A magnetic control circuit breaker with quick self-locking function

Abstract

The application relates to the technical field of magnetic control circuit breakers, in particular to a magnetic control circuit breaker with a quick self-locking function. The magnetic control circuit breaker comprises a mechanism box and a pole column arranged on the top of the mechanism box. A vacuum arc-extinguishing chamber is arranged in the pole column. A static conducting contact and a dynamic conducting contact are arranged in the vacuum arc-extinguishing chamber. An insulating pull rod is fixedly connected to the lower end of the dynamic conducting contact. A permanent magnet operating mechanism is arranged in the mechanism box. The permanent magnet operating mechanism comprises a columnar mounting box and a dynamic iron core arranged in the columnar mounting box. A lateral heat conduction structure which can be turned on and turned off along with the opening and closing actions is arranged in the middle section of a main shaft. The joule heat generated by the main circuit current can be horizontally led out through the low-thermal-resistance heat conduction disc and the low-thermal-resistance heat conduction cover. The heat is blocked from invading the permanent magnet operating mechanism downward by the heat insulation disc and the heat insulation cover. The heat transferred to the permanent magnet is reduced from the main heat conduction path, and the irreversible demagnetization problem of the neodymium-iron-boron permanent magnet under the long-term high-temperature working condition is relieved.

Description

Technical Field

[0001] This invention relates to the field of magnetically controlled circuit breaker technology, specifically a magnetically controlled circuit breaker with a fast self-locking function. Background Technology

[0002] With the continuous advancement of the smart grid industry and the increasing level of distribution automation, the requirements for equipment reliability and long-term service life in power distribution systems are becoming increasingly stringent. Permanent magnet operated vacuum circuit breakers, as core power electronic components in the distribution network field, are widely used in outdoor pole-mounted switches, ring main units, and other scenarios due to their advantages of simple structure, long mechanical life, and low maintenance costs.

[0003] The poles of a permanent magnet operated vacuum circuit breaker are equipped with vacuum interrupters, each containing moving and stationary contacts. In the closed state, these contacts are in close contact, forming a conductive circuit. As the load current continuously flows through the contacts and the moving conductor, continuous Joule heating is generated due to the conductor resistance and contact resistance. Because the vacuum interrupter is in a high-vacuum environment, there is no air convection heat transfer. The heat generated inside can only be dissipated through two paths: first, through the interrupter's shielding cover, it is transferred to the pole housing via thermal radiation, but this path provides very limited heat dissipation; second, through the moving conductor, which is fixed to the moving contact, it is transferred axially downwards via solid-state heat conduction, which is the primary heat dissipation path for the vacuum interrupter.

[0004] The lower end of the moving conductive rod is directly connected to the moving iron core of the permanent magnet operating mechanism via an insulated pull rod. The permanent magnet and excitation coil of the permanent magnet operating mechanism are arranged around the moving iron core, and the moving iron core is attracted by the magnetic force of the permanent magnet to achieve a steady-state maintenance of the closed position. In this structure, the Joule heat carried by the moving conductive rod will be continuously conducted downward along the axial direction, and directly transferred to the permanent magnet and coil assembly through the insulated pull rod and the moving iron core, causing the operating temperature of the permanent magnet to rise continuously.

[0005] The neodymium iron boron permanent magnet material widely used in the industry is quite sensitive to operating temperature and exhibits irreversible demagnetization at high temperatures. When equipment operates under high load and high temperature conditions for extended periods, the magnetic properties of the permanent magnet will irreversibly decay, leading to a decrease in the closing holding force. This can cause the closing position to shift and the opening and closing action characteristics to become discrete. The increased contact resistance further exacerbates the temperature rise, creating a vicious cycle. In severe cases, it can lead to closing failure and opening failure, directly threatening the safety of power grid operation. Summary of the Invention

[0006] The purpose of this invention is to provide a magnetically controlled circuit breaker with a fast self-locking function to solve the problems mentioned in the background art.

[0007] The objective of this invention can be achieved through the following technical solutions: A magnetically controlled circuit breaker with a fast self-locking function, preferably, includes a mechanism box and three poles disposed on its top. The poles are provided with a vacuum interrupter, and the vacuum interrupter is provided with a stationary conductive contact and a moving conductive contact. An insulating pull rod is fixedly connected to the lower end of the moving conductive contact. The mechanism box is equipped with a permanent magnet operating mechanism, which includes a columnar mounting box and a moving iron core inside it, a permanent magnet surrounding the moving iron core, and an excitation coil. The lower end of the insulating tie rod is fixedly connected to a main shaft, and the lower section of the main shaft extends into the cylindrical mounting box and is fixedly connected to the moving iron core. The contact end face between the pole post and the mechanism box is provided with a conductive lifting groove, and a low thermal resistance heat-conducting cover is fixed to the inner wall of the conductive lifting groove. A low thermal resistance heat-conducting plate is fixedly connected to the middle section of the main shaft, and the low thermal resistance heat-conducting plate is located inside the conductive lifting groove. When the switch is closed, the main shaft drives the low thermal resistance heat conduction plate to move upward and presses it tightly against the end face of the low thermal resistance heat conduction cover to form a lateral heat conduction path. When the circuit breaker is opened, the main shaft drives the low thermal resistance heat conduction plate to move axially downward and separates from the end face of the low thermal resistance heat conduction cover, thus disconnecting the lateral heat conduction path.

