CN201655711U - Permanent magnetic operating mechanism of breaker - Google Patents

Abstract

The utility model relates to an operating mechanism of a breaker used for medium and high voltage distributing lines, belonging to electrical equipment. The permanent magnetic operating mechanism of the breaker comprises a movable shaft, coils and a permanent magnet, wherein the movable shaft is positioned at the axis position of the coils; the permanent magnet is annular and is fixed on the movable shaft, and the outer diameter of the permanent magnet is smaller than the inner diameter of the coil; and at least two coils are arranged in an annular cylinder body coaxially. On the basis of the structure, the operating mechanism can also be characterized in that the cylinder body is magnet-conducting, the axial section of the cylinder body is hollow-H-shaped, and two ends thereof are provided with an upper magnet-conducting cover plate and a lower magnet-conducting cover plate. The permanent magnetic operating mechanism of the breaker enhances the interaction among magnetic fields, increases the use ration of the magnetic fields, realizes reactive maintenance of on-off state, optimizes on-off characteristic, promotes the controllability of the breaker, has simple structure and low cost and improves the reliability of the whole breaker.

Description

Permanent magnet operating mechanism for circuit breakers

Technical field

The utility model relates to an operating mechanism for a medium and high voltage power distribution line circuit breaker, which belongs to electrical equipment.

Background technique

At present, in the power industry at home and abroad, the operating mechanism of the vacuum circuit breaker used for power distribution lines mainly uses the principle of electromagnetic field to attract ferromagnetic materials, that is, by energizing the coils near the upper or lower ends of the movable shaft to attract and fix the ferromagnetic materials. The armature on the movable shaft drives the movable part to move up or down to realize the closing or opening of the circuit breaker. Since this kind of operating mechanism uses the attraction force of the electromagnet to the ferromagnetic material to drive the moving parts to move, the moving parts can only be accelerated and cannot be decelerated during the movement process. Reactive power maintenance in the closing state (that is, it is necessary to energize and consume power in the coil to maintain the opening or closing state). With the continuous development of technology, scientific and technical personnel have made major improvements: a permanent magnet is installed between the two coils. When the circuit breaker is in the closed state, the magnetic field generated by the permanent magnet moves to the movable shaft above. The armature interacts with each other, and the position of the armature can be kept without energizing the coil, so as to realize the reactive power maintenance in the closing state; when the circuit breaker is in the opening state, similarly, the magnetic field generated by the permanent magnet and the moving to the bottom The armature on the movable shaft interacts to realize the reactive power maintenance of the opening state. This improved circuit breaker operating mechanism solves the problem of reactive power maintenance in the opening and closing state (that is, realizes bistable state) by specially installing permanent magnets for reactive power maintenance, but at the same time makes the entire circuit breaker The structure of the operating mechanism is more complex, the cost is higher, and the reliability is worse, and the closing process of the circuit breaker can only be accelerated, not decelerated, the closing performance is not ideal, and the controllability is poor.

Contents of the invention

The technical problem to be solved by the utility model is to design an operating mechanism for the vacuum circuit breaker with good controllability, high reliability, simple structure and low cost, and can realize bistable state at the same time.

The permanent magnet operating mechanism of the circuit breaker proposed by the utility model includes a movable shaft, a coil and a permanent magnet. The movable shaft is located at the axial position of the coil; the permanent magnet is ring-shaped and fixed on the movable shaft. Smaller than the inner diameter of the coil; the coil is divided into at least two, coaxially placed in the annular cylinder.

On the basis of the above structure, the utility model can also be: wherein the cylinder body is magnetically conductive, and its axial section is hollow "H" shape; the two ends of the cylinder body are provided with a magnetically conductive upper cover plate and a lower bottom plate.

Because the utility model fixes the permanent magnet on the movable shaft, it replaces the armature as the driving element for opening and closing, greatly improves the utilization rate of the magnetic field, simplifies the structure of the mechanism, reduces the production cost, and improves the reliability of the entire circuit breaker ;The energized coil has both attraction and repulsion to the permanent magnet, so that the operating mechanism can both accelerate and decelerate during the opening and closing process, and has better opening and closing characteristics; The suction force can also realize the reactive power maintenance of the opening and closing state of the circuit breaker operating mechanism.

