Load switch

Abstract

The utility model relates to the technical field of load switches, and discloses a load switch which comprises a shell, a contact structure arranged on the shell, an arc extinguishing device and an operating mechanism, the contact structure comprises a moving contact and a static contact, insulating sleeves are connected between the moving contact and the shell and between the static contact and the shell, the arc extinguishing device comprises an arc extinguishing chamber, an arc extinguishing sheet and a run-on plate, and the operating mechanism is arranged on the shell. The operating mechanism is used for driving the moving contact and the static contact to be connected or disconnected, a rotating shaft is arranged on the insulating sleeve, the moving contact and the run-on plate are both rotationally connected to the rotating shaft, the run-on plate is connected with the moving contact, the operating mechanism can drive the moving contact to rotate around the rotating shaft, and when the moving contact is connected with the static contact, the run-on plate extends into the arc extinguish chamber. According to the load switch, the run-on plate and the moving contact are jointly and rotationally connected to the rotating shaft, so that the possibility of position deviation between the moving contact and the static contact during closing is reduced, the operating mechanism is not easy to damage, and the service life of the load switch is prolonged.

Description

Technical Field

[0001] This application relates to the technical field of load switches, and in particular to a load switch. Background Technology

[0002] A load switch is a type of switching device that falls between a circuit breaker and a disconnector. It works in conjunction with a fuse to provide short-circuit protection and has a simple arc-extinguishing device. It can safely disconnect the rated load current and a certain multiple of the overload current, making it an important switching device in a power system.

[0003] In related technologies, a load switch includes a housing, a contact structure mounted on the housing, an arc-extinguishing device, and an operating mechanism. The contact structure includes a moving contact and a stationary contact. The arc-extinguishing device includes an arc-extinguishing chamber for containing the electric arc, an arc-extinguishing plate disposed within the arc-extinguishing chamber for generating arc-extinguishing gas, and an arc-initiating plate for guiding the electric arc into the arc-extinguishing chamber. When an electric arc is generated by the moving contact and the stationary contact separating or connecting, the arc-initiating plate first guides the electric arc into the arc-extinguishing chamber. Then, the arc-extinguishing plate generates arc-extinguishing gas at the high temperature of the electric arc to quickly extinguish the arc and reduce the erosion of the moving and stationary contacts by the arc. The operating mechanism includes multiple cooperating rotating shafts and connecting rods to drive the moving contact to connect or disconnect with the stationary contact.

[0004] However, after long-term opening and closing, the operating mechanism of the aforementioned load switch is prone to loosening or wear, causing the moving contact to be misaligned when connected to the stationary contact. This, in turn, leads to further damage to the operating mechanism, resulting in the moving contact being unable to open and close normally with the stationary contact. Consequently, the service life of the load switch is short, and therefore, improvements are needed. Utility Model Content

[0005] In order to extend the service life of load switches, this application provides a load switch.

[0006] The load switch provided in this application adopts the following technical solution:

[0007] A load switch includes a housing, a contact structure disposed on the housing, an arc-extinguishing device, and an operating mechanism. The contact structure includes a moving contact and a stationary contact. An insulating sleeve connects the moving contact and the stationary contact to the housing. The arc-extinguishing device includes an arc-extinguishing chamber for containing an electric arc, an arc-extinguishing plate disposed within the arc-extinguishing chamber for generating arc-extinguishing gas, and an arc-initiating plate for guiding the electric arc into the arc-extinguishing chamber. The operating mechanism is used to drive the moving contact to connect or disconnect with the stationary contact. A rotating shaft is provided on the insulating sleeve. The moving contact is rotatably connected to the rotating shaft. The arc-initiating plate is rotatably connected to the rotating shaft and connected to the moving contact. The operating mechanism can drive the moving contact to rotate around the rotating shaft. When the moving contact is connected to the stationary contact, the arc-initiating plate extends into the arc-extinguishing chamber.

[0008] By adopting the above technical solution, during the closing operation, the operating mechanism drives the moving contact to rotate around the rotating shaft, connecting the moving contact with the stationary contact. Simultaneously, it drives the arc-initiating plate to rotate synchronously around the rotating shaft, extending the arc-initiating plate into the arc-extinguishing chamber. This achieves synchronization between the opening and closing of the moving contact and the action of the arc-initiating plate. The arc-initiating plate moves along a fixed trajectory within the arc-extinguishing chamber, guiding the moving contact. Compared to the moving contact rotating alone, this allows the moving contact to rotate more precisely to the position aligned with the stationary contact. This prevents the moving contact from misaligning with the stationary contact during closing, reducing the risk of damage to the operating mechanism due to misalignment and extending the service life of the load switch. During the opening operation, the arc-initiating plate also moves along a fixed trajectory within the arc-extinguishing chamber, guiding the rotation of the moving contact and making its rotation trajectory and position more stable.