[0008] Preferably, a bellows is sleeved on the outer periphery of the upper section of the main shaft, and the bottom of the bellows is fixedly connected to the bottom of the vacuum interrupter. A heat insulation plate is provided at the bottom of the low thermal resistance heat conduction plate; The top of the columnar mounting box extends into the interior of the low thermal resistance heat-conducting cover, and a heat insulation sleeve is fixedly fitted around the outer periphery of the columnar mounting box, with the heat insulation sleeve positioned between the low thermal resistance heat-conducting cover and the columnar mounting box.

[0009] Preferably, a buffer groove is provided at the top of the guide lifting groove, and limit grooves are symmetrically opened on the inner wall of the buffer groove, and a limit slider is provided inside the buffer groove; The two ends of the limiting slider are respectively embedded in two limiting grooves, and the limiting slider is movably sleeved on the outer periphery of the main shaft, with a sliding assembly gap formed between the limiting slider and the main shaft. A buffer spring is fixed to the top of the limiting slider, and the buffer spring is disposed between the limiting slider and the buffer groove. The top of the low thermal resistance heat-conducting plate is provided with a lifting ring that abuts against the limiting slider.

[0010] Preferably, the bottom of the spindle extends through the cylindrical mounting box, and a reset stop is fixedly connected to the lower end of the spindle; A reset spring is provided between the reset stop and the columnar mounting box, and the reset spring is sleeved on the outer circumference of the main shaft; The bottom of the low thermal resistance heat-conducting cover extends into the interior of the mechanism box, and a first annular heat dissipation fin is provided on the outer periphery of one end of the cover located inside the mechanism box. A second annular heat dissipation fin is provided on the outer periphery of the end of the columnar mounting box that does not extend into the interior of the low thermal resistance heat-conducting cover. Ventilation openings are symmetrically arranged at both ends of the mechanism box.

[0011] Preferably, the interior of the ventilation opening is provided with a plurality of window blades, and the end of the rotating shaft of the window blades is fixedly connected with a transmission gear; The mechanism box has symmetrically opened lifting slides inside, and a transmission rack is slidably arranged inside the lifting slide. The transmission rack meshes with the transmission gear, and the bottom of the transmission rack is fixedly connected to the reset stop.

[0012] Preferably, the main shaft is divided into three sections along the axis: an upper section, a middle section, and a lower section. The upper section of the main shaft passes through the mechanism box and the pole column and extends into the vacuum interrupter chamber. The lower section of the main shaft is fixedly connected to the moving iron core. The inner wall of the vacuum interrupter is provided with a shielding layer.

[0013] Preferably, a short-circuit ring is provided at the bottom of the columnar mounting box, and guide rods are symmetrically provided at the bottom of the short-circuit ring. The guide rods extend to the bottom of the columnar mounting box and are fixedly connected to a transmission rod. The bottom of the mechanism box is provided with three opening slide grooves, and opening sliders are slidably connected inside the opening slide grooves. The top of the opening sliders is provided with inclined guide rails adapted to the transmission rod. When the circuit breaker slider slides along the circuit breaker groove, it drives the transmission rod to slide along the inner wall of the inclined guide rail, pushing the short-circuit ring to move upward along the main shaft axis.

[0014] Preferably, the top of the opening slider is provided with an active guide rail, one end of which is symmetrically fixed with a tension spring, and the other end of the tension spring is fixedly connected to the inner wall of the mechanism box. The mechanism box is internally connected to a drive rod, which is rotatably connected to a manual sliding rod. One end of the manual sliding rod is embedded in the drive rail.

[0015] Preferably, one end of the active rod extends out of the mechanism box and is fixedly connected to a hand-operated handle; Rotating the hand-operated handle drives the active rod to rotate, which in turn pushes the opening slider to slide through the eccentric wheel and the hand-operated sliding rod, causing the short-circuit ring to move upward and contact the permanent magnet to destroy the magnetic circuit. The reset spring then overcomes the magnetic attraction and pulls the main shaft to complete the opening.

[0016] Preferably, when the window leaf rotates to the fully open or fully closed position, it works in conjunction with the magnetic attraction of the permanent magnet to maintain the steady state of opening and closing, thereby achieving rapid self-locking.

[0017] The beneficial effects of this invention are: 1. The present invention provides a lateral heat-conducting structure in the middle section of the main shaft that can be switched on and off with the opening and closing of the circuit. The Joule heat generated by the main circuit can be laterally discharged through the attached low thermal resistance heat-conducting plate and low thermal resistance heat-conducting cover. In conjunction with the heat insulation plate and heat insulation sleeve, the heat is blocked from penetrating downward into the permanent magnet operating mechanism. The heat transferred to the permanent magnet is reduced from the main heat conduction path, which alleviates the problem of irreversible demagnetization of neodymium iron boron permanent magnets under long-term high temperature conditions and extends the service life of the core components of the magnetic circuit.

[0018] 2. This invention employs a dual-spring combined with a limiting slide rail structure. During the closing process, the buffer spring intervenes when the moving and stationary contacts approach each other, reducing the impact force of the contacts, suppressing contact bounce, and reducing contact erosion and mechanical wear. In the initial opening stage, the reset spring and the buffer spring jointly provide downward power to ensure rapid contact separation and improve arc extinguishing reliability. When the limiting slider reaches the lower limit position of the slide rail, the buffer spring stops outputting power, and only the reset spring completes the remaining opening stroke and acts as a limit, avoiding overshoot and impact damage to components. Simultaneously, the ventilation window opens and closes synchronously with the opening and closing stroke. When the circuit is closed, the temperature inside the enclosure is higher than the ambient temperature; opening the window only enhances heat dissipation and does not pose a risk of condensation. After the circuit is opened and the power is cut off, the temperature inside the enclosure gradually drops, and closing the ventilation opening can prevent the intrusion of warm and humid air from the outside, fundamentally avoiding condensation and corrosion problems. This truly balances heat dissipation efficiency and outdoor moisture protection requirements, meeting the high operational reliability requirements of power distribution equipment in the smart grid industry.

