Contact arc extinguishing mechanism in circuit breaker

Abstract

The utility model relates to the technical field of low-voltage electric appliance manufacturing, in particular to a contact arc extinguishing mechanism in a circuit breaker, which comprises an arc extinguishing structure, a static contact is arranged in the arc extinguishing structure, a movable contact capable of rotating is arranged in the arc extinguishing structure, the static contact and the movable contact can be contacted or separated, and the arc extinguishing structure comprises an arc extinguishing cavity and a protective cover. Arc isolating walls are arranged on two sides of the arc extinguishing cavity; an arc extinguishing grid plate A, an arc extinguishing grid plate B, an arc extinguishing grid plate C and an arc extinguishing grid plate D are arranged between the two arc isolating walls; the protective cover comprises a separator plate A arranged on the static contact, two sides of the separator plate A are provided with separator plates B, one side of each separator plate B is provided with a separator plate C, and the separator plate C and the upper surface of the separator plate A are fixed. Compared with the prior art, the contact arc extinguishing mechanism in the circuit breaker has a better air blowing effect through the good arrangement of the protective cover and the flash barrier, and through the good arrangement of the arc extinguishing grid sheets, the arc is better pulled in the early stage of breaking and better enters the arc extinguishing cavity in the later stage of breaking.

Description

Technical Field

[0001] This utility model relates to the field of low-voltage electrical appliance manufacturing technology, specifically to the contact arc extinguishing mechanism in a circuit breaker. Background Technology

[0002] A circuit breaker is an electrical product that automatically disconnects power supply for protection under overload and short-circuit conditions. With the continuous development of power systems, higher requirements are placed on the breaking capacity of circuit breakers. Low-voltage circuit breakers mainly utilize the deionization effect of arc-extinguishing plates to enhance the dielectric recovery strength, extinguish the arc, and prevent reignition. To achieve better arc-extinguishing capability, common methods include: 1. Increasing the opening distance between the moving and stationary contacts to lengthen the arc; 2. Increasing the number of arc-extinguishing plates. These methods inevitably lead to an increase in the size of the circuit breaker, hindering its miniaturization. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this utility model provides a contact arc-extinguishing mechanism for circuit breakers, which features small size and good arc-extinguishing performance.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution: a contact arc extinguishing mechanism in a circuit breaker, including an arc extinguishing structure, wherein a stationary contact is provided in the arc extinguishing structure, and a rotatable moving contact is provided in the arc extinguishing structure, wherein the stationary contact and the moving contact can perform contact or separation operations, and the arc extinguishing structure includes an arc extinguishing cavity and a protective cover.

[0007] Both sides of the arc-extinguishing cavity are provided with arc-blocking walls, and between the two arc-blocking walls are arc-extinguishing grid plates A, B, C and D.

[0008] The arc-extinguishing grid plate B has an inclined surface A and an inclined surface B. The connection between the inclined surface A and the inclined surface B has a notch A. The notch A is biased towards one side of the arc-extinguishing grid plate B. The arc-extinguishing grid plates B are arranged alternately according to the position of the notch A. The projection of the notch A on the plane of the arc-extinguishing grid plate A is located inside the arc-extinguishing grid plate A.

[0009] The arc-extinguishing grid plate C has a notch B at the middle position in the lateral direction;

[0010] The arc-extinguishing grid plate D has a movable arc-inducing plate extending outward from the middle position in the lateral direction. When the movable contact is in the open position, one end of the movable arc-inducing plate is close to the movable contact.

[0011] The protective cover includes a partition A disposed on the stationary contact. The partition A is arranged in a horizontal direction. Partitions B are provided on both sides of the partition A. The partitions B are arranged in a vertical direction. A partition C is provided on one side of the partition B. The partition C is fixed to the upper surface of the partition A.

[0012] Furthermore, the arc-extinguishing structure also includes an arc-blocking plate, which has a plurality of elongated holes. There are gaps between the arc-extinguishing grid plates A, B, C, and D, and the gaps correspond one-to-one with the elongated holes.

[0013] Furthermore, the overlapping area of ​​the cross section near the arc-blocking plate in the gap with the elongated hole increases sequentially from bottom to top.

[0014] Furthermore, the stationary contact is also provided with a stationary arc-inducing plate, one end of which is located below the arc-extinguishing grid plate A.

[0015] Furthermore, a number of magnetic conductive sheets are provided below the stationary contact.

