Novel permanent magnetic mechanism suitable for permanent magnetic circuit breaker and ring main unit

Abstract

The invention discloses a novel permanent magnetic mechanism suitable for a permanent magnetic circuit breaker and a ring main unit, which is characterized in that a static iron core and a movable iron core are oppositely arranged in an aluminum alloy shell along the axial direction, an internal pull rod penetrates through the axis of the aluminum alloy shell, and the internal pull rod movably penetrates through the static iron core and is connected with the movable iron core; a shaft fixing ring is movably arranged on an inner pull rod of the aluminum alloy shell, the shaft fixing ring movably abuts against the side, away from the static iron core, of the movable iron core, and the two sides of the shaft fixing ring are axially limited through a locking nut and a total stroke adjusting nut which are connected to the inner pull rod in a threaded mode. The mechanism is provided with a total stroke adjusting mechanism, an overtravel adjusting mechanism and a switching-on and switching-off speed adjusting mechanism, respective adjustment is achieved through special nuts, the problem of synchronous change of the opening distance and the overtravel of a traditional mechanism is solved, an aluminum alloy shell and a closed magnetic circuit are adopted, magnetic leakage is reduced, the magnetic field utilization rate and the impact resistance are improved, and spring pre-tightening force is changed through spring adjusting nuts; the switch-on and switch-off speed is accurately controlled, various loads are adapted, and the breaking risk is reduced.

Description

Technical Field

[0001] This invention relates to a permanent magnet mechanism, and more particularly to a novel permanent magnet mechanism suitable for permanent magnet circuit breakers and ring main units. Background Technology

[0002] With the continuous development of power systems, the scale of power grids is expanding, and transmission voltage levels are constantly increasing, placing higher demands on the performance of circuit breakers. Compared to traditional electromagnetic and spring mechanisms, permanent magnet mechanisms have fewer parts, making assembly and debugging simpler and reducing production and maintenance costs. Permanent magnet mechanisms maintain the opening and closing states through the magnetic force generated by permanent magnets, eliminating the need for additional mechanical locking devices. This reduces failures caused by mechanical wear and jamming, improving the reliability and stability of the mechanism's operation. The opening and closing response speed of permanent magnet mechanisms is fast and stable, more accurately meeting the power system's requirements for switching action time. Furthermore, permanent magnet mechanisms are more energy-efficient than other mechanisms during opening and closing operations. Permanent magnet mechanisms in high-voltage switchgear, with adjustable total stroke, overtravel, and opening / closing speed, can better adapt to the complex operating conditions of the power grid, improving the reliability and safety of grid operation.

[0003] Traditional permanent magnet mechanisms use an adjustment mechanism to change the total stroke. By adjusting the length or angle of the crank arm, the movement distance of the permanent magnet mechanism during opening and closing is changed, thus adjusting the total stroke. One end of the crank arm is connected to the permanent magnet, and the other end is connected to the drive component. When the total stroke needs to be adjusted, the locking nut on the crank arm is loosened, the crank arm is rotated to the appropriate position, and then locked again, thereby changing the movement distance of the permanent magnet and thus the total stroke. The adjustability of the connecting rod can also be used to change the total stroke of the permanent magnet mechanism. The length or connection method of the connecting rod can be changed, causing the movement distance of the permanent magnet mechanism during opening and closing to change, thus achieving the purpose of adjusting the total stroke. However, the above adjustment mechanisms usually adjust the overtravel and opening distance simultaneously, making it impossible to flexibly adjust the overtravel; adjustment can only be made through the total stroke, which brings great difficulties to installation and commissioning. Installers often need to spend a lot of time and effort adjusting the entire mechanism to meet the actual needs as much as possible, but still, it is difficult to achieve the most ideal effect. Furthermore, traditional permanent magnet mechanisms are limited by their mechanical structure, making it difficult to adjust the opening and closing speeds. This can easily lead to the opening and closing speeds being unable to adapt to various loads, increasing the risk of interruption failure. Additionally, the inflexible adjustment of the contact end speed of the permanent magnet mechanism may cause secondary arcing or mechanical damage. Summary of the Invention

[0004] To address the shortcomings of the aforementioned technologies, this invention provides a novel permanent magnet mechanism suitable for permanent magnet circuit breakers and ring main units.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a new type of permanent magnet mechanism applicable to permanent magnet circuit breakers and ring main units, including an aluminum alloy shell, a stationary iron core and a moving iron core arranged opposite each other along the axial direction inside the aluminum alloy shell, and an internal tie rod passing through the axis of the aluminum alloy shell, the internal tie rod movingly passing through the stationary iron core and connected to the moving iron core. The aluminum alloy shell, being non-ferromagnetic and possessing a permeability close to that of vacuum, effectively reduces interference from the original magnetic field caused by the reverse magnetic field generated by eddy currents. This shell not only reduces the weight of the mechanism but also improves corrosion resistance and heat dissipation.

