An open-close type current transformer

Abstract

The application discloses an open-close type current transformer and particularly relates to the technical field of current transformers, which comprises a body, a backing plate, a mounting bottom plate, a reset assembly, a strutting sleeve and a clamping sleeve, and a plurality of deformation notches are formed in the peripheral edge of the strutting sleeve and penetrate the inner cavity of the strutting sleeve. In the application, the cable is clamped by the clamping sleeve, and the reset assembly generates damping force when the backing plate slides on the top surface of the mounting bottom plate, so that the vibration force is transmitted to the body when the external control cabinet vibrates, the body is damped and buffered by the reset assembly, the body can be buffered, in addition, the cable is inserted into the clamping sleeve, the body and the clamping sleeve move synchronously when the body is vibrated, the clamping sleeve synchronously drives the cable to move, the position of the clamping sleeve and the body is relatively unchanged, so that the cable always maintains the coaxial state with the busbar hole of the body, and the clamping force of the clamping sleeve on the cable is increased to increase the resistance when the cable is pulled.

Description

Technical Field

[0001] This invention belongs to the field of current transformer technology, specifically relating to a switchable current transformer. Background Technology

[0002] A current transformer is an instrument that measures current by converting a large primary current into a small secondary current based on the principle of electromagnetic induction. A current transformer consists of a closed iron core and windings. Its primary winding has very few turns and is connected in series with the circuit whose current needs to be measured. Therefore, it often carries the entire current of the circuit. The secondary winding has more turns and is connected in series with the measuring instrument and protection circuit. When the current transformer is operating, its secondary circuit is always closed. Therefore, the impedance of the series coils of the measuring instrument and protection circuit is very small, and the operating state of the current transformer is close to a short circuit. The current transformer measures the large primary current by converting it into a small secondary current; the secondary side must not be open-circuited. A current transformer generally includes an iron core, busbar holes, and secondary terminals.

[0003] For example, a current transformer disclosed in Chinese Patent Publication No. CN223038717U relates to the field of current measurement technology. It includes a current transformer body with two connecting parts fixedly connected to its upper surface. An adjustment structure is provided on one side of the current transformer body. The adjustment structure includes a long rod, one end of which is fixedly connected to the current transformer body. A long tube is slidably connected to the arc surface of the long rod, and a screw is rotatably connected to the arc surface of the long tube. A connecting plate is threadedly connected to the arc surface of the screw. An adjustment rod is fixedly connected to the lower surface of the connecting plate, and a limit plate is fixedly connected to the lower end of the adjustment rod. A U-shaped frame is connected to the arc surface of the long tube. This current transformer allows the current transformer body to move flexibly forward, backward, left, and right within a certain range in the distribution box, solving the problem that a relatively fixed current transformer body after installation necessitates re-drilling holes for installation after changes in the wiring layout within the distribution box, increasing the overall complexity.

[0004] In existing technologies, cables are typically passed through the busbar holes of current transformers for current magnitude detection. When the cable passes through the busbar hole, it is generally required that the cable and the busbar hole maintain a certain coaxiality. This coaxiality helps ensure uniform current distribution, thereby reducing magnetic field inhomogeneity and improving measurement accuracy. Especially under high-frequency or high-current conditions, cable eccentricity can cause uneven magnetic field distribution, leading to measurement errors. However, in existing technologies, current transformers are generally installed inside distribution cabinets. If the distribution cabinet is impacted, the current transformer may become loose. In this case, the relative positions of the cable and the busbar hole will change, resulting in a significant deviation between the cable and the busbar hole's axis. Furthermore, bending of the cable within the busbar hole can also affect the uniformity of the magnetic field, thus impacting the accuracy of current detection. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an openable current transformer.

[0006] The technical solution adopted to solve the above-mentioned technical problems is: a switchable current transformer, including the body of the switchable current transformer, and further including:

[0007] A pad is detachably connected to the bottom of the main body, and the bottom of the pad is in contact with a mounting base plate. The pad can slide freely on the top surface of the mounting base plate.