Description of drawings

Fig. 1 is the structural principle diagram of the utility model embodiment;

Fig. 2 is a schematic diagram of the structure of the utility model applied to a vacuum circuit breaker.

Detailed ways

The utility model will be described in detail below in conjunction with the accompanying drawings and embodiments, but the technical solution of the utility model is not limited thereto. In practical applications, the vacuum circuit breaker is usually placed vertically, and the vacuum chamber is located above the operating mechanism; of course, it can also be placed vertically in reverse, horizontally or obliquely according to actual needs.

In the embodiment of the present invention shown in FIG. 1 , a movable shaft 2 , an upper coil 4 , a lower coil 6 and a permanent magnet 3 are included. The movable shaft 2 is located on the axis of the upper coil 4 and the lower coil 6 . The upper coil 4 and the lower coil 6 are coaxially placed in the annular cylinder 5 . Each coil has an inner diameter of 50mm, an outer diameter of 98mm, and a height of 28mm, and the two coils are coaxially arranged on the upper and lower parts of the cylinder. The cylinder is used as the support frame of the upper and lower coils, and plays the role of installing and fixing the coils. The wall thickness of the cylinder is 10mm, so as to ensure sufficient mechanical strength. An upper cover plate 1 can also be provided above the upper coil 4, and a lower base plate 7 can also be provided below the lower coil 6. The upper cover plate 1 and the lower base plate 7 are connected to the upper and lower ends of the cylinder body 5 respectively, and the two coils are connected together. Enclosed, the coil is located in the inner cavity formed by the cylinder body 5 , the upper cover plate 1 and the lower bottom plate 7 . The permanent magnet 3 and the movable shaft 2 are located in the hollow of the cylinder body 5 . The permanent magnet 3 is ring-shaped, with a height of 40mm and an outer diameter of 45mm, which is smaller than the inner diameter of the coil. It is fixed on the movable shaft 2 with a diameter of 12mm (it can be fixed by screw parts, or can be fixed by welding, riveting, etc.), It can drive the movable shaft 2 to move up and down together. When the lower coil 6 is passed into a reverse current (the direction of the magnetic field that the coil generates at the permanent magnet 3 is opposite to the direction of the permanent magnet 3 magnetic field), the permanent magnet 3 is pushed upward by the coil 6; otherwise, when the upper coil 4. When the reverse current is passed into and the magnetic field opposite to the direction of the permanent magnetic field is generated at the permanent magnet 3, the permanent magnet 3 is pushed downward by the repulsion force of the coil 4; When the direction of the magnetic field at the 3 places is the same as that of the permanent magnet 3, the coil and the permanent magnet 3 will generate an attractive force to attract each other. Therefore, by changing the current passed into the coil, the permanent magnet 3 can be subjected to an upward or downward force, so that the permanent magnet 3 drives the movable shaft 2 to move upward or downward together. The permanent magnet 3 acts as a driving element for opening and closing in the utility model, which can be directly integrally processed into a desired shape, or can be assembled by multiple pieces of the same diameter. The movable shaft 2 is made of non-magnetic material (such as stainless steel, aluminum alloy, etc.), so as not to affect the magnetic field between the permanent magnet 3 and the coil.

