A magnetically controlled tripping device for circuit breakers and its usage method

Abstract

This application discloses a magnetically controlled tripping device for a circuit breaker and its usage method. The tripping device includes a lever, a bracket, an iron core operating rod, and a magnetic control assembly. One end of the lever is the tripping action end, the middle of the lever is rotatably mounted on the bracket, and the other end of the lever is movably connected to the iron core operating rod. The iron core operating rod pries the lever and limits it within the magnetic control assembly. The usage method employs the aforementioned tripping device; when an external sensing device detects that the current value i or the current rise rate di / dt in the main circuit exceeds a predetermined value, the magnetic control assembly causes the internal iron core operating rod to rise, driving the tripping action end of the lever to descend, thus performing the tripping operation. The beneficial effects of this application are: when an overload or short-circuit current is detected in the main circuit, the device can respond quickly, with a fast tripping speed, protecting equipment and personnel safety; utilizing the magnetic control principle combined with the lever principle, it has a simple structure, is easy to install, has few mechanical parts, low wear, long service life, and high reliability.

Description

Technical Field

[0001] This application belongs to the field of electrical switch technology, specifically relating to a magnetically controlled tripping device for a circuit breaker and its usage method. Background Technology

[0002] In rail electric traction systems, DC circuit breakers, as switching protection devices, must not only be able to normally close, carry, and interrupt rated operating current, but also have the ability to connect and interrupt short-circuit currents and overload currents. The process of interrupting short-circuit and overload currents on a circuit breaker must first involve the tripping device, which disengages the circuit breaker's latching mechanism, allowing the circuit breaker contacts to separate and thus completing the load-bearing disconnection process. Therefore, the tripping device is crucial to the circuit breaker's ability to interrupt short-circuit and overload currents. The rapid response and reliability of the tripping device significantly impact the circuit breaker's breaking capacity, safety, and the safe operation of the entire power supply system. The response time and reliability of the tripping device are important indicators for evaluating circuit breaker performance.

[0003] To ensure reliable circuit breaker tripping under load, various tripping devices are installed on circuit breakers using different operating principles, such as shunt tripping devices, indirect tripping devices, undervoltage tripping devices, and overload tripping devices. These devices improve or guarantee response time and tripping reliability. However, existing tripping devices cannot meet the requirements for rapid tripping and urgently need optimization and upgrading. Summary of the Invention

[0004] The purpose of this application is to provide a magnetically controlled tripping device for a circuit breaker and its usage method. This is a type of indirect tripping device, which is a redundancy for the reliable tripping function of the circuit breaker. When the external sensing device senses that the current value i or the current rise rate di / dt in the main circuit exceeds a predetermined value, it triggers the external control circuit of the coil in the tripping device. The device uses electromagnetic force generated by electromagnetic principle and force conversion using lever principle to achieve tripping, thus solving the problem that existing tripping devices cannot trip quickly.

[0005] The objective of this application is achieved through the following technical solution:

[0006] A magnetically controlled tripping device for a circuit breaker includes a lever, a bracket, an iron core operating rod, and a magnetic control assembly. One end of the lever is the tripping end, the middle of the lever is rotatably mounted on the bracket, and the other end of the lever is movably connected to the iron core operating rod. The iron core operating rod pries the lever and limits it within the magnetic control assembly.

[0007] Furthermore, the tripping end is provided with an arc-shaped working surface.

[0008] Furthermore, the other end of the lever is provided with a semi-circular movable groove, and the ball end of the iron core operating rod is movably disposed in the semi-circular movable groove.

[0009] Furthermore, by adjusting the relative distance L between the ball end and the bottom of the semi-circular hole movable groove, different positions of the ball end within the semi-circular hole movable groove can be changed to obtain different force matching relationships.

[0010] Furthermore, the iron core operating lever includes a ball end, a push rod housing, and a moving iron core. The part of the push rod housing extending out of the magnetic control assembly is connected to the ball end, and the part of the push rod housing located in the magnetic control assembly has the moving iron core built in.