[0008] A reset assembly is provided on the mounting base plate, and the reset assembly is used to generate a damping force on the sliding of the pad on the top surface of the mounting base plate;

[0009] There are two expansion sleeves, which are respectively connected to the two axial end faces of the main body. The outer diameter of the expansion sleeve decreases sequentially in the direction away from the main body. The smallest outer diameter of the expansion sleeve is fixed to a clamping sleeve. Multiple deformation notches penetrating the inner cavity of the expansion sleeve are opened around the periphery of the expansion sleeve.

[0010] Through the above technical solution, the clamping sleeve clamps the cable, and the reset component generates damping force when the pad slides on the top surface of the mounting base. This allows the vibration force from the external control cabinet to be transmitted to the main body, where the reset component provides damping and buffering. Furthermore, when the cable passes through the clamping sleeve, the main body and clamping sleeve move synchronously when the main body vibrates, causing the clamping sleeve to move the cable synchronously. Since the relative positions of the clamping sleeve and the main body remain unchanged, the cable always maintains coaxiality with the busbar hole of the main body. Additionally, the expansion sleeve can produce elastic contraction and expansion deformation, ensuring the clamping sleeve maintains clamping force on the cable. When the cable is pulled, the two expansion sleeves undergo corresponding elastic contraction deformation, increasing the clamping force on the cable and increasing the resistance when the cable is pulled. This keeps the cable between the two clamping sleeves taut, resulting in a high degree of coaxiality between the cable and the current transformer busbar hole.

[0011] Furthermore, the reset assembly includes a protrusion fixed to the bottom of the pad, and the top of the mounting base plate has a first receiving cavity. The protrusion extends downward into the first receiving cavity, and a spiral spring is installed in the first receiving cavity. The inner ring of the spiral spring is fixedly sleeved around the periphery of the protrusion, and the end of the outer ring of the spiral spring is fixed to the inner wall of the first receiving cavity.

[0012] Through the above technical solution, the spiral spring has elastic deformation capability, which causes the protrusion to move when the pad slides on the surface of the mounting base plate, thereby causing the spiral spring to deform. After the vibration force on the pad disappears, the deformation of the spiral spring itself recovers, thereby causing the protrusion to move to the center position of the inner coil of the spiral spring in the initial state, that is, driving the pad and the body to return to the initial state.

[0013] Furthermore, a limiting pin is coaxially and fixedly inserted through the protrusion, and the mounting base plate has a connecting hole for the limiting pin to pass freely through. The inner diameter of the connecting hole is larger than the outer diameter of the limiting pin. A stop part is fixedly sleeved at the lower end of the limiting pin, and a second receiving cavity is opened on the bottom surface of the mounting base plate for the stop part to pass freely through. The inner diameter of the second receiving cavity is larger than the outer diameter of the stop part.

[0014] With the above technical solution, when the body is subjected to vibration, the stop part will move in the second receiving cavity. Since the inner diameter of the second receiving cavity is larger than the outer diameter of the stop part and the outer diameter of the limiting pin is smaller than the inner diameter of the connecting hole, the body can move when subjected to vibration.

[0015] Furthermore, a plurality of the aforementioned deformation notches are arranged in an array along the axial direction of the spreading sleeve, and the deformation notches extend to the periphery of the clamping sleeve.

[0016] The above technical solution makes the deformation amplitude of the multiple parts divided by the multiple deformation notches of the spreading sleeve and the clamping sleeve tend to be consistent.

[0017] Furthermore, the inner wall surface of the clamping sleeve is provided with a rubber layer.

[0018] The above technical solution, through the setting of the rubber layer, makes the frictional resistance between the cable and the inner wall of the clamping sleeve greater, thereby preventing the cable from sliding on its own inside the clamping sleeve and increasing the resistance to the cable sliding inside the clamping sleeve when it is pulled.

[0019] Furthermore, the mounting base plate is equipped with support seats on both sides of the axial ends of the main body, and a fixing plate is connected to the upper end of the support seat. The top of the fixing plate is provided with a relaxation component.