In the utility model, the cylinder body 5 where the upper coil 4 and the lower coil 6 are placed can also be magnetically conductive (such as DT4C, No. 20 steel, etc.), and the upper cover plate 1 above the cylinder body 5 and the lower bottom plate 7 below can also be Be magnetically conductive (for example DT4C, No. 20 steel etc.), cylinder body 5, upper cover plate 1 and lower bottom plate 7 three constitute the unobstructed magnetic circuit of self closure. That is to say, the outer ends of the two coils are respectively wrapped by ferromagnetic materials, and the permanent magnet moves in the inner cavity formed by the coils and ferromagnetic materials, thereby greatly constraining the direction of the magnetic field lines and reducing the magnetic resistance. The thickness of the ferromagnetic material is such that its magnetic field does not saturate. The annular cylinder 5 can also be designed in the form of a hollow "H" in the axial section, that is, there is an annular "beam" in the middle of the cylinder, and the two coils are respectively located on the upper and lower parts of the "H"-shaped "beam" of the cylinder. It is surrounded by the upper and lower inner cavities formed by the cylinder body 5, the upper cover plate 1 and the lower bottom plate 7, which not only greatly reduces the magnetic flux leakage, but also prevents mutual inductance between the two coils. There will be no mutual interference when turning on and off the current, and the response speed and control performance will be improved. The upper cover plate 1 and the lower base plate 7 can also interact with the permanent magnet 3, thereby realizing the bistable state of the circuit breaker: when the movable shaft 2 moves upward to a suitable position, the permanent magnet 3 and the upper cover plate 1 attract each other, realizing a non-stop circuit breaker. Power retention; when the movable shaft 3 moves down to a proper position, the permanent magnet 3 and the lower bottom plate 7 attract each other to realize reactive power retention. At the same time, when the circuit breaker is in the closing state, the contact pressure of the moving and static contacts of the circuit breaker can be significantly increased and the resistance thereof can be reduced by utilizing the large suction force generated by the upper cover plate 1 on the permanent magnet 3 .

In the present utility model, using the upper coil 4 and the lower coil 6 to drive the built-in permanent magnet 3 can significantly improve the opening and closing performance of the entire circuit breaker. When the circuit breaker is in the opening position, the permanent magnet 3 and the lower coil 6 are at the closest position. At this time, if the reverse current is passed to the lower coil 6, the upward repulsive force generated by the lower coil 6 on the permanent magnet 3 is the maximum value. , the moving parts move upward under the action of this repulsive force to perform the closing operation driven by acceleration and the closing speed increases rapidly. When the closing is at the end stage, in order to keep the final closing speed of the circuit breaker within a reasonable range (to avoid excessive impact force at the moment of closing), the reverse current in the lower coil 6 can be disconnected and given The upper coil 4 is fed with a reverse current. At this time, the permanent magnet 3 is closer to the upper coil 4, and the upper coil 4 generates a greater downward repulsion to the permanent magnet 3, so that the closing speed of the circuit breaker is quickly reduced to an ideal range. Internally, perform the closing operation of the deceleration drive. The acceleration and deceleration phases during opening are similar.

In addition, during the closing process, the permanent magnet 3 can also be accelerated and decelerated by passing current through two coils at the same time, so as to linearize the electromagnetic driving force during the entire closing process and improve the controllability of the mechanism. That is, when the permanent magnet 3 needs to be accelerated and driven, a reverse current is passed into the lower coil 6 to make it generate an upward repulsion force on the permanent magnet 3, and at the same time, a forward current is passed to the upper coil 4 to make it generate an upward repulsion to the permanent magnet 3. of suction. If it is necessary to decelerate the permanent magnet 3, feed the forward current to the lower coil 6 to make it generate a downward suction force on the permanent magnet 3, and feed the reverse current to the upper coil 4 to make it generate a downward suction to the permanent magnet 3. under the repulsion. In this way, the upward total electromagnetic force received by the permanent magnet 3 during the closing acceleration process and the downward total electromagnetic force received during the closing deceleration process are approximately in a linear relationship with its movement displacement, and the closing controllability of the mechanism is significantly improved. . The acceleration and deceleration phases during opening are similar.

In the embodiment shown in Figure 2 where the utility model is applied to a vacuum circuit breaker, the movable shaft 2 in the operating mechanism 10 and the vacuum chamber moving contact 9 protruding from the vacuum chamber 8 are screwed together, In this way, the movable shaft 2 can drive the movable contact 10 of the circuit breaker to move up and down together, thereby realizing closing and opening of the circuit breaker.

