Protective drop-out fuse

Abstract

The invention discloses a protective drop-out fuse, relates to the technical field of drop-out fuses, and aims to solve the technical problem that arc extinguishing work cannot be well performed in a part of environments by a chemical arc extinguishing mode. The end part of the mounting bracket is obliquely provided with an insulating support through a bolt; a fastening support arm is arranged at the top of the insulating support; a rotating shaft connecting support arm is arranged at the bottom of the insulating support; the rotating shaft connecting support arm is provided with a protective fusion tube assembly through a rotating fastener. The protective fusion tube assembly comprises a fusion tube main body. According to the invention, different current working conditions are generated based on the magnitude of current passing numerical values, the magnetic induction coil drives the armature to carry out adjustment operation of different rising lengths through the different current working conditions, so that the multi-stage arc extinguishing structure carries out arc extinguishing work in different states, and the arc extinguishing work of the protection type fusion tube assembly is effectively maintained in a mechanical mode. And the condition of insufficient stability of chemical arc extinguishing is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of drop-out fuses, and more particularly to a protective drop-out fuse. Background Art

[0002] Drop-out fuses are usually installed in high-rise distribution lines. When the drop-out fuse is in normal operation, the fuse tube forms a closed position with the help of the fuse tension. When a system fault occurs, the fault current causes the fuse to blow quickly. After the fuse blows, the lower static contact loses tension and flips down, causing the tightening mechanism to release the fuse tube, and the fuse tube falls to form an obvious open position.

[0003] The existing protective drop-out fuse is equipped with an inner steel paper tube inside to decompose a large amount of non-conductive gases such as carbon dioxide and nitrogen under the high temperature of the arc, forming a longitudinal high-pressure airflow to blow out the arc. In high-altitude areas, the air pressure is low, which may lead to insufficient gas pressure and inability to effectively blow the arc; in a dirty environment, the surface of the fuse tube may be contaminated, affecting the gas emission path and the lack of non-conductive gases such as carbon dioxide and nitrogen decomposed in a corrosive environment, resulting in arc extinguishing failure. Therefore, how to propose a protective drop-out fuse with mechanized arc extinguishing to reduce the situation where the current working condition causes damage or explosion to the equipment due to continuous combustion. In view of this, we propose a protective drop-out fuse. Summary of the invention

[0004] The object of the present invention is to provide a protective drop-out fuse to solve the technical problem that chemical arc extinguishing cannot perform arc extinguishing work well in some environments.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a protective drop-out fuse, comprising a mounting bracket; an insulating support is obliquely arranged at the end of the mounting bracket through bolts; a buckle support arm is arranged at the top of the insulating support; a rotating shaft connecting support arm is arranged at the bottom of the insulating support; the rotating shaft connecting support arm is provided with a protective fuse tube assembly through a rotating fastener; the protective fuse tube assembly comprises a fuse tube body; the fuse tube body is rotatably arranged at the rotating end of the rotating shaft connecting support arm through a rotating fastener; wherein, a restoring chamber and an arc extinguishing chamber are sequentially arranged inside the fuse tube body from top to bottom; a movable contact is buckled and arranged on the top of the fuse tube body; wherein at least one magnetic induction coil is fixedly arranged at the bottom of the movable contact relative to the inside of the fuse tube body; wherein the movable contact is fixedly connected to the connecting end of the magnetic induction coil; an armature is penetrated inside the fuse tube body; an auxiliary support seat is fixedly arranged on the top of the armature; a multi-stage restoring spring is arranged on the top of the auxiliary support seat; a multi-stage arc extinguishing structure is arranged at the bottom of the armature; wherein the multi-stage arc extinguishing structure is a telescopic mechanism.

[0006] Based on the magnitude of the current passing value, the present invention generates different current conditions, and through different current conditions, the magnetic induction coil drives the armature to perform different ascending length adjustment operations, so as to cause the multi-stage arc extinguishing structure to perform arc extinguishing work in different states, and effectively maintain the arc extinguishing work of the protective fuse tube assembly in a mechanical manner, effectively reducing the insufficient stability of chemical arc extinguishing.

