power generation facilities to secure small current interruption performance.

As shown, the arc-extinguishing structure <NUM> includes side plates <NUM>, a grid <NUM>, a discharge cover <NUM>, an arc guide <NUM> and a magnet <NUM>.

More specifically, the grid <NUM> acts as a cooling plate that divides and cools incoming arc. The grid <NUM> includes a plurality of grids spaced apart from each other and disposed between both opposing side plates <NUM> positioned at both opposing sides of the discharge cover <NUM>.

For this purpose, a fixing protrusion <NUM> is formed on each of both opposing ends of the grid <NUM>, and a through-hole <NUM> corresponding to the fixing protrusion <NUM> is formed in each side plate <NUM>.

The grid <NUM> has a downwardly inclined portion <NUM> so that a lower portion thereof extends from a center toward each of both opposing ends in an inclined manner.

The discharge cover <NUM> is coupled to a top of each of the side plates <NUM>, and the arc guide <NUM> is coupled to a bottom of each of the side plates <NUM>.

To this end, arc guide fixing means <NUM> and discharge cover coupling means <NUM> are formed in each of the side plates <NUM>.

The discharge cover <NUM> is positioned on tops of the side plates <NUM> and the plurality of grids. Side plate coupling means <NUM> corresponding to the discharge cover coupling means <NUM> of the side plate is formed on the discharge cover <NUM>.

<FIG> shows an example in which the side plate coupling means <NUM> is embodied as a protrusion, and the discharge cover coupling means <NUM> is embodied as a through-hole.

The arc guide <NUM> is fixed to the side plate so as to be positioned under the plurality of grids <NUM>.

Further, the arc guide <NUM> includes a magnet receiving groove <NUM>, a guide plate <NUM> and side plate fixing means <NUM>. The magnet receiving groove <NUM> has a shape corresponding to that of the magnet <NUM>.

Further, the magnet receiving groove <NUM> extends in the arrangement direction of the grids <NUM>, and the guide plate <NUM> extends toward the grid <NUM>.

The side plate fixing means <NUM> may be formed in the magnet receiving groove <NUM>.

The guide plate <NUM> may be embodied as an upwardly inclined portion corresponding to the downwardly inclined portion <NUM> of the grid <NUM>.

The side plate fixing means <NUM> is constructed for fixing the arc guide <NUM> to the side plate <NUM>, and corresponds to the arc guide fixing means <NUM>. Further, each of the arc guide fixing means <NUM> and the side plate fixing means <NUM> may be embodied as a through-hole.

The magnet <NUM> extends in a longitudinal direction of the arc guide <NUM> as the arrangement direction of the grids. Different poles are magnetized at upper and lower portions of the magnet in an orthogonal direction to the extension direction, that is, an arrangement direction of the grid <NUM> and the arc guide <NUM>.

In an example, in <FIG>, the upper portion is magnetized as a S pole as a first pole 1500a, and a lower portion is magnetized as a N pole as a second pole 1500b.

As described above, as the magnet is mounted and coupled to the arc guide <NUM>, the magnetic field-based driving force increases to a maximum level, thereby enabling rapid cooling and extinguishing of the arc.

Further, a mounting hole <NUM> is formed in the magnet <NUM>. The mounting hole <NUM> is formed to correspond to the side plate fixing means and the arc guide fixing means embodied as the through-hole.

Further, the guide plate of the arc guide <NUM> in which the magnet receiving groove <NUM> is formed has a dimension of one side thereof which is larger than a dimension of the opposite side thereof. This is based on an overall structure of the arc-extinguishing structure <NUM> mounted on the circuit breaker.

Further, the magnet receiving groove <NUM> is formed so that a dimension of one side thereof is larger than a dimension of the opposite side thereof in a corresponding manner to the above structure. The magnet <NUM> coupled to the magnet receiving hole <NUM> is formed so that a dimension of one side thereof is larger than a dimension of the opposite side thereof in a corresponding manner to the above structure.