[0009] Meanwhile, the arc-starting plate automatically extends into the arc-extinguishing chamber as the moving contact rotates, directly guiding the arc into the arc-extinguishing area. Compared to a fixed arc-starting plate or a separate drive source driving the arc-starting plate into the arc-extinguishing chamber, this shortens the arc dwell time, improves arc-extinguishing efficiency, and reduces the risk of ablation of the moving and stationary contacts.

[0010] Optionally, the arc-extinguishing chamber is disposed on one side of the stationary contact, the arc-extinguishing chamber is arc-shaped, and the arc-initiating plate includes a movable part rotatably connected to the rotating shaft and an arc-initiating part connected to the movable part. The arc shape of the arc-initiating part is the same as the arc shape of the arc-extinguishing chamber.

[0011] By adopting the above technical solution, when the arc-initiating part moves within the arc-extinguishing chamber, its movement trajectory is arc-shaped. Compared to the arc-initiating part moving along a straight trajectory within the arc-extinguishing chamber, this extends the moving distance of the arc-initiating part. The arc-shaped arc-extinguishing chamber can prolong the residence time of the arc near the arc-extinguishing plate, improving the effect of the arc-extinguishing plate in generating gas arcs and enhancing the arc-extinguishing capability. Simultaneously, it allows the arc-initiating part to guide the moving contact over a longer distance, further improving the stability of the moving contact's rotation trajectory.

[0012] Optionally, the side wall of the arc-extinguishing chamber is provided with an extension at one end near the arc-initiating part. The extension is provided with a guide hole that communicates with the arc-extinguishing chamber. The guide hole is provided with a guide slope on its wall, and the guide slope is inclined toward the direction in which the arc-initiating part extends into the arc-extinguishing chamber.

[0013] By adopting the above technical solution, when the arc-initiating part is about to enter the arc-extinguishing chamber, the guide slope provides a guiding gradient for the arc-initiating part, allowing it to smoothly contact the inner wall of the arc-extinguishing chamber as it rotates into it. This enables the arc-initiating part to enter the arc-extinguishing chamber more smoothly, reducing mechanical friction and the risk of jamming between the arc-initiating part and the inner wall of the arc-extinguishing chamber. In addition, the guide slope can help the arc to be quickly focused to the central area of ​​the arc-extinguishing chamber, avoiding local energy accumulation caused by arc dispersion and improving the reliability of the arc-extinguishing device.

[0014] Optionally, the moving contact includes two opposing conductive plates, and when the moving contact is connected to the stationary contact, the stationary contact is clamped between the two conductive plates.

[0015] By adopting the above technical solution, when the circuit is closed, the stationary contact is clamped between the two conductive plates, which enhances the stability of the connection between the moving and stationary contacts and reduces the possibility of poor contact caused by uneven contact pressure on one side. At the same time, the stationary contact and both conductive plates form current paths, reducing contact resistance and heat loss.

[0016] Optionally, a connecting rod is connected between the two conductive sheets, and a limiting ring is provided at both ends of the connecting rod. The diameter of the limiting ring is larger than the diameter of the connecting rod, and the two limiting rings are respectively located on the side of the two conductive sheets away from each other.

[0017] By adopting the above technical solution, the connecting rod and the limiting ring can prevent the two conductive plates from moving away from each other, reducing the possibility of deformation of the conductive plates due to mechanical vibration during the opening and closing of the moving contact, which is conducive to maintaining a constant distance between the two conductive plates and maintaining a stable contact pressure between the conductive plates and the stationary contact.

[0018] Optionally, a compression spring is connected between the limiting ring and the conductive sheet.

[0019] By adopting the above technical solution, after repeated opening and closing, material wear will occur between the conductive sheet and the stationary contact, causing the distance between the two conductive sheets to increase. This prevents the two conductive sheets from properly clamping the stationary contact. The compression spring can push the conductive sheet closer to the other conductive sheet, thereby shortening the distance between the two conductive sheets and facilitating the clamping of the stationary contact. Simultaneously, the compression spring can also provide elastic compensation when the conductive sheet clamps the stationary contact, automatically adjusting the contact pressure between the conductive sheet and the stationary contact, resulting in good stability of the clamping force. The compression spring can also absorb mechanical shocks during the opening and closing process, reducing vibration of the moving contact and extending the life of the conductive sheet.