[0011] Furthermore, the magnetic control assembly includes a magnetic yoke, a coil body, a permanent magnet, a magnetic guide plate, and a release spring. The iron core operating rod is located at the center of the magnetic yoke, the coil body is located inside the magnetic yoke, the bottom end of the magnetic guide plate is opposite to the bottom end of the iron core operating rod, the permanent magnet is located at the bottom end of the magnetic guide plate, and a release spring is provided between the magnetic guide plate and the iron core operating rod.

[0012] Furthermore, the coil body includes enameled wire and a coil frame, with the enameled wire wound around the coil frame and the lead-out end of the enameled wire connected to an external control circuit.

[0013] Furthermore, the top end of the coil frame abuts against the magnetic yoke, and the bottom end of the coil frame abuts against the magnetic plate.

[0014] Furthermore, the magnetic control assembly also includes an end cap, and the bottom end of the magnetic yoke is provided with a stepped opening. The end cap is fixed at the stepped opening, and the permanent magnet is sandwiched between the end cap and the magnetic guide plate.

[0015] Furthermore, the magnetic control assembly also includes a spring support, which is fixed to the magnetic plate, and the release spring is sleeved on the spring support.

[0016] Furthermore, the stop end face of the magnetic yoke and the stop end face of the iron core operating rod are mutually matching tapered end faces.

[0017] A method of using a circuit breaker magnetic tripping device, wherein the above-mentioned circuit breaker magnetic tripping device is used;

[0018] Tripping operation: When the external sensing device detects that the current value i or the current rise rate di / dt in the main circuit exceeds the predetermined value, the external control circuit causes the coil body to flow with positive current, the electromagnetic holding force on the iron core operating rod is weakened, and the iron core operating rod is pushed upward under the action of the tripping spring, which drives the tripping action end of one end of the lever to descend, thus performing the tripping operation.

[0019] Reset Operation: After the tripping action is completed, the external control circuit causes a reverse current to flow into the coil body, and the iron core operating rod is subjected to a downward electromagnetic force. The iron core operating rod moves downward under the action of overcoming the tripping spring, which drives the tripping action end of one end of the lever to rise. After the magnetic plate is in contact with the moving iron core, the external control circuit de-energizes the coil body.

[0020] The beneficial effects of this application are:

[0021] (1) When an overload or short-circuit current is detected in the main circuit, the device can respond quickly and trip quickly to protect the equipment and personnel safety.

[0022] (2) The device uses the magnetic control principle combined with the lever principle to trip the circuit breaker. It has a simple structure, is easy to install, has few mechanical parts, low wear, long service life and high reliability.

[0023] (3) Use an external control circuit to perform short-term control on the coil of the device to achieve tripping and reset operations.

[0024] (4) During the installation process, the relative position of the ball end of the iron core operating rod and the semi-circular hole movable slot of the lever can be adjusted to obtain the matching relationship of different positions and forces, so as to meet the use of different types of circuit breakers.

[0025] The aforementioned main solution and its various further alternatives can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of this application, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected by this application, and will not be exhaustively listed here. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the usage status of this application.

[0027] Figure 2 This is a structural cross-sectional view of this application (in the un-disengaged state).

[0028] Figure 3 This is a structural cross-sectional view of this application (in the disengaged state).

[0029] Figure 4 This is a structural appearance drawing of this application.

[0030] Figure 5 This is a schematic diagram of the lever structure in this application.

[0031] Figure 6 This is a structural schematic diagram of the iron core operating rod of this application.

[0032] In the diagram: 1. Lever; 2. Bracket; 3. Iron core operating lever; 4. Magnetic yoke; 5. Coil body; 6. End cap; 7. Permanent magnet; 8. Magnetic guide plate; 9. Spring support; 10. Tripping spring; 11. Arc-shaped working surface; 12. Semi-circular hole movable slot; 31. Ball end; 32. Push rod housing; 33. Moving iron core; 41. U-shaped groove; 51. Coil frame; 111. Shift fork; 112. Moving contact assembly; 113. Stationary contact assembly. Detailed Implementation

[0033] The following non-limiting embodiments are used to illustrate this application.