[0006] The stationary and moving iron cores are arranged axially opposite each other along the aluminum alloy shell. An internal tie rod passes through the stationary and moving iron cores along the axis and is connected to the moving iron core. This arrangement allows the moving iron core to move stably along the axis under the influence of a magnetic field, realizing the opening and closing function. A shaft fixing ring is movably installed on the internal tie rod, and axial limit is achieved by locking nuts and total stroke adjusting nuts, which can precisely adjust the movement range of the moving iron core and realize the mechanical adjustment of the total stroke.

[0007] A shaft fixing ring is movably installed on the internal tie rod of the aluminum alloy housing. The shaft fixing ring movably abuts against the side of the moving iron core away from the stationary iron core, and the two sides of the shaft fixing ring are axially limited by locking nuts and total stroke adjusting nuts that are threaded to the internal tie rod.

[0008] Furthermore, a closed magnetic circuit is provided inside the stationary iron core, which includes a permanent magnet, a magnetic ring, and a coil; the magnetic ring surrounds the permanent magnet; and the coil is wound around the stationary iron core on the side of the permanent magnet and the magnetic ring.

[0009] The closed magnetic path within the stationary iron core consists of a permanent magnet, a magnetically conductive ring, and a coil. The magnetically conductive ring surrounds the permanent magnet, providing a low-resistivity path for the permanent magnet's magnetic field, forcing the magnetic lines of force to concentrate through the working air gap, and suppressing magnetic leakage. This reduces the loss of magnetic field energy and improves magnetic field utilization.

[0010] A stationary iron core is wound around a permanent magnet and a magnetic ring. When energized, the coil generates an electromagnetic force that superimposes on or cancels out the magnetic field of the permanent magnet, driving the moving iron core to move and thus achieving the opening and closing action. This closed magnetic circuit design also enhances shock resistance and ensures the stability and reliability of the magnetic field.

[0011] Furthermore, the moving iron core is movably connected to the internal tie rod via a spring adjusting nut, and the inner ring of the moving iron core is threadedly connected to the outer ring of the spring adjusting nut. This connection method allows the moving iron core to move flexibly axially.

[0012] Furthermore, the inner pull rod inside the aluminum alloy housing is fitted with a spring, one end of which rests against the spring adjusting nut, and the other end of which rests against the aluminum alloy housing.

[0013] An internal tie rod with an outer spring rests on a spring adjusting nut at one end and on an aluminum alloy housing at the other, forming a spring system for storing energy during opening and closing and maintaining contact pressure at the contacts. The spring stores energy during opening and provides contact pressure during closing, ensuring good contact between the contacts and improving the reliability and stability of opening and closing operations.

[0014] Furthermore, on one side of the internal tie rod section nut, the total stroke adjusting nut is located away from the spring adjusting nut. This layout allows for independent operation when adjusting the total stroke and overtravel, avoiding mutual interference and improving the accuracy and convenience of adjustment.

[0015] Furthermore, the internal tie rod extends from the stationary iron core through the end of the aluminum alloy housing and is threaded with an overtravel adjusting nut to change the overtravel distance of the moving iron core when the circuit is closed.

[0016] An internal tie rod extends from the stationary iron core through the end of the aluminum alloy housing and is threaded to an overtravel adjusting nut. By rotating the overtravel adjusting nut, the overtravel distance of the moving iron core during closing can be changed. This ensures that the contacts maintain sufficient contact pressure even after wear, extending the service life of the contacts and improving the reliability and stability of the equipment.

[0017] A novel method for adjusting the mechanical characteristics of a permanent magnet mechanism includes a total stroke adjustment method, an overtravel adjustment method, and a closing / opening speed adjustment method. The total stroke adjustment method is to rotate the total stroke adjustment nut in the open state of the permanent magnet mechanism to change the effective length of the internal tie rod, measure the opening distance of the moving contact, and adjust cyclically until the opening distance reaches the preset value. With the permanent magnet mechanism in the open position, rotate the total stroke adjusting nut to change the effective length of the internal tie rod, measure the opening distance of the moving contact, and cyclically adjust until the opening distance reaches the preset value. This method can precisely control the movement range of the moving contact, ensuring that the total stroke meets the design requirements, thereby improving the accuracy and reliability of the opening and closing operations.

