A contact arc extinguishing device for circuit breaker

Abstract

The present invention discloses a contact arc extinguishing device for a circuit breaker, comprising an arc extinguishing chamber (1) and a contact system (2), wherein the contact system (2) comprises a moving contact system (201) and a stationary contact system (202), and is characterized in that: the moving contact system (201) comprises a long moving contact assembly (201a), an arc-striking grid (105) is arranged on the top of the arc extinguishing chamber (1), the arc-striking end (105a) of the arc-striking grid (105) is a downward three-bend structure, the contact end (201a03) of the long moving contact assembly (201a) is an upward hook-shaped protrusion, and when the moving contact system (201) and the stationary contact system (202) are disconnected, an M-shaped current path can be formed between the arc-striking end (105a) of the arc-striking grid (105) and the contact end (201a03) of the long moving contact assembly (201a). The contact arc extinguishing device of the circuit breaker enhances the arc extinguishing capability of the arc extinguishing chamber by improving the contact arc extinguishing device of the circuit breaker, thereby ensuring that the electrical life and breaking capacity of the frame circuit breaker meet the requirements of relevant standards.

Description

Technical Field

[0001] The invention belongs to the technical field of low-voltage electrical appliances, and in particular relates to a contact arc extinguishing device for a circuit breaker, which is suitable for direct current and alternating current power supply systems. Background Art

[0002] Circuit breakers are the most important power distribution equipment in low-voltage power distribution systems. With the continuous improvement of power engineering team power supply and power transmission and distribution equipment requirements, the performance requirements for circuit protection switches are also getting higher and higher. Miniaturization, high performance, modularization, and high reliability are the main development directions of air circuit breakers at this stage. Contacts and arc extinguishing systems are important components of circuit breakers. The contact shape and size design in the contact system is very critical and directly related to the electrical life and breaking capacity of the circuit breaker.

[0003] At the same time, with the rapid development of new energy, DC power systems have also made great progress. The existing commonly used frame circuit breakers are mainly used in AC power systems, and there are fewer frame circuit breakers used in DC power systems. Since the DC system does not have a natural zero-crossing phenomenon compared to the AC system, it cannot extinguish the arc at the moment when the AC current crosses zero like the AC system. It can only rely on quickly stretching and cooling the arc so that the arc voltage exceeds the power supply voltage, and then extinguish the arc, so it is more difficult to extinguish the arc. Therefore, it is very difficult to extinguish the DC arc. Chinese patent ZL201621171400.X discloses an arc extinguishing system for a DC molded case circuit breaker, including a static contact, and an arc extinguishing chamber and an arc extinguishing cover arranged on the static contact, the arc extinguishing chamber includes two arc isolation plates arranged on the static contact, and arc extinguishing grids evenly spaced between the two arc isolation plates, the arc extinguishing cover includes two spaced wall panels closely arranged on the static contact, one end of the two wall panels is also close to the arc extinguishing grid, so that the arc extinguishing cover, the arc extinguishing chamber and the static contact cooperate to form a relatively closed air chamber, and the moving contact in the circuit breaker moves in the air chamber. The DC molded case circuit breaker solves the problem of difficulty in extinguishing arcs at low currents, and improves its short-circuit breaking capability, etc. However, the arc generated by the circuit breaker cannot be completely extinguished, and it is easy to overflow the arc extinguishing chamber, which poses a safety hazard to the use of the circuit breaker. Summary of the invention

[0004] The purpose of the present invention is to provide a contact arc extinguishing device for a circuit breaker in order to solve the technical problem that arcs in existing frame circuit breakers are difficult to extinguish in DC systems. By improving the structure of the contact arc extinguishing device for the circuit breaker, the arc extinguishing ability of the arc extinguishing chamber is enhanced, thereby ensuring that the electrical life and breaking capacity of the frame circuit breaker meet the requirements of relevant standards.

[0005] Technical Solution

[0006] In order to achieve the above technical objectives, the present invention designs a contact arc extinguishing device for a circuit breaker, which includes an arc extinguishing chamber and a contact system, wherein the contact system includes a moving contact system and a stationary contact system, and the engagement or disconnection of the moving contact system and the stationary contact system controls the on-off of the circuit of the circuit breaker, and is characterized in that: the moving contact system includes a long moving contact assembly, an arc-striking grid is arranged on the top of the arc extinguishing chamber, the arc-striking end of the arc-striking grid is a downward three-fold structure, and the contact end of the long moving contact assembly is an upward hook-shaped protrusion, and when the moving contact system and the stationary contact system are disconnected, an M-shaped current path can be formed between the arc-striking end of the arc-striking grid and the contact end of the long moving contact assembly.

[0007] Furthermore, the arc extinguishing chamber comprises a left partition plate and a right partition plate, and the arc striking grid is inserted into the left partition plate and the right partition plate.