[0007] Preferably, a connecting sliding seat for basic support and guidance of the armature is provided between the fuse tube main body and the restoring force cavity and the arc extinguishing cavity; a fuse buckle for connecting with the fuse is provided at the output end of the magnetic induction coil, and the input end of the magnetic induction coil is fixedly connected with the moving contact; a guiding buckle is provided at the bottom of the armature.

[0008] Preferably, the auxiliary supporting seat is in a "U" shape, and the top of the multi-stage restoring force spring is fixedly connected with the fuse tube main body, and the multi-stage restoring force spring is in a "hourglass" shape.

[0009] Preferably, the multi-stage arc extinguishing structure includes a main driving hollow shaft arranged at the axis position of the fuse tube main body; an auxiliary buckle adapted to the guiding buckle is provided at the top of the main driving hollow shaft; and a dividing groove is provided at the top of the main driving hollow shaft.

[0010] Preferably, a multi-stage pulling component is arranged outside the main driving hollow shaft; the multi-stage pulling component includes a plurality of dividing grid ring blocks arranged concentrically; receiving grooves are provided on both sides of the dividing grid ring block; a sliding shaft is arranged in the receiving groove; springs are arranged on both the upper and lower sides of the sliding shaft; a force limiting block is arranged between the two springs; wherein, the cross section of the dividing grid ring block is in a "[" shape.

[0011] Preferably, for relatively small current conditions of the moving contact, the magnetic induction coil is energized and magnetically actuated to drive the armature to move upward, and the multi-stage restoring force spring moves along a relatively small compression path, causing the armature to upwardly drag the main driving hollow shaft through the guiding buckle, causing the plurality of dividing grid ring blocks to be stretched and separated, forming an axially stretching and separating structure for generating an arc under relatively small current conditions.

[0012] Preferably, for relatively large current conditions of the moving contact, the magnetic induction coil is energized and magnetically actuated to drive the armature to move upward, and the multi-stage restoring force spring moves along a relatively large compression path, causing the armature to upwardly drag the main driving hollow shaft through the guiding buckle, and the lifting distance of the main driving hollow shaft is greater than the maximum stretching distance of the multi-stage pulling component, causing the guiding buckle to be separated from the auxiliary buckle, and cooperating with the spring arrangement, causing the plurality of dividing grid ring blocks to perform upward and downward restoring force pulling and adjustment, forming an axially multi-stage partition structure for generating an arc under relatively large current conditions.

[0013] A method for using a protective drop-out fuse, comprising the following steps: S100. Fuse installation: The fuse is installed and connected to the fuse buckle through a fastener, and the other end of the fuse is installed and connected to the rotating shaft connecting arm connecting component; S200. Switch-on processing: A tool is used to push the loop buckle on the side of the protective fuse tube assembly to rotate, so that the moving contact is buckled with the fixed contact; S300. Arc extinguishing processing: If a small current condition occurs; based on the moving contact, a small current condition is generated, causing the fuse to melt and generate an arc. At the same time, compared with the conventional current, the current increases in the small current condition, causing the magnetic induction coil to drive the main drive hollow shaft to lift through the armature, and the multi-stage restoring spring moves through a relatively small compression path. The armature lift drives the main drive hollow shaft and multiple partition grid ring blocks to stretch, so as to radially partition the arc; If a large current condition occurs; based on the moving contact, a large current condition is generated, causing the fuse to melt and generate an arc. At the same time, compared with the conventional current, the current increases in the large current condition, causing the magnetic induction coil to drive the main drive hollow shaft to lift through the armature, and the multi-stage restoring spring moves through a relatively large compression path. The armature lift drives the main drive hollow shaft and multiple partition grid ring blocks to stretch fully, causing the guiding buckle to separate from the auxiliary buckle. Based on the action of gravity and the elastic restoring force of the spring, the multiple partition grid ring blocks are adjusted by up and down restoring pulling to continuously extinguish the arc generated in the large current condition for a short time.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. Based on the magnitude of the current passing through, different current conditions are generated in the present invention. Different current conditions cause the magnetic induction coil to drive the armature to perform different ascending length adjustment operations, so that the multi-stage arc extinguishing structure performs arc extinguishing work in different states. And the arc extinguishing work of the protective fuse tube assembly is effectively maintained by mechanical means, effectively reducing the insufficient stability of chemical arc extinguishing.

