An arc-extinguishing chamber for a DC circuit breaker and the DC circuit breaker

Abstract

This invention discloses an arc-extinguishing chamber for a DC circuit breaker and the DC circuit breaker itself. The circuit breaker includes two opposing arc-blocking plates and several arc-extinguishing grids arranged parallel between the two arc-blocking plates. A magnetic blow-out mechanism is provided on either side or opposite sides of the arc-extinguishing chamber. The magnetic blow-out mechanism includes an iron sheet and a coil wound around the outside of the iron sheet. One end of the coil is electrically connected to a stationary contact, and the other end is electrically connected to a conductive element. The conductive element can contact the moving contact during the breaking process. The coil generates a magnetic field under the action of the arc voltage generated by the breaking of the stationary and moving contacts. Utilizing the magnetic field generated by the short-circuit current enhances the magnetic blow-out effect, thereby drawing the arc into the arc-extinguishing chamber more quickly and extinguishing the arc faster.

Description

Technical Field

[0001] The present invention specifically relates to an arc-extinguishing chamber for a DC circuit breaker and a DC circuit breaker. Background Technology

[0002] During the process of circuit breaking, circuit breakers generate a large number of electric arcs. The generation of electric arcs is accompanied by high temperature and high pressure. Existing arc-extinguishing chambers generally use magnetic blowing or air blowing mechanisms to quickly introduce the electric arc generated when the moving and stationary contacts break into the arc-extinguishing chamber for arc extinguishing. Magnetic blowing mechanisms generally use magnets, but magnets are prone to demagnetization under high temperature conditions, which affects the magnetic blowing effect. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an arc-extinguishing chamber for a DC circuit breaker and a DC circuit breaker.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] An arc-extinguishing chamber for a DC circuit breaker includes two opposing arc-blocking plates and several arc-extinguishing grids arranged parallel between the two arc-blocking plates. Gas-generating hoods are provided on both sides of the inlet of each arc-extinguishing grid. Each gas-generating hood has a recessed cavity with one open end. A magnetic blowing mechanism is provided within the recessed cavity. The magnetic blowing mechanism includes an iron sheet and a coil wound around the outside of the iron sheet. One end of the coil is electrically connected to a stationary contact, and the other end extends out of the gas-generating hood and is electrically connected to a conductive element. The conductive element can contact the moving contact during the breaking process. The coil generates a magnetic field under the action of the arc voltage generated by the breaking of the stationary and moving contacts.

[0006] An arc-extinguishing chamber for a DC circuit breaker includes two opposing arc-blocking plates and several arc-extinguishing grids arranged parallel between the two arc-blocking plates. Gas-generating hoods are provided on both sides of the inlet of the arc-extinguishing grids. A magnetic blowing mechanism is provided on the lower side of the arc-extinguishing chamber. The magnetic blowing mechanism includes an iron sheet and a coil wound around the outside of the iron sheet. One end of the coil is electrically connected to the stationary contact, and the other end is electrically connected to conductive elements located on both sides of the moving contact. The conductive elements can contact the moving contact during the breaking process of the moving contact. The coil generates a magnetic field under the action of the arc voltage generated by the breaking of the moving and stationary contacts.

[0007] The front end of the gas generating hood is provided with two sets of ejection devices arranged opposite each other. The ejection device includes a housing and a cover plate that cooperates with it. An opening groove is provided on one side of the housing. The conductive element is placed inside the housing and partially extends out of the housing from the opening groove. An elastic element is provided between the conductive element and the cover plate. The upper end of the conductive element is provided with an inclined surface.

[0008] The upper end of the conductive component is provided with an arc-blocking plate, the arc-blocking plate extends out of the housing through the opening groove, and an elastic element is provided between the arc-blocking plate and the cover plate, and the upper and lower sides of the arc-blocking plate are provided with inclined surfaces.

[0009] The inner wall of the housing is symmetrically provided with limiting blocks, which divide the interior of the housing into upper and lower spaces. The conductive component is placed in the lower space, and the arc-blocking plate is placed in the upper space.

[0010] The arc-blocking plate has guide blocks on both sides, and the housing has corresponding guide grooves that are adapted to the guide blocks.

[0011] The upper and lower ends of the cavity are provided with limiting grooves, and the upper and lower ends of the iron sheet are inserted into the limiting grooves.

