Rapid permanent magnet operating mechanism of small-air-gap vacuum circuit breaker and switching-on and switching-off method

Abstract

The invention provides a small-air-gap vacuum circuit breaker rapid permanent magnet operating mechanism and a switching-on and switching-off method, and belongs to the field of medium and low voltage vacuum circuit breakers. The mechanism comprises a guide rod, a permanent magnet, an inner static iron core, an outer static iron core, an opening spring, a coil and a movable iron core, wherein the outer side wall of the movable iron core is provided with an axial groove. By reducing the air gap between the movable iron core and the static iron core, the magnetic resistance in the switching-on process is effectively reduced, so that the switching-on response time is shortened, and switching-on is accelerated.

Description

Technical Field

[0001] The invention belongs to the field of medium and low voltage vacuum circuit breakers, and in particular relates to a fast permanent magnetic operating mechanism of a small air gap vacuum circuit breaker and a closing and opening method. Background Art

[0002] Vacuum circuit breakers have quickly occupied the medium-voltage circuit breaker market with their advantages of small size, light weight, suitable for frequent operation, and arc extinguishing without maintenance. The operating mechanisms equipped with vacuum circuit breakers are usually electromagnetic, spring and permanent magnet. Among them, the permanent magnet operating mechanism has attracted people's attention due to its many advantages such as high reliability, low energy consumption, maintenance-free, and synchronous operation. The permanent magnet operating mechanism is mainly divided into monostable and bistable. For the traditional monostable structure, its structure is simpler than that of the bistable. However, the monostable structure has significant disadvantages in improving the dynamic performance of the circuit breaker. In order to increase the opening speed, it usually causes the closing speed to change. The main reason is that the spring elastic force is large, and the electromagnetic force generated by the coil can only drive the circuit breaker to operate when it reaches a high value. These problems limit the further improvement of the dynamic performance of the monostable permanent magnet mechanism. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a fast permanent magnet operating mechanism and a closing and opening method for a small air gap vacuum circuit breaker, which solves the problem of long closing speed reaction time of a monostable fast permanent magnet mechanism.

[0004] To achieve the above object, the technical solution adopted by the present invention is: A fast permanent magnetic operating mechanism for a small air gap vacuum circuit breaker, comprising a guide rod, a permanent magnet, inner and outer static iron cores, a gate opening spring, a coil and a moving iron core, wherein the inner static iron core and the outer static iron core of the inner and outer static iron cores are separated by a permanent magnet, and the inner static iron core has a center hole; the inner static iron core has two upper and lower center holes with different diameters, the diameter of the upper center hole is larger than the diameter of the guide rod, the diameter of the lower center hole is larger than the diameter of the upper center hole, and larger than the outer diameter of the gate opening spring; The guide rod passes through the internal static iron core and is fixedly connected to the moving iron core. There is a groove in the center above the moving iron core to provide space for the inner and outer static iron cores and the opening spring. The opening spring is arranged on the outside of the guide rod, and the two ends of the opening spring are respectively fixed to the internal static iron core and the moving iron core. There is an air gap between the lower outer diameter of the internal static iron core and the upper inner diameter of the moving iron core. There is an air gap between the lower inner diameter of the external static iron core and the outer diameter of the moving iron core. The coil is installed between the moving iron core and the internal static iron core, and there is an air gap between the moving iron cores.

[0005] As a further improvement of the structure of the present invention, the inner and outer static iron cores and the moving iron core are cylindrical or rectangular in shape.

