A circuit breaker operating mechanism with short circuit trip

Abstract

The utility model relates to a circuit breaker operating mechanism with short-circuit tripping, belonging to low-voltage electric appliance technical field. Including drive link assembly, movable contact assembly, static contact assembly, energy storage assembly and lock catch device, one end of drive link assembly is hinged with energy storage assembly, the other end is hinged with movable contact assembly through connecting rod, when circuit breaker receives closing signal, energy storage assembly releases energy and drives drive link assembly to act, drive link assembly drives movable contact assembly to move to static contact assembly through connecting rod, drive link assembly includes jump catch spare that contacts with lock catch device, rotatory setting pivot spare, when movable contact assembly and static contact assembly just contact, the included angle between connecting rod and pivot spare is theta 1, when closing position, the included angle between connecting rod and pivot spare is theta 2, the proportional relationship of included angle theta 1 and included angle theta 2 is 0.8 < (sin theta 1 / sin theta 2) <1.5. Advantage: reduced the short-circuit current needed for circuit breaker operating mechanism unlocking, makes operating mechanism have faster corresponding speed.

Description

Technical Field

[0001] This utility model belongs to the field of low-voltage electrical appliance technology, specifically relating to a circuit breaker operating mechanism with short-circuit trip capability. Background Technology

[0002] Universal circuit breakers, commonly used for circuit protection, typically consist of a contact system and a mechanism. To ensure rapid and reliable arc extinguishing, thereby safely interrupting short-circuit currents of tens or even hundreds of thousands of amperes and protecting the entire power distribution system and equipment, circuit breakers require significant electrodynamic force and short-circuit capacity. This necessitates a sufficiently fast unlocking mechanism to open the contacts. However, the current electronic trip units of circuit breakers are not fast enough in terms of speed from current detection to response and contact opening. Here, electrodynamic force mainly refers to the mechanical force provided by the circuit breaker's operating mechanism during closing and opening, as well as the electrodynamic repulsion generated by the contact system when a large current passes through it. Short-circuit capacity typically refers to the circuit breaker's rated short-circuit breaking capacity, representing the maximum short-circuit current that the circuit breaker can safely interrupt.

[0003] Addressing the need for quick-release mechanisms, the "Short-Circuit Breaker Operating Mechanism with a Locking Device that Can Be Released During a Short Circuit" described in Chinese Invention Patent Publication No. CN1082711C involves setting a mechanism disintegration device on a transmission component that cooperates with a traction rod. This disintegration device has a flexible element that determines a calibration threshold. When the short-circuit current is lower than this threshold, the electrodynamic force transmitted from the contacts is insufficient to overcome the force provided by the flexible element in the disintegration device, and the disintegration device does not operate. When the short-circuit current is higher than this threshold, the disintegration device operates to unlock the mechanism.

[0004] During the closing operation of a circuit breaker, when the moving and stationary contacts collide, a collision force is generated between the contacts, which is in the same direction as the electrodynamic force and is 3 to 5 times the normal contact force. To ensure the reliability of the circuit breaker's normal closing operation, the disintegration device must be correctly set. The disintegration threshold force it provides is generally set to be greater than the peak value of the contact collision force and must ensure a certain margin. This design brings a critical systemic trade-off: when a short-circuit fault occurs and the circuit breaker needs to disconnect, the short-circuit current at the contacts needs to provide a greater electrodynamic force to overcome the greater threshold force provided by the flexible components in the disintegration device before the disconnection movement can begin. The direct consequence of this is that it raises the disconnection threshold, greatly increases the short-circuit capacity required for the circuit breaker to disconnect, and easily leads to disconnection risks. In some critical situations, if the electrodynamic force provided by the short-circuit current is insufficient to overcome this increased threshold force, it will lead to a delayed or complete failure of the disconnection action, failing to disconnect the fault in time, thereby endangering the safety of the power system.

[0005] To address the need to reduce threshold short-circuit current, the "Electromagnetic Relay with Improved Magnetic Circuit Mechanism" mentioned in Chinese Invention Patent Publication No. CN1168114C adds an electromagnetic compensation device after the stationary contact. This electromagnetic compensation device requires the stationary contact portion to be designed with a "U" shape to increase the electrodynamic force of the stationary contact portion on the moving contact portion, thereby overcoming the force provided by the flexible component in the disintegration device and enabling the disintegration device to unlock. The aforementioned "U"-shaped magnetizing compensation device for the stationary contact portion requires a conductive circuit parallel to the moving guide rod and with a length not less than the length of the moving guide rod. This magnetizing compensation device not only occupies circuit breaker space but also increases the length of the circuit breaker's conductive circuit, which is not only detrimental to the circuit breaker's temperature rise design but also increases the difficulty of component processing and contact insulation design.