[0018] The overtravel adjustment method is to manually close the circuit breaker to fully close the contacts after the total travel adjustment is completed, rotate the overtravel adjustment nut, measure the overtravel, and cycle the adjustment until the overtravel reaches the design requirements, and then tighten the locking nut. After the total stroke adjustment is completed, manually close the circuit to fully close the contacts, rotate the overtravel adjusting nut, measure the overtravel, and cycle the adjustment until the overtravel meets the design requirements. Then tighten the locking nut. This method allows for independent adjustment of the overtravel, ensuring that the contacts maintain good contact pressure even after wear, reducing arc loss, and extending mechanical life.

[0019] The method for adjusting the opening and closing speed involves connecting the permanent magnet mechanism to a mechanical characteristic testing device, recording the current opening and closing speed parameters, rotating the spring adjusting nut to change the spring preload, performing opening and closing operations and measuring the speed, and cyclically adjusting until the speed reaches the specified range.

[0020] The permanent magnet mechanism is connected to a mechanical characteristic testing device to record the current opening and closing speed parameters. The spring preload is changed by rotating the spring adjusting nut, and opening and closing operations are performed while measuring the speed. This process is repeated until the speed reaches the specified range. This adjustment method allows for precise control of the opening and closing speed, making it adaptable to various loads, reducing the risk of interruption failure, and improving the adaptability and reliability of the equipment.

[0021] Furthermore, the total stroke adjustment method includes the following steps; The effective length of the internal tie rod can be changed by rotating the total stroke adjusting nut; Measure the opening distance of the moving contact to see if it reaches the preset value; If the requirements are not met, adjustments need to be made repeatedly by continuously rotating the total stroke adjusting nut and measuring the opening distance until the opening distance meets the standard.

[0022] Furthermore, the overtravel adjustment method includes the following steps; Manually close the circuit breaker to fully close the contacts; Rotate the overtravel adjusting nut and measure the overtravel to see if it meets the design requirements. If the requirements are not met, the adjustment needs to be repeated, involving rotating the overtravel adjusting nut and measuring the overtravel. Once the overtravel reaches the design requirements, tighten the lock nut.

[0023] Furthermore, the method for adjusting the opening and closing speed includes the following steps; The permanent magnet mechanism is connected to the mechanical characteristic testing equipment. First, the equipment is initialized and the current opening and closing speed parameters are recorded. Rotate the spring adjusting nut to change the spring preload; Then, the opening and closing operations are performed, and the opening and closing speeds are measured using equipment; Based on the measurement results, repeatedly adjust the spring adjusting nut until the speed reaches the specified range.

[0024] This method of adjusting mechanical properties has the following advantages: Total stroke adjustment precisely controls the position of the moving contact: By rotating the total stroke adjusting nut, the effective length of the internal tie rod can be changed, enabling precise control of the moving contact's range of motion, thereby accurately adjusting the total stroke and ensuring that the final position of the moving contact meets the design requirements.

[0025] Flexible adjustment of total stroke: The total stroke can be easily increased or decreased according to actual needs. Simply screw the nut outward or inward. The operation is simple and flexible.

[0026] Ensuring adjustment accuracy: The adjustment process requires multiple measurements and fine-tuning until the total stroke reaches the specified standard value. This rigorous adjustment method ensures the accuracy of the total stroke and meets the power system's requirements for the precision of switch operation.

[0027] Independent overtravel adjustment: The overtravel adjustment mechanism adjusts the overtravel independently through the overtravel adjustment nut, which is independent of the total stroke adjustment. This solves the problem of synchronous adjustment of overtravel and opening distance in traditional mechanisms, and improves the flexibility and accuracy of adjustment.

[0028] Ensure contact pressure: Overtravel adjustment is closely related to the pre-compression of the spring. By adjusting the overtravel, it can be ensured that the contact maintains sufficient contact pressure after wear, reducing arc loss, extending mechanical life, and ensuring good conductivity.

[0029] Verifying the adjustment effect: After adjusting the overtravel, the contact pressure is verified by closing the circuit again. This allows for a direct check of the adjustment effect, ensuring reliable contact of the contacts and improving the reliability of equipment operation.

[0030] Adjustment of opening and closing speed Precise control of opening and closing speed: By changing the preload of the spring, the opening and closing speed can be precisely controlled to reach the specified range and meet the requirements of different loads and operating conditions.

[0031] Adaptable to various loads: It can adjust the opening and closing speed according to the actual load conditions, improve the adaptability of the permanent magnet mechanism to various loads, reduce the risk of interruption failure, and ensure the stable operation of the power grid.