[0012] The arc-extinguishing grid is provided with comb-like teeth on both the upper and lower surfaces, and a curved space is formed between two adjacent arc-extinguishing grids.

[0013] A DC circuit breaker employing the above-mentioned arc-extinguishing chamber for DC circuit breakers includes a base and a stationary contact assembly and a moving contact assembly disposed within the base, wherein the above-mentioned arc-extinguishing chamber for DC circuit breakers is provided between the moving contact assembly and the stationary contact assembly.

[0014] The beneficial effects of this invention are as follows: By winding the coil around an iron sheet, the magnetic field generated by the short-circuit current is used to enhance the magnetic blow-out effect, thereby drawing the arc into the arc-extinguishing chamber more quickly and extinguishing the arc faster. Furthermore, the magnetic field changes with the magnitude of the short-circuit current. When a short-circuit current occurs in the circuit, the coil and the circuit are connected, and the coil generates a magnetic field, increasing the Lorentz force. During the breaking process, due to the connection between the coil and the circuit and the current-limiting effect of the circuit breaker, the current in the coil changes with the short-circuit current, and the generated magnetic force also changes accordingly. When the breaking is complete, the product cuts off the current; at this time, there is no current in the coil, and the magnetic field disappears. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the arc-extinguishing mechanism in Example 1.

[0016] Figure 2 This is a cross-sectional schematic diagram of the arc-extinguishing mechanism in Example 1.

[0017] Figure 3 This is a schematic diagram of the arc-extinguishing chamber in Example 1.

[0018] Figure 4 This is a partial cross-sectional view of the arc-extinguishing chamber in Example 1.

[0019] Figure 5 This is a cross-sectional schematic diagram of the arc-extinguishing chamber in Example 2.

[0020] Figure 6 This is a schematic diagram of the catapult device.

[0021] Figure 7 This is a cross-sectional schematic diagram of the catapult device.

[0022] Figure 8 This is a schematic diagram of the shell structure.

[0023] Figure 9 This is a schematic diagram of the arc-blocking plate.

[0024] Figure 10 This is the equivalent circuit for the arc-extinguishing mechanism.

[0025] Figure 11 This is a three-dimensional diagram of the magnetic field in Example 1.

[0026] Figure 12 This is a three-dimensional view of the magnetic field in Example 2.

[0027] Figure 13 This is a schematic diagram of the internal structure of a DC circuit breaker.

[0028] In the diagram, 1 is the arc-extinguishing chamber, 2 is the ejector device, 3 is the moving contact assembly, 4 is the stationary contact assembly, 5 is the base, 11 is the arc-blocking plate, 12 is the arc-extinguishing grid, 13 is the gas-generating hood, 14 is the coil, 15 is the iron sheet, 121 is the comb-like teeth, 131 is the limiting groove, 132 is the cavity, 21 is the shell, 22 is the cover plate, 23 is the arc-blocking plate, 24 is the conductive component, 25 is the elastic component, 211 is the guide groove, 212 is the limiting block, 213 is the opening groove, and 231 is the guide block. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0031] As shown in the figure, Embodiment 1 of the present invention discloses an arc-extinguishing chamber 1 for a DC circuit breaker, which includes two opposing arc-blocking plates 11 and a plurality of arc-extinguishing grids 12 arranged in parallel between the two arc-blocking plates. The arrayed arc-extinguishing grids form an inlet and an outlet. Gas-generating hoods 13 are provided on both sides of the inlet of the arc-extinguishing grids. The gas-generating hoods 13 are fixedly mounted on the arc-blocking plates. The gas-generating hood has a cavity 132 with one end open. The opening of the cavity faces the moving contact mechanism for easy assembly. A magnetic blowing mechanism is provided in the cavity. The magnetic blowing mechanism includes an iron sheet 15. A coil 14 is wound around the iron sheet. One end of the coil is electrically connected to the stationary contact, and the other end extends out of the gas-generating hood and is electrically connected to a conductive element. The conductive element can contact the moving contact during the breaking of the moving contact. The coil generates a magnetic field under the action of the arc voltage generated by the breaking of the moving and stationary contacts.