The arc-extinguishing structure <NUM> further includes a fastener <NUM>. The fastener <NUM> combines the arc guide fixing means <NUM>, the mounting hole <NUM> and the side plate fixing means <NUM> to each other. Thus, the arc guide may be fixed to the side plate in a state in which the magnet is coupled to the arc guide.

Further, the fastener <NUM> may have an insulating layer <NUM> made of silicon or the like coated thereon.

<FIG> is a configuration diagram schematically showing an arc-extinguishing structure for a direct-current air circuit breaker according to a second implementation not according to the invention. <FIG> is a schematic diagram showing an arc guide in the arc-extinguishing structure shown in <FIG>. <FIG> is a schematic diagram showing a magnet in the arc-extinguishing structure shown in <FIG>.

As shown, an arc-extinguishing structure <NUM> differs from the arc-extinguishing structure <NUM> shown in <FIG> only in terms of the magnet and the magnet receiving groove <NUM> accommodating therein the magnet.

More specifically, the arc-extinguishing structure <NUM> includes both side plates <NUM>, a grid <NUM>, a discharge cover <NUM>, an arc guide <NUM>, and magnets 2500a and 2500b.

The magnet includes a first magnet 2500a and a second magnet 2500b.

In addition, the side plates <NUM>, the grid <NUM>, and the discharge cover <NUM> are respectively identical with the side plates <NUM>, the grid <NUM>, and the discharge cover <NUM> of the arc-extinguishing structure <NUM> according to the first embodiment as described above, and detailed descriptions thereof will be omitted.

The arc guide <NUM> has a magnet receiving groove <NUM>, a guide plate <NUM>, and side plate fixing means <NUM>. The magnet receiving groove <NUM> includes a first magnet receiving groove 2410a into and to which the first magnet 2500a is inserted and coupled and a second magnet receiving groove 2410b into and to which the second magnet 2500b is inserted and coupled.

Further, each of the first magnet receiving groove 2410a and the second magnet receiving groove 2410b is formed in an area where the side plate fixing means <NUM> is not formed.

The arc guide <NUM> is formed to extend in the longitudinal direction from one side to the opposite side and at the same time, to extend downward from one side. Accordingly, the arc guide <NUM> may have the first magnet receiving groove 2410a extending from one side downwardly and the second magnet receiving groove 2410b extending from one side to the opposite side.

The first magnet 2500a extends downward so as to correspond to the first magnet receiving groove 2410a, while the second magnet 2500b extends in a longitudinal direction so as to correspond to the second magnet receiving groove 2410b.

Upper and lower portions of each of the first magnet 2500a and the second magnet 2500b are magnetized to have different poles in an orthogonal direction to the extension direction of the arc guide <NUM>, that is, in an arrangement direction of the grid <NUM> and the arc guide <NUM>.

In an example of <FIG>, a upper portion of each of the first poles 2500a' and 2500b' is magnetized as the S pole, while a lower portion of each of the second poles 2500a" and 2500b" is magnetized as the N pole.

Further, while the first magnet 2500a is inserted into the first magnet receiving groove 2410a, and the second magnet 2500b is inserted into the second magnet receiving groove 2410b, the arc guide <NUM> is fixed to the side plate <NUM> by fastening a fastener <NUM> to the arc guide fixing means <NUM> and the side plate fixing means <NUM>.

<FIG> is a block diagram schematically showing a direct-current air circuit breaker having an arc-extinguishing structure according to the present disclosure.

As shown, the arc-extinguishing structure <NUM> or <NUM>, a fixed conductor assay <NUM> and a movable conductor assay <NUM> are mounted on a body of the direct-current air circuit breaker.

Further, the movable conductor assay <NUM> is mounted to face toward the fixed conductor assay <NUM>. The arc-extinguishing structure <NUM> or <NUM> is positioned above the fixed conductor assay <NUM> and the movable conductor assay <NUM> to extinguish the arc generated when the contacts are removed from each other.

<FIG> is a schematic first use state diagram of the arc-extinguishing structure according to the first embodiment in the direct-current air circuit breaker shown in <FIG>. <FIG> is a schematic second use state diagram of the arc-extinguishing structure according to the first embodiment in the direct-current air circuit breaker shown in <FIG>.