[0032] Real-time monitoring and adjustment: By connecting the permanent magnet mechanism to the mechanical characteristic testing equipment, the opening and closing speed parameters can be monitored in real time, and repeated adjustments can be made based on the measurement results to achieve precise control of the opening and closing speed, thereby improving adjustment efficiency and accuracy.

[0033] This invention designs a total stroke adjustment mechanism, an overtravel adjustment mechanism, and a closing / opening adjustment mechanism. Each mechanism uses an independent adjusting nut to separately adjust the total stroke, overtravel, and closing / opening speed, avoiding the problem of simultaneous changes in opening distance and overtravel in traditional adjustment methods. Furthermore, by using an aluminum alloy housing and setting a closed magnetic circuit (including a permanent magnet, a magnetic ring, and a coil), magnetic leakage is reduced, magnetic field utilization is improved, shock resistance is enhanced, and the stability and reliability of the magnetic field are ensured. Additionally, a spring adjusting nut is used to change the spring preload, thereby precisely controlling the closing / opening speed, solving the problem of difficult adjustment of the closing / opening speed in traditional permanent magnet mechanisms, making it adaptable to various loads and reducing the risk of interruption failure. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the present invention.

[0035] Figure 2 This is a flowchart of the mechanical characteristic adjustment process of the present invention.

[0036] In the diagram: 1. Overtravel adjusting nut; 2. Internal tie rod; 3. Aluminum alloy housing; 4. Static iron core cylinder; 5. Permanent magnet; 6. Magnetic ring; 7. Spring; 8. Coil; 9. Coil retaining ring; 10. Moving iron core; 11. Spring adjusting nut; 12. Locking nut; 13. Shaft retaining ring; 14. Total stroke adjusting nut. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0038] In this embodiment, Figure 1 A structural diagram of a novel permanent magnet mechanism is shown. Its components include a permanent magnet mechanism overtravel adjustment nut 1, an internal pull rod 2, an aluminum alloy shell 3, a stationary iron core 4, a permanent magnet 5, a magnetic ring 6, a spring 7, a coil 8, a coil fixing ring 9, a moving iron core 10, a spring adjustment nut 11, a locking nut 12, a shaft fixing ring 13, and a total stroke adjustment nut 14. The various adjustment nuts, locking nuts, and shaft fixing rings form a total stroke adjustment mechanism, an overtravel adjustment mechanism, and a closing / opening adjustment mechanism, which respectively realize the function of step-by-step adjustment of the total stroke, overtravel, and closing / opening speed of the permanent magnet mechanism.

[0039] The total stroke adjustment mechanism includes an internal pull rod 2, a locking nut 12, a shaft fixing ring 13, and a total stroke adjusting nut 14. The total stroke of the permanent magnet mechanism is adjusted by changing the effective length of the internal pull rod 2. The overtravel adjustment mechanism is connected to the internal pull rod 2 via the overtravel adjusting nut 1. It is used to adjust the overtravel of the mechanism to ensure that the contacts maintain sufficient contact pressure after wear. As the contact material wears, to ensure sufficient contact pressure after wear, a slight overtravel is required. The mechanical characteristics of the permanent magnet circuit breaker are changed by adjusting the overtravel adjusting nut. The opening and closing adjustment mechanism uses a spring adjusting nut 11 to initialize the spring, ensuring that the opening and closing speeds reach the standard.

[0040] Its structure and function are as follows: A stationary iron core 4 and a moving iron core 10 are arranged axially opposite each other inside the aluminum alloy shell 3. Due to its non-ferromagnetic nature and permeability close to that of vacuum, the aluminum alloy shell 3, as a conductor, generates eddy currents in an alternating magnetic field. According to Lenz's law, the counter-magnetic field generated by the eddy currents hinders the change in the original magnetic field. A large number of counter-magnetic fields superimpose with the original magnetic field, causing a change in the total magnetic field strength in the magnetic circuit. Inside the permanent magnet mechanism, the magnetic field that could originally pass smoothly through the upper shell is disturbed by the counter-magnetic field, and some magnetic lines of force will be twisted and deflected. This results in an uneven magnetic field distribution, thereby reducing the electromagnetic force acting on the moving iron core 10 and the stationary iron core 4. Moreover, due to the presence of the counter-magnetic field, the magnetic reluctance of the magnetic circuit increases, further affecting the propagation efficiency of the magnetic field. When the magnetic reluctance of the magnetic circuit increases to a certain extent, it will lead to a decrease in magnetic field strength, which may not be able to meet the electromagnetic force requirements for the normal opening and closing of the permanent magnet mechanism. Therefore, considering the manufacturing cost and the final effect, in this embodiment, using a 1cm thickness for the aluminum alloy shell 3 is the most practical and economical approach. Meanwhile, the use of an aluminum alloy housing 3 not only reduces the weight of the entire mechanism but also improves the corrosion resistance and heat dissipation of the permanent magnet mechanism. The internal tie rod 2 of the permanent magnet mechanism restricts its movement trajectory through linear bearings, ensuring linear movement of the contacts.

