Miniature direct-current circuit breaker

Abstract

The present invention relates to a miniature direct-current circuit breaker, comprising a shell, and a movable contact, a stationary contact, a movable arc runner, a stationary arc runner, a magnetic blow-out conductor, a vertical arc chute and a horizontal arc chute which are arranged in the shell, wherein the stationary arc runner extends to an upper end of the vertical arc chute, the movable arc runner extends to an outer end of the horizontal arc chute, the magnetic blow-out conductor is arranged on an inner wall of the shell, the magnetic blow-out conductor comprises a vertical conductor vertically arranged in front of the vertical arc chute and a horizontal conductor horizontally arranged above the horizontal arc chute, the horizontal conductor is connected to a lower end of the vertical conductor, an upper end of the vertical conductor of the magnetic blow-out conductor is connected to the movable arc runner, and an outer end of the horizontal conductor is connected to an external conductor. The thickness of the present invention is only 18 mm; an arc chute structure in the miniature circuit breaker is changed, and the horizontal arc chute is additionally arranged, so that interruption and arc extinguishing of high voltage is achieved; and the magnetic blow-out conductor is used to increase the moving speed of an electric arc to the arc chute, so that the arc extinguishing capability is improved.

Description

Small DC circuit breakers Technical Field

[0001] The invention relates to a low-voltage switch, in particular to a small DC circuit breaker. Background Art

[0002] Miniature DC circuit breakers are used in the miniature circuit breaker series for overload protection, short-circuit protection, and infrequent line switching of DC lines. With China's continued rapid economic growth, many fields, including telecommunications power supply, power systems, DC power supply, rail transportation, shipbuilding, and metallurgy, are also developing rapidly, and the requirements for DC systems are also increasing.

[0003] For DC voltages, the arc cannot extinguish naturally at this point because the current never crosses zero. Therefore, existing DC circuit breakers install magnets that generate a magnetic force on the arc, forcing it to move to the arc-extinguishing grid, thereby dividing and severing the arc and shutting off the current. However, the magnetic force generated by the magnets is constant, pushing the arc in only one direction. This limits the configuration of the arc-extinguishing hood. To cope with higher voltages, small DC circuit breakers require a more powerful arc-extinguishing system to extinguish the arc.

[0004] Summary of the Invention

[0005] In view of the above-mentioned deficiencies, the present invention provides a small DC circuit breaker suitable for use in high-voltage DC lines, which can effectively extinguish high-voltage arcs.

[0006] To achieve the above objectives, the present invention adopts a small DC circuit breaker, including a housing and a moving contact, a static contact, a moving arc-striking piece, a static arc-striking piece, and an arc-extinguishing cover arranged in the housing. The moving contact is relatively arranged in front of the static contact for movement, the front end of the static arc-striking piece is connected to the static contact, and the upper end of the moving arc-striking piece is arranged on the outside of the moving contact. The arc-extinguishing cover includes a vertical arc-extinguishing cover arranged vertically and a horizontal arc-extinguishing cover arranged horizontally. The inner ends of the vertical arc-extinguishing cover and the horizontal arc-extinguishing cover are close to each other, the rear end of the static arc-striking piece extends to the upper end of the vertical arc-extinguishing cover, and the lower end of the moving arc-striking piece extends to the outer end of the horizontal arc-extinguishing cover. The small DC circuit breaker also includes a magnetic blown conductor, which is arranged on the inner wall of the housing. The magnetic blown conductor includes a vertical conductor section arranged vertically in front of the vertical arc-extinguishing cover and a horizontal conductor section arranged horizontally above the horizontal arc-extinguishing cover. The horizontal conductor is connected to the lower end of the vertical conductor, the upper end of the vertical conductor of the magnetic blown conductor is connected to the moving arc-striking piece, and the outer end of the horizontal conductor is connected to the external conductor.