[0020] Optionally, the arc-initiating part can be detachably connected to the movable part.

[0021] By adopting the above technical solution, when the arc-starting part undergoes ablation after long-term use, it can be removed from the movable part first, and then a new arc-starting part can be installed on the movable part. This simplifies the arc-starting plate maintenance process, and performance can be restored simply by replacing the arc-starting part, reducing overall operation and maintenance costs. In addition, the detachable design of the arc-starting part facilitates the replacement of arc-starting plates of different materials or shapes (such as copper alloys or high-temperature resistant ceramics) according to the arc energy requirements, improving the adaptability of the arc-extinguishing device.

[0022] Optionally, a fixing bolt connects the arc-drawing part and the movable part.

[0023] By adopting the above technical solution, when it is necessary to fix the arc-initiating part to the movable part, it is only necessary to tighten the fixing bolts on the arc-initiating part and the movable part. The operation is convenient and quick, and the connection between the arc-initiating part and the movable part is highly stable. Furthermore, the installation angle of the arc-initiating plate can be optimized by adjusting the preload of the fixing bolts to adapt to different arc-extinguishing scenarios.

[0024] Optionally, the movable part includes two oppositely arranged movable pieces, with an installation gap formed between the two movable pieces for the insertion of the arc portion.

[0025] By adopting the above technical solution, when the arc-initiating part needs to be installed on the movable part, it can be first inserted into the installation gap, and then the fixing bolts can be tightened onto the two movable plates and the arc-initiating part. Compared with the single-sided connection between the movable part and the arc-initiating part via fixing bolts, the structure of the arc-initiating part being clamped by two movable plates can disperse the mechanical stress of the fixing bolts, reducing the risk of the arc-initiating part breaking due to arc impact. The two movable plates and the installation gap provide space for modular installation of the arc-initiating part, which can be adapted to arc-initiating parts of different thicknesses or shapes, enhancing the flexibility of the arc-extinguishing device.

[0026] Optionally, an adjusting bolt is connected between the two movable plates. A fixed rod is provided on the moving contact. The fixed rod and the adjusting bolt are provided with two opposing connecting plates. The two connecting plates are located between the two movable plates. A roller is rotatably connected to the adjusting bolt. The roller is located between the two connecting plates. An oblong hole is provided on the connecting plate for the adjusting bolt to pass through. The length of the oblong hole is greater than the diameter of the adjusting bolt. When the adjusting bolt slides in the oblong hole, the movable plate moves towards or away from the moving contact.

[0027] By adopting the above technical solution, when there is a machining dimensional error in the length of the arc-initiating part, or when the arc-initiating part is shortened due to long-term use and burning, the adjusting bolt can be loosened first, and then the movable plate can be pushed towards the moving contact, allowing the adjusting bolt to slide in the oblong hole. This reduces the angle between the movable plate and the moving contact, thereby reducing the distance between the arc-initiating part and the moving contact to compensate for the shortened length of the arc-initiating part. Finally, the adjusting bolt can be tightened. When the adjusting bolt is tightened, the connecting plate is pressed against the movable plate and the roller, fixing the positions of the movable plate and the arc-initiating part. Through the above settings, the arc-initiating part can promptly ignite the arc during closing or opening, reducing the possibility that the arc-initiating part is too short to ignite the arc normally, while ensuring that the arc-initiating part can enter the arc-extinguishing chamber in a timely manner to guide the moving contact.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] 1. By mounting the moving contact and the arc-starting plate together on the rotating shaft of the insulating sleeve, synchronous rotation is achieved, reducing mechanical wear and positional deviation caused by multi-axis linkage, significantly extending the life of the operating mechanism, and thus extending the service life of the load switch;

[0030] 2. The arc-shaped structure of the arc-extinguishing chamber and the arc-shaped arc-initiating part of the arc-initiating plate form a matching path, which, together with the guide slope of the extension part, ensures that the electric arc is quickly and accurately introduced into the arc-extinguishing chamber, thereby improving the gas arc extinguishing efficiency;

[0031] 3. The arc-starting part and the moving part are connected by fixing bolts, which facilitates the replacement of worn parts or adapts to different arc-extinguishing requirements, reducing maintenance costs. Attached Figure Description

[0032] Figure 1 This is an overall structural diagram of Embodiment 1 of this application.