For example: when the circuit breaker is closing, a reverse current is applied to the lower coil 6, and the lower coil 6 generates an upward electromagnetic repulsion force on the permanent magnet 3. At this time, the electromagnetic force is compatible with the pulling force of the vacuum chamber 8 and the upper cover plate 1. The sum of the suction force of the permanent magnet 3 is greater than the sum of the suction force of the lower base plate 7 to the permanent magnet 3 and the gravity of the movable part. The permanent magnet 3 drives the movable shaft 2 and the movable contact 9 to move upward together under the action of the combined external force. Implement the closing operation. When the closing is carried out to the end stage, the reverse current in the lower coil 6 is disconnected and the reverse current is passed into the upper coil 4, so the upper coil 4 generates downward electromagnetic repulsion to the permanent magnet 3, At this time, the sum of the suction force of the upper cover plate 1 to the permanent magnet 3 and the pulling force of the vacuum chamber 8 is less than the sum of the electromagnetic force, the suction force of the lower base plate 7 to the permanent magnet 3 and the gravity of the movable parts, and the moving parts start to decelerate, realizing the ideal combination. brake. After the closing is completed, the current flowing into the coil is disconnected. At this time, the distance between the permanent magnet 3 and the upper cover plate 1 is closer to the lower base plate 7. The sum of the suction force of the bottom plate 7 on the permanent magnet 3 and the gravity of the movable parts ensures the rated closing pressure of the moving and static contacts and realizes reliable reactive power maintenance in the closing state. In the same way, the effective opening of the circuit breaker can be achieved by passing reverse currents in the upper coil 4 and the lower coil 6 successively, and the opening process can be effectively controlled by changing the current passed into the coils. After the opening is completed, the sum of the suction force of the upper cover plate 1 to the permanent magnet 3 and the pulling force of the vacuum chamber is much smaller than the sum of the suction force of the lower bottom plate 7 to the permanent magnet 3 and the gravity of the movable parts. The sum of the suction force and the gravity of the movable parts can realize the reliable reactive power maintenance of the opening state. The above is explained according to the way that the circuit breaker is placed vertically, but the technical solution of the utility model is not limited thereto.

Throughout the whole invention, since the permanent magnet is fixed on the movable shaft, the replacement armature serves as the driving element for opening and closing, and also serves as the power source for reactive power retention, that is, it is realized by attracting the upper cover plate 1 and the lower bottom plate 7 The bistable state greatly improves the utilization rate of the magnetic field, simplifies the structure of the mechanism, reduces the production cost, and improves the reliability of the entire circuit breaker; the built-in permanent magnet is driven by the energized coil, and the energized coil has both suction force and The repulsive force enables the operating mechanism to both accelerate and decelerate during the opening and closing process, and can also control the opening and closing speed of the operating mechanism in real time by changing the magnitude and direction of the current passing into the coil, significantly improving the opening and closing performance of the entire circuit breaker Simultaneous energization of the upper and lower coils can also linearize the magnetic field in the moving area of the permanent magnet, further significantly improving the controllability of the circuit breaker; the magnetic conduction cylinder 5 with a hollow H-shaped axial section can also significantly improve the magnetic circuit of the magnetic field , and effectively suppress the mutual inductance between the upper coil 4 and the lower coil 6, thereby greatly speeding up the response speed of the on-off current in the coil and improving the control performance of the entire operating mechanism. The utility model effectively improves the stability and reliability of the circuit breaker, obviously improves the comprehensive performance of the circuit breaker, satisfies industry standards and use requirements, and can be used for medium and high voltage power distribution lines.

Claims (3)

1. the permanent-magnet operating mechanism of a circuit breaker includes movable axis, coil and permanent magnet, and movable axis is positioned at the axial location of coil, it is characterized in that: permanent magnet is a ring-type, is fixed on the movable axis, and the permanent magnet external diameter is less than internal coil diameter; Coil is divided into two at least, the coaxial annular cylinder that places.

2. the permanent-magnet operating mechanism of circuit breaker according to claim 1, it is characterized in that: described cylinder body is a magnetic conduction, its axial cross section is hollow " H " type.

3. the permanent-magnet operating mechanism of circuit breaker according to claim 1, it is characterized in that: described cylinder body two ends are provided with the upper cover plate and the lower shoe of magnetic conduction.

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