[0007] The effect of the above scheme is to increase the length of the arc extinguishing hood by using vertical arc extinguishing hood and horizontal arc extinguishing hood, so that the arc extinguishing hood can accommodate more arc extinguishing grids, thereby improving the segmented arc extinguishing capability of high-voltage arcs. At the same time, the magnetic blowing conductor arranged in front of the vertical arc extinguishing hood and the horizontal arc extinguishing hood will generate an electromagnetic field when the contacts are disconnected, thereby promoting the arc to accelerate toward the vertical arc extinguishing hood and the horizontal arc extinguishing hood, thereby increasing the arc extinguishing speed, reducing the temperature rise in the shell, and realizing high-voltage arc extinguishing.

[0008] The present invention further provides a lower arc discharge channel formed within the housing below the horizontal arc chute. The bottom surface of the lower arc discharge channel is provided with an arc discharge opening, and a metal grid is disposed on the inner side of the bottom surface of the lower arc discharge channel. The metal grid absorbs ash generated by the horizontal arc chute, preventing high-temperature ash from contacting the housing, thereby improving heat dissipation and enhancing safety.

[0009] The present invention further provides an arc-strike grid disposed between the vertical arc-extinguishing hood and the horizontal arc-extinguishing hood, with both sides of the arc-strike grid connected to the inner ends of the vertical arc-extinguishing hood and the horizontal arc-extinguishing hood, respectively. The arc-strike grid can guide arcs accumulated in corners into the arc-extinguishing hoods on both sides, thereby improving arc extinguishing efficiency.

[0010] The present invention further provides that the horizontal arc extinguishing hood extends below the vertical arc extinguishing hood, the arc extinguishing grids of the horizontal arc extinguishing hood below the vertical arc extinguishing hood are arranged at an angle, and the remaining grids in the vertical and horizontal arc extinguishing hoods are arranged equidistantly. The use of the oblique arc extinguishing hood can also effectively extinguish arcs in corners.

[0011] The present invention is further provided with an arc isolation plate on the inner side of the magnetic blow conductor to isolate the magnetic blow conductor from the arc starting plate to prevent arcing and short circuit.

[0012] The present invention is further provided with a magnetizing sheet at the center of the magnetic blowing conductor to improve the magnetic blowing effect.

[0013] The present invention is further configured such that the inclination angle of the inclined arc-extinguishing grid on the horizontally placed arc-extinguishing hood gradually increases from the inside to the outside.

[0014] The present invention is further configured such that the upper end of the magnetic blowing conductor extends toward one end of the moving arc-striking piece close to the moving contact and is bent at the top to form a welding surface, which is connected to the top of the moving arc-striking piece.

[0015] The present invention is further configured such that the small DC circuit breaker further includes a bimetallic strip and a bimetallic positioning piece, the lower end of the bimetallic strip is connected to the bimetallic positioning piece, and the lower end of the magnetic blow conductor is connected to the bimetallic positioning piece through a flexible connection.

[0016] The present invention is further configured such that the total number of arc extinguishing grids arranged in the vertical arc extinguishing hood and the horizontal arc extinguishing hood is at least 25.

[0017] The thickness of the present invention is only 1P (i.e. 18mm). By changing the arc extinguishing cover structure inside the small circuit breaker and adding a horizontal arc extinguishing cover, segmented arc extinguishing of high voltage is achieved. At the same time, a magnetic blowing conductor is used to accelerate the speed of the arc moving toward the arc extinguishing cover, thereby improving the arc extinguishing ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic diagram of a specific embodiment 1 of the present invention.

[0019] FIG2 is an exploded view of the specific embodiment 1 of the present invention.

[0020] FIG3 is a schematic diagram of the arc extinguishing hood and the magnetic blow conductor of the specific embodiment 1 of the present invention.

[0021] FIG4 is a front view of the arc extinguishing cover and the magnetic blow conductor of the specific embodiment 1 of the present invention.

[0022] FIG5 is a schematic diagram of a specific embodiment 2 of the present invention.

[0023] FIG6 is a schematic diagram of specific embodiment 3 of the present invention.

[0024] FIG7 is a test waveform diagram of specific embodiment 1 of the present invention.