[0006] In view of the aforementioned existing technology, the applicant has made beneficial designs, and the technical solutions to be introduced below are produced in this context. Utility Model Content

[0007] The purpose of this utility model is to provide a circuit breaker operating mechanism with short-circuit trip capability, which can quickly unlock and trip when there is a fault with a large current.

[0008] The purpose of this utility model is achieved as follows: a circuit breaker operating mechanism with short-circuit trip capability includes a drive linkage assembly, a moving contact assembly, a stationary contact assembly, an energy storage assembly, and a locking device. One end of the drive linkage assembly is hinged to the energy storage assembly, and the other end is hinged to the moving contact assembly via a connecting rod. When the circuit breaker receives a closing signal, the energy storage assembly releases energy, driving the drive linkage assembly to move. The drive linkage assembly drives the moving contact assembly towards the stationary contact assembly via the connecting rod. The drive linkage assembly includes a trip fastener that contacts and cooperates with the locking device, a rotatable shaft, and a first connecting rod and a second connecting rod respectively connected between the trip fastener and the shaft. When the moving contact assembly and the stationary contact assembly just come into contact, the angle between the connecting rod and the shaft is θ1. In the closed position, the angle between the connecting rod and the shaft is θ2. The ratio of angles θ1 and θ2 is 0.8 < (sinθ1 / sinθ2) < 1.5.

[0009] In a specific embodiment of this utility model, the locking device includes a hinge shaft, a locking member and a side plate member that are hinged together on the hinge shaft and can move relative to each other. A reset member is provided between the locking member and the side plate member. When the electrodynamic force transmitted at the moving and stationary contacts overcomes the force of the reset member, the locking member and the side plate member move relative to each other, and the locking device unlocks.

[0010] In another specific embodiment of this utility model, the reset element is a spring.

[0011] In another specific embodiment of this utility model, the moving contact assembly includes a contact support, a moving guide rod, and a contact spring. The moving guide rod is hinged to the contact support, and the contact spring is disposed between the contact support and the moving guide rod.

[0012] Due to the adoption of the above-mentioned structure, this utility model has the following advantages compared with the prior art: it reduces the short-circuit current required for the circuit breaker operating mechanism to unlock, enables the operating mechanism to have a faster response speed, can significantly improve the time required for the operating mechanism to perform the tripping action, and can promptly cut off the fault, thereby ensuring the safety of the power system. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the structure of the operating mechanism of this utility model when it is in the open state;

[0015] Figure 3 This is a schematic diagram of the structure of the operating mechanism of this utility model when it is in the fully engaged state;

[0016] Figure 4 This is a schematic diagram of the structure of the operating mechanism of this utility model when it is in the closed state;

[0017] Figure 5 This is a schematic diagram of an insulating device installed on the connecting rod and the rotating shaft in this utility model.

[0018] Figure 6 This is a schematic diagram of an insulating plate installed on the rear side of a circuit breaker in this utility model;

[0019] Figure 7 This is a schematic diagram of an embodiment of the secondary terminal assembly on the front side of the circuit breaker of this utility model;

[0020] Figure 8 This is a schematic diagram of another embodiment of the secondary terminal assembly on the front side of the circuit breaker of this utility model.

[0021] In the diagram: 1. Drive linkage assembly, 11. Jump fastener, 12. Rotatable shaft, 121. Swing plate, 13. First link, 14. Second link; 2. Moving contact assembly, 21. Contact support, 22. Moving guide rod, 23. Contact spring; 3. Stationary contact assembly; 4. Energy storage assembly; 5. Locking device, 51. Hinge shaft, 52. Locking element, 53. Side plate, 54. Reset element; 6. Connecting rod; 100. First insulating element; 200. Second insulating element; 300. Mounting shaft; 400. Insulating plate; 500. Secondary terminal assembly, 501. First bracket, 502. Mounting strip, 503. Terminal; 504. Second bracket. Detailed Implementation

[0022] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. However, the description of the embodiments is not a limitation on the technical solution. Any formal but not substantive changes made based on the concept of this utility model should be considered within the protection scope of this utility model.