[0015] 2. In the present invention, the "U"-shaped auxiliary support seat divides the axial position of the arc extinguishing cavity into multiple cavities to form a basic arc extinguishing work through partitioning; and through the setting of the "hourglass"-shaped multi-stage restoring spring in the present invention, it is possible to effectively distinguish between small or large current conditions. Based on the "hourglass"-shaped multi-stage restoring spring, the armature ascending power can only perform basic compression work in the small current condition, and in the large current condition, the armature ascending power needs to be synchronized to over-compress the multi-stage restoring spring. This method effectively controls the required armature ascending adjustment in the large current condition and reduces unnecessary maintenance work caused by mis-triggering the specified value current.

[0016] 3. The present invention forms a basic connection state and an excessive separation state through the elastic buckle setting of the guide buckle head and the auxiliary buckle head. In the basic connection state, the guide buckle head and the auxiliary buckle head always have an elastic buckle connection state, which reduces the process of replacing the fuse after the fuse is blown and the resetting operation steps of the protective drop-type fuse. In the excessive separation state, the guide buckle head and the auxiliary buckle head are completely separated. This method is relatively a one-time operation and is not convenient for resetting. However, the isolation effect brought by the complete separation of the guide buckle head and the auxiliary buckle head can effectively extinguish the arc, and the dynamic and efficient arc extinguishing work lasts for 2-5 seconds, which reduces the situation where it is easy to reignite a few seconds after the initial arc extinguishing.

[0017] 4. The present invention can effectively pull and pull a plurality of concentrically arranged separation grid ring blocks up and down by setting a sliding shaft in coordination with a force-limiting block, and between two springs arranged up and down. Under high current conditions, the main driving hollow shaft and the armature are excessively stretched upward, causing the upper spring to be compressed and the lower spring to be stretched, and forming a traction force during separation, causing the separation grid ring block opening to be closed for a certain period of time, and elastically stretched up and down under the action of the spring, causing the separation grid ring block opening to be repeatedly closed for 2-5 seconds, and multiple arc extinguishing treatments are performed on the arc and the re-ignition arc.

[0018] 5. The present invention is based on a small current condition in which the movable contact operates, causing the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the small current condition increases, causing the magnetic induction coil to lift the main drive hollow shaft through the armature drive, and the multi-stage restoring spring to move in a relatively small compression path. The armature lifts and drives the main drive hollow shaft and multiple separation grid ring blocks to stretch, so as to radially separate the arc. In this way, the protective fuse tube assembly is less damaged and the accessories are easy to reset and replace.

[0019] 6. The present invention is based on a large current working condition of the movable contact, which causes the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the large current condition increases, causing the magnetic induction coil to lift the main driving hollow shaft through the armature drive, and the multi-stage restoring spring to move in a relatively large compression path. The armature lifting drives the main driving hollow shaft and multiple separation grid ring blocks to be fully stretched, causing the guide buckle head to separate from the auxiliary buckle head. Based on gravity and the elastic restoring effect of the spring, the multiple separation grid ring blocks are adjusted to pull and pull the arc up and down to generate a short-term continuous arc extinguishing work for the arc generated in the large current condition. Although this method increases the damage to the protective fuse tube assembly, it effectively improves the arc extinguishing effect, thereby improving the protection type of the drop-type fuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall side view structure of the present invention; Figure 2It is a schematic diagram of the cross-sectional three-dimensional structure of the protective melting tube assembly of the present invention; Figure 3 It is a schematic diagram of the three-dimensional split structure of the protective melting tube assembly of the present invention; Figure 4 It is a schematic diagram of the internal side view of the protective melting tube assembly of the present invention; Figure 5 It is a schematic diagram of the cross-sectional three-dimensional structure of the multi-stage drawer assembly of the present invention; Figure 6 For the present invention Figure 5 Schematic diagram of the local enlarged structure at point A in the middle.