[0034] Example 1

[0035] refer to Figures 1-6 As shown, a magnetically controlled tripping device for a circuit breaker includes a lever 1, a bracket 2, an iron core operating rod 3, and a magnetic control assembly.

[0036] refer to Figure 1 As shown in the diagram, the left half illustrates the operating conditions of the magnetically controlled tripping device for a circuit breaker. In the diagram, the fork 111, through an electromagnetic drive mechanism, brings the moving contact in the moving contact assembly 112 into contact with the stationary contact in the stationary contact assembly 113, completing the circuit breaker closing operation. When the fork 111 is subjected to a downward force from the lever 1, causing it to move downwards and complete the tripping, the moving contact separates from the stationary contact under the action of the closing energy storage spring, resulting in a breaking operation. Throughout this process, the downward movement of the fork 111 due to force to complete the tripping is the tripping phenomenon.

[0037] One end of lever 1 is the tripping end, which directly contacts and presses against the lever to complete the tripping action. The middle part of lever 1 is rotatably mounted on bracket 2, allowing lever 1 to rotate relative to bracket 2. The other end of lever 1 is movably connected to the iron core operating rod 3, changing the position of the iron core operating rod 3, which in turn drives the tripping end of lever 1 to swing up and down through the action of the other end of lever 1.

[0038] When the iron core operating lever 3 pries the lever 1 and confines it within the magnetic control assembly, the change in the magnetic field inside the assembly causes the iron core operating lever 3 to exert an upward or downward force. When the iron core operating lever 3 moves upward, it causes the tripping end to press down, initiating a tripping action; when the iron core operating lever 3 moves downward, it causes the tripping end to rise, releasing the trip and resetting the lever. Under normal conditions, the iron core operating lever 3 remains in the low position, and the lever 1 remains in the ready-to-trip state.

[0039] The release end of lever 1 is provided with an arc-shaped action surface 11, which helps to reduce the friction between the contact surface of lever 1 and shift fork 111, avoid stress concentration during release, reduce jamming, and improve service life and stability.

[0040] refer to Figure 3 and Figure 4 The other end of lever 1 is provided with a semi-circular movable groove 12. The cross-section of the semi-circular movable groove 12 is semi-circular, and a slot is opened on the side of the groove for the iron core operating rod 3 to pass through. The ball end 31 of the iron core operating rod 3 is movably disposed in the semi-circular movable groove 12. When the iron core operating rod 3 is held in the non-disengaged state, the lower part of the ball end 31 of the iron core operating rod 3 contacts and is limited by the slot of the semi-circular movable groove 12; when the iron core operating rod 3 moves upward, the upper part of the ball end 31 contacts the top of the semi-circular movable groove 12, and the contact point slides as the lever 1 rotates; when the iron core operating rod 3 moves downward, the lower part of the ball end 31 contacts the slot of the semi-circular movable groove 12, and the contact point slides as the lever 1 rotates.

[0041] The ball end 31 has low friction at the contact point with the semi-circular hole movable groove 12, and it limits the downward release movement of the lever 1, ensuring the release gap H value between the lever 1 and the fork 111 and avoiding accidental contact. At the same time, a certain gap δ is designed above the ball end 31 and the semi-circular hole movable groove 12, which ensures the free travel of the iron core operating rod 3 in the initial movement.

[0042] The distance between lever 1 and shift fork 111 is H, and the relative position distance between the ball end 31 of the iron core operating rod 3 and the semi-circular hole movable groove 12 of lever 1 is L. Under the condition that H and the pre-pressure generated by the release spring 10 on the iron core operating rod 3 are constant, according to the lever principle F1L1=F2L2, F1 is the impact force generated by the iron core operating rod 3 on lever 1, which is positively correlated with the pre-pressure generated by the release spring 10 on the iron core operating rod 3. L1 is the distance from the ball end 31 of the iron core operating rod 3 to the bracket 2, which includes L. F2 is the release force generated by one end of lever 1 on shift fork 111, and L2 is the distance from one end of lever 1 to the bracket 2. The travel distance of the release force generated by one end of lever 1 is determined by H. Therefore, the magnitude of the release force is related to L. The larger L is, the larger the release force is. By adjusting the relative distance L between the ball end 31 and the bottom of the semi-circular hole movable groove 12, the position of the ball end 31 in the semi-circular hole movable groove 12 can be changed, thereby adjusting the tripping force and matching the force value of the fork 111 when it trips in different types of circuit breakers.