[0019] 3. This invention features a fully mechanical manual tripping mechanism that utilizes the principle of a short-circuit permanent magnet circuit to achieve tripping. The tilting guide rail converts horizontal sliding into axial lifting, and the three-phase operation exhibits good synchronization. This allows for reliable tripping operations even in emergency situations where electrical control fails, enhancing operational safety during equipment malfunctions. The entire solution relies on the circuit breaker's existing axial travel drive for heat conduction and ventilation switching, eliminating the need for additional power components. This simplified transmission chain facilitates production, assembly, and daily maintenance. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a vertical top view of the mechanism box in this invention; Figure 3 yes Figure 2 Sectional view at point AA; Figure 4 This is a horizontal top view of the mechanism box in this invention; Figure 5 yes Figure 4 Top view at point BB; Figure 6 This is a schematic diagram of the internal structure of the buffer groove in this invention; Figure 7 This is a schematic diagram of the internal structure of the columnar mounting box and the low thermal resistance heat-conducting cover in this invention; Figure 8 This is a schematic diagram of the internal structure of the mechanism box in this invention; Figure 9 This is a schematic diagram of the overall structure of the transmission gear in this invention; Figure 10 This is a schematic diagram of the overall structure of the active rod in this invention; Figure 11 This is an exploded view of the internal structure of the tripping slide groove in this invention.

[0021] The following are the reference numerals in the attached diagram: 1. Mechanism box; 2. Pole column; 3. Vacuum interrupter; 4. Static conductive contact; 5. Moving conductive contact; 6. Insulating pull rod; 7. Columnar mounting box; 8. Moving iron core; 9. Permanent magnet; 10. Excitation coil; 11. Main shaft; 12. Bellows; 13. Shielding layer; 14. Conductive lifting groove; 15. Low thermal resistance heat-conducting cover; 16. Low thermal resistance heat-conducting plate; 17. Heat insulation plate; 18. Heat insulation sleeve; 19. First annular heat dissipation fin; 20. Second annular heat dissipation fin; 21. Vent; 22. Buffer groove; 23. Limiting slide groove; 24. Limiting slider; 25. Buffer spring; 26. Lifting ring; 27. Reset stop; 28. Reset spring; 29. ​​Window leaf; 30. Transmission gear; 31. Lifting slide groove; 32. Transmission rack; 33. Short-circuit ring; 34. Guide rod; 35. Transmission rod; 36. Opening slide groove; 37. Opening slider; 38. Inclined guide rail; 39. Active guide rail; 40. Tension spring; 41. Active rod; 42. Eccentric wheel; 43. Manual opening slide rod; 44. Manual opening handle. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] A magnetically controlled circuit breaker with fast self-locking function belongs to the field of power electronic components in the field of power distribution switch. It is mainly used in the medium-voltage power distribution network of the smart grid industry. It can adapt to the long-term grid-connected operation conditions of large temperature difference between day and night, humid and easy condensation, and strong environmental vibration. It meets the actual operation requirements of controllable temperature rise of core magnetic circuit, stable mechanical characteristics and reliable emergency operation when the equipment is continuously carrying current. During operation, the moving conductive rod of the existing permanent magnet operated vacuum circuit breaker will continuously conduct Joule heat downward along the axis. The heat directly acts on the permanent magnet and coil assembly, causing the permanent magnet to operate at a higher temperature. Under long-term high-temperature conditions, irreversible demagnetization is likely to occur. At the same time, conventional passive heat dissipation methods have limited efficiency. If fixed ventilation openings are opened to enhance heat dissipation, the intrusion of warm and humid air from the outside after the circuit breaker is opened and cooled down can easily cause condensation and corrosion of internal metal parts. It is always difficult to meet both heat dissipation requirements and moisture protection. This solution utilizes the existing axial travel of the circuit breaker's main shaft during opening and closing to drive the low thermal resistance heat-conducting plate to engage or disengage with the end face of the low thermal resistance heat-conducting cover, achieving synchronous opening and closing of the lateral heat conduction path. This, combined with a heat insulation structure, prevents heat from reversing into the permanent magnet mechanism. Simultaneously, the ventilation window opens and closes with the opening and closing action; it opens during closing to enhance convection and cooling, and closes after opening to prevent warm, humid air from entering. The overall structure requires no additional drive components and does not increase mechanical losses. It reduces heat input to the permanent magnet through the main heat conduction path, ensuring the long-term stable operation of power electronic components on the distribution network side and improving the operational reliability of smart grid distribution nodes.

[0024] A magnetically controlled circuit breaker with fast self-locking function, such as Figures 1-11 As shown, the device includes a mechanism housing 1 and pole posts 2 fixedly mounted on the top of the mechanism housing 1. Each pole post 2 is encapsulated with a vacuum interrupter 3. The inner wall of the vacuum interrupter 3 is provided with a shielding layer 13 to homogenize the electric field distribution inside the vacuum interrupter 3. A stationary conductive contact 4 and a moving conductive contact 5 are correspondingly arranged inside the vacuum interrupter 3, which work together to realize the on / off control of the main circuit. An insulating pull rod 6 is fixedly connected to the lower end of the moving conductive contact 5, which realizes electrical isolation between the high-voltage energized side and the low-voltage operating side while transmitting axial mechanical power.