[0021] Description of the numbers in the figure: 1. Mounting bracket; 2. Insulating support; 3. Buckle support arm; 4. Rotating shaft connecting support arm; 5. Protective fuse assembly; 6. Fusion tube body; 7. Movable contact; 8. Magnetic induction coil; 9. Armature; 10. Auxiliary support seat; 11. Multi-stage restoring spring; 12. Multi-stage arc extinguishing structure; 601, re-force chamber; 602, arc extinguishing chamber; 603, connecting sliding seat; 801, fuse button; 901, guide buckle head; 1201, main drive hollow shaft; 12011, auxiliary buckle head; 12012, dividing groove; 1202, multi-stage pulling assembly; 12021, dividing fence ring block; 12022, accommodating groove; 12023, sliding shaft; 12034, spring; 12035, force limiting block. DETAILED DESCRIPTION

[0022] like Figures 1 to 6As shown in the figure, a protective drop-out fuse according to the present invention includes a mounting bracket 1; an insulating support 2 is inclined at the end of the mounting bracket 1 by bolts; a buckling arm 3 is arranged on the top of the insulating support 2; a rotating shaft connecting arm 4 is arranged at the bottom of the insulating support 2; a protective fuse tube assembly 5 is arranged on the rotating shaft connecting arm 4 through a rotating fastener; the protective fuse tube assembly 5 includes a fuse tube main body 6; the fuse tube main body 6 is rotatably arranged at the rotating end of the rotating shaft connecting arm 4 through a rotating fastener; wherein, a restoring force cavity 601 and an arc extinguishing cavity 602 are sequentially arranged in the fuse tube main body 6 from top to bottom; a movable contact 7 is buckled and arranged at the top of the fuse tube main body 6; wherein, at least one magnetic induction coil 8 is fixedly arranged at the bottom of the movable contact 7 relative to the inside of the fuse tube main body 6; wherein, the connecting end of the movable contact 7 and the magnetic induction coil 8 is fixedly connected; an armature 9 is arranged through the inside of the fuse tube main body 6; an auxiliary supporting seat 10 is fixedly arranged at the top of the armature 9; a multi-stage restoring force spring 11 is arranged on the top of the auxiliary supporting seat 10; a multi-stage arc extinguishing structure 12 is arranged at the bottom of the armature 9; wherein, the multi-stage arc extinguishing structure 12 is a telescopic mechanism. Based on the magnitude of the current passing through, the present invention generates different current conditions, and through different current conditions, the magnetic induction coil 8 is used to drive the armature 9 to perform different rising length adjustment operations, so as to cause the multi-stage arc extinguishing structure 12 to perform arc extinguishing work in different states, and the arc extinguishing work of the protective fuse tube assembly 5 is effectively maintained in a mechanical manner, effectively reducing the insufficient stability of chemical arc extinguishing.

[0023] In an embodiment of the present invention, a connecting sliding seat 603 for basic support and guidance of the armature 9 is arranged between the fuse tube main body 6 and the restoring force cavity 601 and the arc extinguishing cavity 602; a fuse buckle 801 for connecting with a fuse is arranged at the output end of the magnetic induction coil 8, and the fuse is installed and connected to the fuse buckle 801 through a fastener. Among them, at least one resistance increasing part is arranged on the middle surface of the fuse at least in the arc extinguishing area of the multi-stage arc extinguishing structure 12. By increasing the resistance, the heat generation at this position is relatively large, which is convenient for controlling the arc generation position. And the input end of the magnetic induction coil 8 is fixedly connected to the movable contact 7; a guiding buckle 901 is arranged at the bottom of the armature 9.

[0024] In an embodiment of the present invention, the auxiliary supporting seat 10 is in a "U" shape, and the top of the multi-stage restoring force spring 11 is fixedly connected to the fuse tube main body 6, and the multi-stage restoring force spring 11 is in a "hourglass" shape. In the present invention, the arc extinguishing cavity 602 is axially divided into multiple cavities by the "U"-shaped auxiliary supporting seat 10 to form basic arc extinguishing work; and in the present invention, through the arrangement of the "hourglass"-shaped multi-stage restoring force spring 11, the small or large current conditions can be effectively distinguished. Based on the "hourglass"-shaped multi-stage restoring force spring 11, the rising power of the armature 9 can only perform basic compression work in the small current condition, and the rising power of the armature 9 needs to be synchronized in the large current condition as Figure 4As shown, the multi-stage restoring spring 11 is negatively compressed, which effectively controls the rising adjustment of the armature 9 in high current conditions, reduces the false triggering of the specified value current, and eliminates unnecessary maintenance work.