[0016] Furthermore, between the two arc-extinguishing walls, from bottom to top, are arranged arc-extinguishing grid plates A, a number of arc-extinguishing grid plates B, a number of arc-extinguishing grid plates C, and arc-extinguishing grid plates D; the two partition plates B are symmetrically distributed in partition plate A, and the partition plate C is provided with a groove for the moving contact to rotate; the partition plates A, B, and C are perpendicular to each other.

[0017] Furthermore, the number of arc-extinguishing grid plates B is four, and the number of arc-extinguishing grid plates C is five.

[0018] When a short-circuit fault current flows through the circuit breaker, the stationary contact and the moving contact change from contact to separation, and an electric arc is generated between the stationary contact and the moving contact. The electric arc goes through the following three steps from generation to extinction:

[0019] Step 1: When the moving contact has just opened;

[0020] The current flows in opposite directions in the stationary and moving contacts, and the arc moves toward the arc-extinguishing cavity under the action of the Lorentz magnetic force; the heat generated by the arc causes the surrounding air to expand, and most of the expanded air moves toward the arc-extinguishing cavity through the obstruction of partitions A, B and C; the high temperature generated by the arc causes the protective cover to decompose into molecular gas, which cools the arc and reduces the arc diameter.

[0021] Step 2: When the moving contact rotates to the vicinity of arc-extinguishing grid plate B;

[0022] The current flows in opposite directions between the stationary and moving contacts. Partitions A, B, and C continuously block the expanding air, and the protective cover continuously releases molecular gas. Under the influence of Lorentz magnetic force and the blowing of expanding air, the lower arc moves to the stationary arc-initiating plate and flows through the arc-extinguishing grid plate A. Due to the notch A on the arc-extinguishing grid plate B, the upper arc flows from one notch A to the adjacent notch A, resulting in a zigzag arc current flow. The arc is greatly elongated, and the arc current is further suppressed. Due to the obstruction of the arc-blocking plate, the lower end of the arc-blocking plate has insufficient air output, and the expanding air begins to move upward.

[0023] Step 3: The moving contact is fully opened;

[0024] After the moving contact rotates to the vicinity of the moving arc-initiating plate, the current flow directions of the stationary and moving contacts remain opposite. The partitions A, B, C, and the arc-blocking plate continue to block the expanding air, and the protective cover continues to decompose and release molecular gas. Under the action of Lorentz magnetic force and the blowing of expanding air, the lower section of the arc flows through the arc-extinguishing grid A and the arc-extinguishing grid B; the upper section of the arc moves to the moving arc-initiating plate; under the blowing of expanding air, the middle section of the arc moves into the notch B and finally enters the arc-extinguishing grid C.

[0025] In this plan Figures 10 to 13 The dashed lines in the diagram represent the direction of current and arc.

[0026] Compared with existing technologies, the contact arc-extinguishing mechanism in this circuit breaker has the following advantages: 1. The well-designed protective cover and arc-blocking plate provide better air blowing effect; 2. The well-designed arc-extinguishing grid plate better pulls the arc in the initial stage of breaking and allows the arc to enter the arc-extinguishing chamber better in the later stage of breaking; 3. The well-designed protective cover prevents arc reignition caused by short circuit between moving and stationary contacts; 4. The structure is compact and does not increase the size of conventional circuit breakers. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the external structure of the contact arc extinguishing system of this utility model;

[0028] Figure 2 This utility model Figure 1 A schematic diagram of the split structure;

[0029] Figure 3 This utility model Figure 1 Schematic diagram of the cross-sectional structure in the middle;

[0030] Figure 4 This is a schematic diagram of the arc-extinguishing cavity of this utility model;

[0031] Figure 5 This is a schematic diagram of the structure of the arc-extinguishing grid plate A of this utility model;

[0032] Figure 6This is a schematic diagram of the structure of the arc-extinguishing grid plate B of this utility model;

[0033] Figure 7 This is a schematic diagram of the arc-extinguishing grid plate C of this utility model;

[0034] Figure 8 This is a schematic diagram of the structure of the arc-extinguishing grid plate D of this utility model;

[0035] Figure 9 This is a schematic diagram of the circuit breaker of this utility model when it is closed;

[0036] Figure 10 This is a schematic diagram of the circuit breaker of this utility model when the moving contact has just opened;

[0037] Figure 11 This is a schematic diagram of the circuit breaker of this utility model when the moving contact rotates to the vicinity of the arc-extinguishing grid plate B;

[0038] Figure 12 This is a schematic diagram of the arc-extinguishing cavity current and arc direction of the circuit breaker of this utility model when the moving contact rotates to the vicinity of the arc-extinguishing grid plate B;

[0039] Figure 13 This is a schematic diagram of the circuit breaker of this utility model when the moving contact is fully open.