[0025] FIG8 is a test waveform diagram of specific embodiment 2 of the present invention. DETAILED DESCRIPTION

[0026] As shown in Figures 1 to 4, a specific embodiment 1 of the present invention is a small DC circuit breaker, including a housing 5 and a moving contact 1, a static contact 2, a moving arc-striking piece 3, a static arc-striking piece 4, an arc-extinguishing cover and a magnetic blow conductor 8 arranged in the housing 5. The moving contact 1 is relatively arranged in front of the static contact 2 for movement. The front end of the static arc-striking piece 4 is connected to the lower end of the static contact 2. The upper end of the moving arc-striking piece 3 is arranged near the disconnecting position of the moving contact 1. The moving arc-striking piece 3 forms an arc-striking angle 31 that is convex inward below the disconnecting position of the moving contact 1. The arc-extinguishing cover includes a vertical arc-extinguishing cover 6 arranged vertically and a horizontal arc-extinguishing cover 7 arranged horizontally. The inner ends of the vertical arc-extinguishing cover 6 and the horizontal arc-extinguishing cover 7 are close to each other. The rear end of the static arc-striking piece 4 extends to the upper end of the vertical arc-extinguishing cover 6, and the lower end of the dynamic arc-striking piece 3 extends vertically to the outer end of the horizontal arc-extinguishing cover 7. The magnetic blowing conductor 8 is arranged on the inner wall of the shell 8. The magnetic blowing conductor 8 includes a vertical conductor 81 vertically arranged in front of the vertical arc-extinguishing cover 6 and a horizontal conductor 82 horizontally arranged above the horizontal arc-extinguishing cover 7. The horizontal conductor 82 is connected to the lower end of the vertical conductor 81. The upper end of the vertical conductor 81 of the magnetic blowing conductor 8 extends toward the end of the dynamic arc-striking piece 3 close to the dynamic contact 1 and is bent at the top to form a welding surface 83. The welding surface 83 is connected to the arc-striking angle 31 of the dynamic arc-striking piece 3, and the outer end of the horizontal conductor 82 is connected to the external conductor. A magnetizing sheet 9 is provided at the center of the magnetic blowing conductor 8, a magnetic blowing conductor slot 53 is formed on the inner side of the shell 5, the magnetic blowing conductor 8 is provided in the magnetic blowing conductor slot 53, the shell 5 forms a magnetizing slot 54 separated from the magnetic blowing conductor slot 53 at the center of the magnetic blowing conductor slot 53, the magnetizing sheet 9 is provided in the magnetizing slot 54, an arc isolation plate 10 is provided in the shell, the arc isolation plate 10 covers the magnetic blowing conductor 8 and the inner side of the magnetizing sheet 9, and the arc isolation plate 10 isolates the magnetic blowing conductor 8 and the dynamic and static arc striking sheets (3, 4).

[0027] A transversely arranged vertical arc-extinguishing grid 61 is provided in the vertical arc-extinguishing hood 6, and the opening of the vertical arc-extinguishing grid 61 faces the vertical conductor 81 of the magnetically blown conductor 8. A vertically arranged transverse arc-extinguishing grid 71 is provided in the transverse arc-extinguishing hood 7, and the opening of the transverse arc-extinguishing grid 71 faces the transverse conductor 81 of the magnetically blown conductor 8. One end of the transverse arc-extinguishing hood 7 is provided below the vertical arc-extinguishing hood 6, and the portion of the transverse arc-extinguishing hood 7 provided below the vertical arc-extinguishing hood 6 is not greater than the arc-strike opening depth of the vertical arc-extinguishing grid 61 of the vertical arc-extinguishing hood 6. An L-shaped arc-striking grid 60 is arranged between the arc covers 7. The two sides of the arc-striking grid 60 are respectively arranged at the inner ends of the vertical arc-extinguishing cover 6 and the horizontal arc-extinguishing cover 7 and are parallel to the arc-extinguishing grids (61, 71) in the vertical arc-extinguishing cover 6 and the horizontal arc-extinguishing cover 7. A square grid 62 is arranged on the outside of the arc-striking grid 60. A lower arc discharge channel 51 is formed between the bottom of the horizontal arc-extinguishing cover 7 and the shell 5. The shell 5 forms arc discharge ports 52 at both ends of the lower arc discharge channel 51. A metal grid 70 is arranged on the inside of the shell 5 below the horizontal arc-extinguishing cover 7.