[0033] Figure 2 This is a partial structural schematic diagram of the limiting plate used in Embodiment 1 of this application.

[0034] Figure 3 This is a partial structural schematic diagram of the compression spring used in Embodiment 1 of this application.

[0035] Figure 4 This is a partial structural schematic diagram of the adjusting bolt used in Embodiment 2 of this application.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Housing; 2. Contact structure; 21. Moving contact; 212. Conductive sheet; 213. Connecting rod; 214. Limiting ring; 215. Compression spring; 216. Fixing rod; 22. Stationary contact; 3. Arc extinguishing device; 31. Arc extinguishing chamber; 32. Arc ignition plate; 321. Moving part; 322. Arc ignition part; 323. Moving piece; 324. Fixing bolt; 325. Installation gap; 326. Adjusting bolt; 327. Connecting plate; 328. Oblong hole; 329. Roller; 4. Operating mechanism; 5. Insulating sleeve; 51. Rotating shaft; 52. Limiting plate; 6. Extension part; 61. Guide hole; 62. Guide slope. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0039] This application discloses a load switch.

[0040] Example 1

[0041] Reference Figure 1A load switch includes a housing 1, a contact structure 2 disposed on the housing 1, an arc-extinguishing device 3, and an operating mechanism 4. The arc-extinguishing device 3 includes an arc-extinguishing chamber 31 for containing an electric arc, an arc-extinguishing plate disposed within the arc-extinguishing chamber 31 for generating arc-extinguishing gas, and an arc-guiding plate 32 for guiding the electric arc into the arc-extinguishing chamber 31. The contact structure 2 includes a moving contact 21 and a stationary contact 22. Both the moving contact 21 and the stationary contact 22 are connected to the housing 1 by an insulating sleeve 5. A rotating shaft 51 is provided on the insulating sleeve 5. The moving contact 21 and the arc-guiding plate 32 are rotatably connected to the rotating shaft 51, and the arc-guiding plate 32 is fixedly connected to the moving contact 21. The operating mechanism 4 can drive the moving contact 21 to rotate around the rotating shaft 51, so that the moving contact 21 is connected to or disconnected from the stationary contact 22.

[0042] Reference Figure 1 The arc-extinguishing chamber 31 is located on one side of the stationary contact 22. The arc-initiating plate 32 includes a movable part 321 rotatably connected to the rotating shaft 51 and an arc-initiating part 322 connected to the movable part 321. The arc-initiating part 322 is arc-shaped, and the arc shape of the arc-extinguishing chamber 31 is the same as the arc shape of the arc-initiating part 322, so that the arc-initiating part 322 can enter the arc-extinguishing chamber 31. When the arc-initiating part 322 enters the arc-extinguishing chamber 31, it fits against the inner wall of the arc-extinguishing chamber 31. When the moving contact 21 is connected to the stationary contact 22, the arc-initiating plate 32 extends into the arc-extinguishing chamber 31. The diameter of the circle along which the arc-initiating plate 32 rotates along the rotating shaft 51 is larger than the diameter of the circle along which the moving contact 21 rotates along the rotating shaft 51.

[0043] Reference Figure 1 With the above configuration, when the moving contact 21 rotates toward the stationary contact 22, the arc-inducing plate 32 rotates synchronously with the moving contact 21. The arc-inducing plate 32 moves along a fixed trajectory in the arc-extinguishing chamber 31, thereby guiding the moving contact 21, reducing the positional deviation of the moving contact 21, thereby reducing the mechanical wear of the operating mechanism 4 and extending the service life of the load switch.

[0044] Reference Figure 2 The movable part 321 includes two opposing movable plates 323. An arc-inducing part 322 is detachably connected to the two movable plates 323. A fixing bolt 324 connects the arc-inducing part 322 to the two movable plates 323. An installation gap 325 is formed between the two movable plates 323 for the arc-inducing part 322 to extend into. Both movable plates 323 are rotatably connected to a rotating shaft 51. A limiting plate 52 is provided on the rotating shaft 51 to separate the two movable plates 323. In this embodiment, the detachable connection method is preferably a bolt connection. In other cases, other detachable connection methods can be selected according to customer needs. Any method that can connect and disassemble the arc-inducing part 322 and the movable part 321 is acceptable. With the above configuration, after the arc-inducing part 322 has been eroded by electric arc after long-term use, the arc-inducing part 322 can be disassembled separately to replace it with a new one, which is convenient.