[0008] Furthermore, short moving contact assemblies are symmetrically arranged side by side on both sides of the long moving contact assembly, and the long moving contact assembly and the short moving contact assembly can rotate around the same rotation center.

[0009] Preferably, the outer contour of the hook-shaped protruding contact end of the long moving contact assembly is triangular, and the front end sharp angle is an obtuse angle, and the sharp angle point is located in the lower middle position of the triangle. The contact end of the short moving contact assembly is a hook-shaped protrusion, and the outer contour of the hook-shaped protruding contact end of the short moving contact assembly is an arc shape.

[0010] Beneficial Effects

[0011] The present invention provides a contact arc extinguishing device for a circuit breaker. By improving the structure of the contact arc extinguishing device for the circuit breaker, the arc extinguishing ability of the arc extinguishing chamber is enhanced, ensuring that the electrical life and breaking capacity of the frame circuit breaker in the DC system meet the requirements of relevant standards. At the same time, through practice, the circuit breaker can also be applied to the AC system, and can also meet the requirements of rapid arc extinguishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Attached Figure 1a It is a product schematic diagram of the arc extinguishing system in an embodiment of the present invention.

[0013] Attached Figure 1b It is a schematic diagram of the product structure of the arc extinguishing system in an embodiment of the present invention.

[0014] Attached Figure 2 Schematic diagram of the exploded structure of the arc extinguishing system in the embodiment of the present invention.

[0015] Attached Figure 3 It is a schematic structural diagram of the position of the contact system in the arc extinguishing chamber according to an embodiment of the present invention.

[0016] Attached Figure 4 It is a schematic diagram of the contact system structure in the implementation of the present invention.

[0017] Attached Figure 5 It is a schematic diagram of the structure of the long moving contact assembly in the implementation of the present invention.

[0018] Attached Figure 6 It is a schematic diagram of the structure of the short moving contact assembly in the implementation of the present invention.

[0019] Attached Figure 7 It is a schematic diagram of the internal structure of the arc extinguishing chamber in the implementation of the present invention.

[0020] Attached Figure 8 It is a schematic diagram of the arc extinguishing grid structure in an embodiment of the present invention.

[0021] Attached Fig. 9 It is a schematic diagram of the top arc extinguishing grid structure in an embodiment of the present invention.

[0022] Attached Fig.10 Schematic diagram of the arc striking grid structure in an embodiment of the present invention.

[0023] Attached Fig.11 Schematic diagram of the arc striking angle structure in an embodiment of the present invention.

[0024] Attached Fig.12 It is a structural schematic diagram of the contact system engagement process in an embodiment of the present invention.

[0025] Attached Fig.13 It is a schematic diagram of the structure of the breaking process of the contact system in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0027] Example

[0028] As attached Figure 1a , 1b As shown in FIG. 2 , an arc extinguishing system of a circuit breaker includes an arc extinguishing chamber 1 and a contact system 2, wherein the contact system 2 includes a moving contact system 201 and a stationary contact system 202, and the engagement or disconnection of the moving contact system 201 and the stationary contact system 202 controls the on-off of the circuit breaker, wherein:

[0029] As attached Figure 4 As shown, the moving contact system 201 includes a long moving contact assembly 201a, and short moving contact assemblies 201b are symmetrically arranged side by side on both sides of the long moving contact assembly 201a. The long moving contact assembly 201a is longer than the short moving contact assembly 201b. The long moving contact assembly 201a and the short moving contact assembly 201b can rotate around the same rotation center. Figure 5As shown, the long moving contact assembly 201a is provided with a front long moving contact 201a01 and a rear long moving contact 201a02 in sequence. Figure 6 As shown, the short moving contact assembly 201b is provided with a short moving contact 201b01, the rear long moving contact 201a02 and the short moving contact 201b01 are located on the same horizontal plane, and the front long moving contact 201a01 is located above the rear long moving contact 201a02 and the short moving contact 201b01;

[0030] As attached Figure 2 , 3 As shown in FIG. 4 , the stationary contact system 202 includes a stationary contact plate 202a, on which a front stationary contact 202a01 and a rear stationary contact 202a02 are provided. The front stationary contact 202a01 corresponds to the front long movable contact 201a01, and the rear stationary contact 202a02 corresponds to the rear long movable contact 201a02 and the short movable contact 201b01. Figure 3 As shown, the front static contact 202a01 and the front long moving contact 201a01 are located inside the arc extinguishing system 1, and the rear static contact 202a02, the rear long moving contact 201a02 and the short moving contact 201b01 are located outside the arc extinguishing chamber 1;