[0025] The internal structure of the mechanism box 1 is equipped with a permanent magnet operating mechanism corresponding to each phase pole. The permanent magnet operating mechanism includes a columnar mounting box 7 fixed in the inner cavity of the mechanism box 1. The columnar mounting box 7 integrates and assembles a moving iron core 8, a permanent magnet 9 surrounding the moving iron core 8, and an excitation coil 10. The lower end of the insulating pull rod 6 is fixedly connected to the main shaft 11. The main shaft 11 is divided into three sections along the axis: upper section, middle section, and lower section. The upper section of the main shaft 11 passes upward through the mechanism box 1 and the pole column 2, extends into the vacuum interrupter 3, and is fixedly connected to the lower end of the insulating pull rod 6. A bellows 12 is also fixedly connected to the outer periphery of the rod body of the main shaft 11 that extends into the vacuum interrupter 3. The bottom of the bellows 12 is sealed and fixedly connected to the bottom of the vacuum interrupter 3. It can deform synchronously with the extension and retraction of the main shaft 11, and always maintain the high vacuum sealing state of the vacuum interrupter 3. The lower section of the main shaft 11 extends downward into the interior of the columnar mounting box 7 and is fixedly connected to the moving iron core 8 on the same axis. It moves axially back and forth synchronously with the moving iron core 8.

[0026] At the end face where the pole post 2 contacts the mechanism box 1, a coaxially surrounding main shaft guide lifting groove 14 is provided. A low thermal resistance heat-conducting cover 15 is fixedly connected to the inner wall of the guide lifting groove 14. The middle section of the main shaft 11 is located inside the guide lifting groove 14, and a low thermal resistance heat-conducting plate 16 is fixedly sleeved on the middle section of the main shaft 11, which can move up and down in the groove together with the main shaft 11. A buffer groove 22 is provided at the top of the guide lifting groove 14. The inner wall of the buffer groove 22 is symmetrically provided with limiting slide grooves 23. A limiting slider 24 is provided inside the buffer groove 22. The two protruding parts of the limiting slider 24 are respectively embedded in the two limiting slide grooves 23, and can only slide axially and cannot deflect circumferentially. The limiting slider 24 is movably sleeved on the outer circumference of the main shaft 11. The axial travel of the limiting slide groove 23 is used to limit the extreme position of the downward movement of the limiting slider 24, forming a double spring graded action structure with the return spring 28 and the buffer spring 25. A buffer spring 25 is fixedly connected to the top of the limiting slider 24, and the upper end of the buffer spring 25 abuts against the top wall of the buffer groove 22; an annular lifting ring 26 is provided on the top of the low thermal resistance heat conduction plate 16, and the top surface of the lifting ring 26 can abut against the bottom surface of the limiting slider 24.

[0027] A heat insulation plate 17 is provided at the bottom of the low thermal resistance heat conduction plate 16 to prevent heat from radiating and transferring downwards to the operating mechanism area. The top of the columnar mounting box 7 extends upwards into the internal cavity of the low thermal resistance heat conduction cover 15. A heat insulation sleeve 18 is fixedly fitted on the upper outer periphery of the columnar mounting box 7, filling the space between the low thermal resistance heat conduction cover 15 and the columnar mounting box 7 to prevent heat from the heat conduction cover from being conducted downwards through the shell of the columnar mounting box 7. The bottom of the low thermal resistance heat conduction cover 15 extends downwards into the interior of the mechanism box 1. A first annular heat dissipation fin 19 is provided on the outer periphery of its end inside the mechanism box 1 to increase the contact area with the air inside the mechanism box 1 and improve heat exchange efficiency. The columnar mounting box 7, which does not extend into the lower outer periphery of the low thermal resistance heat conduction cover 15, is also provided with a second annular heat dissipation fin 20 to help dissipate the heat generated by the operation of the permanent magnet operating mechanism itself. Ventilation openings 21 are symmetrically provided on the side walls at both ends of the mechanism box 1 to form air circulation channels between the inside and outside of the mechanism box 1.

[0028] The bottom of the main shaft 11 extends downward through the bottom wall of the columnar mounting box 7, and a reset stop 27 is fixedly connected to the end of the protruding end. A reset spring 28 is provided between the reset stop 27 and the bottom wall of the columnar mounting box 7. The reset spring 28 is sleeved on the outer circumference of the main shaft 11 to provide a reset driving force for the opening action. Multiple rotatable window blades 29 are evenly arranged inside the ventilation port 21. A transmission gear 30 is fixedly connected to the end of the rotating shaft of each window blade 29. A lifting slide groove 31 is symmetrically opened at corresponding positions on the inner wall of the mechanism box 1. A transmission rack 32 is slidably assembled in the lifting slide groove 31. The transmission rack 32 meshes with the transmission gear 30, and the bottom of the transmission rack 32 is fixedly connected to the reset stop 27, so it can move up and down with the reset stop 27.

