A knife blade contact fuse

Abstract

The utility model belongs to the technical field of fuse, especially involve a knife type contact fuse, including the fuse pipe, the inside of fuse pipe is equipped with the cavity, the both ends outside of cavity and fuse pipe are linked together, the both ends of fuse pipe all are provided with the sealing plate for the cavity is shielded, is equipped with the mounting hole of cavity communication on the sealing plate, the both ends of fuse pipe are provided with the knife type contact respectively, the first end of knife type contact is located in the cavity, the second end of knife type contact is through mounting hole and is stretched out fuse pipe outside, the first end of two knife type contacts is connected with the melt, and the melt is the sheet structure, the forward charging current flows through the melt and generates the first magnetic field perpendicular to the sheet shape surface of melt, is equipped with at least two permanent magnets in the fuse pipe, and the second magnetic field perpendicular to the sheet shape surface of melt is formed between two permanent magnets, and the direction of first magnetic field is opposite with the direction of second magnetic field. Through the utility model, can realize the fusing time of prolonging normal charging current, shortens the fusing time of reverse fault current.

Description

Technical Field

[0001] This utility model belongs to the field of fuse technology, and in particular relates to a knife-type contact fuse. Background Technology

[0002] After a photovoltaic (PV) system is connected to the grid, its power generation characteristics differ significantly from those of a traditional synchronous generator-dominated grid, impacting the operating logic, setting principles, and reliability of voltage and current protection devices in multiple dimensions. The core of a fuse is its fusible element, whose operation depends solely on the current amplitude and duration, unable to identify the current direction. In a grid-connected PV system, when the PV system draws power from the grid at night, the normal charging current flows from "grid → load / energy storage." However, during a short circuit on the PV side or an inverter fault, the fault current flows from "load / energy storage → grid." This results in the normal charging current and the reverse fault current having opposite directions, which the fuse cannot distinguish. Furthermore, when the amplitudes of the normal charging current and the reverse fault current are the same, the fuse's breaking time is also the same, making it impossible to differentiate between the two. Utility Model Content

[0003] The purpose of this utility model is to provide a knife-type contact fuse, which aims to solve the technical problem that existing fuses cannot differentiate between normal charging current and reverse fault current, thereby extending the fusing time for normal charging current and shortening the fusing time for reverse fault current.

[0004] To achieve the above objectives, this utility model provides a knife-type contact fuse, comprising a fuse tube with an internal cavity that is connected to the outer sides of both ends of the fuse tube. Each end of the fuse tube has a sealing plate for shielding the cavity, and the sealing plate has a mounting hole communicating with the cavity. Knife-type contacts are respectively provided at both ends of the fuse tube. The first end of each knife-type contact is located inside the cavity, and the second end of each knife-type contact extends out of the fuse tube through the mounting hole. A molten material is connected between the first ends of the two knife-type contacts. The molten material has a sheet-like structure. A forward charging current flows through the molten material and generates a first magnetic field perpendicular to the sheet-like surface of the molten material. At least two permanent magnets are provided inside the fuse tube, and a second magnetic field perpendicular to the sheet-like surface of the molten material is formed between the at least two permanent magnets. The direction of the first magnetic field is opposite to the direction of the second magnetic field.

[0005] As an optional solution of this utility model, a reverse fault current flows through the melt and generates a third magnetic field perpendicular to the sheet-like surface of the melt, the direction of the third magnetic field being the same as the direction of the second magnetic field.

[0006] As an optional embodiment of this utility model, the sealing plate is detachably disposed on both sides of the fusion tube via a connecting mechanism, the connecting mechanism comprising: A sealing gasket is disposed between the molten tube and the sealing plate; A connecting bolt passes through the sealing plate and the sealing gasket in sequence, and the connecting bolt is threadedly connected to the fusion tube.

[0007] As an optional embodiment of this utility model, the blade-shaped contact is provided with a fixing mechanism, which is used to fix the position of the blade-shaped contact within the cavity. The fixing component includes: A fixing plate is disposed on the blade-shaped contact. The fixing bolt has a threaded hole on the fixing plate, and the sealing plate and the sealing gasket both have a connecting hole corresponding to the threaded hole. The fixing bolt passes through the connecting hole in sequence through the sealing plate and the sealing gasket, and the fixing bolt is threadedly connected to the fixing plate.

[0008] As an optional embodiment of this invention, the two permanent magnets are mirror-mounted on the inner walls of the melt tube on the front and rear sides of the melt sheet-like surface.