[0025] In an embodiment of the present invention, the multi-stage arc extinguishing structure 12 includes a main driving hollow shaft 1201 arranged at the axial position of the fuselage body 6; an auxiliary buckle head 12011 adapted to the guide buckle head 901 is provided at the top of the main driving hollow shaft 1201; and a dividing groove 12012 is opened at the top of the main driving hollow shaft 1201. The present invention forms a basic connection state and an excessive separation state through the elastic buckle setting of the guide buckle head 901 and the auxiliary buckle head 12011. In the basic connection state, the guide buckle head 901 and the auxiliary buckle head 12011 always have an elastic buckle connection state, which reduces the process of replacing the fuse after the fuse is blown and the resetting operation steps of the protective drop-type fuse. In the excessive separation state, the guide buckle head 901 and the auxiliary buckle head 12011 are completely separated. This method is relatively a one-time operation and is not convenient for resetting. However, the isolation effect brought by the complete separation of the guide buckle head 901 and the auxiliary buckle head 12011 can effectively extinguish the arc, and the dynamic and efficient arc extinguishing work lasts for 2-5 seconds, which reduces the situation where it is easy to reignite a few seconds after the initial arc extinguishing.

[0026] In an embodiment of the present invention, a multi-stage pulling assembly 1202 is arranged on the outside of the main driving hollow shaft 1201; the multi-stage pulling assembly 1202 includes a plurality of partitioning fence ring blocks 12021 arranged in concentric circles; receiving grooves 12022 are arranged on both sides of the partitioning fence ring block 12021; a sliding shaft 12023 is arranged in the receiving groove 12022; springs 12034 are arranged on both sides of the upper and lower sides of the sliding shaft 12023; a force limiting block 12035 is arranged between the two springs 12034; wherein, the cross section of the partitioning fence ring block 12021 is in the shape of a "[". The present invention can effectively pull and pull a plurality of concentrically arranged separation grid ring blocks 12021 up and down by setting a sliding shaft 12023 in coordination with a force-bearing limit block 12035, and between two upper and lower springs 12034. Under high current conditions, the main driving hollow shaft 1201 and the armature 9 are excessively stretched upward, causing the upper spring 12034 to be compressed and the lower spring 12034 to be stretched, and forming a traction force during separation, causing the opening of the separation grid ring block 12021 to be closed for a certain period of time, and elastic upward and downward stretching is formed under the action of the spring 12034, causing the opening of the separation grid ring block 12021 to be repeatedly closed for 2-5 seconds, thereby performing multiple arc extinguishing treatments on the arc and the re-ignited arc.

[0027] In the embodiment of the present invention, the movable contact 7 causes the magnetic induction coil 8 to perform electromagnetic work to drive the armature 9 to move upward under the relatively small current working condition, and the multi-stage return spring 11 moves in a relatively small compression path, so that the armature 9 drags the main drive hollow shaft 1201 upward through the guide buckle head 901, causing a plurality of separation grid ring blocks 12021 to stretch and separate, forming an axial stretching separation structure that generates an arc under the small current working condition. The present invention is based on the movable contact 7 performing a small current working condition, causing the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the small current working condition increases, causing the magnetic induction coil 8 to drive the main drive hollow shaft 1201 to rise through the armature 9, and the multi-stage return spring 11 moves in a relatively small compression path, and the armature 9 is lifted to drive the main drive hollow shaft 1201 and a plurality of separation grid ring blocks 12021 to stretch, so as to radially separate the arc. In this way, the protective fuse tube assembly 5 is less damaged, and the accessories are easy to reset and replace.

[0028] In an embodiment of the present invention, the movable contact 7 causes the magnetic induction coil 8 to perform electromagnetic work under a relatively large current condition to drive the armature 9 to move upward, and the multi-stage return spring 11 moves in a relatively large compression path, causing the armature 9 to drag the main drive hollow shaft 1201 upward through the guide buckle head 901, and the lifting distance of the main drive hollow shaft 1201 is greater than the maximum stretching distance of the multi-stage pulling assembly 1202, causing the guide buckle head 901 to separate from the auxiliary buckle head 12011, and cooperating with the spring 12034 setting, causing a number of separation gate ring blocks 12021 to be adjusted to be pulled and pulled up and down by return forces, thereby forming an axial multi-stage isolation structure that generates an arc under a large current condition. The present invention is based on the movable contact 7 operating under high current conditions, causing the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the high current condition increases, causing the magnetic induction coil 8 to drive the main drive hollow shaft 1201 to lift through the armature 9, and the multi-stage restoring spring 11 to move in a relatively large compression path. The lifting of the armature 9 drives the main drive hollow shaft 1201 and multiple separation grid ring blocks 12021 to be fully stretched, causing the guide buckle head 901 to separate from the auxiliary buckle head 12011. Based on gravity and the elastic restoring effect of the spring 12034, the multiple separation grid ring blocks 12021 are adjusted to pull and pull up and down to generate an arc in the high current condition to perform a short-term continuous arc extinguishing work. Although this method increases the damage to the protective fuse tube assembly 5, it effectively improves the arc extinguishing effect, thereby improving the protection type of the drop-type fuse.

