Backup protection system and circuit breaker

Abstract

The invention relates to a backup protection system and a circuit breaker, and belongs to the technical field of circuit breakers. Through the structural cooperation between the magnet yoke and the armature, the spring cannot generate torsional deformation in the process that the pin shaft in the backup protection device penetrates through the concentric holes in the magnet yoke and the armature and the spring, and the influence of the elastic force of the spring is avoided. And after the pin shaft, the magnet yoke, the armature and the spring are positioned, the elastic force of the spring can be applied through simple operation, and the magnet yoke and the armature are limited, so that the assembly of the backup protection device is completed. And when the short-circuit current far exceeds the set current value of the electronic tripping system, the circuit breaker can be quickly and effectively driven to trip and open to cut off a fault circuit, and the requirement of improving the production efficiency can be met.

Description

Technical Field

[0001] This invention relates to backup protection systems and circuit breakers, and belongs to the field of circuit breaker technology. Background Technology Generally, electronic molded case circuit breakers primarily achieve their protection function by using an electronic tripping system, which includes a current transformer, electronic controller, and flux actuator, to disconnect faulty circuits. However, when the short-circuit current significantly exceeds the set current value of the electronic tripping system, the tripping unit of the system only activates after the short-circuit signal undergoes a series of transformations by the electronic tripping system's control unit, thus slowing down the disconnection of the faulty circuit. Therefore, the electronic tripping system of a circuit breaker typically requires the use of a backup protection device. When the short-circuit current significantly exceeds the set current value of the electronic tripping system, the backup protection device activates before the electronic tripping system, causing the circuit breaker to trip and disconnect the faulty circuit, reducing the risk of short-circuit damage.

[0002] Most backup protection devices used in molded case circuit breakers consist of components such as a yoke, armature, pin, and spring, as well as a support bracket. The bracket is typically fixed to the yoke and serves to rotatably connect and limit the armature's movement, as specified in CN202321402886.3 and CN202421910695.2. During backup protection device assembly, the armature is usually aligned with the concentric holes on the bracket, and the springs are twisted until they contact the armature and bracket respectively, or twisted until they contact the armature and yoke respectively. Then, the pin is passed through the multiple concentric holes and springs to complete the assembly. Throughout the process, the spring's elastic force remains constant, affecting the assembly operation and speed. To ensure the stability and accuracy of the backup protection device, the radial dimensions of the concentric holes in the armature and bracket are often very close to the radial dimensions of the pin, resulting in a small radial clearance between the pin and the holes. This makes it quite difficult to keep the armature and the concentric holes on both sides of the bracket in a straight line during assembly, under the action of the spring's elastic force, and to quickly insert the pin through the concentric holes and the spring, thus reducing assembly efficiency.

[0003] Therefore, there is currently a lack of a backup protection system that can solve the above problems. Summary of the Invention

[0004] To address the aforementioned problems, firstly, the present invention provides a backup protection system for molded case circuit breakers that is easy to assemble and has reliable performance.

[0005] The backup protection system is installed inside the circuit breaker and includes stationary contacts, moving contacts, and a backup protection device. The stationary contacts are installed in the base, the arc-extinguishing chamber is located above the stationary contacts, the moving contacts are rotatably connected to the mechanism and installed in the base, a portion of the moving contact bridge of the moving contacts extends into the arc-extinguishing chamber, the traction rod is rotatably connected to the mechanism, the electronic tripping system, the partition and the backup protection device are installed in the base, and the partition is located behind the backup protection device and abuts against the armature. In the backup protection device, the armature can rotate around the pin axis towards the side of the magnetic yoke, and during the rotation, it hits the traction rod to drive the mechanism to trip and open the circuit, causing the moving contact to separate from the stationary contact and cut off the fault circuit.

[0006] Furthermore, the base is provided with a limiting groove and a limiting wall, which are respectively adapted to the pin and armature in the backup protection device; the pin is inserted into the limiting groove to form a positioning; the limiting bosses on both sides of the armature are located between the limiting walls of the base, which restrict the armature from moving a large distance along the pin axis.