[0029] For emergency situations involving electrical control failure, this circuit breaker is also equipped with a purely mechanical manual tripping mechanism. A short-circuit ring 33 is installed at the bottom inner side of the cylindrical mounting box 7, coaxially sleeved around the outer circumference of the main shaft 11 and slidable axially. The permanent magnet 9 is a ring structure arranged around the moving iron core 8, with its lower end face axially opposite to the upper end face of the short-circuit ring 33. Two guide rods 34 are symmetrically fixed at the bottom of the short-circuit ring 33, extending downwards through the bottom wall of the cylindrical mounting box 7 to the bottom of the mounting box 7. The lower ends of the two guide rods 34 are jointly fixedly connected to a transmission rod 35. Tripping grooves 36 are respectively provided at the bottom inner side of the mechanism box 1 corresponding to the three phase positions. Tripping sliders 37 are slidably connected inside the tripping grooves 36, and the top of the tripping sliders 37 has an inclined guide rail 38 adapted to the transmission rod 35. The top of the trip slider 37 is also provided with an active guide rail 39. One end of the active guide rail 39 is symmetrically fixedly connected with a tension spring 40, and the other end of the tension spring 40 is fixed to the inner wall of the mechanism box 1 to provide a reset force for the trip slider 37. Inside the mechanism box 1, a horizontally arranged active rod 41 is also rotatably connected. Three eccentric wheels 42 are evenly fixed on the rod body corresponding to the three phase positions. A manual trip slider 43 is rotatably connected to the eccentric shaft of each eccentric wheel 42. The end of the manual trip slider 43 is embedded in the active guide rail 39 corresponding to the trip slider 37. One end of the active rod 41 protrudes outward from the side wall of the mechanism box 1, and a manual trip handle 44 is fixedly connected to the end, serving as the input end for external manual operation.

[0030] In operation, when the circuit breaker performs a closing operation, the excitation coil 10 is supplied with a closing current, and the resulting excitation magnetic field drives the moving iron core 8 to move the main shaft 11 upward. The main shaft 11 pushes the moving conductive contact 5 upward synchronously through the insulating pull rod 6. In the initial stage of the main shaft's upward movement, the reset stop 27 compresses the reset spring 28 synchronously with the main shaft to store energy; at this time, the lifting ring 26 has not yet contacted the limit slider 24, the buffer spring 25 remains in its initial state and is not under force, and the limit slider 24 stays at the lower limit position of the limit groove 23.

[0031] As the main shaft continues to move upward, the moving conductive contact 5 approaches the stationary conductive contact 4, entering the closing stage. The lifting ring 26 at the top of the low thermal resistance heat-conducting plate 16 contacts the bottom surface of the limiting slider 24, pushing the limiting slider 24 to slide upward along the limiting groove 23, gradually compressing the buffer spring 25. When the closing is fully completed, the upper end surface of the low thermal resistance heat-conducting plate 16 and the lower end surface of the low thermal resistance heat-conducting cover 15 are axially pressed together, forming a complete lateral heat conduction path. The intervention of the buffer spring 25 during the closing stage can effectively weaken the collision impact force between the moving conductive contact 5 and the stationary conductive contact 4, suppressing contact bounce and hard wear.

[0032] The Joule heat generated by the main circuit current flow is conducted along the moving conductive contact 5 and the insulating pull rod 6 to the main shaft 11. After reaching the middle section of the main shaft, it is transferred to the low thermal resistance heat-conducting cover 15 through the attached low thermal resistance heat-conducting plate 16. Since the low thermal resistance heat-conducting cover 15 is fixed to the inner wall of the conduction lifting groove 14, which is located at the contact end face between the pole post 2 and the mechanism box 1, the heat of the low thermal resistance heat-conducting cover 15 itself can be directly dissipated to the outside through the pole post 2. At the same time, the heat exchange area can be expanded by the first annular heat dissipation fin 19 connected to one end of the mechanism box 1, and the heat can be quickly dissipated to the outside in conjunction with the convection air inside the box formed by the vent 21. This effectively reduces the heat that continues to be transferred downward along the main shaft 11 to the permanent magnet 9, and reduces the operating temperature rise of the permanent magnet 9. The heat insulation plate 17 at the bottom of the low thermal resistance heat-conducting plate and the heat insulation sleeve 18 on the outer periphery of the columnar mounting box together form a heat insulation barrier to prevent the heat conducted laterally from entering the permanent magnet operating mechanism in the reverse direction, ensuring that the heat is dissipated directionally to the outside.

[0033] During the closing process, the reset block 27 moves upward synchronously with the main shaft 11, driving the transmission rack 32 to slide upward along the lifting slide groove 31. Through gear meshing, it drives each transmission gear 30 to rotate synchronously, thereby driving all the window leaves 29 to flip open synchronously, so that the ventilation openings 21 on both sides of the mechanism box 1 form a through convection channel. When the external air flows over the surface of the first annular heat dissipation fin 19 and the second annular heat dissipation fin 20, it can quickly carry away heat, further enhancing the heat dissipation effect inside the mechanism box.

[0034] After the circuit breaker is closed and the excitation coil 10 is de-energized, the magnetic attraction force generated by the permanent magnet 9 attracts the moving iron core 8, which serves as the main force to maintain the steady state of the circuit breaker, resist the interference of external vibrations, avoid the deviation of the closing position, and achieve rapid self-locking of the closing state.

[0035] Then, when the circuit breaker performs an electric tripping operation, the excitation coil 10 is supplied with tripping current, and the resulting reverse magnetic field counteracts the magnetic attraction of the permanent magnet 9. In the initial stage of tripping, the reset spring 28 and the buffer spring 25 simultaneously release their elastic potential energy, and the two springs together push the main shaft 11 downward, obtaining a greater initial tripping acceleration, ensuring that the moving conductive contact 5 and the stationary conductive contact 4 separate quickly, and improving the reliability of arc extinguishing. Pulling the moving conductive contact 5 to separate from the stationary conductive contact 4 disconnects the main circuit.

[0036] When the limit slider 24 slides down with the main shaft to the lower limit position of the limit slide groove 23, it is blocked by the lower end surface of the slide groove and cannot continue to move downward. The buffer spring 25 then stops releasing power and no longer provides downward thrust to the main shaft 11. The remaining opening stroke is driven independently by the reset spring 28 to avoid overshooting of the opening and causing component impact, and to ensure smooth opening.