[0043] The core operating lever 3 includes a ball end 31, a push rod housing 32, and a moving iron core 33. The part of the push rod housing 32 extending out of the magnetic control assembly is integrally connected to the ball end 31, realizing the movable connection between the core operating lever 3 and the lever 1. The part of the push rod housing 32 located in the magnetic control assembly houses the moving iron core 33. The magnetic force of the magnetic control assembly acts on the moving iron core 33 to achieve specific magnetic control lifting.

[0044] The magnetic control assembly includes a magnetic yoke 4, a coil body 5, an end cap 6, a permanent magnet 7, a magnetic guide plate 8, a spring support 9, and a trip spring 10. The magnetic yoke 4, end cap 6, and magnetic guide plate 8 are all made of ferromagnetic material to ensure the construction of the magnetic circuit and magnetic field. The surfaces of the magnetic yoke 4 and end cap 6 are coated with insulating varnish, and the lever 1 is made of non-metallic material to prevent it from conducting electricity or leaking current and affecting the normal operation of the device.

[0045] The iron core operating rod 3 is located at the center of the magnetic yoke 4 and is sleeved thereon. The coil body 5 is located inside the magnetic yoke 4. The magnetic guide plate 8 is opposite to the bottom end of the iron core operating rod 3. The permanent magnet 7 is located at the bottom end of the magnetic guide plate 8. A release spring 10 is provided between the magnetic guide plate 8 and the iron core operating rod 3.

[0046] Initially, due to the magnetic field, the moving part, the iron core operating lever 3, contacts the magnetic plate 8. During the tripping action, a forward current flows through the coil body 5, weakening the magnetic flux circuit. The iron core operating lever 3, under the action of the tripping spring 10, disengages from the magnetic plate 8, simultaneously moving the lever 1. During the reset action, a reverse current flows through the coil body 5, increasing the magnetic flux circuit. The iron core operating lever 3, overcoming the action of the tripping spring 10, contacts the magnetic plate 8, simultaneously moving the lever 1.

[0047] The coil body 5 includes enameled wire and a coil bobbin 51. The enameled wire is wound around the coil bobbin 51, and an annular groove for mounting the coil bobbin 51 is formed inside the magnetic yoke 4. The top end of the coil bobbin 51 abuts against the magnetic yoke 4, and the bottom end of the coil bobbin 51 is abutted against by a magnetic plate 8, thereby fixing the coil bobbin 51 within the magnetic yoke 4. A U-shaped groove 41 is formed at the end of the magnetic yoke 4 near the coil body 5, allowing the lead-out end of the enameled wire to be connected to an external control circuit.

[0048] The bottom end of the magnetic yoke 4 is provided with a stepped opening, and the end cover 6 is fixed at the stepped opening and fastened by riveting. The permanent magnet 7 is sandwiched between the end cover 6 and the magnetic plate 8, that is, the end cover 6 abuts and limits the permanent magnet 7, the permanent magnet 7 abuts and limits the magnetic plate 8, and the magnetic plate 8 abuts and limits the coil frame 51.

[0049] The spring support 9 is fixed on the magnetic plate 8, and the trip spring 10 is sleeved on the spring support 9. The spring support 9 provides guidance and limit for the trip spring 10, and the spring support 9 does not move upward with the operating lever. In the initial state, the trip spring 10 is in a pre-compressed state. In the active state, the energy stored in the trip spring 10 is released, pushing the iron core operating lever 3 to move upward.