[0007] Furthermore, the part where the yoke and armature engage is U-shaped, the part where the armature and yoke engage is a plane, and an annular space is formed between the yoke and the armature for the second conductive component to pass through.

[0008] Furthermore, one end of the first conductive component in the moving contact is connected to the moving contact bridge, and the other end of the first conductive component is connected to the second conductive component. The second conductive component passes through the backup protection device and is connected to the third conductive component. The circuit can completely pass through the backup protection device, so that the change in electromagnetic field generated when a large short-circuit current passes through drives the backup protection device to work.

[0009] Furthermore, the pin passes through the concentric holes on the yoke and armature, as well as the spring, to position the internal structure of the backup protection device.

[0010] Furthermore, the first end of the spring abuts against the magnetic yoke, and the second end of the spring abuts against the armature.

[0011] Furthermore, the two ends of the U-shaped part where the magnetic yoke and armature cooperate are provided with limiting planes and limiting ends.

[0012] Furthermore, the armature is provided with a moving surface and a moving end; the armature is always in contact with the magnetic yoke due to the elastic force of the spring.

[0013] Secondly, the present invention provides a circuit breaker equipped with the aforementioned backup protection system.

[0014] The beneficial effects of this invention are: This invention, through the structural cooperation between the magnetic yoke and the armature, ensures that the spring does not twist or deform during the insertion of the pin through the concentric holes on the magnetic yoke and armature, thus avoiding the influence of the spring's elastic force. After the positioning of the pin, yoke, armature, and spring is completed, the spring's elastic force can be applied and the magnetic yoke and armature can be limited through a simple operation, completing the assembly of the backup protection device. While ensuring the functional requirement of quickly and effectively driving the circuit breaker to trip and disconnect the faulty circuit when the short-circuit current far exceeds the electronic tripping system's set current value, this invention also meets the need to improve production efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a circuit breaker; Figure 2 This is a schematic diagram of the internal structure of a circuit breaker; Figure 3 A schematic diagram showing the structure of the backup protection device and its base; Figure 4 This is a schematic diagram showing the interaction between the backup protection device and the moving contact conductive assembly. Figure 5 This is a schematic diagram of a backup protection device; Figure 6 This is a cross-sectional view of the limiting end contact moving surface during the assembly of the backup protection system; Figure 7 A cross-sectional view of the structure of the moving end contacting the limiting plane during the assembly of the backup protection system; Figure 8 A schematic diagram of the magnetic yoke for the backup protection system; Figure 9 This is a schematic diagram of the armature of the backup protection system.

[0016] In the diagram, 1. Base; 2. Housing; 3. Stationary contact; 4. Moving contact; 41. Moving contact bridge; 42. First conductive component; 43. Second conductive component; 44. Third conductive component; 5. Mechanism; 6. Traction rod; 7. Arc extinguishing chamber; 8. Electronic tripping system; 9. Backup protection device; 91. Magnetic yoke; 911. Limiting plane; 912. Limiting end; 92. Armature; 921. Moving surface; 922. Moving end; 923. Limiting boss; 93. Pin; 94. Spring; 941. First end; 942. Second end; 10. Partition; 11. Limiting groove; 12. Limiting wall. Detailed Implementation

[0017] 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, not all, of the embodiments of the present invention. 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.

[0018] In this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] In this invention, the terms "first" and "second" are used only to distinguish similar components / parts in different positions or with different characteristics, and have no other limiting meaning; "upper" refers to the direction in which each component is away from the ground, and "lower" refers to the direction in which each component is away from the ground.

[0020] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0021] In a first aspect, the present invention provides a backup protection system for molded case circuit breakers that is easy to assemble and has reliable performance.