[0028] The arc-striking grid 60 can be integrated with the horizontal arc-extinguishing hood 7 or the vertical arc-extinguishing hood 6. The shape of the arc-striking grid 60 may not be L-shaped, but may use other angles or a larger arc to connect the vertical arc-extinguishing hood 6 and the horizontal arc-extinguishing hood 7.

[0029] There are at least 25 arc quenching grids in total in the vertical arc quenching hood 6 and the horizontal arc quenching hood 7. In this embodiment, the vertical arc quenching hood 6 has 11 vertical arc quenching grids 61 and the horizontal arc quenching hood 7 has 17 horizontal arc quenching grids 71.

[0030] The specific embodiment of the present invention further includes a bimetallic strip 11 and a bimetallic positioning member 12. The lower end of the bimetallic strip 11 is connected to the bimetallic positioning member 12. The outer end of the horizontal conductor 82 of the magnetic blow conductor 8 is connected to the bimetallic positioning member 12 through a soft connection.

[0031] In the present invention, the moving arc-striking piece 3, the static arc-striking piece 4, the vertical arc-extinguishing cover 6 and the horizontal arc-extinguishing cover 7 form a square arc-extinguishing space. A C-shaped magnetic blown conductor 8 is arranged in the center of the square arc-extinguishing space. The vertical conductor 81 and the horizontal conductor 82 of the magnetic blown conductor 8 are respectively arranged on the inner sides of the vertical arc-extinguishing cover 6 and the horizontal arc-extinguishing cover 7. The moving contact 1 and the static contact 2 are arranged at the corner between the moving arc-striking piece 3 and the static arc-striking piece 4. When the switch is disconnected, an arc is generated between the moving contact 1 and the static contact 2, and the arc is extended in the direction along the moving arc-striking piece 3 and the static arc-striking piece 4. The center of the arc extinguishing space moves, and a current loop of static arc striking piece 4-arc pulling-moving arc striking piece 3-magnetic blowing conductor 8 is formed at this time. The current loop on the magnetic blowing conductor 8 generates electromagnetic induction phenomenon. The vertical conductor 81 of the magnetic blowing conductor 8 generates an Ampere force that blows the arc toward the vertical arc extinguishing cover 6, and the horizontal conductor 82 of the magnetic blowing conductor 8 generates an Ampere force that blows the arc toward the horizontal arc extinguishing cover 7. The two Ampere forces accelerate the arc to blow toward the arc extinguishing cover, reducing the residence time of the arc in the circuit breaker, reducing the temperature rise, preventing the circuit breaker from burning, and improving the arc extinguishing ability.

[0032] As shown in Figure 5, specific embodiment 2 of the present invention is a small DC circuit breaker, in which short horizontal arc-quenching grids 72 and long horizontal arc-quenching grids 73 of different lengths are arranged in the horizontal arc-quenching hood 7. The short horizontal arc-quenching grids 72 are arranged in the horizontal arc-quenching hood 7 below the vertical arc-quenching hood 6, and the upper ends of the long horizontal arc-quenching grids 73 extend to the front of the lowest vertical arc-quenching grid 61 of the vertical arc-quenching hood 6.

[0033] As shown in Figure 6, specific embodiment 3 of the present invention is a small DC circuit breaker, whose horizontal arc-quenching hood 7 extends to the bottom of the vertical arc-quenching hood 6, and the horizontal arc-quenching grids 71 ​​of the horizontal arc-quenching hood 7 below the vertical arc-quenching hood 6 are arranged tilted, specifically using three tilted horizontal arc-quenching grids 74. The tilt angle of the tilted horizontal arc-quenching grids 74 on the horizontal arc-quenching hood 7 gradually increases from the inside to the outside, and the remaining grids in the vertical arc-quenching hood 6 and the horizontal arc-quenching hood 7 are arranged at equal distances.

[0034] The specific embodiments of the present invention have all passed the 500V breaking test. The specific test waveforms are shown in Figures 7 and 8. Compared with the NB1-63DC DC circuit breaker of Chint Electric, which is also a small DC circuit breaker and adopts a 1P form factor with a rated voltage of 125V, the present invention also adopts a small circuit breaker with a 1P form factor and a rated voltage of 500V, which is a significant improvement.