[0032] Embodiment 2 of the present invention discloses an arc-extinguishing chamber 1 for a DC circuit breaker, which includes two opposing arc-blocking plates 11 and a plurality of arc-extinguishing grids 12 arranged in parallel between the two arc-blocking plates. The arrayed arc-extinguishing grids form an inlet and an outlet. Gas-generating hoods 13 are provided on both sides of the inlet of the arc-extinguishing grids. The gas-generating hoods 13 are fixedly mounted on the arc-blocking plates. A groove is provided at the bottom of the housing of the DC circuit breaker, and a magnetic blowing mechanism is provided in the groove. The magnetic blowing mechanism is located below the stationary contact. The magnetic blowing mechanism includes an iron sheet 15, and a coil 14 is wound around the iron sheet. One end of the coil is electrically connected to the stationary contact, and the other end extends upward, passes through the housing, and is electrically connected to conductive elements provided on both sides of the moving contact. The conductive elements can contact the moving contact during the breaking process of the moving contact. The coil generates a magnetic field under the action of the arc voltage generated by the breaking of the moving and stationary contacts.

[0033] The front end of the gas generating hood is equipped with two sets of opposing ejection devices 2. These ejection devices are mainly used to quickly shut off the passage between the circuit breaker interior and the arc-extinguishing chamber. When the moving contact is completely disengaged from the ejection device, it can block the airflow entering the circuit breaker interior from the arc-extinguishing chamber. Each ejection device includes a housing 21 and a cover plate 22 that cooperates with it. An opening slot 213 is provided on one side of the housing. The conductive element 24 is placed inside the housing and partially extends out of the housing from the opening slot. An elastic element 25, which is a spring, is provided between the conductive element and the cover plate. The upper end of the conductive element has an inclined surface. The opposing inclined surfaces form a V-shaped opening, which allows the moving contact to better exert force on the conductive element to move inward. During use, when the moving contact breaks, it will compress the conductive element to extend and retract into the housing. Due to the presence of the internal spring, the conductive element can fit tightly against both sides of the moving contact, forming a passage. The conductive element is preferably made of metal and is electrically connected to one end of the coil. The cross-section of the conductive element is T-shaped to prevent it from completely coming out of the opening slot of the housing and to be confined inside. Multiple positioning holes for limiting the spring are provided on its rear side to prevent the spring from shifting.

[0034] When the circuit is closed, the moving contact presses against the conductive element, and under the action of the spring force, there is a tight contact between the conductive element and the moving contact.

[0035] A catapult device is used to direct the short-circuit current to the coil, generating a magnetic field. When the moving and stationary contacts are in contact, there is no current in the coil. When the moving contact opens to a certain position, the arc is extinguished, and no external magnetic field is needed. The moving contact and the conductive parts are no longer in contact, the arc voltage is 0, there is no current in the coil, and the magnetic field disappears.

[0036] The distance between the conductive component and the moving contact is 22.7 mm. The upper end of the conductive component is provided with an arc-blocking plate 23, which extends out of the housing through the opening groove. An elastic element is provided between the arc-blocking plate and the cover plate, and the upper and lower sides of the arc-blocking plate are provided with inclined surfaces.

[0037] The portion of the arc-blocking plate exposed above the housing should be wider than the portion of the conductive component exposed above the housing. The arc-blocking plate and the conductive component are independent and do not interfere with each other, ensuring that the coil is not energized when the moving contact moves to the position of the arc-blocking plate. This allows the magnetic field to change with the magnitude of the short-circuit current. A magnetic field is required when the product is disconnected; at this time, the short-circuit current is directed to the coil to generate the magnetic field. When the product disconnection is complete, there is no short-circuit current in the coil and no magnetic field is generated.

[0038] The cross-section of the arc-blocking plate is also T-shaped to ensure that the arc-blocking plate will not come out of the housing. Both the upper and lower sides are set as bevels. When the two arc-blocking plates are placed opposite each other, they form two V-shaped openings, which makes it easy for the moving contact to squeeze the arc-blocking plate regardless of whether it moves downward or upward, so that the presence of the arc-blocking plate will not interfere with the movement of the moving contact.

[0039] The inner wall of the housing is symmetrically provided with limiting blocks 212, which divide the interior of the housing into upper and lower spaces. The conductive component is placed in the lower space, and the arc-blocking plate is placed in the upper space. The limiting blocks extend inward, and there may be a gap or direct contact between the two, so that two spaces are formed inside. The limiting blocks provide a certain support for the arc-blocking plate, and they isolate the conductive component from the arc-blocking plate to ensure that the two do not interfere with each other.