[0022] The backup protection system is installed inside the circuit breaker, including a stationary contact 3, a moving contact 4, and a backup protection device 9; the stationary contact 3 is installed in the base 1, the arc-extinguishing chamber 7 is located above the stationary contact 3, the moving contact 4 is rotatably connected to the mechanism 5 and installed in the base 1, a portion of the moving contact bridge 41 of the moving contact 4 extends into the arc-extinguishing chamber 7, the traction rod 6 is rotatably connected to the mechanism 5, the electronic tripping system 8, the partition 10 and the backup protection device 9 are installed in the base 1, the partition 10 is located behind the backup protection device 9 and abuts against the armature 92; The armature 92 in the backup protection device 9 can rotate around the pin 93 towards the side closer to the magnetic yoke 91, and during the rotation, it hits the traction rod 6 to drive the mechanism 5 to trip and open the circuit, so that the moving contact 4 separates from the stationary contact 3 and cuts off the fault circuit.

[0023] In some embodiments, the base 1 is provided with a limiting groove 11 and a limiting wall 12, which are respectively adapted to the pin 93 and armature 92 in the backup protection device 9; the pin 93 is inserted into the limiting groove 11 to form a positioning; the limiting bosses 923 on both sides of the armature 92 are located between the limiting wall 12 of the base 1, which restricts the armature 92 from moving a large distance along the axial direction of the pin 93.

[0024] In some embodiments, the mating portion of the yoke 91 and the armature 92 is U-shaped, the mating portion of the armature 92 and the yoke 91 is a plane, and an annular space is formed between the yoke 91 and the armature 92 for the second conductive component 43 to pass through.

[0025] In some embodiments, one end of the first conductive component 42 in the moving contact 4 is connected to the moving contact bridge 41, and the other end of the first conductive component 42 is connected to the second conductive component 43. The second conductive component 43 passes through the backup protection device 9 and is connected to the third conductive component 44. The circuit can completely pass through the backup protection device 9, so that the change in electromagnetic field generated when the short-circuit large current passes through drives the backup protection device 9 to work.

[0026] In some embodiments, the pin 93 passes through the concentric holes on the yoke 91 and the armature 92, as well as the spring 94, to position the internal structure of the backup protection device 9.

[0027] In some embodiments, the first end 941 of the spring 94 abuts against the yoke 91, and the second end 942 of the spring 94 abuts against the armature 92.

[0028] In some embodiments, the two ends of the U-shaped portion where the magnetic yoke 91 and armature 92 cooperate are provided with a limiting plane 911 and a limiting end 912.

[0029] In some embodiments, the armature 92 is provided with a moving surface 921 and a moving end 922; the armature 92 is always in contact with the yoke 91 due to the elastic force of the spring 94.

[0030] Example 1 This embodiment provides a circuit breaker equipped with a backup protection system.

[0031] In the backup protection device 9, the pivot 93 passes sequentially through the concentric holes on the magnetic yoke 91 and armature 92, and the spring 94 to complete the positioning of each part. Then, the first end 941 of the spring 94 abuts against the magnetic yoke 91, applying force to the armature 92 and pushing it to rotate around the pivot 93 towards the U-shaped end face of the magnetic yoke 91. The second end 942 of the spring 94 then abuts against the armature 92 and is twisted as the armature 92 rotates. During rotation, the limiting end 912 of the magnetic yoke 91 preferentially abuts against the moving surface 921 on the armature 92. If the armature 92 continues to rotate, the moving surface 921 will compress and interfere with the limiting end 912, preventing further movement of the armature 92. Simultaneously, the elastic force generated by the twisting of the second end 942 of the spring 94 during the rotation of the armature 92 is opposite in direction to the force applied to the armature 92. Subsequently, by increasing the force applied to the armature 92, the elastic force of the spring 94 is overcome, and the elastic deformation generated by the compression between the moving surface 921 of the armature 92 and the limiting end 912 of the magnetic yoke 91 is sufficient to forcibly push the moving surface 921 to rotate past the limiting end 912. After the above process is completed, the moving surface 921 and the limiting end 912 no longer come into contact, and the elastic deformation between them disappears.

