Miniature DC circuit breaker

Abstract

The utility model relates to a miniature direct current circuit breaker, which comprises a shell, and a moving contact, a static contact, a moving arc striking sheet, a static arc striking sheet and an arc extinguishing chamber which are arranged in the shell, the moving contact is relatively arranged in front of the static contact and moves, the front end of the static arc striking sheet is connected to the static contact, the upper end of the moving arc striking sheet is arranged on the outer side of the moving contact, and the lower end of the static arc striking sheet is connected to the arc extinguishing chamber. The arc extinguishing cover is arranged between the rear end of the static arc striking sheet and the lower end of the movable arc striking sheet, the two magnetic blow-out conductors are arranged on the inner walls of the two sides of the shell between the movable contact and the arc extinguishing cover and between the static contact and the arc extinguishing cover respectively, the magnetic blow-out conductors are annular, the upper ends of the magnetic blow-out conductors are connected to the movable arc striking sheet, and the lower ends of the magnetic blow-out conductors are connected to the lower end of the movable arc striking sheet. According to the utility model, the double magnetic blow-out conductors are arranged on the inner walls of the two sides of the shell, so that the electromagnetic field intensity generated when the contact is broken is improved, an electric arc is pushed to move towards the direction of the arc extinguishing cover at a higher speed, the arc extinguishing speed is improved, the temperature rise in the shell is reduced, and high-voltage arc extinguishing is realized.

Description

Technical Field

[0001] The utility model relates to a small circuit breaker, in particular to a small direct current 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 conversion of DC lines. With China's continuous and rapid growth, many fields such as communication power supply, power system, DC power supply, rail transportation, shipbuilding and metallurgy are also developing rapidly, and their requirements for DC systems are also increasing.

[0003] For DC voltage, since the current does not cross zero, the arc cannot be extinguished naturally at the zero crossing point. Therefore, in the existing DC circuit breaker, magnets are installed to generate magnetic induction force on the arc, so that the arc can move to the arc extinguishing grid, thereby dividing and cutting off the arc and cutting off the current. However, the direction of the magnetic induction force generated by the magnet is constant, and it can only push the arc forward in one direction, which limits the setting method of the arc extinguishing cover. In order to cope with higher voltages, small DC circuit breakers require a stronger arc extinguishing system to extinguish the arc. Summary of the invention

[0004] In view of the above-mentioned deficiencies, the utility model provides a small DC circuit breaker suitable for high-voltage DC lines, which can effectively extinguish high-voltage arcs.

[0005] In order to achieve the above purpose, the utility model adopts a small DC circuit breaker, including a shell 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 shell. 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, the upper end of the moving arc-striking piece is arranged on the outside of the moving contact, and the arc-extinguishing cover is arranged between the rear end of the static arc-striking piece and the lower end of the moving arc-striking piece. The small DC circuit breaker also includes two magnetic blowing conductors, which are respectively arranged on the inner walls on both sides of the shell between the moving and static contacts and the arc-extinguishing cover. The magnetic blowing conductor is annular, the upper end of the magnetic blowing conductor is connected to the moving arc-striking piece, and the lower end of the magnetic blowing conductor is connected to the external conductor.

[0006] The effect of the above scheme is to set double magnetic blowing conductors on the inner walls on both sides of the shell, so as to increase the electromagnetic field strength generated when the contacts are disconnected, push the arc to move toward the arc extinguishing hood at a faster speed, increase the arc extinguishing speed, reduce the temperature rise in the shell, and achieve high-voltage arc extinguishing.

[0007] The utility model is further configured such that the two magnetic blowing conductors are divided into an upper magnetic blowing conductor and a lower magnetic blowing conductor, the upper magnetic blowing conductor and the lower magnetic blowing conductor are connected to the external conductor by a soft wire, the upper magnetic blowing conductor is connected to the moving arc-starting piece by a soft wire, and the lower magnetic blowing conductor is connected to the moving arc-starting piece by a hard connection. The upper magnetic blowing conductor connected by a soft wire can be turned over during assembly, which is convenient for assembly.