[0050] The stop end face of the magnetic yoke 4 and the stop end face of the iron core operating rod 3 are matching conical end faces. Specifically, the relative end face angles of the iron core operating rod 3 and the magnetic yoke 4 are α and β, respectively, and α=β. The purpose is to enable the iron core operating rod 3 to automatically center during movement, reduce offset and jamming, and ensure the accuracy and reliability of the action.

[0051] The advantages of this tripping device are: it can respond quickly when an overload or short-circuit current is detected in the main circuit, with fast tripping speed, protecting equipment and personnel safety; the device uses magnetic control principle combined with lever principle to trip the circuit breaker, with simple structure, convenient installation, few mechanical parts, low wear, long service life, and high reliability; the device coil is controlled by an external control circuit for short time to realize tripping and reset operations; during installation, the relative position of the ball end of the operating rod and the semi-circular hole of the lever can be adjusted to obtain different position and force matching relationships to meet the use of different types of circuit breakers.

[0052] Example 2

[0053] refer to Figures 1-6 As shown, a method of using a circuit breaker magnetic tripping device is described, employing the circuit breaker magnetic tripping device of Example 1.

[0054] refer to Figure 1 As shown in the diagram, the left half illustrates the operating conditions of the magnetically controlled tripping device for a circuit breaker. In the diagram, the fork 111, through an electromagnetic drive mechanism, brings the moving contact in the moving contact assembly 112 into contact with the stationary contact in the stationary contact assembly 113, completing the circuit breaker closing operation. When the fork 111 is subjected to a downward force from the lever 1, causing it to move downwards and complete the tripping, the moving contact separates from the stationary contact under the action of the closing energy storage spring, resulting in a breaking operation. Throughout this process, the downward movement of the fork 111 due to force to complete the tripping is the tripping phenomenon.

[0055] In the initial state: the force and movement of lever 1 on the shift fork 111 are generated by the lever principle through the movement of the iron core operating rod 3. In the initial state, the position of lever 1 is as follows: Figure 2 As shown, the magnetic field generated by the permanent magnet 7 forms a magnetic circuit on the yoke 4, end cap 6, magnetic plate 8, and moving iron core 33, causing the iron core operating rod 3 to be subjected to a downward electromagnetic attraction. This electromagnetic attraction overcomes the pressure of the trip spring 10 on the iron core operating rod 3, causing the trip spring 10 to be pre-compressed and stored.

[0056] refer to Figure 3As shown, the tripping operation is as follows: When the external sensing device detects that the current value i or the current rise rate di / dt in the main circuit exceeds the predetermined value, the external control circuit causes a short-term (0.5s) positive current to flow into the coil body 5, generating a magnetic field opposite to that of the permanent magnet 7. The electromagnetic holding force on the iron core operating rod 3 weakens, and the iron core operating rod 3 is pushed upward under the elastic force of the tripping spring 10. That is, the magnetic control component causes the internal iron core operating rod 3 to rise, driving the tripping end of one end of the lever 1 to descend, thus performing the tripping operation. Specifically, after the iron core operating rod 3 moves δ of its idle stroke, it contacts the lever 1, causing the lever 1 to rotate around the bracket 2, so that the left side of the lever 1 moves downward until it contacts the shift fork 111, and continues to move downward until the shift fork 111 completes the release, causing the moving contact of the moving contact assembly 112 to separate from the stationary contact of the stationary contact assembly 113, and finally stops due to the inherent stroke S limit of the iron core operating rod 3.

[0057] Reset Operation: After the tripping action is completed, the external control circuit causes a short-term (0.5s) reverse current to flow into the coil body 5, generating the same magnetic field as the permanent magnet 7, increasing the magnetic flux density of the magnetic circuit. The iron core operating rod 3 is subjected to a downward electromagnetic force, and the iron core operating rod 3 moves downward under the action of the tripping spring 10, driving the tripping end of the lever 1 to rise. After the magnetic plate 8 and the moving iron core 33 are in contact, the external control circuit de-energizes the coil body 5, completing the reset operation.