[0023] In the following description, all directional (or orientational) concepts involving up, down, left, right, front, and back refer to the position of the figure being described, and are intended to facilitate public understanding. Therefore, they should not be construed as a special limitation on the technical solution provided by this utility model.

[0024] See Figure 1 and Figure 2 This utility model relates to an operating mechanism for a circuit breaker with short-circuit tripping capability, comprising a drive linkage assembly 1, a moving contact assembly 2, a stationary contact assembly 3, an energy storage assembly 4, and a locking device 5. One end of the drive linkage assembly 1 is hinged to the energy storage assembly 4, and the other end is hinged to the moving contact assembly 2 via a connecting rod 6. When the circuit breaker receives a closing signal, the energy storage assembly 4 releases energy, causing the drive linkage assembly 1 to move. The drive linkage assembly 1 then moves the moving contact assembly 2 toward the stationary contact assembly 3 via the connecting rod 6. The drive linkage assembly 1 includes a tripping member 11 that contacts and engages with the locking device 5, a rotatably mounted shaft 12, and a first connecting rod 13 and a second connecting rod 14 respectively connected between the tripping member 11 and the shaft 12. The moving contact assembly 2 includes a contact support 21, a moving guide rod 22, and a contact spring 23. The moving guide rod 22 is hinged to the contact support 21, and the contact spring 23 is disposed between the contact support 21 and the moving guide rod 22.

[0025] When the moving contact assembly 2 and the stationary contact assembly 3 just come into contact, the angle between the connecting rod 6 and the rotating shaft 12 is θ1; when the circuit is closed, the angle between the connecting rod 6 and the rotating shaft 12 is θ2. There is a proportional relationship between the angles θ1 and θ2: 0.8 < (sinθ1 / sinθ2) < 1.5.

[0026] Furthermore, the locking device 5 includes a hinge shaft 51, a locking member 52 and a side plate member 53 that are hinged together on the hinge shaft 51 and can move relative to each other, and a reset member 54, which is a spring, is provided between the locking member 52 and the side plate member 53.

[0027] The closing operation procedure of this circuit breaker is as follows.

[0028] See you later Figure 1 and Figure 2When the circuit breaker is in the energy-storage open state, upon receiving a closing command, the energy storage component 4 releases energy, pushing the drive linkage assembly 1 to move. Since the trip fastener 11 in the drive linkage assembly 1 is locked by the locking device 5 and cannot rotate, the rotating shaft 12 in the drive linkage assembly 1 rotates clockwise. Before the moving and stationary contacts make contact, the moving contact assembly 2 is in an unobstructed state, meaning the rotating shaft 12 will not be subjected to the resisting torque of the moving contact assembly 2 during rotation. At this time, the force between the trip fastener 11 and the locking device 5 is insufficient to overcome the force of the reset component 54 in the locking device 5, causing the locking component 52 and the side plate component 53 to move relative to each other, thereby unlocking the locking device 5.

[0029] During the movement of the moving contact assembly 2, the moving guide rod 22 will come into contact with and collide with the stationary contact assembly 3, generating a collision force F. 碰撞 The direction of this force is perpendicular to the surface of the stationary contact. When the operating mechanism continues to move in the closing direction against the force of the contact spring 23 until it reaches the closing position, a force F exists between the moving and stationary contacts due to the action of the contact spring 23. 弹簧压力 The direction of this force is also perpendicular to the surface of the stationary contact. F 弹簧压力 The force is transmitted through the connecting rod 6, causing the rotating shaft 12 to tend to rotate counterclockwise. Then, the force is transmitted through the drive linkage assembly 1, causing the jump fastener 11 and the locking device 5 to generate a force F1, which in turn causes the side plate 53 in the locking device 5 to tend to rotate clockwise. At this time, the reset member 54 in the locking device 5 prevents the side plate 53 from rotating, keeping the locking device 5 in the locked state, thereby keeping the mechanism in the closed state.