[0009] As an optional solution of this utility model, the inner wall of the melting tube is provided with a flow guide groove, which extends along the bottom of the inner wall of the melting tube to both ends of the melting tube.

[0010] As an optional solution of this utility model, the knife-type contact fuse also includes a fuse support, and the fuse support is provided with a plug-in mechanism on both sides. The plug-in mechanism includes a front fixing plate and a rear fixing plate, and a gap is formed between the rear surface of the front fixing plate and the front surface of the rear fixing plate for plugging in the knife-type contact.

[0011] As an optional embodiment of this utility model, the front surface of the front fixing piece and the rear surface of the rear fixing piece are provided with elastic rings, which are used to adjust the size of the gap.

[0012] The knife-type contact fuse provided in this embodiment of the utility model has at least one of the following technical effects: This application provides a knife-type contact fuse. At least two permanent magnets are disposed within the fuse tube, forming a second magnetic field perpendicular to the surface of the fuse sheet. When a forward charging current flows through the fuse, a first magnetic field perpendicular to the surface of the fuse sheet is generated. The direction of the first magnetic field is opposite to that of the second magnetic field. At this time, the second and first magnetic fields cancel each other out, reducing the magnetic attraction and magnetic blow-out forces on the hollow fuse, thus extending the fusing time of the normal charging current. When a reverse fault current flows through the fuse, a third magnetic field perpendicular to the surface of the fuse sheet is generated. The direction of the third magnetic field is the same as that of the second magnetic field. At this time, the second and first magnetic fields reinforce each other, increasing the magnetic attraction and magnetic blow-out forces on the hollow fuse, thus shortening the fusing time of the reverse fault current. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is an overall schematic diagram of a knife-type contact fuse and a fuse support according to the present invention.

[0015] Figure 2 This is a schematic diagram of a knife-type contact fuse according to the present invention.

[0016] Figure 3 This is a schematic diagram of the fuse tube of a knife-type contact fuse according to the present invention.

[0017] Figure 4 This is a schematic diagram of the connection mechanism and fixing mechanism of a knife-type contact fuse according to the present invention.

[0018] Figure 5 This is a schematic diagram of a fuse support for a knife-type contact fuse according to the present invention.

[0019] The following are the labeling elements in the figure: 1. Fuse tube; 2. Knife-shaped contact; 3. Fuse support; 4. Sealing plate; 401. Anti-reverse component; 5. Connecting mechanism; 501. Sealing gasket; 502. Connecting bolt; 51. First connecting hole; 52. Second mounting hole; 42. Mounting hole; 6. Fixing mechanism; 601. Fixing plate; 602. Fixing bolt; 603. Second threaded hole; 604. Second connecting hole; 62. Third mounting hole; 101. Cavity; 102. Fuse; 103. First permanent magnet; 104. Second permanent magnet; 105. Drainage groove; 106. First threaded hole; 7. Insertion mechanism; 701. Front fixing plate; 702. Rear fixing plate; 703. Elastic ring. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0021] In the description of the embodiments of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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 embodiment of the invention according to the specific circumstances.

[0024] In specific embodiments of this utility model, such as Figure 1 As shown, a knife-type contact fuse is provided, including a fuse tube 1, with knife-type contacts 2 respectively provided at both ends of the fuse tube 1. The first end of the knife-type contact 2 is located inside the fuse tube 1, and the second end of the knife-type contact 2 is inserted into a fuse support 3.

[0025] Reference Figure 2 The molten tube 1 has a cavity 101 inside, which is connected to the outer sides of both ends of the molten tube 1. To keep the cavity 101 closed, sealing plates 4 are provided at both ends of the molten tube 1 to shield the cavity 101. The sealing plates 4 have mounting holes 42 that are connected to the cavity 101. The first end of the knife-shaped contact 2 is located inside the cavity 101, and the second end of the knife-shaped contact 2 extends out of the molten tube 1 through the mounting holes 42. The first ends of the two knife-shaped contacts 2 are connected to the melt 102, which is a diamond-shaped mesh sheet melt. The two ends of the melt 102 are connected to the melt 102. The sheet-like surfaces are respectively attached to the sides of the two knife-shaped contacts 2, and the sheet-like surfaces of the melt 102 are perpendicular to the horizontal plane. Two permanent magnets are mirror-arranged on the front and back sides of the sheet-like surfaces of the melt 102, namely the first permanent magnet 103 and the second permanent magnet 104. The first permanent magnet 103 and the second permanent magnet 104 are both fixed on the inner wall of the melt tube 1. The back of the first permanent magnet 103 and the front of the second permanent magnet 104 have opposite polarities. A second magnetic field perpendicular to the sheet-like surface of the melt 102 is formed between the first permanent magnet 103 and the second permanent magnet 104.