[0058] The foregoing basic examples and their further alternative examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed in this application. In the scheme of this application, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A magnetically controlled tripping device for a circuit breaker, comprising a lever (1), characterized in that: It also includes a bracket (2), an iron core operating rod (3) and a magnetic control assembly. One end of the lever (1) is the tripping end, the middle part of the lever (1) is rotatably mounted on the bracket (2), and the other end of the lever (1) is movably connected to the iron core operating rod (3). The iron core operating rod (3) pries the lever (1) and limits it within the magnetic control assembly. The tripping action is completed by direct contact pressing at the tripping end. The release end is provided with an arc-shaped action surface (11); the other end of the lever (1) is provided with a semi-circular hole movable groove (12), and the ball end (31) of the iron core operating rod (3) is movably disposed in the semi-circular hole movable groove (12); the cross section of the semi-circular hole movable groove is semi-circular, and the side of the groove is provided with a slot for the iron core operating rod to pass through. By adjusting the relative distance L between the ball end (31) and the bottom of the semi-circular hole movable groove (12), different positions of the ball end (31) in the semi-circular hole movable groove (12) can be changed to obtain different force matching relationships; When the core operating lever (3) remains in the undisengaged state, the lower part of the ball end (31) of the core operating lever (3) contacts and limits the groove of the semi-circular hole movable groove (12); when the core operating lever (3) moves upward, the upper part of the ball end (31) contacts the top of the semi-circular hole movable groove (12), and the contact point slides as the lever (1) rotates; when the core operating lever (3) moves downward, the lower part of the ball end (31) contacts the groove of the semi-circular hole movable groove (12), and the contact point slides as the lever (1) rotates.

2. The circuit breaker magnetic tripping device according to claim 1, characterized in that: The iron core operating rod (3) includes a ball end (31), a push rod housing (32) and a moving iron core (33). The part of the push rod housing (32) extending out of the magnetic control assembly is connected to the ball end (31), and the part of the push rod housing (32) located in the magnetic control assembly has the moving iron core (33) built in.

3. The circuit breaker magnetic tripping device according to claim 2, characterized in that: The magnetic control assembly includes a magnetic yoke (4), a coil body (5), a permanent magnet (7), a magnetic guide plate (8), and a trip spring (10). The iron core operating rod (3) is located at the center of the magnetic yoke (4), the coil body (5) is located inside the magnetic yoke (4), the magnetic guide plate (8) is opposite to the bottom end of the iron core operating rod (3), the permanent magnet (7) is located at the bottom end of the magnetic guide plate (8), and a trip spring (10) is provided between the magnetic guide plate (8) and the iron core operating rod (3).

4. The circuit breaker magnetic tripping device according to claim 3, characterized in that: The magnetic control assembly also includes a spring support (9), which is fixed on the magnetic plate (8), and a release spring (10) is sleeved on the spring support (9).

5. The circuit breaker magnetic tripping device according to claim 3, characterized in that: The stop end face of the magnetic yoke (4) and the stop end face of the iron core operating rod (3) are matching tapered end faces.

6. A method of using a magnetically controlled tripping device for a circuit breaker, characterized in that: The circuit breaker magnetic tripping device as described in claim 4 is used; Tripping operation: When the external sensing device detects that the current value i or the current rise rate di / dt in the main circuit exceeds the predetermined value, the external control circuit causes the coil body (5) to flow with positive current, the electromagnetic holding force on the iron core operating rod (3) is weakened, and the iron core operating rod (3) is pushed upward under the elastic force of the tripping spring (10), which drives the tripping end of the lever (1) to descend and perform the tripping operation; Reset operation: After the tripping action is completed, the external control circuit causes the coil body (5) to flow with reverse current, and the iron core operating rod (3) is subjected to downward electromagnetic force. The iron core operating rod (3) moves downward under the action of overcoming the tripping spring (10), which drives the tripping end of the lever (1) to rise. After the magnetic plate (8) and the moving iron core (33) are in contact, the external control circuit de-energizes the coil body (5).

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