[0040] The arc-blocking plate has guide blocks 231 on both sides, and the housing has corresponding guide grooves 211 that are adapted to the guide blocks, which serve as guides and also provide support to ensure that the arc-blocking plate is always above the conductive component and does not contact it.

[0041] When the product is closed, the moving contact is pressed into the V-shaped space formed by the two inclined surfaces of the arc-blocking plate. Through the arc-blocking plate, the conductive component is pressed, causing the conductive component to contact the moving contact. By adjusting the spring force of the elastic component, the friction between the conductive component and the moving contact is controlled, so that the moving contact can close smoothly.

[0042] When the product trips, the moving contact and the conductive part gradually separate. When they are completely separated, an electric arc is formed between the conductive part and the moving contact. This electric arc is interrupted by the closed arc-blocking plate, and the electric arc is quickly extinguished.

[0043] The upper and lower ends of the cavity are provided with limiting grooves 131. The upper and lower ends of the iron sheet are inserted into the limiting grooves. The limiting grooves are located on the center line of the cavity, ensuring that the inserted iron sheet is in the middle. The iron sheet is wrapped with a coil on the outside. The iron sheet is fixed by insertion. The assembly is simple and it is convenient to insert the iron sheet with the coil. It can also ensure that it is always in the center.

[0044] The equivalent circuit of the present invention is as follows: Figure 10 As shown, K1 represents the opening and closing of the circuit breaker, K2 represents the contact between the moving contact and the conductive part, and the coil and iron sheet are equivalent to the resistor R2 and the inductor L1.

[0045] When K1 is closed (closed), K2 is also closed (sliding spring and moving contact are in contact); since the impedance in the main circuit is very small, the inductor branch is short-circuited, and no current flows through it.

[0046] When K1 is disconnected (trigger tripped), K2 is also closed (sliding spring and moving contact are in contact). Since the current in the branch inductor cannot change abruptly, the current is still 0. As the moving and stationary contacts separate, the breakdown discharge between the moving and stationary contacts generates an arc. At this time, since the arc voltage acts on the inductor and continues, a normal response current will be generated on the inductor, thereby generating a magnetic field and producing a magnetic blow-out effect, causing the arc to move towards the arc extinguishing chamber.

[0047] A three-dimensional diagram of the magnetic field in Embodiment 1 of the present invention is shown below. Figure 11 As shown, when the coil generates a magnetic field, the magnetic fields of the coils on both sides are in the same direction, and an electric field force is formed that leads the arc towards the arc-extinguishing chamber. Therefore, under the action of the magnetic field, the arc is caused to move towards the arc-extinguishing chamber.

[0048] The magnetic field three-dimensional diagram of Embodiment 2 of the present invention is as follows: Figure 12 As shown, when the coil generates a magnetic field, the magnetic field generated at the bottom creates an electric field force that guides the arc toward the arc-extinguishing chamber, causing the arc to move toward the arc-extinguishing chamber.

[0049] The arc-extinguishing grid is provided with comb-shaped teeth 121 on both its upper and lower surfaces, and a curved space is formed between two adjacent arc-extinguishing grids. When the arc-extinguishing grid is provided with comb-shaped teeth on both its upper and lower surfaces and is placed between two arc-blocking plates, the comb-shaped teeth of the adjacent arc-extinguishing grids are staggered, so that a maze-like structure is formed between the two arc-extinguishing grids. The electric arc is pulled into the arc-extinguishing chamber by the combined force of air blowing and magnetic blowing and is cut into short arcs by the arc-extinguishing grid.

[0050] When the electric arc enters the labyrinth structure under the action of the magnetic field, the electric arc comes into close contact with the comb-like teeth, forming a serpentine shape. The arc length increases, the arc is stretched thinner, and the energy dissipates quickly, which is conducive to arc extinguishing. Moreover, because the arc is stretched by the labyrinth structure, the arc extinguishing effect is enhanced. Especially when breaking high-voltage short-circuit current, the volume of the arc extinguishing chamber can be reduced.

[0051] A DC circuit breaker employing the above-mentioned arc-extinguishing chamber for DC circuit breakers includes a base and a stationary contact assembly 4 and a moving contact assembly 3 disposed within the base, wherein the above-mentioned arc-extinguishing chamber for DC circuit breakers is provided between the moving contact assembly and the stationary contact assembly.