[0041] An internal tie rod 2 runs along the axis of the aluminum alloy housing 3, movably passes through the stationary iron core 4, and connects to the moving iron core 10. A shaft fixing ring 13 is movably mounted on the internal tie rod 2, abutting against the side of the moving iron core 10 away from the stationary iron core 4. Its two sides are axially limited by locking nuts 12 and total stroke adjusting nuts 14 threaded onto the internal tie rod 2. The stationary iron core 4 contains a closed magnetic circuit, including a permanent magnet 5, a magnetic guide ring 6, and a coil 8. The magnetic guide ring 6 surrounds the permanent magnet 5. The main function of the permanent magnet 5 is to generate a magnetic field and transmit it to surrounding materials, magnetizing them. The magnetic guide ring 6 provides a low magnetic resistance path for the magnetic field of the permanent magnet 5, forcing the magnetic lines of force to concentrate through the working air gap, suppressing magnetic leakage, and simultaneously serving as a support structure to prevent displacement of the permanent magnet 5 and enhance impact resistance. The coil 8 is used for electromagnetic drive; when energized, it generates electromagnetic force, which superimposes or cancels the magnetic field of the permanent magnet 5, driving the moving iron core 10 to move and achieve the opening and closing action. The coil 8 has a stationary iron core 4 wound around it beside the permanent magnet 5 and the magnetic ring 6. The coil fixing ring 9 ensures the stability of the coil 8 and prevents it from loosening or shifting. The stationary iron core 4, the permanent magnet 5, and the coil 8 together form a closed magnetic circuit, reducing magnetic leakage and improving the utilization rate of the magnetic field.

[0042] The moving iron core 10 is a movable component directly connected to the contact head system, converting electromagnetic energy into mechanical kinetic energy and electromagnetic force into linear motion to achieve the contact opening and closing function. The moving iron core 10 is movably connected to the internal pull rod 2 via a spring adjusting nut 11, with its inner ring threadedly connected to the outer ring of the spring adjusting nut 11. A spring 7 is sleeved on the internal pull rod 2, with one end abutting against the spring adjusting nut 11 and the other end against the aluminum alloy housing 3. The spring 7 is used for opening energy storage and maintaining contact pressure. The locking nut 12 is located on the side of the internal pull rod 2 closer to the spring adjusting nut 11, and the total stroke adjusting nut 14 is located on the side farther from the spring adjusting nut 11. The internal pull rod 2 extends from one side of the stationary iron core 4 through the end of the aluminum alloy housing 3, and is threadedly connected to the overtravel adjusting nut 1 to change the overtravel distance when the moving iron core 10 is closed. Therefore, in the new permanent magnet mechanism, a stationary iron core 4 and a moving iron core 10 are arranged axially opposite each other inside the aluminum alloy housing 3. An internal tie rod 2 passes through the housing axis and moves through the stationary iron core 4 before connecting to the moving iron core 10. This arrangement allows the moving iron core 10 to move stably axially under the action of a magnetic field, realizing the opening and closing function. A shaft fixing ring 13 is movably installed on the internal tie rod 2, which abuts against the side of the moving iron core 10 away from the stationary iron core 4. It is axially limited by a locking nut 12 and a total stroke adjusting nut 14, which can precisely adjust the movement range of the moving iron core 10 and realize the mechanical adjustment of the total stroke.

[0043] The closed magnetic path within the stationary iron core 4 consists of a permanent magnet 5, a magnetic ring 6, and a coil 8. The magnetic ring 6 surrounds the permanent magnet 5, and the coil 8 is wound around its side. This structure reduces magnetic leakage, improves magnetic field utilization, and enhances impact resistance. The moving iron core 10 is movably connected to the internal pull rod 2 via a spring adjusting nut 11. A spring 7 is fitted over the internal pull rod 2, with its two ends abutting against the spring adjusting nut 11 and the aluminum alloy housing 3, respectively, forming a spring system for storing energy during opening and closing and maintaining contact pressure. By adjusting the spring preload, the opening and closing speed can be precisely controlled. The locking nut 12 and the total stroke adjusting nut 14 are located on the sides of the internal pull rod 2 closest to and furthest from the spring adjusting nut 11, respectively, facilitating the adjustment of the total stroke and overtravel. The internal pull rod 2 passes through the end of the aluminum alloy housing 3 and is threadedly connected to the overtravel adjusting nut 1, which can change the overtravel distance of the moving iron core 10 when it is closed. These structural designs work together to enable the permanent magnet mechanism to flexibly adjust the total stroke, overtravel, and opening and closing speeds according to different power system scenarios, solving the problem that traditional permanent magnet mechanisms are difficult to adapt to diverse application scenarios.