[0030] See Figure 3 and Figure 4 When the circuit breaker operating mechanism is in the closed and open states, the relative positions of the contact support 21 in the moving contact assembly 2 and the stationary contact assembly 3 are approximately the same. The contact force between the moving and stationary contacts is perpendicular to the stationary contact, meaning the lever arm to the rotation axis of the contact support 21 is the same. At this time, the angle between the connecting rod 6 and the contact support 21 is approximately 90°. It can be assumed that the proportional relationship of the contact force between the moving and stationary contacts transmitted to the connecting rod 6 is the same in both states. Assuming this proportional relationship is K1, and the connecting rod 6 is a two-force member, the force it exerts on the rotating shaft 12 is F2. The direction of this force is the direction of the line connecting the hinge points at both ends of the connecting rod 6. F2 = K1 * F 接触 The torque exerted by connecting rod 6 on rotating shaft 12 is M = F2 * L 33 *sin(θ), where L 33Let θ be the length of the rotating shaft 12, and θ be the angle between the rotating shaft 12 and the connecting rod 6. To ensure that the circuit breaker operating mechanism can close normally, a threshold needs to be set so that during the closing process, the contact force between the contacts can be transmitted through the connecting rod 6 to the trip fastener 11 and the locking device 5 to generate a force F1, assuming their proportional relationship is K2. When F1 exceeds a threshold F... 阀值 When the force of the reset member 54 in the locking device 5 is overcome, causing the locking member 52 and the side plate member 53 to move relative to each other, the locking device 5 can be unlocked.

[0031] Furthermore, at the moment the circuit breaker is just closed, F1 = F 碰撞 *K1*K2*sin(θ1) <F 阀值 When the circuit breaker is in the closed position, F1 = F 弹簧压力 *K1*K2*sin(θ2) <F 阀值 .

[0032] When a fault current occurs in the circuit, the conductive circuit (i.e., the conductive circuit formed after the moving and stationary contacts come into contact) applies an electrodynamic force F to the contact support 21. 电动 Electric power F 电动 The contact force generated by the contact spring 23 is transmitted through the connecting rod 6 and the drive linkage assembly 1, and a force F1' is generated between the jump fastener 11 and the locking device 5. At this time, F1' is greater than the threshold F. 阀值 This allows the locking element 52 and the side plate element 53 to move relative to each other, thus unlocking the locking device 5. At this time, the operating mechanism performs a tripping operation, separating the moving and stationary contacts and cutting off the fault current in the circuit.

[0033] When the circuit is closed and there is a large fault current, F1' = (F 弹簧压力 +F 电动 )*K1*K2*sin(θ2)>F 阀值 The larger the fault current, the greater the electrodynamic force in the conductive circuit, and the greater the breaking capacity of the circuit breaker, which is not conducive to the circuit breaker's breaking, thus reducing the threshold F for unlocking the latching device 5. 阀值 The required electrical power can reduce the short-circuit current required for the circuit breaker operating mechanism to unlock.

[0034] To ensure the circuit breaker can close normally and quickly unlock and trip during fault current, the following must be met:

[0035] (F 弹簧压力 +F 电动 )*K1*K2*sin(θ2)>F 阀值 >F 碰撞 *K1*K2*sin(θ1)

[0036] Right now

[0037] (F弹簧压力 +F 电动 sin(θ2)>F 碰撞 *sin(θ1)

[0038]

[0039] F 弹簧压力 Related to circuit breaker temperature rise, F 碰撞 The speed of the moving guide rod 22 at the moment of collision between the moving and stationary contacts is related to the speed of the moving guide rod 22. Under the premise that the circuit breaker meets the performance and operational reliability requirements, the above two values ​​can be considered as determined values. In order to reduce the short-circuit current value that causes the operating mechanism locking device 5 to disintegrate, that is, to reduce the ratio of sin(θ1) to sin(θ2), considering the installation space of the operating mechanism and the driving efficiency, the ratio range is preferably 0.8 < (sinθ1 / sinθ2) < 1.5, and the optimal θ1 value is around 135°.

[0040] like Figure 5 To prevent the connecting rod 6 and the rotatable shaft 12 from becoming energized, thus causing phase-to-phase breakdown, and to improve operator safety, insulating devices are provided on the connecting rod 6 and the rotatable shaft 12. The insulating devices include a first insulating element 100 and a second insulating element 200. The connecting rod 6 and the rotatable shaft 12 are hinged together by a mounting shaft 300, forming a rotationally fitted mounting relationship.