[0052] The embodiments should not be regarded as limitations on the present invention, but any improvements made based on the spirit of the present invention should be within the protection scope of the present invention.

Claims

1. An arc-extinguishing chamber for a DC circuit breaker, comprising two opposing arc-blocking plates and a plurality of arc-extinguishing grid plates arranged parallel between the two arc-blocking plates, characterized in that: The arc-extinguishing grid plate has gas generating hoods on both sides of its inlet. Each gas generating hood has a cavity with one end open. A magnetic blowing mechanism is installed inside the cavity. The magnetic blowing mechanism includes an iron sheet and a coil wound around the outside of the iron sheet. One end of the coil is electrically connected to the stationary contact, and the other end extends out of the gas generating hood and is electrically connected to conductive elements installed on both sides of the moving contact. The conductive elements can contact the moving contact during the breaking process. The coil generates a magnetic field under the action of the arc voltage generated by the breaking of the moving and stationary contacts. The front end of the gas generating hood has two sets of opposing ejection devices. Each ejection device includes a housing and a cover plate that cooperates with it. One side of the housing has an opening slot. The conductive element is placed inside the housing and partially extends out of the housing from the opening slot. An elastic element is provided between the conductive element and the cover plate. The upper end of the conductive element has an inclined surface. The two opposing inclined surfaces form a V-shaped opening.

2. An arc-extinguishing chamber for a DC circuit breaker, comprising two opposing arc-blocking plates and a plurality of arc-extinguishing grid plates arranged parallel between the two arc-blocking plates, characterized in that: Gas generating hoods are provided on both sides of the inlet of the arc-extinguishing grid. A magnetic blowing mechanism is provided on the lower side of the arc-extinguishing chamber. The magnetic blowing mechanism includes an iron sheet and a coil wound around the outside of the iron sheet. One end of the coil is electrically connected to the stationary contact, and the other end is electrically connected to the conductive parts located on both sides of the moving contact. The conductive parts can contact the moving contact during the breaking process. The coil generates a magnetic field under the action of the arc voltage generated by the breaking of the moving and stationary contacts. Two sets of ejection devices are provided at the front end of the gas generating hood. The ejection device includes a housing and a cover plate that cooperates with it. An opening slot is provided on one side of the housing. The conductive parts are placed inside the housing and partially protrude from the housing through the opening slot. An elastic element is provided between the conductive parts and the cover plate. An inclined surface is provided on the upper end of the conductive parts. The two inclined surfaces formed a V-shaped opening.

3. An arc-extinguishing chamber for a DC circuit breaker according to claim 1 or 2, characterized in that: The upper end of the conductive component is provided with an arc-blocking plate, the arc-blocking plate extends out of the housing through the opening groove, and an elastic element is provided between the arc-blocking plate and the cover plate, and the upper and lower sides of the arc-blocking plate are provided with inclined surfaces.

4. The arc-extinguishing chamber for a DC circuit breaker according to claim 3, characterized in that: The inner wall of the housing is symmetrically provided with limiting blocks, which divide the interior of the housing into upper and lower spaces. The conductive component is placed in the lower space, and the arc-blocking plate is placed in the upper space.

5. An arc-extinguishing chamber for a DC circuit breaker according to claim 4, characterized in that: The arc-blocking plate has guide blocks on both sides, and the housing has corresponding guide grooves that are adapted to the guide blocks.

6. The arc-extinguishing chamber for a DC circuit breaker according to claim 1, characterized in that: The gas generating hood has limiting grooves at both the upper and lower ends, and the iron sheet is inserted into the limiting grooves at both the upper and lower ends.

7. An arc-extinguishing chamber for a DC circuit breaker according to claim 1, characterized in that: The arc-extinguishing grid is provided with comb-like teeth on both the upper and lower surfaces, and a curved space is formed between two adjacent arc-extinguishing grids.

8. A DC circuit breaker employing the arc-extinguishing chamber of a DC circuit breaker as described in any one of claims 1-7, characterized in that: It includes a base and a stationary contact assembly and a moving contact assembly disposed within the base, wherein the moving contact assembly and the stationary contact assembly are provided with the aforementioned arc-extinguishing chamber for a DC circuit breaker.

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