[0031] As attached Figure 1a , 1b As shown in FIGS. 2 and 3 , the arc extinguishing chamber 1 comprises a left partition plate 101 and a right partition plate 102, and both ends of the arc extinguishing grid group 103 are respectively inserted into the left partition plate 101 and the right partition plate 102. Figure 7 , 8As shown in Figure 9, a top arc-extinguishing grid 104 is provided at the upper end of the arc-extinguishing grid group 103, and the two ends of the top arc-extinguishing grid 104 are inserted on the left partition 101 and the right partition 102. An arc-striking grid 105 is provided above the top arc-extinguishing grid 104, and the arc-striking grid 105 is inserted on the left partition 101 and the right partition 102. Feet 103a01 extend from both sides of the front end of the arc-extinguishing grid group 103, and the gas-generating hood 106 covers the feet 103a01 and is located below the top arc-extinguishing grid 104. The front static contact 202a01 and the front long moving contact 201a01 are located in the arc-extinguishing chamber formed by the left partition 101, the right partition 102, the arc-extinguishing grid group 103 and the gas-generating hood 106. The arc extinguishing grid group 103 includes a plurality of arc extinguishing grids 103a, which are arranged at equal intervals, and the horizontal distance between the plurality of arc extinguishing grids 103a and the front static contact 202a01 gradually increases from the bottom of the arc extinguishing grid group 103 upward, then gradually decreases to the middle of the arc extinguishing grid group 103, then gradually increases upward from the middle of the arc extinguishing grid group 103, and finally gradually decreases to the arc striking grid 105 at the top of the arc extinguishing grid group 103, forming a "3" shape. The inner cavity of the gas generating hood 106 is a "3" shape corresponding to the arc extinguishing grid group 103. Specifically, the arc extinguishing grid group 103 in this embodiment includes a total of 18 arc extinguishing grids 103a arranged at equal intervals from bottom to top; the horizontal distances of the 18 arc extinguishing grids 103a from the 1st to the 11th from the bottom to the front static contact 202a01 gradually increase from near to far; the horizontal distances of the 12th and 13th arc extinguishing grids 103a from the front static contact 202a01 become closer again; the horizontal distances of the 14th to the 18th arc extinguishing grids 103a from the front static contact 202a01 gradually increase from near to far again; the horizontal distance of the arc striking grid 105 from the front static contact 202a01 becomes closer again.

[0032] As attached Fig.10 As shown in FIG. 1 , the arc-striking end 105a of the arc-striking grid 105 is a downward three-bend structure. Figure 2 , 3As shown in Figure 4, the contact end 201a03 of the long moving contact assembly 201a is upwardly hooked, and the outer contour of the hooked protruding contact end 201a03 of the long moving contact assembly 201a is triangular, and the front end sharp angle is an obtuse angle, and the sharp angle point is located in the middle and lower part of the triangle. The contact end 201b02 of the short moving contact assembly 201b is a hook-shaped protrusion, and the outer contour of the hooked protruding contact end 201b02 of the short moving contact assembly 201b is an arc. When the moving contact system 201 and the static contact system 202 are disconnected, an M-shaped current path can be formed between the arc-striking end 105a of the arc-striking grid 105 and the contact end 201a03 of the long moving contact assembly 201a. The three-bend structure of the arc striking end 105a will greatly enhance the electric field strength there, which will be more conducive to leading the arc to the top of the arc extinguishing chamber 1, lengthening the length of the arc and increasing the arc voltage, which will greatly improve the breaking capacity.

[0033] At the same time, if attached Figure 4 As shown, the front end of the static contact plate 202a is located in front of the front static contact 202a01 and is provided with an arc starting angle 202a03, and the rear end of the arc starting angle 202a03 is flush with the front static contact 202a01. Fig.11 As shown, the arc striking angle 202a03 is in a trapezoidal dovetail shape, and the width of the arc striking angle 202a03 gradually increases from the side located at the front static contact 202a01 to the side away from the front static contact 202a01. The trapezoidal dovetail arc striking angle 202a03 will increase the electromagnetic field strength at the end of the front static contact 202a01, which will be more conducive to the arc being transferred out of the front static contact 202a01. At the same time, the 3-shaped arc extinguishing grid group 103 will also enhance the magnetic field strength here to accelerate the transfer of the arc, quickly lead the arc root to the bottom of the arc extinguishing grid group 103 and move it to the rear end of the arc extinguishing chamber 1, which helps to lengthen the arc length, increase the arc voltage, and improve the arc breaking ability.

[0034] As attached Fig.12 As shown, when the moving contact system 201 and the stationary contact system 202 are engaged, the front stationary contact 202a01 and the front long moving contact 201a01 come into contact before the rear stationary contact 202a02 and the rear long moving contact 201a02 and the short moving contact 201b01.

[0035] As attached Fig.13 As shown, when the moving contact system 201 and the stationary contact system 202 are disconnected, the front stationary contact 202a01 and the front long moving contact 201a01 are disconnected later than the rear stationary contact 202a02 and the rear long moving contact 201a02 and the short moving contact 201b01.