[0008] The utility model is further configured that a lower arc isolation plate is arranged on the inner side of the lower magnetic blowing conductor, the lower arc isolation plate is connected to the inner wall of the shell, and the lower magnetic blowing conductor is embedded in the lower arc isolation plate, and an upper arc isolation plate is arranged on the inner side of the upper magnetic blowing conductor, the upper arc isolation plate is connected to the inner wall of the shell, and the upper magnetic blowing conductor is embedded in the upper arc isolation plate. The arc isolation plate isolates the magnetic blowing conductor and the arc starting sheet to prevent arc short circuit.

[0009] The utility model is further configured that a magnetizing sheet is arranged at the center of the magnetic blowing conductor, and a magnetizing block is also arranged inside the static contact to increase the magnetic field strength and accelerate arc extinguishing.

[0010] The utility model is further configured such that the upper end of the lower magnetic blowing conductor extends toward one end of the moving arc-starting piece close to the moving contact and is bent at the top end to form a welding surface, and the welding surface is connected to the top end of the moving arc-starting piece.

[0011] The utility model is further configured that the small DC circuit breaker also 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 soft connection.

[0012] The utility model is further configured to form a positioning column on the upper arc isolation plate, and the top end of the positioning column presses against the lower arc isolation plate to prevent the arc isolation plates on both sides from deforming and shifting; the shape of the upper arc isolation plate is adapted to the shell and the static contact, which facilitates the positioning of the upper arc isolation plate in the shell and the positioning of the static contact through the arc isolation plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is an exploded view of a specific embodiment of the utility model.

[0014] Figure 2 It is an assembly diagram of a magnetic blown conductor according to a specific embodiment of the utility model. DETAILED DESCRIPTION

[0015] like Figure 1 , Figure 2As shown, a specific embodiment of the utility model is a small DC circuit breaker, comprising a housing 3 and a moving contact 4, a stationary contact 5, a moving arc-striking piece 6, a stationary arc-striking piece 7, an arc-extinguishing cover 8, a bimetallic piece 9 and a bimetallic positioning piece 91 arranged in the housing 3, the moving contact 4 is relatively arranged in front of the stationary contact 5 for movement, the front end of the stationary arc-striking piece 7 is connected to the stationary contact 5, the upper end of the moving arc-striking piece 6 is arranged on the outside of the moving contact 4, and the arc-extinguishing cover 9 is arranged to connect the rear end of the stationary arc-striking piece 7 with the moving arc-striking piece 6. The small DC circuit breaker further comprises two magnetic blowing conductors (1, 2), which are respectively arranged on the inner walls on both sides of the shell 3 between the moving and static contacts (4, 5) and the arc extinguishing cover 8, and the magnetic blowing conductors (1, 2) are ring-shaped, and the upper ends of the magnetic blowing conductors (1, 2) are connected to the moving arc-starting piece 6, and the lower ends of the bimetallic strip 9 are connected to the bimetallic positioning piece 91, and the lower ends of the magnetic blowing conductors (1, 2) are connected to the bimetallic positioning piece 91 through a soft wire 10.

[0016] The two magnetic blowing conductors (1, 2) are divided into an upper magnetic blowing conductor 1 and a lower magnetic blowing conductor 2. The upper magnetic blowing conductor 1 and the lower magnetic blowing conductor 2 are connected to the double metal positioning piece 91 by a soft wire 10. The upper magnetic blowing conductor 1 is connected to the moving arc-starting piece 6 by a soft wire 10. The upper end of the lower magnetic blowing conductor 2 extends toward the end of the moving arc-starting piece 6 close to the moving contact 4 and is bent at the top to form a welding surface 22. The welding surface 22 is welded to the top of the moving arc-starting piece 6. The upper magnetic blowing conductor 1 connected by the soft wire 10 can be flipped during assembly, which is convenient for assembly.