[0045] Reference Figure 2 An extension 6 is fixed to one end of the side wall of the arc-extinguishing chamber 31 near the arc-initiating part 322. The width of the extension 6 is greater than the width between the side walls of the arc-extinguishing chamber 31. A guide hole 61 communicating with the arc-extinguishing chamber 31 is provided on the extension 6. A guide slope 62 is provided on the wall of the guide hole 61. The guide slope 62 is inclined in the direction in which the arc-initiating part 322 extends into the arc-extinguishing chamber 31. During the process of the arc-initiating part 322 entering the arc-extinguishing chamber 31, the guide slope 62 can guide the arc-initiating part 322 to make smooth contact with the inner wall of the arc-extinguishing chamber 31, so that the arc-initiating part 322 accurately enters the arc-extinguishing chamber 31 and is less likely to rub against or get stuck with the inner wall of the arc-extinguishing chamber 31.

[0046] Reference Figure 2 and Figure 3 The moving contact 21 includes two opposing conductive plates 212, both rotatably mounted on a rotating shaft 51. A connecting rod 213 connects the two conductive plates 212, with limit rings 214 fixed at both ends of the connecting rod 213. The diameter of the limit rings 214 is larger than the diameter of the connecting rod 213, and the two limit rings 214 are located on the side of the two conductive plates 212 furthest from each other. A compression spring 215 connects the limit rings 214 and the conductive plates 212, passing through the connecting rod 213. The conductive plates 212 are positioned between the limit plate 52 and the moving plate 323, so the limit plate 52 can also separate the two conductive plates 212. When the circuit is closed, the moving contact 21 connects with the stationary contact 22, and the stationary contact 22 is clamped between the two conductive plates 212.

[0047] Reference Figure 2 and Figure 3 With the above settings, when the moving contact 21 is connected to the stationary contact 22, the stationary contact 22 is clamped between the two conductive plates 212, making the connection between the moving contact 21 and the stationary contact 22 more stable, and the compression spring 215 can push the conductive plate 212 closer to the other conductive plate 212, so that the clamping effect of the two conductive plates 212 on the stationary contact 22 is good.

[0048] The implementation principle of a load switch according to an embodiment of this application is as follows: When closing or opening, the arc-initiating plate 32 rotates synchronously with the moving contact 21 around the rotating shaft 51, so that the arc-initiating plate 32 enters or exits the arc-extinguishing chamber 31 along a fixed trajectory. This reduces the positional deviation between the moving contact 21 and the stationary contact 22 during closing and opening, reduces the risk of damage to the operating mechanism 4 due to misalignment of the moving contact 21 and the stationary contact 22, and extends the service life of the load switch. At the same time, the synchronous entry or exit of the arc-initiating plate 32 into or out of the arc-extinguishing chamber 31 reduces the risk of burn-out of the stationary contact 22 or the moving contact 21 due to the delay of the arc-initiating plate 32.

[0049] Example 2

[0050] Reference Figure 4 The difference between this embodiment and Embodiment 1 is that: an adjusting bolt 326 connects the two movable pieces 323, a fixing rod 216 is provided on the moving contact 21, and two opposing connecting plates 327 are provided on the fixing rod 216 and the adjusting bolt 326. The connecting plates 327 are rotatably connected to the fixing rod 216 and the adjusting bolt 326, and the two connecting plates 327 are located between the two movable pieces 323. A roller 329 is rotatably connected to the adjusting bolt 326. The part where the adjusting bolt 326 and the roller 329 are connected is not threaded. The roller 329 is located between the two connecting plates 327. When the adjusting bolt 326 is tightened, the connecting plate 327 is pressed against the movable piece 323 and the roller 329, so that the position of the movable piece 323 is fixed.

[0051] Reference Figure 4 The connecting plate 327 has a waist-shaped hole 328 for the adjusting bolt 326 to pass through. The length of the waist-shaped hole 328 is greater than the diameter of the adjusting bolt 326. When the adjusting bolt 326 slides in the waist-shaped hole 328, the movable piece 323 moves towards or away from the moving contact 21.