[0036] Since the front static contact 202a01 and the front long moving contact 201a01 are disconnected later than the rear static contact 202a02 and the rear long moving contact 201a02 and the short moving contact 201b01, the arc will only appear between the front static contact 202a01 and the front long moving contact 201a01. Under the air medium, at the moment when the front static contact 202a01 and the front long moving contact 201a01 are disconnected, the resistance and temperature of the contact point increase continuously. When the temperature reaches the melting temperature of the contact material, a metal bridge of molten metal is formed at the contact point. If the front long moving contact 201a01 continues to disconnect, the metal bridge will be broken to generate an arc. The arc is initially ignited by the metal vapor of the front static contact 202a01 and the front long moving contact 201a01. Then, when the arc is elongated, the surrounding air medium gradually enters the arc gap to transform the metal phase arc into a gas phase arc supported by free. The gas phase arc is continuously elongated by the front static contact 202a01 and the front long moving contact 201a01, and is finally extinguished under the joint action of the arc extinguishing grid group 103 and the gas generating hood 106 in the arc extinguishing chamber 1. The present invention realizes that the arc is only generated between the front static contact 202a01 and the front long moving contact 201a01, that is, the arc is directly generated inside the arc extinguishing chamber 1, eliminating the process of transferring the arc from the outside to the inside of the arc extinguishing chamber 1; at the same time, the arc generated inside the arc extinguishing chamber 1 will be more effectively compressed and cooled in the narrow space formed by the arc extinguishing grid group 103 and the gas generating hood 106, thereby increasing the arc resistance and raising the arc voltage, and finally achieving faster arc extinguishing.

[0037] In this embodiment, the front long moving contact 201a01, the rear long moving contact 201a02, the short moving contact 201b01, the front static contact 202a01, and the rear static contact 202a02 are respectively made of the same or different materials as the corresponding long moving contact assembly 201a, the short moving contact assembly 201b, and the static contact plate 202a, and the corresponding structures are made into split or integrated types.

[0038] The present invention provides a contact arc extinguishing device for a circuit breaker. By improving the structure of the contact arc extinguishing device for the circuit breaker, the arc extinguishing ability of the arc extinguishing chamber is enhanced, ensuring that the electrical life and breaking capacity of the frame circuit breaker in the DC system meet the requirements of relevant standards. At the same time, through practice, the circuit breaker can also be applied to the AC system, and can also meet the requirements of rapid arc extinguishing.

[0039] The structures, proportions, sizes, etc. illustrated in the accompanying drawings of the embodiments of the present invention are only used to match the contents disclosed in the specification so as to be understood and read by those familiar with the technology, and are not used to limit the limiting conditions under which the present invention can be implemented, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical contents disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", "clockwise", "counterclockwise", etc. cited in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of the relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical contents.

Claims

1. A contact arc extinguishing device for a circuit breaker, comprising an arc extinguishing chamber (1) and a contact system (2), wherein the contact system (2) comprises a moving contact system (201) and a stationary contact system (202), and the connection or disconnection of the moving contact system (201) and the stationary contact system (202) controls the on-off of the circuit breaker, characterized in that: The moving contact system (201) comprises a long moving contact assembly (201a); an arc-striking grid (105) is arranged on the top of the arc-extinguishing chamber (1); the arc-striking end (105a) of the arc-striking grid (105) is a downward three-fold structure; the contact end (201a03) of the long moving contact assembly (201a) is an upward hook-shaped protrusion; when the moving contact system (201) and the stationary contact system (202) are disconnected, an M-shaped current path can be formed between the arc-striking end (105a) of the arc-striking grid (105) and the contact end (201a03) of the long moving contact assembly (201a).

2. A contact arc extinguishing device for a circuit breaker according to claim 1, characterized in that: The arc extinguishing chamber (1) comprises a left partition plate (101) and a right partition plate (102), and the arc striking grid (105) is inserted into the left partition plate (101) and the right partition plate (102).

3. The contact arc extinguishing device of a circuit breaker according to claim 1, characterized in that: The short moving contact assemblies (201b) are symmetrically arranged side by side on both sides of the long moving contact assembly (201a); the long moving contact assembly (201a) and the short moving contact assembly (201b) are capable of rotating around the same rotation center.

4. A contact arc extinguishing device for a circuit breaker as claimed in claim 3, characterized in that: The outer contour of the hook-shaped protruding contact end (201a03) of the long moving contact assembly (201a) is in a triangular shape, and the front end sharp angle is an obtuse angle, and the sharp angle point is located in the middle and lower part of the triangle; the contact end (201b02) of the short moving contact assembly (201b) is a hook-shaped protrusion, and the outer contour of the hook-shaped protruding contact end (201b02) of the short moving contact assembly (201b) is in an arc shape.

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