[0044] Figure 2The flowchart illustrating the mechanical characteristic adjustment of this invention is shown, covering total stroke adjustment, overtravel adjustment, and opening / closing speed adjustment. Total stroke adjustment must be performed when the permanent magnet mechanism is in the open position. At this time, by rotating the locking nut of the permanent magnet mechanism and adjusting the total stroke adjusting nut, the effective length of the internal tie rod can be changed, thereby adjusting the movement range of the moving contact. This adjustment method can precisely control the final position of the moving contact, thus achieving a change in the total stroke. If it is necessary to increase the total stroke, the nut should be screwed outwards; conversely, if it is necessary to decrease the total stroke, the nut should be screwed inwards. After each adjustment operation, the total stroke must be remeasured to ensure that it reaches the specified standard value. Multiple measurements and fine-tuning may be required during the adjustment process to ensure the accuracy of the adjustment results and to ensure that the total stroke meets the design requirements.

[0045] The overtravel adjustment mechanism affects the final position of the moving contact through the overtravel adjustment nut, thereby adjusting the overtravel. The overtravel adjustment is primarily related to the pre-compression of the spring. The spring provides contact pressure during the closing process. After completing the total stroke adjustment and fixing the permanent magnet mechanism locking nut, a manual closing operation is required to fully close the contacts. At this time, the overtravel of the moving contact should be measured. If the measurement result does not meet the design requirements, adjustment is needed by repeatedly rotating the overtravel adjustment nut and re-measuring the overtravel until the overtravel meets the design requirements. At this point, the overtravel adjustment nut can be fixed, and the locking nut of the fixing mechanism can be tightened to the overtravel fixing mechanism.

[0046] The overtravel adjustment mechanism changes the spring pre-compression by rotating the overtravel adjustment nut. After adjusting the total stroke and securing the permanent magnet mechanism with the locking nut, manually close the circuit again. If the contacts cannot close completely, this indicates that the total stroke adjustment may be inadequate and needs to be readjusted. With the contacts fully closed, measure the moving contact overtravel, then rotate the overtravel adjustment nut to change the connecting rod length, and perform the closing operation again to verify the contact pressure. Ensuring reliable contact reduces arc loss and extends mechanical life. Even if the contact surface wears during long-term use, sufficient contact pressure is maintained, ensuring good conductivity.

[0047] The elastic potential energy and deformation degree of a spring affect the kinetic energy and resistance of a permanent magnet mechanism during the opening and closing process. By changing parameters such as the spring's preload and stiffness, the energy provided or consumed by the spring during opening and closing can be adjusted, thereby controlling the opening and closing speed. The spring's preload refers to the force applied before installation, which affects the initial state of the spring during opening and closing. When the preload increases, the elastic potential energy stored in the spring before it begins to move increases. During closing, the additional elastic potential energy is converted into the kinetic energy of the moving contact, giving the moving contact a greater initial velocity, thus accelerating the closing speed. However, during opening, a larger preload means the spring needs to overcome greater resistance to release energy, which leads to a slower opening speed. Conversely, reducing the preload slows down the closing speed while accelerating the opening speed.

[0048] After adjusting the total stroke and overtravel, connect the permanent magnet mechanism to the mechanical characteristic testing equipment, initialize it, and record the current opening and closing speed parameters. The opening and closing speed adjustment mechanism changes the spring preload by rotating the spring adjusting nut. When the spring adjusting nut is rotated, the spring seat moves towards the spring, further compressing the spring and increasing the preload; rotating in the opposite direction decreases the preload. This is how the opening and closing speed of the permanent magnet mechanism is changed. After each rotation of the spring adjusting nut, an opening and closing operation needs to be performed, and the opening and closing speed needs to be measured using the equipment. Adjust the spring adjusting nut repeatedly based on the measurement results until the opening and closing speed reaches the specified range; at this point, the commissioning work is complete.

[0049] This adjustment process has the following advantages: Precise control: It can precisely adjust the total stroke, overtravel and opening / closing speed to ensure that all parameters meet the design requirements.

[0050] Independent adjustment: Total stroke, overtravel, and opening / closing speed can be adjusted independently without interference, improving the flexibility and accuracy of adjustment.