[0026] When a forward charging current flows through the melt 102, a first magnetic field is generated perpendicular to the sheet-like surface of the melt 102. The direction of the first magnetic field is opposite to that of the second magnetic field. At this time, the second magnetic field and the first magnetic field cancel each other out, and the melt 102 inside the cavity 101 is almost unaffected by magnetic attraction and magnetic blowing forces. However, the melt in the prior art is inevitably affected by the magnetic attraction and magnetic blowing forces of the first magnetic field. Therefore, under normal charging current, the arc pre-time and arc-burning time of the melt 102 of this invention are longer than those of the prior art. When a reverse fault current flows through the melt 102, a third magnetic field is generated perpendicular to the sheet-like surface of the melt. The direction of the third magnetic field is the same as that of the second magnetic field. At this time, the second magnetic field and the first magnetic field reinforce each other, and the magnetic attraction and magnetic blowing forces on the melt 102 inside the cavity 101 are enhanced. However, the melt in the prior art is only affected by the third magnetic field. Therefore, the arc pre-time and arc-burning time of the melt 102 of this invention are reduced compared to the prior art.

[0027] Specifically, the expression for calculating magnetic attraction force is as follows:

[0028] in, Indicates magnetic attraction; Indicates magnetic flux density; Indicates the area of ​​the melt; It represents the magnetic permeability in a vacuum.

[0029] Specifically, the expression for calculating magnetic blowout force is as follows:

[0030] in, Indicates magnetic blowout force; Indicates current; Indicates magnetic flux density; Indicates the length of the melt.

[0031] In a specific embodiment of this invention, the direction of the forward charging current is from the power grid to the load, and the direction of the first magnetic field around the melt 102 is perpendicular to the sheet-like surface of the melt 102 and faces the second permanent magnet 104. The rear surface of the second permanent magnet 104 has the N pole polarity, and the front surface of the first permanent magnet 103 has the S pole polarity. The direction of the second magnetic field is perpendicular to the sheet-like surface of the melt 102 and faces the first permanent magnet 103, and the direction of the first magnetic field is opposite to the direction of the second magnetic field. The direction of the reverse fault current is from the load to the power grid, and the direction of the third magnetic field around the melt 103 is perpendicular to the sheet-like surface of the melt 102 and faces the first permanent magnet 103, and the direction of the third magnetic field is the same as the direction of the second magnetic field.

[0032] Reference Figure 3 The inner wall of the molten tube 1 is also provided with a flow channel 105. The flow channel 105 extends from the bottom of the inner wall of the molten tube 1 to both ends of the molten tube. When the molten body 1 melts, the flow channel 105 guides the melt fragments to collect at the bottom of the inner wall of the molten tube 1, so as to avoid the fragments from splashing and causing secondary failures.

[0033] Reference Figure 4 The sealing plate 4 is detachably mounted on both sides of the molten tube 1 via a connecting mechanism 5. The connecting mechanism 5 includes a sealing gasket 501 and a connecting bolt 502. The sealing gasket 501 is disposed between the molten tube 1 and the sealing plate 4. The sealing gasket 501 has a second mounting hole 52 corresponding to the mounting hole 42 for the knife-shaped contact 2 to pass through. The four corners of the sealing plate 4 and the sealing gasket 501 are respectively provided with a first connecting hole 51. The four corners at both ends of the molten tube 1 are provided with a first threaded hole 106 corresponding to the first connecting hole 51. The connecting bolt 502 passes through the sealing plate 4 and the sealing gasket 501 in sequence through the first connecting hole 51. The connecting bolt 502 is threadedly connected to the molten tube 1 through the first threaded hole 106.

[0034] Reference Figure 4A fixing mechanism 6 is provided on the knife-shaped contact 2. The fixing mechanism 6 is used to fix the position of the knife-shaped contact 2 in the cavity 101. The fixing mechanism 6 includes a fixing plate 601 and a fixing bolt 602 provided on the knife-shaped contact 2. The fixing plate 601 is located between the sealing gasket 401 and the fusible tube 1. The fixing plate 601 has a third mounting hole 62 corresponding to the mounting hole 42 and the second mounting hole 52 for the knife-shaped contact 2 to pass through. The fixing plate 601 has a second threaded hole 603. The sealing plate 4 and the sealing gasket 401 both have a second connecting hole 604 corresponding to the second threaded hole 603. The fixing bolt 602 passes through the second connecting hole 604 in sequence through the sealing plate 4 and the sealing gasket 501. The fixing bolt 602 is threadedly connected to the fixing plate 601 through the second threaded hole 603.