[0017] A lower arc isolation plate 21 is arranged on the inner side of the lower magnetic blowing conductor 2, the lower arc isolation plate 21 is connected to the inner wall of the shell 3, and the lower magnetic blowing conductor 2 is embedded in the lower arc isolation plate 21. An upper arc isolation plate 11 is arranged on the inner side of the upper magnetic blowing conductor 1, the upper arc isolation plate 11 is connected to the inner wall of the shell 3, and the upper magnetic blowing conductor 1 is embedded in the upper arc isolation plate 11. The arc isolation plates (11, 21) isolate the magnetic blowing conductors (1, 2) from the arc-starting plates to prevent arc short circuit. A magnetizing plate 12 is arranged at the center of the two magnetic blowing conductors (1, 2), and the magnetizing plate 12 is respectively arranged between the upper and lower arc isolation plates (11, 21) and the shell 3, and a magnetizing block 51 is arranged inside the static contact 5.

[0018] A positioning column 13 extending inward is formed on the upper arc isolation plate 11, and the top end of the positioning column 13 is pressed against the lower arc isolation plate 21 to prevent the arc isolation plates (11, 21) on both sides from deforming and shifting; the shape of the upper arc isolation plate 11 is compatible with the housing 3 and the static contact 5, so that the upper arc isolation plate 11 is conveniently positioned in the housing 3, and the static contact 5 is positioned through the upper arc isolation plate 11.

[0019] The arc extinguishing hood 8 of this specific embodiment is formed by two arc extinguishing hoods arranged in an L shape, and the fronts of the two arc extinguishing hoods correspond to the sides of the magnetic blow conductor respectively.

[0020] The up and down mentioned in this specific embodiment are based on the direction of the drawings, and the same transformations need to be made when the direction of the drawings is changed.

[0021] The preferred embodiments of the utility model 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 stationary contact, a moving arc-striking piece, a stationary arc-striking piece, and an arc-extinguishing cover arranged in the housing, wherein the moving contact is arranged in front of the stationary contact for movement, the front end of the stationary arc-striking piece is connected to the stationary contact, the upper end of the moving arc-striking piece is arranged outside the moving contact, and the arc-extinguishing cover is arranged between the rear end of the stationary arc-striking piece and the lower end of the moving arc-striking piece, characterized in that: The small DC circuit breaker also includes two magnetic blowing conductors, which are respectively arranged on the inner walls on both sides of the shell between the moving and static contacts and the arc extinguishing cover. The magnetic blowing conductors are ring-shaped, the upper ends of the magnetic blowing conductors are connected to the moving arc-starting pieces, and the lower ends of the magnetic blowing conductors are connected to the external conductors.

2. The small DC circuit breaker according to claim 1, characterized in that: The two magnetic blowing conductors are divided into an upper magnetic blowing conductor and a lower magnetic blowing conductor. The upper magnetic blowing conductor and the lower magnetic blowing conductor are connected to the external conductor by soft wires, the upper magnetic blowing conductor is connected to the moving arc-starting piece by soft wires, and the lower magnetic blowing conductor is connected to the moving arc-starting piece by hard wires.

3. The small DC circuit breaker according to claim 2, characterized in that: A lower arc isolation plate is arranged on the inner side of the lower magnetic blowing conductor, the lower arc isolation plate is connected to the inner wall of the shell, and the lower magnetic blowing conductor is embedded in the lower arc isolation plate; an upper arc isolation plate is arranged on the inner side of the upper magnetic blowing conductor, the upper arc isolation plate is connected to the inner wall of the shell, and the upper magnetic blowing conductor is embedded in the upper arc isolation plate.

4. The small DC circuit breaker according to claim 1 or 2, characterized in that: A magnetizing sheet is arranged at the center of the magnetic blowing conductor.

5. The small DC circuit breaker according to claim 2, characterized in that: The upper end of the lower magnetic blowing conductor extends toward one end of the moving arc-starting piece close to the moving contact and is bent at the top end to form a welding surface, and the welding surface is connected to the top end of the moving arc-starting piece.

6. The small DC circuit breaker according to claim 1 or 2, characterized in that: The small DC circuit breaker also 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 soft connection.

7. The small DC circuit breaker according to claim 3, characterized in that: A positioning column is formed on the upper arc isolation plate, and the top end of the positioning column is pressed against the lower arc isolation plate. The shape of the upper arc isolation plate is matched with the housing and the static contact.

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