[0051] High adaptability: By adjusting the spring preload, it can adapt to various loads and working conditions, reducing the risk of interruption failure.

[0052] Extended service life: Overtravel adjustment can compensate for contact wear, maintain good conductivity, and extend the service life of the equipment.

[0053] Real-time monitoring and adjustment: The opening and closing speeds are monitored in real time using mechanical characteristic testing equipment, and adjustments are made based on the measurement results to ensure the accuracy and reliability of the adjustment.

[0054] In summary, this invention presents an innovative permanent magnet mechanism system that integrates a total stroke adjustment mechanism, an overtravel adjustment mechanism, and a closing / opening adjustment mechanism. Each mechanism is equipped with an independent adjusting nut, enabling precise individual adjustment of the total stroke, overtravel, and closing / opening speed. This innovative design cleverly avoids the drawbacks of the linkage between opening distance and overtravel in traditional adjustment modes, greatly improving the flexibility and accuracy of adjustment. Regarding materials and structure, this invention preferentially uses an aluminum alloy shell, whose non-ferromagnetic properties effectively reduce eddy current losses. Simultaneously, the closed magnetic circuit design—comprising a permanent magnet, a magnetic ring, and a coil—significantly enhances the utilization rate of the magnetic field, strengthens its impact resistance, and lays a solid foundation for the stability and reliability of the magnetic field.

[0055] By cleverly adjusting the spring preload using a spring adjusting nut, this invention successfully overcomes the challenge of adjusting the opening and closing speeds of traditional permanent magnet mechanisms, achieving precise control over these speeds. This breakthrough not only broadens the application load range of the equipment but also significantly reduces the risks associated with switching operations, thereby improving overall safety.

[0056] The advantages of this invention are multi-dimensional and significant. First, its streamlined component design significantly reduces unnecessary parts compared to traditional electromagnetic and spring mechanisms, making assembly and debugging processes efficient and convenient, directly reducing the economic costs of production and subsequent maintenance. Second, this invention eliminates the easily malfunctioning mechanical locking device in traditional mechanisms, instead relying on the stable magnetic field force generated by a permanent magnet to maintain the opening and closing state. This change greatly reduces the probability of failures caused by common problems such as wear and jamming of mechanical components, significantly improving the reliability of equipment operation.

[0057] In terms of performance, this invention achieves high-speed and stable opening and closing response actions, precisely adapting to the stringent requirements of power systems for the action time of switching equipment, thus ensuring the stability of power grid operation. Simultaneously, in terms of energy utilization, this invention exhibits superior energy-saving characteristics in the opening and closing operation process, aligning with the current trend of green energy conservation. Regarding adaptability to complex operating conditions, this invention possesses strong adaptability, capable of readily handling diverse power grid operating scenarios, comprehensively improving the reliability and security of the power grid.

[0058] Of particular note is that this invention achieves completely independent adjustment of total stroke, overtravel, and opening / closing speed, thoroughly solving the problem of mutual constraint between overtravel and opening distance adjustment in traditional permanent magnet mechanisms. This independent adjustment mechanism gives operators greater flexibility, enabling precise adjustments according to actual needs, and greatly improving the applicability and adjustment efficiency of the equipment.

[0059] Furthermore, this invention fully considers the wear and tear issues that occur during long-term operation of the equipment. Through a clever overtravel adjustment design, even after the contacts have experienced a certain degree of wear, sufficient contact pressure can still be maintained between the contacts, thereby extending the service life of the equipment and reducing its total life cycle cost.

[0060] Overall, this invention, with its innovative design, superior performance, and multi-dimensional advantages, provides a novel permanent magnet mechanism solution for the field of permanent magnet circuit breakers and ring main units that is efficient, reliable, flexible, and energy-saving. It is expected to be widely used in power systems and create significant benefits.

[0061] The above embodiments are not intended to limit the present invention. Unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. The present invention is not limited to the above examples. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the technical solutions of the present invention are also within the protection scope of the present invention. Furthermore, the technical features involved in the different embodiments of the present application described above can be combined with each other as long as they do not conflict with each other.

Claims

1. A novel permanent magnet mechanism suitable for permanent magnet circuit breakers and ring main units, characterized in that, It includes an aluminum alloy shell (3), and a stationary iron core (4) and a moving iron core (10) are arranged opposite each other along the axial direction inside the aluminum alloy shell (3). An internal tie rod (2) passes through the axis of the aluminum alloy shell (3), and the internal tie rod (2) moves through the stationary iron core (4) and is connected to the moving iron core (10). A shaft fixing ring (13) is movably provided on the internal pull rod (2) of the aluminum alloy housing (3). The shaft fixing ring (13) is movably abutted against the side of the moving iron core (10) away from the stationary iron core (4). The two sides of the shaft fixing ring (13) are axially limited by the locking nut (12) and the total stroke adjusting nut (14) on the internal pull rod (2) through threaded connection.