[0006] The present invention provides a closing and opening method of a fast permanent magnetic operating mechanism of a small air gap vacuum circuit breaker: The closing method is as follows: When the mechanism receives the closing signal, the coil begins to pass current, and the direction of the magnetic field generated by the current is consistent with the direction of the permanent magnet's magnetic field; the coil and the permanent magnet act together on the moving iron core; as the current increases, when the current reaches a certain value, the moving iron core overcomes the reaction force of the opening spring and the gravity of the moving iron core and begins to move upward; when the moving iron core reaches the closing position, the coil stops passing power, and the moving iron core is kept in the closing position by the magnetic force generated by the permanent magnet; The specific opening method is as follows: When the mechanism receives the trip signal, current starts to flow into the coil, and the direction of the magnetic field generated by the current is opposite to the direction of the magnetic field of the permanent magnet; the coil and the permanent magnet act together on the moving iron core; as the current increases, when the current reaches a certain value, the reaction force of the trip spring and the gravity of the moving iron core are greater than the magnetic force, and the moving iron core begins to move downward; when the moving iron core reaches the trip position, the coil stops flowing, and the moving iron core is kept in the trip position by the magnetic force generated by the permanent magnet.

[0007] Beneficial effects: Compared with the prior art, the fast permanent magnetic operating mechanism and the closing and opening method of a small air gap vacuum circuit breaker provided by the present invention have the following beneficial effects: The present invention aims to solve the problem that the traditional monostable permanent magnet mechanism affects the closing speed of the circuit breaker when improving its opening dynamic performance. The static iron core structure is optimized so that the air gap between the moving iron core and the static iron core is reduced when the operating mechanism is in the opening position, and there is only a small air gap, thereby reducing the magnetic resistance of the magnetic circuit, so that the mechanism can generate sufficient magnetic force to drive the moving iron core when the current is at a small value during the closing process, thereby shortening the closing response time. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a structural schematic diagram of the present invention in the closed position; Figure 2 It is a structural schematic diagram of the present invention in the open position; In the figure: 1 guide rod, 2 permanent magnet, 3 inner and outer static iron cores, 4 opening spring, 5 coil, 6 moving iron core. DETAILED DESCRIPTION

[0009] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments: A fast permanent magnetic operating mechanism for a small air gap vacuum circuit breaker, the closing position is as follows Figure 1 As shown, the opening position is as follows Figure 2 As shown, it includes a guide rod 1, a permanent magnet 2, inner and outer static iron cores 3, a trip spring 4, a coil 5, and a moving iron core 6. The inner and outer static iron cores 3 are separated by a permanent magnet 2, and the inner static iron core has a center hole; the inner static iron core has two upper and lower center holes with different diameters, the upper center hole has a diameter greater than the guide rod 1, and the lower center hole has a diameter greater than the upper center hole, and is greater than the outer diameter of the opening spring 4; The guide rod 1 passes through the internal static iron core and is fixedly connected to the moving iron core 6. There is a groove in the center above the moving iron core 6 to provide space for the inner and outer static iron cores 3 and the opening spring 4. The opening spring 4 is provided on the outside of the guide rod 1. The two ends of the opening spring 4 are respectively fixed to the internal static iron core and the moving iron core 6. There is a small air gap between the lower outer diameter of the internal static iron core and the upper inner diameter of the moving iron core 6. There is a small air gap between the lower inner diameter of the external static iron core and the outer diameter of the moving iron core 6. The coil 5 is installed between the moving iron core 6 and the internal static iron core, and there is an air gap between the moving iron core 6; The contact surface between the moving iron core and the internal static iron core may be in other shapes that do not affect the movement of the moving iron core; The shapes of the static iron core 3 and the moving iron core 6 can be cylindrical or rectangular; The position of the permanent magnet 2 in the static iron core 3 can be changed; When the moving iron core 6 is in the opening position, there is a certain small air gap contact surface between the moving iron core 6 and the internal static iron core; A closing method for a fast permanent magnetic operating mechanism of a small air gap vacuum circuit breaker: when the mechanism receives a closing signal, the coil 5 starts to pass current, and the direction of the magnetic field generated by the current is consistent with the direction of the magnetic field of the permanent magnet 2; the coil and the permanent magnet act together on the moving iron core 6; as the current increases, when the current reaches a certain value, the moving iron core 6 overcomes the reaction force of the opening spring 4 and the gravity of the moving iron core 6 and starts to move upward; when the moving iron core 6 reaches the closing position, the coil stops passing power, and the moving iron core 6 is kept in the closing position by the magnetic force generated by the permanent magnet 2; A method for opening a fast permanent magnetic operating mechanism of a small air gap vacuum circuit breaker: when the mechanism receives an opening signal, current begins to flow into the coil 5, and the direction of the magnetic field generated by the current is opposite to the direction of the magnetic field of the permanent magnet 2; the coil and the permanent magnet act together on the moving iron core 6; as the current increases, when the current reaches a certain value, the reaction force of the opening spring 4 and the gravity of the moving iron core 6 are greater than the magnetic force, and the moving iron core 6 begins to move downward; when the moving iron core 6 reaches the opening position, the coil stops being energized, and the moving iron core 6 is kept in the opening position by the magnetic force generated by the permanent magnet 2.