[0040] In the diagram: 1. Arc extinguishing structure; 2. Stationary contact; 3. Moving contact; 4. Arc extinguishing cavity; 41. Arc quenching wall; 42. Arc extinguishing grid A; 43. Arc extinguishing grid B; 431. Inclined surface A; 432. Inclined surface B; 433. Notch A; 44. Arc extinguishing grid C; 441. Notch B; 45. Arc extinguishing grid D; 451. Moving arc-inducing plate; 46. Gap; 5. Protective cover; 51. Partition A; 52. Partition B; 53. Partition C; 54. Groove; 6. Arc quenching plate; 61. Long slot; 7. Stationary arc-inducing plate; 8. Magnetic conductive plate. Detailed Implementation

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0042] Please see Figure 1 This utility model provides a technical solution: the contact arc extinguishing mechanism in the circuit breaker includes an arc extinguishing structure 1, a stationary contact 2 inside the arc extinguishing structure 1, and a rotatable moving contact 3 inside the arc extinguishing structure 1. The stationary contact 2 and the moving contact 3 can make or break contact. The arc extinguishing structure 1 includes an arc extinguishing cavity 4 and a protective cover 5.

[0043] like Figure 1When the circuit breaker is closed, the moving contact 3 and the stationary contact 2 are in contact; when the circuit breaker is opened, the moving contact 3 and the stationary contact 2 are separated.

[0044] The arc-extinguishing cavity 4 is provided with arc-blocking walls 41 on both sides. Between the two arc-blocking walls 41, there are arc-extinguishing grid plates A42, B43, C44 and D45. Between the two arc-blocking walls 41, from bottom to top, there are arc-extinguishing grid plates A42, a number of arc-extinguishing grid plates B43, a number of arc-extinguishing grid plates C44 and D45. There are four arc-extinguishing grid plates B43 and five arc-extinguishing grid plates C44.

[0045] The arc-extinguishing grid plate B43 has inclined surfaces A431 and B432. At the connection between inclined surfaces A431 and B432, there is a notch A433. The notch A433 is biased to one side of the arc-extinguishing grid plate B43. The arc-extinguishing grid plates B43 are arranged alternately according to the position of the notch A433. The projection of the notch A433 on the plane of the arc-extinguishing grid plate A42 is located within the arc-extinguishing grid plate A42.

[0046] like Figures 2-3 The arc-extinguishing cavity 4 includes arc-isolating walls 41 on both sides for fixing and insulation. Between the arc-isolating walls 41, arc-extinguishing grid plates A42, a number of arc-extinguishing grid plates B43, a number of arc-extinguishing grid plates C44, and an arc-extinguishing grid plate D45 are evenly arranged from bottom to top. Arc-extinguishing grid plate A42 has no notches. Arc-extinguishing grid plate B43 has inclined surfaces A431 and B432, with a notch A433 between them. The notch A433 is biased towards one side of the arc-extinguishing grid plate B43, and the arc-extinguishing grid plates B43 are arranged alternately according to the position of the notch A433. In this way, when the circuit breaker trips, the arc does not enter the arc-extinguishing cavity 4 directly in a straight line, but connects between the notches A433, entering the arc-extinguishing cavity 4 in a zigzag manner. This elongates the arc, limits the current, and facilitates arc extinguishing. The projection of the notch A433 onto the plane of the arc-extinguishing grid A42 is located within the arc-extinguishing grid A42. This ensures that the arc flows through the arc-extinguishing grid A42 first, which is beneficial for the arc to flow through each notch A433.

[0047] The arc-extinguishing grid C44 has a notch B441 at the middle position in the transverse direction.

[0048] The notch B441 is arranged in the middle position, which is conducive to the arc smoothly entering the arc extinguishing grid plates on the arc extinguishing chamber 4 in the later stage of the break, thus ensuring the effective utilization rate of the arc extinguishing grid plates.

[0049] The arc-extinguishing grid plate D45 has a moving arc-leading plate 451 extending outward from the middle of the transverse direction. When the moving contact 3 is in the open position, one end of the moving arc-leading plate 451 is close to the moving contact 3.