2. The novel permanent magnet mechanism applicable to permanent magnet circuit breakers and ring main units according to claim 1, characterized in that: The stationary iron core (4) is provided with a closed magnetic circuit, which includes a permanent magnet (5), a magnetic ring (6) and a coil (8); the magnetic ring (6) surrounds the permanent magnet (5); the coil (8) winds the stationary iron core (4) around the permanent magnet (5) and the magnetic ring (6).

3. The novel permanent magnet mechanism applicable to permanent magnet circuit breakers and ring main units according to claim 2, characterized in that: The moving iron core (10) is movably connected to the internal pull rod (2) through the spring adjusting nut (11), and the inner ring of the moving iron core (10) is threadedly connected to the outer ring of the spring adjusting nut (11).

4. The novel permanent magnet mechanism applicable to permanent magnet circuit breakers and ring main units according to claim 3, characterized in that: The inner pull rod (2) inside the aluminum alloy housing (3) is fitted with a spring (7). One end of the spring (7) rests against the spring adjusting nut (11), and the other end of the spring (7) rests against the aluminum alloy housing (3).

5. The novel permanent magnet mechanism applicable to permanent magnet circuit breakers and ring main units according to claim 4, characterized in that: The locking nut (12) on the internal tie rod (2) is located on the side closer to the spring adjusting nut (11), and the total stroke adjusting nut (14) on the internal tie rod (2) is located on the side away from the spring adjusting nut (11).

6. The novel permanent magnet mechanism applicable to permanent magnet circuit breakers and ring main units according to claim 1 or 5, characterized in that: The internal tie rod (2) extends from one side of the stationary iron core (4) through the end of the aluminum alloy housing (3) and is threaded with an overtravel adjustment nut (1) to change the overtravel distance of the moving iron core (10) when the circuit is closed.

7. A method for adjusting the mechanical characteristics of a novel permanent magnet mechanism according to any one of claims 1-6, characterized in that, This includes methods for adjusting total stroke, overtravel, and opening / closing speed; The total stroke adjustment method is to rotate the total stroke adjustment nut in the open state of the permanent magnet mechanism to change the effective length of the internal tie rod, measure the opening distance of the moving contact, and adjust cyclically until the opening distance reaches the preset value. The overtravel adjustment method is to manually close the circuit breaker to fully close the contacts after the total travel adjustment is completed, rotate the overtravel adjustment nut, measure the overtravel, and cyclically adjust until the overtravel reaches the design requirements, and then tighten the locking nut. The method for adjusting the opening and closing speed involves connecting the permanent magnet mechanism to a mechanical characteristic testing device, recording the current opening and closing speed parameters, rotating the spring adjusting nut to change the spring preload, performing opening and closing operations and measuring the speed, and cyclically adjusting until the speed reaches the specified range.

8. The method for adjusting the mechanical characteristics of the novel permanent magnet mechanism according to claim 7, characterized in that: The total stroke adjustment method includes the following steps; The effective length of the internal tie rod can be changed by rotating the total stroke adjusting nut; Measure the opening distance of the moving contact to see if it reaches the preset value; If the requirements are not met, adjustments need to be made repeatedly by continuously rotating the total stroke adjusting nut and measuring the opening distance until the opening distance meets the standard.

9. The method for adjusting the mechanical characteristics of the novel permanent magnet mechanism according to claim 7, characterized in that: The overtravel adjustment method includes the following steps; Manually close the circuit breaker to fully close the contacts; Rotate the overtravel adjusting nut and measure the overtravel to see if it meets the design requirements. If the requirements are not met, the adjustment needs to be repeated, involving rotating the overtravel adjusting nut and measuring the overtravel. Once the overtravel reaches the design requirements, tighten the lock nut.

10. The method for adjusting the mechanical characteristics of the novel permanent magnet mechanism according to claim 7, characterized in that: The method for adjusting the opening and closing speed includes the following steps; The permanent magnet mechanism is connected to the mechanical characteristic testing equipment. First, the equipment is initialized and the current opening and closing speed parameters are recorded. Rotate the spring adjusting nut to change the spring preload; Then, the opening and closing operations are performed, and the opening and closing speeds are measured using equipment; Based on the measurement results, repeatedly adjust the spring adjusting nut until the speed reaches the specified range.

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