[0010] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A fast permanent magnetic operating mechanism for a small air gap vacuum circuit breaker, comprising a guide rod (1), a permanent magnet (2), inner and outer static iron cores (3), a trip spring (4), a coil (5) and a moving iron core (6), characterized in that: The inner and outer static iron cores (3) are separated by a permanent magnet (2) in the middle, and the inner static iron core has a center hole; the inner static iron core has two upper and lower center holes of different diameters, the diameter of the upper center hole is larger than the diameter of the guide rod (1), the diameter of the lower center hole is larger than the diameter of the upper center hole, and larger than the outer diameter of the opening spring (4); The guide rod (1) passes through the internal static iron core and is fixedly connected to the moving iron core (6); a groove is provided at the center of the upper part of the moving iron core (6) to provide space for the inner and outer static iron cores (3) and the opening spring (4); an opening spring (4) is provided on the outer side of the guide rod (1); the two ends of the opening spring (4) are respectively fixed to the internal static iron core and the moving iron core (6); an air gap exists between the lower outer diameter of the internal static iron core and the upper inner diameter of the moving iron core (6); and an air gap exists between the lower inner diameter of the external static iron core and the outer diameter of the moving iron core (6); The coil (5) is installed between the moving iron core (6) and the internal static iron core, and an air gap exists between the moving iron core (6).

2. The fast permanent magnetic operating mechanism for a small air gap vacuum circuit breaker according to claim 1, characterized in that: The inner and outer static iron cores (3) and the moving iron core (6) are cylindrical or rectangular in shape.

3. A closing and opening method for a fast permanent magnetic operating mechanism of a small air gap vacuum circuit breaker using the method according to any one of claims 1 or 2, characterized in that: The closing method is as follows: When the mechanism receives a closing signal, the coil (5) begins to pass current, and the direction of the magnetic field generated by the current is consistent with the direction of the magnetic field of the permanent magnet (2); the coil (5) and the permanent magnet (2) act together on the moving iron core (6); as the current increases, when the current reaches a certain value, the moving iron core (6) overcomes the reaction force of the opening spring (4) and the gravity of the moving iron core (6) and begins to move upward; when the moving iron core (6) reaches the closing position, the coil (5) stops passing current, and the moving iron core (6) is kept in the closing position by the magnetic force generated by the permanent magnet (2); The specific opening method is as follows: When the mechanism receives a trip signal, the coil (5) begins to pass current, and the direction of the magnetic field generated by the current is opposite to the direction of the magnetic field of the permanent magnet (2); the coil (5) and the permanent magnet (2) act together on the moving iron core (6); as the current increases, when the current reaches a certain value, the reaction force of the trip spring (4) and the gravity of the moving iron core (6) are greater than the magnetic force, and the moving iron core (6) begins to move downward; when the moving iron core (6) reaches the trip position, the coil (5) stops passing power, and the moving iron core (6) is kept in the trip position by the magnetic force generated by the permanent magnet (2).

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