[0037] During the opening process, the low thermal resistance heat conduction plate 16 moves downward synchronously with the main shaft 11 and disengages from the end face of the low thermal resistance heat conduction cover 15, and the lateral heat conduction path is automatically disconnected. During the entire movement, there is no relative sliding friction between the end faces of the two heat conduction components, which will not generate wear debris to contaminate the internal insulation space, and also reduces the problem of contact surface wear, effectively extending the service life of the equipment.

[0038] Simultaneously, the reset stop 27 drives the transmission rack 32 to slide downwards along the lifting slide 31, driving the transmission gear 30 to rotate in the opposite direction, causing all the window leaves 29 to flip and close synchronously, completely sealing the ventilation opening 21. Unlike the closed state where the temperature inside the mechanism box 1 is higher than the outside, and the cold air entering only plays a convective cooling role without the risk of condensation; after the circuit is opened and the power is cut off, there is no continuous heat source inside the mechanism box 1, and the overall temperature will gradually change with the ambient temperature. In outdoor operating environments with large day-night temperature differences, when the equipment is in the open state at night, the temperature inside the mechanism box 1 will gradually drop to a lower level as the outside temperature decreases, and the internal metal components will also maintain a low temperature simultaneously; when the daytime temperature rises rapidly and the ambient humidity increases, due to the heat exchange rate of the mechanism box 1 and the heat capacity of the metal itself, the temperature rise inside the mechanism box 1 and the metal components will lag significantly and cannot rise rapidly with the outside temperature. At this time, if the ventilation opening 21 remains open, the warm and humid outside air will enter the mechanism box 1 and, upon contact with the still low-temperature metal component surface, the water vapor will condense to form condensation. The closed vent 21 can effectively prevent warm and humid air from entering the mechanism box 1, avoid component corrosion and lubrication failure, and further improve the long-term operational reliability of the equipment in outdoor environments.

[0039] Finally, if the electrical control system fails and cannot electrically open the circuit breaker, an emergency opening can be completed through a manual mechanism. Rotating the manual opening handle 44 on the outside of the mechanism box 1 drives the drive rod 41 to rotate synchronously. The three eccentric wheels 42 deflect synchronously with the drive rod, and push the three-phase synchronous opening slider 37 to slide horizontally along the opening groove 36 through the manual opening slide rod 43.

[0040] During the sliding of the tripping slider, the high section of the inclined guide rail 38 gradually moves to below the transmission rod 35, lifting the transmission rod 35 upwards. This, in turn, pushes the short-circuit ring 33 upwards along the main shaft 11 via the guide rod 34. When the short-circuit ring 33 moves upwards and comes into contact with the permanent magnet 9, the working magnetic circuit of the permanent magnet is short-circuited, and the magnetic attraction force on the moving iron core 8 is greatly reduced. The return spring 28 can then overcome the remaining magnetic attraction force, pulling the main shaft 11 downwards to complete the tripping action.

[0041] After the operation is completed, release the hand-operated handle 44. The tension of the tension spring 40 will pull the tripping slider 37 to slide back along the tripping groove 36 to reset. The inclined guide rail 38 returns to the low position, and the short-circuit ring 33 falls back to the initial position with the transmission rod 35. The magnetic circuit returns to normal, preparing for the next closing operation.

[0042] The working principle of a magnetically controlled circuit breaker with fast self-locking function provided by this invention is as follows: First, after the closing action is initiated, the excitation coil 10 inside the cylindrical mounting box 7 is supplied with closing current. The resulting excitation magnetic field drives the moving iron core 8 to move upward. The main shaft 11, which is fixed to the moving iron core 8, moves upward synchronously, pushing the moving conductive contact 5 towards the stationary conductive contact 4 through the insulating pull rod 6. In the initial stage of the main shaft 11 moving upward, only the return spring 28 is continuously compressed and stores energy, while the buffer spring 25 does not participate in the force. At this time, the limit slider 24 stays at the lower limit position of the limit groove 23 and does not move upward with the main shaft 11.

[0043] When the moving conductive contact 5 approaches the stationary conductive contact 4, the lifting ring 26 on top of the low thermal resistance heat-conducting plate 16 fixed in the middle section of the main shaft 11 contacts the bottom surface of the limiting slider 24, pushing the limiting slider 24 upward along the limiting slide grooves 23 on both sides, and the buffer spring 25 begins to be compressed. After the circuit is fully closed, the upper end face of the low thermal resistance heat-conducting plate 16 presses tightly against the end face of the low thermal resistance heat-conducting cover 15 fixed in the inner wall of the conduction lifting groove 14, and the lateral heat conduction passage is connected. The buffer spring 25 intervenes when the moving conductive contact 5 approaches the stationary conductive contact 4, which can absorb the mechanical impact at the end of the closing and weaken the collision force between the moving conductive contact 5 and the stationary conductive contact 4.

[0044] The Joule heat generated by the main circuit current flow is conducted along the moving conductive contact 5 and the insulating pull rod 6 to the main shaft 11. After reaching the middle section of the main shaft 11, it is laterally conducted to the pole post 2 and the wall of the mechanism box 1 through the attached heat conduction plate and heat conduction cover, thereby reducing the heat conducted downward to the permanent magnet 9. The heat insulation plate 17 at the bottom of the low thermal resistance heat conduction plate 16 and the heat insulation sleeve 18 on the top of the columnar mounting box 7 form a double barrier to prevent the conducted heat from entering the permanent magnet mechanism in the reverse direction.