[0050] When the moving contact 3 is in the open position, one end of the moving arc ignition piece 451 is close to the moving contact 3, so that the arc can jump smoothly to the top of the arc extinguishing cavity 4.

[0051] The protective cover 5 includes a partition A51 disposed on the stationary contact 2. The partition A51 is arranged in a horizontal direction. Partitions B52 are provided on both sides of the partition A51. The two partitions B52 are symmetrically distributed in the partition A51. The partitions B52 are arranged in a vertical direction. A partition C53 is provided on one side of the partition B52. The partition C53 is fixed to the upper surface of the partition A51. The partition C53 is provided with a groove 54 that allows the moving contact 3 to rotate. The partitions A51, B52 and C53 are perpendicular to each other.

[0052] like Figure 1 The protective cover 5 includes a horizontal partition A51, a vertical partition B52, and a partition C53, all perpendicular to each other. Partition C53 has a groove 54 for the rotation of the moving contact 3. Partition A51 prevents a short circuit caused by back-to-back breakdown between the moving contact 3 and the stationary contact 2, while partition B52 prevents side arcing. Simultaneously, the three partitions cooperate to form a semi-enclosed cavity, allowing expanding air to blow forward and upward.

[0053] like Figure 1 The arc-extinguishing structure 1 also includes an arc-blocking plate 6, which has a plurality of elongated holes 61. There are gaps 46 between the arc-extinguishing grid plates A42, B43, C44 and D45. The gaps 46 correspond one-to-one with the elongated holes 61. The overlapping area of ​​the cross section of the gap 46 near the arc-blocking plate 6 and the elongated holes 61 increases from bottom to top.

[0054] This ensures that the air outlet on the lower side of the arc-extinguishing chamber 4 is resisted, so that the expanded air maintains a certain pressure in the arc-extinguishing chamber and the air is discharged upward.

[0055] The stationary contact 2 is also provided with a stationary arc-inducing plate 7, one end of which is located below the arc-extinguishing grid plate A42.

[0056] This moves the arc to the stationary arc-starting plate 7, reducing the burning of the stationary contact by the arc.

[0057] Several magnetic plates 8 are also provided below the stationary contact 2.

[0058] This increases the magnetic induction intensity inside the arc-extinguishing cavity, allowing the electric arc to move to the arc-extinguishing cavity 4 more quickly.

[0059] When a short-circuit fault current flows through the circuit breaker, the stationary contact 2 and the moving contact 3 change from contact to separation, and an electric arc is generated between the stationary contact 2 and the moving contact 3. The electric arc goes through the following three steps from generation to extinction:

[0060] Step 1: When the moving contact 3 has just opened;

[0061] like Figure 1 and Figure 10 As shown, the current flows in opposite directions in the stationary contact 2 and the moving contact 3. Under the action of the Lorentz magnetic force, the electric arc moves towards the arc-extinguishing cavity 4. The heat generated by the electric arc causes the surrounding air to expand. Through the obstruction of the partitions A51, B52 and C53, most of the expanded air moves towards the arc-extinguishing cavity 4. The high temperature generated by the electric arc causes the protective cover 5 to decompose into molecular gas, which cools the electric arc and reduces the diameter of the electric arc.

[0062] Step 2: When the moving contact 3 rotates to the vicinity of the arc-extinguishing grid plate B43;

[0063] like Figure 1 , Figure 11 and Figure 12 As shown, the current flows in opposite directions in stationary contact 2 and moving contact 3. Partitions A51, B52, and C53 continuously block the expanding air, and the protective cover 5 continuously releases molecular gas. Under the influence of Lorentz magnetic force and the blowing of expanding air, the lower arc moves to the stationary arc-initiating plate 7 and flows through the arc-extinguishing grid plate A42. Due to the notch A433 on the arc-extinguishing grid plate B43, the upper arc flows from one notch A433 to another adjacent notch A433, resulting in a zigzag flow of the arc current. The arc is greatly elongated, and the arc current is further suppressed. Due to the obstruction of the arc-blocking plate 6, the lower end of the arc-blocking plate 6 has insufficient air output, and the expanding air begins to move upwards.