As shown in <FIG>, when the magnet <NUM> is installed on the arc guide <NUM>, a magnetic field is distributed as shown by an arrow in small current interruption.

Further, when the direct-current air circuit breaker performs the small current interruption, the magnetic field is uniformly distributed around the magnet.

Further, as shown in <FIG>, a magnitude of the arc magnetic field-based driving force is determined based on a magnetic field magnitude of the magnet, and a direction of the force is orthogonal to a direction of the magnetic field and a current direction.

That is, the arc magnetic field-based driving force F acts toward the grid <NUM> as shown by an arrow, based on the magnetic field distribution and a connection direction of the small current. Further, (a) in <FIG> shows the driving force F when the current is output in an extension direction of the arc guide <NUM>, while (b) in <FIG> shows the driving force F when the current is input in the extension direction of the arc guide <NUM>.

Eventually, when the small current interruption occurs, the arc magnetic field-based driving force acts in a lateral direction of the grid <NUM>, based on the magnetic field distribution and the small current connection direction. as the arc magnetic field-based driving force F is generated in this way, not only arc extinguishing occurs quickly, but also arc backflow does not occur and arc stagnation does not occur.

<FIG> is a schematic first use state diagram of the arc-extinguishing structure according to the second implementation not according to the invention in the direct-current air circuit breaker shown in <FIG>. <FIG> is a schematic second use state diagram of the arc-extinguishing structure according to the second implementation not according to the invention in the direct-current air circuit breaker shown in <FIG>.

As shown in <FIG>, when the magnet <NUM> is installed on the arc guide <NUM>, the magnetic field is distributed as shown in an arrow in the small current interruption.

As described above, in both the arc-extinguishing structure <NUM> according to the first embodiment of the present disclosure and the arc-extinguishing structure <NUM> according to the second embodiment, the arc extinguishing may be achieved quickly, the arc backflow does not occur, and the arc stagnation does not occur. In the arc-extinguishing structure <NUM>, the magnet may have a maximum size to maximize the arc magnetic field-based driving force F. The arc-extinguishing structure <NUM> may be easily installed regardless of the side plate fixing means <NUM>, and thus, assembly and productivity thereof may be improved.

Claim 1:
An arc-extinguishing structure (<NUM>) for a direct-current air circuit breaker, the structure comprising:
a plurality of cooling plates (<NUM>) configured to divide and cool an incoming arc;
both opposing side plates (<NUM>) respectively coupled to both opposing sides of each of the plurality of cooling plates (<NUM>) so that the plurality of the cooling plates (<NUM>) are stacked and spaced from each other;
a discharge cover (<NUM>) positioned on top of the side plates (<NUM>) and the plurality of cooling plates (<NUM>);
arc guides (<NUM>) each coupled to one of the side plates (<NUM>), respectively, such that the arc guides (<NUM>) are positioned below the plurality of cooling plates (<NUM>) on the side of the structure opposite to the discharge cover (<NUM>) and extend from one first to one opposite side along an edge of the stack of the plurality of cooling plates (<NUM>);
magnets (<NUM>);
wherein the each arc guide (<NUM>) comprises a magnet receiving groove (<NUM>) and wherein the magnets (<NUM>) are adapted to be received in the magnet receiving groove (<NUM>),
wherein the magnet receiving grooves (<NUM>) have a shape corresponding to that of the magnets (<NUM>);
wherein each magnet (<NUM>) has upper and lower portions in a vertical arrangement where the plurality of cooling plates (<NUM>) are arranged vertically,
the discharge cover (<NUM>) is positioned on top and the arc guides (<NUM>) are placed below the plurality of cooling plates (<NUM>);
characterized in that:
the upper portions of the magnets (<NUM>) have one pole and the lower portions have another pole;
in each arc guide a width of the magnet receiving groove (<NUM>) is larger on said first side than a width on said opposite side; and
a width of one side of the magnet (<NUM>) coupled to the magnet receiving groove (<NUM>) is larger than a width of an opposite side thereof.