[0052] The implementation principle of a load switch in this application embodiment is as follows: When the arc-initiating part 322 is too short due to machining dimensional errors or long-term arc erosion, the adjusting bolt 326 can be loosened first, and then the movable piece 323 can be pushed towards the moving contact 21, so that the adjusting bolt 326 moves towards the fixed rod 216 until the distance between the arc-initiating part 322 and the moving contact 21 is short enough. This reduces the risk of arc ignition not being possible in time due to the arc-initiating part 322 being too short, and at the same time ensures that the arc-initiating part 322 can enter the arc-extinguishing chamber 31 in time to guide the moving contact 21.

[0053] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A load switch, comprising a housing (1), a contact structure (2) disposed on the housing (1), an arc-extinguishing device (3), and an operating mechanism (4), wherein the contact structure (2) comprises a moving contact (21) and a stationary contact (22), and an insulating sleeve (5) is connected between the moving contact (21), the stationary contact (22), and the housing (1); the arc-extinguishing device (3) comprises an arc-extinguishing chamber (31) for containing an electric arc, an arc-extinguishing plate disposed in the arc-extinguishing chamber (31) for generating arc-extinguishing gas, and an arc-guiding plate (32) for guiding the electric arc to the arc-extinguishing chamber (31); and the operating mechanism (4) is used to drive the moving contact (21) to connect or disconnect from the stationary contact (22), characterized in that: The insulating sleeve (5) is provided with a rotating shaft (51), the moving contact (21) is rotatably connected to the rotating shaft (51), the arc-inducing plate (32) is rotatably connected to the rotating shaft (51), the arc-inducing plate (32) is connected to the moving contact (21), the operating mechanism (4) can drive the moving contact (21) to rotate around the rotating shaft (51), when the moving contact (21) is connected to the stationary contact (22), the arc-inducing plate (32) extends into the arc-extinguishing chamber (31).

2. A load switch according to claim 1, characterized in that: The arc-extinguishing chamber (31) is located on one side of the stationary contact (22). The arc-extinguishing chamber (31) is arc-shaped. The arc-inducing plate (32) includes a movable part (321) rotatably connected to the rotating shaft (51) and an arc-inducing part (322) connected to the movable part (321). The arc shape of the arc-inducing part (322) is the same as the arc shape of the arc-extinguishing chamber (31).

3. A load switch according to claim 2, characterized in that: The side wall of the arc-extinguishing chamber (31) is provided with an extension (6) at one end near the arc-initiating part (322). The extension (6) is provided with a guide hole (61) communicating with the arc-extinguishing chamber (31). The guide hole (61) is provided with a guide slope (62) on its wall. The guide slope (62) is inclined in the direction in which the arc-initiating part (322) extends into the arc-extinguishing chamber (31).

4. A load switch according to claim 1, characterized in that: The moving contact (21) includes two opposing conductive plates (212). When the moving contact (21) is connected to the stationary contact (22), the stationary contact (22) is held between the two conductive plates (212).

5. A load switch according to claim 4, characterized in that: A connecting rod (213) is connected between the two conductive sheets (212). The connecting rod (213) has a limiting ring (214) at both ends. The diameter of the limiting ring (214) is larger than the diameter of the connecting rod (213). The two limiting rings (214) are respectively located on the side of the two conductive sheets (212) away from each other.

6. A load switch according to claim 5, characterized in that: A compression spring (215) is connected between the limiting ring (214) and the conductive sheet (212).

7. A load switch according to claim 2, characterized in that: The arc-drawing part (322) is detachably connected to the movable part (321).

8. A load switch according to claim 7, characterized in that: A fixing bolt (324) connects the arc-drawing part (322) and the movable part (321).

9. A load switch according to claim 7, characterized in that: The movable part (321) includes two oppositely arranged movable pieces (323), and an installation gap (325) is formed between the two movable pieces (323) for the insertion of the arc part (322).

10. A load switch according to claim 9, characterized in that: An adjusting bolt (326) is connected between the two movable plates (323). A fixed rod (216) is provided on the moving contact (21). The fixed rod (216) and the adjusting bolt (326) are provided with two opposing connecting plates (327). The two connecting plates (327) are located between the two movable plates (323). A roller (329) is rotatably connected to the adjusting bolt (326). The roller (329) is located between the two connecting plates (327). A waist-shaped hole (328) is provided on the connecting plate (327) for the adjusting bolt (326) to pass through. The length of the waist-shaped hole (328) is greater than the diameter of the adjusting bolt (326). When the adjusting bolt (326) slides in the waist-shaped hole (328), the movable plate (323) moves towards or away from the moving contact (21).

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