[0035] Reference Figure 5 Both sides of the fuse holder are provided with a plug-in mechanism 7. The plug-in mechanism 7 includes a front fixing plate 701 and a rear fixing plate 702. A gap is formed between the rear surface of the front fixing plate 701 and the front surface of the rear fixing plate 702 for plugging in the knife-type contact 2.

[0036] The front surface of the front fixing plate 701 and the rear surface of the rear fixing plate 702 are provided with elastic rings 703. The first end of the elastic ring 703 is fixed to the front surface of the front fixing plate 701, and the second end of the elastic ring 703 protrudes along the bottom of the insertion mechanism 7 and is fixed to the rear surface of the rear fixing plate 702. When the narrow blade of the knife-shaped contact 2 is inserted into the insertion mechanism 7, the elastic ring 703 undergoes elastic deformation, forcing the insertion gap of the insertion mechanism 7 to increase, so that the side of the knife-shaped contact 2 can be inserted into the insertion mechanism. At the same time, the elastic ring 703 also provides lateral pressure to the front fixing plate 701 and the rear fixing plate 702 to fix the knife-shaped contact 2 inserted into the insertion mechanism 7.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A knife blade contact fuse comprising a fuse tube, characterized in that, The molten tube has an internal cavity that is connected to the outer sides of both ends of the molten tube. Each end of the molten tube has a sealing plate to shield the cavity, and the sealing plate has a mounting hole communicating with the cavity. Each end of the molten tube has a blade-shaped contact. The first end of the blade-shaped contact is located inside the cavity, and the second end of the blade-shaped contact extends out of the molten tube through the mounting hole. A molten material is connected between the first ends of the two blade-shaped contacts. The molten material has a sheet-like structure. A forward charging current flows through the molten material and generates a first magnetic field perpendicular to the sheet-like surface of the molten material. At least two permanent magnets are located inside the molten tube, and a second magnetic field perpendicular to the sheet-like surface of the molten material is formed between the at least two permanent magnets. The direction of the first magnetic field is opposite to the direction of the second magnetic field.

2. The knife blade contact fuse of claim 1, wherein, A reverse fault current flows through the melt and generates a third magnetic field perpendicular to the sheet-like surface of the melt. The direction of the third magnetic field is the same as that of the second magnetic field.

3. The knife-type contact fuse according to claim 1, characterized in that, The sealing plate is detachably mounted on both sides of the molten tube via a connecting mechanism, the connecting mechanism comprising: A sealing gasket is disposed between the molten tube and the sealing plate; A connecting bolt passes through the sealing plate and the sealing gasket in sequence, and the connecting bolt is threadedly connected to the fusion tube.

4. The knife blade contact fuse of claim 3, wherein, The blade-shaped contact is provided with a fixing mechanism, which is used to fix the position of the blade-shaped contact within the cavity. The fixing mechanism includes: A fixing plate is disposed on the blade-shaped contact. The fixing bolt has a threaded hole on the fixing plate, and the sealing plate and the sealing gasket both have a connecting hole corresponding to the threaded hole. The fixing bolt passes through the connecting hole in sequence through the sealing plate and the sealing gasket, and the fixing bolt is threadedly connected to the fixing plate.

5. The knife-type contact fuse according to claim 1, characterized in that, The two permanent magnets are mirror images of each other on the inner walls of the melt tube on the front and rear sides of the melt sheet surface.

6. The knife blade contact fuse of claim 1, wherein, The inner wall of the melting tube is provided with a flow guide groove, which extends along the bottom of the inner wall of the melting tube towards both ends of the melting tube.

7. The knife blade contact fuse of claim 1, wherein, It also includes a fuse holder, on both sides of which are provided with a plug-in mechanism. The plug-in mechanism includes a front fixing plate and a rear fixing plate. A gap is formed between the rear surface of the front fixing plate and the front surface of the rear fixing plate for the insertion of the knife-shaped contact.

8. The knife blade contact fuse of claim 7, wherein, The front surface of the front fixing piece and the rear surface of the rear fixing piece are provided with elastic rings, which are used to adjust the size of the gap.

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