[0045] Simultaneously, the reset stop 27 at the lower end of the main shaft 11 moves upward synchronously with the rod, causing the transmission rack 32 fixed on the reset stop 27 to slide upward along the lifting slide groove 31. The transmission rack 32 meshes with the transmission gear 30 inside the vent 21, causing all the window leaves 29 to flip and open synchronously, forming a through convection between the vents on both sides of the mechanism box 1. The first annular heat dissipation fin 19 at the lower end of the low thermal resistance heat conduction cover 15 and the second annular heat dissipation fin 20 at the lower end of the columnar mounting box 7 expand the heat exchange area, which, together with the convective air, quickly removes the heat inside the mechanism box 1.

[0046] After the excitation coil 10 is de-energized, the magnetic attraction of the permanent magnet 9 attracts the moving iron core 8 as the main holding force to maintain the closed steady state and resist the interference of external vibration.

[0047] Then, after the tripping action is initiated, the excitation coil 10 is supplied with reverse current to counteract the magnetic attraction of the permanent magnet 9. In the initial stage of tripping, the reset spring 28 and the buffer spring 25 release elastic potential energy at the same time, and together push the reset stop 27 to drive the main shaft 11 downward. The superimposed force of the two springs can obtain a faster initial tripping speed, ensuring that the moving conductive contact 5 and the stationary conductive contact 4 quickly separate and extinguish the arc, and the main circuit is disconnected.

[0048] When the limit slider 24 slides down with the main shaft 11 to the lower limit position of the limit groove 23, it is blocked by the end face of the limit groove 23 and cannot continue to move down. The buffer spring 25 then stops releasing power and no longer provides the main shaft 11 with the downward thrust. The remaining opening stroke is driven independently by the reset spring 28, which effectively reduces the impact strength of the components caused by the overshoot of the main shaft 11 opening downward movement.

[0049] During the opening process, the low thermal resistance heat conduction plate 16 moves down synchronously with the main shaft 11, detaches from the end face of the low thermal resistance heat conduction cover 15, and the lateral heat conduction path is disconnected.

[0050] Synchronously, the reset stop 27 drives the transmission rack 32 to slide down along the lifting slide 31, driving the transmission gear 30 to rotate in the opposite direction. All window leaves 29 simultaneously flip and close, completely sealing the ventilation opening 21. Under closed operation, the temperature inside the mechanism box 1 is higher than the outside temperature. When the ventilation opening 21 is open, the entry of cold air only enhances heat dissipation, with no risk of condensation. After the circuit breaker is opened, the mechanism box 1 loses its continuous heat source, and the overall temperature gradually changes with the environment. Due to the heat exchange rate and metal heat capacity limitations of the mechanism box 1, the temperature change of the internal metal components lags behind the fluctuations in the external ambient temperature. If the ventilation opening 21 is open, warm and humid air from the outside will easily condense upon contact with the still low-temperature metal surface. Closing the ventilation opening 21 can prevent warm and humid air from entering the mechanism box 1, avoiding condensation and corrosion on the internal metal surface, and extending the outdoor operating life of the equipment.

[0051] Finally, when the electrical control fails and the circuit cannot be opened electrically, the manual opening handle 44 on the outside of the rotating mechanism box 1 is rotated, which drives the active rod 41 inside the box to rotate synchronously. The eccentric wheel 42 on the active rod 41, which is synchronously set for the three phases, deflects with the rod body and pushes the opening slider 37 to slide horizontally along the opening slide groove 36 through the manual opening slide rod 43. The tension spring 40 at the end of the active guide rail 39 is stretched and stored.

[0052] When the trip slider 37 slides, the inclined guide rail 38 at its top gradually lifts the transmission rod 35, which pushes the short-circuit ring 33 at the bottom of the columnar mounting box 7 to move upward along the axis through the guide rod 34. When the short-circuit ring 33 moves up to the point where its upper end face is in close contact with the lower end face of the permanent magnet 9, the high magnetic permeability of the short-circuit ring 33 provides the permanent magnet 9 with a low magnetic resistance bypass that does not pass through the working air gap of the moving iron core 8. Most of the working magnetic flux of the permanent magnet flows away through the short-circuit ring, and the magnetic attraction force acting on the moving iron core 8 is greatly reduced.

[0053] After releasing the hand-operated handle 44, the tension spring 40 retracts and pulls the tripping slider 37 to reset in the opposite direction along the tripping slide groove 36. The inclined guide rail 38 returns to the low position, and the short-circuit ring 33 falls back to the initial position with the transmission rod 35. The magnetic circuit returns to normal, reserving conditions for subsequent closing operations.

[0054] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A magnetically controlled circuit breaker with fast self-locking function, characterized in that: It includes a mechanism box (1) and three pole posts (2) set on its top. The pole posts (2) are equipped with a vacuum interrupter (3). The vacuum interrupter (3) is equipped with a static conductive contact (4) and a moving conductive contact (5). An insulating pull rod (6) is fixed to the lower end of the moving conductive contact (5). The mechanism box (1) is equipped with a permanent magnet operating mechanism, which includes a columnar mounting box (7) and a moving iron core (8) inside it, a permanent magnet (9) surrounding the moving iron core (8) and an excitation coil (10). The lower end of the insulating pull rod (6) is fixedly connected to a main shaft (11), and the lower section of the main shaft (11) extends into the columnar mounting box (7) and is fixedly connected to the moving iron core (8); The contact end face between the pole post (2) and the mechanism box (1) is provided with a conductive lifting groove (14), and a low thermal resistance heat-conducting cover (15) is fixed to the inner wall of the conductive lifting groove (14). The middle section of the main shaft (11) is fixed with a low thermal resistance heat conduction plate (16), which is located inside the conduction lifting groove (14).