[0029] Working principle: This embodiment provides a protective drop-out fuse, and the steps for use are as follows: S100, fuse installation, installing and connecting the fuse to the fuse buckle head 801 through a fastener, and installing the other end of the fuse to the shaft connecting arm 4 connecting assembly; S200, closing process: using a tool to push the ring buckle on the side of the protective fuse assembly 5 to rotate so that the movable contact 7 is buckled with the fixed contact; S300, arc extinguishing process: If a low current condition occurs, the movable contact 7 performs a low current condition, causing the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the low current condition increases, causing the magnetic induction coil 8 to drive the main drive hollow shaft 1201 to rise through the armature 9, and the multi-stage restoring spring 11 to move in a relatively small compression path, and the armature 9 is lifted to drive the main drive hollow shaft 1201 and the multiple separation grid ring blocks 12021 to stretch, so as to radially separate the arc. If a high current condition occurs; based on the high current condition of the movable contact 7, the fuse is blown and an arc is generated. At the same time, relative to the conventional current, the current in the high current condition increases, causing the magnetic induction coil 8 to drive the main drive hollow shaft 1201 to lift through the armature 9, and the multi-stage restoring spring 11 to move in a relatively large compression path. The lifting of the armature 9 drives the main drive hollow shaft 1201 and multiple separation grid ring blocks 12021 to be stretched and fully stretched, causing the guide buckle head 901 to separate from the auxiliary buckle head 12011. Based on gravity and the elastic restoring effect of the spring 12034, the multiple separation grid ring blocks 12021 are adjusted to pull up and down to generate an arc in the high current condition to perform a short-term continuous arc extinguishing work.

[0030] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A protective drop-out fuse, characterized in that: It includes an installation bracket (1); an insulating support (2) is arranged at the end of the installation bracket (1) in an inclined manner through bolts; a buckling support arm (3) is arranged at the top of the insulating support (2); a rotating shaft connecting support arm (4) is arranged at the bottom of the insulating support (2); a protective fuse tube assembly (5) is arranged on the rotating shaft connecting support arm (4) through a rotating fastener; The protective fuse tube assembly (5) includes a fuse tube main body (6); The fuse tube main body (6) is rotatably arranged at the rotating end of the rotating shaft connecting support arm (4) through a rotating fastener; wherein, a restoring force cavity (601) and an arc extinguishing cavity (602) are sequentially arranged in the fuse tube main body (6) from top to bottom; A movable contact (7) is buckled and arranged at the top of the fuse tube main body (6); Wherein, at least one magnetic induction coil (8) is fixedly arranged at the bottom of the movable contact (7) relative to the inside of the fuse tube main body (6); wherein, the connecting end of the movable contact (7) and the magnetic induction coil (8) is fixedly connected; An armature (9) is arranged through the fuse tube main body (6); An auxiliary supporting seat (10) is fixedly arranged at the top of the armature (9); a multi-stage restoring force spring (11) is arranged at the top of the auxiliary supporting seat (10); A multi-stage arc extinguishing structure (12) is arranged at the bottom of the armature (9); wherein, the multi-stage arc extinguishing structure (12) is a telescopic mechanism.

2. A protective drop-out fuse according to claim 1, characterized in that: A connecting sliding seat (603) for basic support and guidance of the armature (9) is arranged between the fuse tube main body (6) relative to the restoring force cavity (601) and the arc extinguishing cavity (602); A fuse holder (801) for connecting with a fuse is arranged at the output end of the magnetic induction coil (8), and the input end of the magnetic induction coil (8) is fixedly connected with the movable contact (7); A guiding buckle (901) is arranged at the bottom of the armature (9).