[0041] Specifically, the rotating shaft 12 is provided with a swing arm 121 that cooperates with the connecting rod 6, and the mounting shaft 300 pins the swing arm 121 and the connecting rod 6. The first insulating member 100 is a sheet that covers the side of the rotating shaft 12 near the moving contact assembly 2. After covering, the first insulating member 100 covers the swing arm 121 and part of the column of the rotating shaft 12. The second insulating member 200 covers the connecting rod 6. Preferably, the entire connecting rod 6 is covered by the second insulating member 200, and the second insulating member 200 has a clearance hole corresponding to the pin hole on the connecting rod 6. Preferably, after the mounting shaft 300 is installed, a cap can be provided on the clearance hole to close it. To ensure that the gap between the first insulating element 100 and the second insulating element 200 is sealed after completion, a dike is provided on the side of the second insulating element 200 facing the first insulating element 100, and the lower part of the first insulating element 100 extends into the dike. The two are staggered, which has a better sealing effect.

[0042] Figure 6This is a schematic diagram of an insulating plate 400 installed on the rear side of a circuit breaker. The insulating plate 400 is mounted on the rear side of the circuit breaker with screws, thereby increasing the creepage distance between the circuit breaker's outgoing line and the side plates on both sides of the circuit breaker, thus preventing breakdown. Preferably, the insulating plate 400 has a notch that mates with the outgoing line. Typically, the insulating plate 400 is plug-in to the outgoing line.

[0043] Figure 7 , 8 This is a structural schematic diagram of the secondary terminal assembly 500 on the front side of the circuit breaker. (See diagram below.) Figure 7 This is the first embodiment. The secondary terminal assembly 500 includes a first bracket 501, a mounting strip 502, and terminals 503. The terminals 503 are mounted on the mounting strip 502, and the mounting strip 502 is fixed to the first bracket 501, thereby completing the assembly of the entire secondary terminal assembly 500. In this embodiment, preferably, the first bracket 501 is made of insulating material, and the mounting strip 502 is a U-shaped metal bracket.

[0044] like Figure 8 This is a second embodiment of the secondary terminal assembly 500. The difference from the first embodiment is that it further includes a second bracket 504. The terminal 503 is mounted on the mounting strip 502, and the mounting strip 502 is mounted on the second bracket 504. The mounting strip 502, the first bracket 501, and the second bracket 503 are integrated by screws. In this embodiment, preferably, the mounting strip 502, the first bracket 501, and the second bracket 503 are all metal components.

Claims

1. A circuit breaker operating mechanism with short-circuit trip capability, comprising a drive linkage assembly (1), a moving contact assembly (2), a stationary contact assembly (3), an energy storage assembly (4), and a locking device (5), wherein one end of the drive linkage assembly (1) is hinged to the energy storage assembly (4), and the other end is hinged to the moving contact assembly (2) via a connecting rod (6); when the circuit breaker receives a closing signal, the energy storage assembly (4) releases energy to drive the drive linkage assembly (1) to move, and the drive linkage assembly (1) drives the moving contact assembly (2) to move toward the stationary contact assembly (3) via the connecting rod (6); the drive linkage assembly (1) includes a trip fastener (11) that contacts and cooperates with the locking device (5), a rotating shaft (12) that is rotatably disposed, and a first connecting rod (13) and a second connecting rod (14) respectively connected between the trip fastener (11) and the rotating shaft (12), characterized in that: When the moving contact assembly (2) and the stationary contact assembly (3) just come into contact, the angle between the connecting rod (6) and the rotating shaft (12) is θ1. When the circuit is closed, the angle between the connecting rod (6) and the rotating shaft (12) is θ2. The ratio of the angles θ1 and θ2 is 0.8 < (sinθ1 / sinθ2) < 1.

5.

2. The circuit breaker operating mechanism with short-circuit tripping capability according to claim 1, characterized in that: The locking device (5) includes a hinge shaft (51), a locking member (52) and a side plate (53) that are hinged together on the hinge shaft (51) and can move relative to each other. A reset member (54) is provided between the locking member (52) and the side plate (53). When the electrodynamic force transmitted at the moving and stationary contacts overcomes the force of the reset member (54), the locking member (52) and the side plate (53) move relative to each other, and the locking device (5) is unlocked.

3. The circuit breaker operating mechanism with short-circuit tripping capability according to claim 2, characterized in that: The reset component (54) is a spring.

4. The circuit breaker operating mechanism with short-circuit tripping capability according to claim 1, characterized in that: The moving contact assembly (2) includes a contact support (21), a moving guide rod (22), and a contact spring (23). The moving guide rod (22) is hinged to the contact support (21), and the contact spring (23) is disposed between the contact support (21) and the moving guide rod (22).

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