[0035] The upper and lower parts described in this specific embodiment are based on the directions of the drawings, and the same transformations need to be made when the directions of the drawings are changed.

[0036] The preferred embodiments of the present invention in the above specific embodiments, other obvious changes or combinations such as using arc-starting grids and inclined arc-extinguishing grids to combine arc-extinguishing hoods, etc., are also within the protection scope of the claims.

Claims

1. A small DC circuit breaker, comprising a housing and a moving contact, a static contact, a moving arcing piece, a static arcing piece, and an arc extinguishing cover disposed within the housing. The moving contact is arranged to move in front of the static contact. The front end of the static arcing piece is connected to the static contact. The upper end of the moving arcing piece is disposed outside the moving contact. Characterized in that: The arc extinguishing cover includes a vertically disposed vertical arc extinguishing cover and a horizontally disposed horizontal arc extinguishing cover. The inner ends of the vertical arc extinguishing cover and the horizontal arc extinguishing cover are close to each other. The rear end of the static arcing piece extends to the upper end of the vertical arc extinguishing cover. The lower end of the moving arcing piece extends to the outer end of the horizontal arc extinguishing cover. The small DC circuit breaker further includes a magnetic blow conductor disposed on the inner wall of the housing. The magnetic blow conductor includes a vertical conductor vertically disposed in front of the vertical arc extinguishing cover and a horizontal conductor horizontally disposed above the horizontal arc extinguishing cover. The horizontal conductor is connected to the lower end of the vertical conductor. The upper end of the vertical conductor of the magnetic blow conductor is connected to the moving arcing piece, and the outer end of the horizontal conductor is connected to an external conductor.

2. The small DC circuit breaker according to claim 1, Characterized in that: A downward arc discharge channel is formed in the housing below the horizontal arc extinguishing cover. An arc discharge port is opened on the bottom surface of the downward arc discharge channel. A metal grid is disposed on the inner side of the bottom surface of the downward arc discharge channel.

3. The small DC circuit breaker according to claim 1 or 2, Characterized in that: An arcing grid piece is disposed between the vertical arc extinguishing cover and the horizontal arc extinguishing cover. The two sides of the arcing grid piece are respectively connected to the inner ends of the vertical arc extinguishing cover and the horizontal arc extinguishing cover.

4. The small DC circuit breaker according to claim 1 or 2, Characterized in that: The moving arcing piece, the static arcing piece, the vertical arc extinguishing cover and the horizontal arc extinguishing cover enclose a square arc extinguishing space. The magnetic blow conductor is disposed within the square arc extinguishing space. The moving contact and the static contact are disposed at a corner between the moving arcing piece and the static arcing piece within the square arc extinguishing space.

5. The small DC circuit breaker according to claim 1 or 2, Characterized in that: The horizontal arc extinguishing cover extends below the vertical arc extinguishing cover. The arc extinguishing grid pieces of the horizontal arc extinguishing cover below the vertical arc extinguishing cover are inclined. The remaining grid pieces within the vertical arc extinguishing cover and the horizontal arc extinguishing cover are equidistantly disposed.

6. The small DC circuit breaker according to claim 1 or 2, Characterized in that: An arc separating plate is disposed inside the magnetic blow conductor.

7. The small DC circuit breaker according to claim 1 or 2, Characterized in that: A magnetic enhancing piece is disposed at the center of the magnetic blow conductor.

8. The small DC circuit breaker according to claim 5, Characterized in that: The inclination angle of the inclined arc extinguishing grid pieces on the horizontal arc extinguishing cover gradually increases from the inside to the outside.

9. The small DC circuit breaker according to claim 1 or 2, Characterized in that: The upper end of the magnetic blow conductor extends towards the end of the moving arcing piece close to the moving contact and is bent at the top to form a welding surface. The welding surface is connected to the top end of the moving arcing piece.

10. The small DC circuit breaker according to claim 1 or 2, Characterized in that: The small DC circuit breaker further includes a bimetallic strip and a bimetallic positioning member. The lower end of the bimetallic strip is connected to the bimetallic positioning member. The lower end of the magnetic blow conductor is connected to the bimetallic positioning member through a flexible connection.

Images