3. A protective drop-out fuse according to claim 2, characterized in that: The auxiliary supporting seat (10) is in a "U" shape, and the top of the multi-stage restoring force spring (11) is fixedly connected with the fuse tube main body (6), and the multi-stage restoring force spring (11) is in a "hourglass" shape.

4. A protective drop-out fuse according to claim 3, characterized in that: The multi-stage arc extinguishing structure (12) includes a main driving hollow shaft (1201) arranged at the axis position of the fuse tube main body (6); an auxiliary buckle (12011) adapted to the guiding buckle (901) is arranged at the top of the main driving hollow shaft (1201); and a dividing groove (12012) is arranged at the top of the main driving hollow shaft (1201).

5. A protective drop-out fuse according to claim 4, characterized in that: A multi-stage drawing component (1202) is arranged outside the main driving hollow shaft (1201); the multi-stage drawing component (1202) includes a plurality of partition grid ring blocks (12021) arranged in concentric circles; receiving grooves (12022) are arranged on both sides of the partition grid ring block (12021); a sliding shaft (12023) is arranged in the receiving groove (12022); springs (12034) are arranged on both the upper and lower sides of the sliding shaft (12023); a force receiving limit block (12035) is arranged between the two springs (12034); Wherein, the cross section of the partition grid ring block (12021) is in a "[" shape.

6. A protective drop-out fuse according to claim 5, characterized in that: The movable contact (7) causes the magnetic induction coil (8) to perform electromagnetic operation under a relatively small current condition to drive the armature (9) to move upward, and the multi-stage restoring spring (11) moves in a relatively small compression path, causing the armature (9) to drag the main drive hollow shaft (1201) upward through the guide buckle head (901), causing the plurality of separation grid ring blocks (12021) to be stretched and separated, thereby forming an axial stretching separation structure that generates an arc under a small current condition.

7. A protective drop-out fuse according to claim 6, characterized in that: The movable contact (7) causes the magnetic induction coil (8) to perform electromagnetic operation under relatively high current conditions to drive the armature (9) to move upward, and the multi-stage return spring (11) moves in a relatively large compression path, causing the armature (9) to drag the main drive hollow shaft (1201) upward through the guide buckle head (901), and the lifting distance of the main drive hollow shaft (1201) is greater than the maximum stretching distance of the multi-stage pulling assembly (1202), causing the guide buckle head (901) to separate from the auxiliary buckle head (12011), and in conjunction with the spring (12034), the plurality of separation gate ring blocks (12021) are adjusted to be pulled up and down by return force, thereby generating an arc axial multi-stage isolation structure under relatively high current conditions.

8. A method for using a protective drop-out fuse, which is applicable to the protective drop-out fuse according to claim 7, characterized in that: The following steps are involved: S100, installing the fuse, installing and connecting the fuse to the fuse buckle head (801) through a fastener, and installing the other end of the fuse to the shaft connecting arm (4) connecting assembly; S200, closing process: using a tool to push the ring buckle on the side of the protective fuse assembly (5) to rotate so that the movable contact (7) is buckled with the fixed contact; S300, arc extinguishing process: If a low current operating condition occurs; a low current operating condition is performed based on the movable contact (7), causing the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the low current operating condition increases, causing the magnetic induction coil (8) to drive the main drive hollow shaft (1201) to rise through the armature (9), and the multi-stage return spring (11) to move in a relatively small compression path, and the armature (9) is lifted to drive the main drive hollow shaft (1201) and the multiple separation grid ring blocks (12021) to stretch, so as to radially separate the arc; If a high current condition occurs, the movable contact (7) operates under a high current condition, causing the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the high current condition increases, causing the magnetic induction coil (8) to drive the main drive hollow shaft (1201) to lift through the armature (9), and the multi-stage return spring (11) to move in a relatively large compression path. The armature (9) is lifted to drive the main drive hollow shaft (1201) and the plurality of separation grid ring blocks (12021) to stretch and fully stretch, causing the guide buckle head (901) to separate from the auxiliary buckle head (12011). Based on gravity and the elastic return force of the spring (12034), the plurality of separation grid ring blocks (12021) are adjusted to pull up and down to continuously extinguish the arc generated in the high current condition for a short period of time.

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