[0064] Step 3: The moving contact 3 is fully opened;

[0065] like Figure 1 and Figure 13 As shown, after the moving contact 3 rotates to the vicinity of the moving arc-initiating plate 451, the current flow directions of the stationary contact 2 and the moving contact 3 are still opposite. The partitions A51, B52, C53 and the arc-extinguishing plate 6 continue to block the expanding air, and the protective cover 5 continues to decompose and release molecular gas. Under the action of Lorentz magnetic force and the blowing of expanding air, the lower section of the arc flows through the arc-extinguishing grid A42 and the arc-extinguishing grid B43; the upper section of the arc moves to the moving arc-initiating plate 451; under the blowing of expanding air, the middle section of the arc moves to the notch B441 and finally enters the arc-extinguishing grid C44.

[0066] All electrical components mentioned in this article are connected to an external main controller and 380V commercial power supply, and the main controller can be a conventional known device such as a computer that can control it.

[0067] In the description of this specification, the terms "connection", "installation", "fixing", "setting", etc. are interpreted in a broad sense. For example, "connection" can be a fixed connection or an indirect connection through an intermediate component without affecting the relationship between components and the technical effect. It can also be an integral connection or a partial connection. In such cases, those skilled in the art can understand the specific meaning of the above terms in this utility model or utility model according to the specific circumstances.

[0068] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A contact arc-extinguishing mechanism in a circuit breaker, characterized in that: The system includes an arc-extinguishing structure (1), which has a stationary contact (2) and a rotatable moving contact (3). The stationary contact (2) and the moving contact (3) can make or break contact. The arc-extinguishing structure (1) includes an arc-extinguishing cavity (4) and a protective cover (5). The arc-extinguishing cavity (4) is provided with arc-blocking walls (41) on both sides, and arc-extinguishing grid plates A (42), B (43), C (44) and D (45) are provided between the two arc-blocking walls (41). The protective cover (5) includes a partition A (51) disposed on the stationary contact (2), with partitions B (52) on both sides of the partition A (51), and a partition C (53) on one side of the partition B (52), and the partition C (53) is fixed to the upper surface of the partition A (51).

2. The contact arc-extinguishing mechanism in the circuit breaker according to claim 1, characterized in that: The arc-extinguishing grid plate B (43) is provided with inclined surface A (431) and inclined surface B (432), and a notch A (433) is provided at the connection between the inclined surface A (431) and the inclined surface B (432). The arc-extinguishing grid plate C (44) has a notch B (441) at the middle position in the lateral direction. The arc-extinguishing grid plate D (45) has a movable arc-inducing plate (451) extending outward from the middle position in the lateral direction. One end of the movable arc-inducing plate (451) can approach the movable contact (3).

3. The contact arc-extinguishing mechanism in the circuit breaker according to claim 2, characterized in that: The notch A (433) is biased to one side of the arc extinguishing grid plate B (43), and the arc extinguishing grid plates B (43) are arranged alternately according to the position of the notch A (433). The projection of the notch A (433) on the plane of the arc extinguishing grid plate A (42) is located within the arc extinguishing grid plate A (42).

4. The contact arc-extinguishing mechanism in the circuit breaker according to claim 1, characterized in that: The arc extinguishing structure (1) also includes an arc-blocking plate (6), which has a plurality of elongated holes (61). There are gaps (46) between the arc-extinguishing grid plates A (42), B (43), C (44), and D (45). The gaps (46) correspond one-to-one with the elongated holes (61). The overlapping area of ​​the cross section of the gap (46) near the arc-blocking plate (6) on the arc-blocking plate (6) and the elongated holes (61) increases from bottom to top.

5. The contact arc-extinguishing mechanism in the circuit breaker according to claim 1, characterized in that: The stationary contact (2) is also provided with a stationary arc-drawing plate (7), one end of which is located below the arc-extinguishing grid plate A (42).

6. The contact arc-extinguishing mechanism in the circuit breaker according to claim 1, characterized in that: Below the stationary contact (2) are also provided a number of magnetic plates (8).

7. The contact arc-extinguishing mechanism in the circuit breaker according to claim 1, characterized in that: Between the two arc-extinguishing walls (41), arc-extinguishing grid plates A (42), a number of arc-extinguishing grid plates B (43), a number of arc-extinguishing grid plates C (44) and arc-extinguishing grid plates D (45) are arranged sequentially from bottom to top; the two partition plates B (52) are symmetrically distributed in the partition plate A (51), and the partition plate C (53) is provided with a groove (54) for the moving contact (3) to rotate. The partition plates A (51), B (52) and C (53) are perpendicular to each other.

8. The contact arc-extinguishing mechanism in the circuit breaker according to claim 1, characterized in that: The partition A (51) is arranged in the horizontal direction, and the partition B (52) is arranged in the vertical direction.

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