[0032] After the moving surface 921 of the armature 92 rotates past the limiting end 912 of the yoke 91, the force applied to the armature 92 can be removed. Subsequently, due to the influence of the elastic force of the spring 94, the armature 92 rotates away from the U-shaped end face of the yoke 91 until the moving end 922 of the armature 92 abuts against the limiting plane 911 of the yoke 91. However, at this time, the elastic force generated by the second end 942 of the spring 94 twisting to this position is insufficient to cause the elastic deformation between the moving end 922 and the limiting plane 911 to the extent that the moving end 922 can rotate around the pin 93 and pass through the limiting plane 911. Therefore, the moving end 922 can only always abut against the limiting plane 911, so that the positions of the armature 92 and the yoke 91 are relatively fixed. The electromagnetic field change generated when the short-circuit large current passes through the backup protection device 9 causes the armature 92 to overcome the elastic force of the spring 94 and rotate around the pin shaft 93 towards the U-shaped end face of the magnetic yoke 91, and hit the traction rod 6 to drive the mechanism 5 to trip and open the circuit, so that the moving contact 4 separates from the stationary contact 3 and cuts off the fault circuit.

[0033] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A backup protection system, installed inside a circuit breaker, characterized in that, It includes a stationary contact (3) and a moving contact (4) as well as a backup protection device (9); the stationary contact (3) is installed in the base (1), the arc-extinguishing chamber (7) is located above the stationary contact (3), the moving contact (4) is rotatably connected to the mechanism (5) and installed in the base (1), a portion of the moving contact bridge (41) of the moving contact (4) extends into the arc-extinguishing chamber (7), the traction rod (6) is rotatably connected to the mechanism (5), the electronic tripping system (8), the partition (10) and the backup protection device (9) are installed in the base (1), the partition (10) is located behind the backup protection device (9) and abuts against the armature (92); In the backup protection device (9), the armature (92) can rotate around the pin (93) towards the side closer to the magnetic yoke (91), and during the rotation, it hits the traction rod (6) to drive the mechanism (5) to trip and open the circuit, so that the moving contact (4) separates from the stationary contact (3) and cuts off the fault circuit.

2. The backup protection system according to claim 1, characterized in that, The base (1) is provided with a limiting groove (11) and a limiting wall (12), which are respectively adapted to the pin (93) and armature (92) in the backup protection device (9); the pin (93) is inserted into the limiting groove (11) to form a positioning; the limiting bosses (923) on both sides of the armature (92) are located between the limiting wall (12) of the base (1), which restricts the armature (92) from moving a large distance along the axial direction of the pin (93).

3. The backup protection system according to claim 2, characterized in that, The part where the magnetic yoke (91) and armature (92) meet is U-shaped, and the part where the armature (92) and magnetic yoke (91) meet is a plane. An annular space is formed between the magnetic yoke (91) and armature (92) for the second conductive component (43) to pass through.

4. The backup protection system according to claim 3, characterized in that, One end of the first conductive component (42) in the moving contact (4) is connected to the moving contact bridge (41), and the other end of the first conductive component (42) is connected to the second conductive component (43). The second conductive component (43) passes through the backup protection device (9) and is connected to the third conductive component (44). The circuit can pass completely through the backup protection device (9), so that the electromagnetic field change generated when the short-circuit large current passes through drives the backup protection device (9) to work.

5. The backup protection system according to claim 4, characterized in that, The pin (93) passes through the concentric holes on the magnetic yoke (91) and armature (92) as well as the spring (94) to position the internal structure of the backup protection device (9).

6. The backup protection system according to claim 5, characterized in that, The first end (941) of the spring (94) abuts against the magnetic yoke (91), and the second end (942) of the spring (94) abuts against the armature (92).

7. The backup protection system according to claim 6, characterized in that, The two ends of the U-shaped part where the magnetic yoke (91) and armature (92) cooperate are provided with a limiting plane (911) and a limiting end (912).

8. The backup protection system according to claim 7, characterized in that, The U-shaped part of the armature (92) and the magnetic yoke (91) is provided with a moving surface (921) and a moving end (922) at both ends; the armature (92) is always in contact with the magnetic yoke (91) due to the elastic force of the spring (94).

9. A circuit breaker, characterized in that, The system is equipped with a backup protection system as described in any one of claims 1-8.

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