2. The magnetically controlled circuit breaker with fast self-locking function according to claim 1, characterized in that: The upper section of the main shaft (11) is fitted with a bellows (12), and the bottom of the bellows (12) is fixedly connected to the bottom of the vacuum interrupter (3). A heat insulation plate (17) is provided at the bottom of the low thermal resistance heat conduction plate (16). The top of the columnar mounting box (7) extends into the interior of the low thermal resistance heat-conducting cover (15), and the outer periphery of the columnar mounting box (7) is fixedly fitted with a heat insulation sleeve (18), which is located between the low thermal resistance heat-conducting cover (15) and the columnar mounting box (7).

3. The magnetically controlled circuit breaker with fast self-locking function according to claim 1, characterized in that: The top of the guide lifting groove (14) is provided with a buffer groove (22), the inner wall of the buffer groove (22) is symmetrically provided with limit sliding grooves (23), and the buffer groove (22) is provided with a limit slider (24). The two ends of the limiting slider (24) are respectively embedded in two limiting grooves (23), and the limiting slider (24) is movably sleeved on the outer periphery of the main shaft (11), and a sliding assembly gap is formed between the limiting slider (24) and the main shaft (11). A buffer spring (25) is fixedly connected to the top of the limiting slider (24), and the buffer spring (25) is disposed between the limiting slider (24) and the buffer groove (22); The top of the low thermal resistance heat-conducting plate (16) is provided with a lifting ring (26) that abuts against the limiting slider (24).

4. The magnetically controlled circuit breaker with fast self-locking function according to claim 1, characterized in that: The bottom of the spindle (11) extends through the columnar mounting box (7), and a reset stop (27) is fixedly connected to the lower end of the spindle (11). A reset spring (28) is provided between the reset stop (27) and the columnar mounting box (7), and the reset spring (28) is sleeved on the outer periphery of the main shaft (11); The bottom of the low thermal resistance heat-conducting cover (15) extends into the interior of the mechanism box (1), and a first annular heat dissipation fin (19) is provided on the outer periphery of one end of the cover inside the mechanism box (1). The columnar mounting box (7) is provided with a second annular heat dissipation fin (20) on the outer periphery of one end that does not extend into the low thermal resistance heat conduction cover (15). Ventilation openings (21) are symmetrically arranged at both ends of the mechanism box (1).

5. The magnetically controlled circuit breaker with fast self-locking function according to claim 4, characterized in that: The ventilation opening (21) is evenly provided with multiple window blades (29), and a transmission gear (30) is fixedly connected to the end of the rotating shaft of the window blade (29). The mechanism box (1) is symmetrically provided with lifting slide grooves (31), and a transmission rack (32) is slidably arranged inside the lifting slide grooves (31). The transmission rack (32) meshes with the transmission gear (30), and the bottom of the transmission rack (32) is fixedly connected to the reset stop (27).

6. The magnetically controlled circuit breaker with fast self-locking function according to claim 1, characterized in that: The main shaft (11) is divided into three sections along the axis: upper section, middle section and lower section. The upper section of the main shaft (11) extends through the mechanism box (1) and the pole column (2) to the interior of the vacuum interrupter (3). The lower section of the main shaft (11) is fixedly connected to the moving iron core (8). The inner wall of the vacuum interrupter (3) is provided with a shielding layer (13).

7. The magnetically controlled circuit breaker with fast self-locking function according to claim 1, characterized in that: The inner bottom of the columnar mounting box (7) is provided with a short-circuit ring (33), and the bottom of the short-circuit ring (33) is symmetrically provided with guide rods (34). The guide rods (34) extend to the bottom of the columnar mounting box (7) and are fixedly connected with a transmission rod (35). The inner bottom of the mechanism box (1) is provided with three opening slide grooves (36), and the opening slide grooves (36) are slidably connected to the opening sliders (37). The top of the opening sliders (37) is provided with an inclined guide rail (38) adapted to the transmission rod (35). When the tripping slider (37) slides along the tripping groove (36), it drives the transmission rod (35) to slide along the inner wall of the inclined guide rail (38), pushing the short-circuit ring (33) to move upward along the main shaft (11).

8. The magnetically controlled circuit breaker with fast self-locking function according to claim 7, characterized in that: The top of the opening slider (37) is provided with an active guide rail (39), one end of the active guide rail (39) is symmetrically fixed with a tension spring (40), and the other end of the tension spring (40) is fixed to the inner wall of the mechanism box (1); The mechanism box (1) is rotatably connected to an active rod (41). The active rod (41) is evenly provided with three eccentric wheels (42) along the axial direction. The eccentric wheels (42) are eccentrically rotatably connected to a hand slide rod (43). One end of the hand slide rod (43) is embedded in the active guide rail (39).

9. The magnetically controlled circuit breaker with fast self-locking function according to claim 8, characterized in that: One end of the active rod (41) extends out of the mechanism box (1) and is fixedly connected to a hand handle (44). Rotating the hand-operated handle (44) drives the active rod (41) to rotate, and through the eccentric wheel (42) and the hand-operated sliding rod (43), pushes the opening slider (37) to slide, so that the short-circuit ring (33) moves up and contacts the permanent magnet (9) to destroy the magnetic circuit. The reset spring (28) overcomes the magnetic attraction and pulls the main shaft (11) to complete the opening.

10. The magnetically controlled circuit breaker with fast self-locking function according to claim 5, characterized in that: When the window leaf (29) rotates to the fully open or fully closed position, it works in conjunction with the magnetic attraction of the permanent magnet (9) to maintain the steady state of opening and closing, thereby achieving rapid self-locking.

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