[0020] Through the above technical solution, the cable is relaxed by the relaxation component, so that when the body is vibrated and moves, the cable on the outside of the body can relax, while the cable stretched by the two opening sleeves is always in a taut state.

[0021] Furthermore, the relaxation assembly includes two fixed guide wheels vertically rotatably connected to the upper surface of the fixed plate. The horizontal line connecting the two fixed guide wheels is parallel to the axis of the body. A sliding cavity is formed inside the fixed plate, and a piston is coaxially engaged in the sliding cavity. The piston slides freely horizontally within the sliding cavity, and a connecting rod is fixedly connected to the end face of the piston. One end of the connecting rod, which protrudes from the top surface of the fixed plate, is rotatably connected to a floating guide wheel located between the two fixed guide wheels. An oblong hole is formed on the top surface of the fixed plate for the connecting rod to pass freely through. The support base is provided with a drive unit for driving the piston to move within the sliding cavity.

[0022] With the above technical solution, when the main body is vibrated and moves, the drive unit will be triggered to move. The drive unit drives the piston to move in the sliding cavity, so that the piston can squeeze the air in the sliding cavity, and then the piston drives the connecting rod to move, so that the floating guide wheel moves inward towards the inside of the fixed plate. This allows the cable wrapped around the two fixed guide wheels and the floating guide wheel to relax, so that when the main body moves, the cable on the outside of the two clamping sleeves is under great tension, which would cause the cable to pull on the main body and prevent the main body from being unable to cushion the vibration by moving.

[0023] Furthermore, the driving unit includes a hollow cylinder fixed to the wall of the support base, and a sliding block is coaxially engaged inside the hollow cylinder. The sliding block slides freely inside the hollow cylinder, and a communicating cavity is formed between the sliding block and the inner wall of the hollow cylinder.

[0024] A spring is horizontally installed inside the connecting cavity. The two ends of the spring elastically abut against the sliding block and the inner wall of the connecting cavity, respectively. An air pipe is installed on the wall of the hollow cylinder. The end of the air pipe away from the hollow cylinder is installed on the fixed plate and is connected to the inner cavity of the sliding cavity. A conical groove is coaxially opened on the side end face of the sliding block facing the main body. The inner diameter of the conical groove increases sequentially in the direction away from the support seat.

[0025] A drive rod is horizontally connected to the wall of the main body. The end of the drive rod away from the main body is inserted into the conical groove. The outer diameter of the drive rod is smaller than the minimum inner diameter of the conical groove.

[0026] With the above technical solution, when the body moves due to vibration, the end of the drive rod will contact the inner wall of the conical groove and generate a compressive force along the axial direction of the hollow cylinder on the inner wall of the conical groove. This causes the sliding block to move towards the support seat in the sliding cavity, thereby causing the sliding block to compress the air in the hollow cylinder, allowing the air in the hollow cylinder to enter the sliding cavity. This causes the piston to be pushed by the air, thereby causing the piston to slide in the sliding cavity and causing the floating guide wheel to move towards the inside of the fixed guide wheel, thereby allowing the cable to be in a slack state.

[0027] Furthermore, a ball bearing is rotatably fitted into one end of the drive rod that passes through the conical groove, and the ball bearing makes rolling contact with the inner wall of the conical groove.

[0028] The above technical solution uses balls rolling on the inner wall of the conical groove, which reduces wear between the end of the drive rod and the inner wall of the conical groove, while also preventing excessive wear on the inner wall of the conical groove.

[0029] Furthermore, the hollow cylinder opening is provided with an inwardly turned annular protrusion, which is used to limit the sliding of the sliding block inside the hollow cylinder.

[0030] Through the above technical solution, the annular protrusion limits the movement of the sliding block away from the support seat, thereby preventing the sliding block from coming out of the hollow cylinder.

[0031] The beneficial effects of this invention are as follows:

[0032] 1. In this invention, the cable is clamped by the clamping sleeve, and the reset component generates a damping force on the pad when it slides on the top surface of the mounting base plate. When the external control cabinet vibrates, the vibration force is transmitted to the main body. The reset component dampens and buffers the main body, allowing it to buffer the vibration. In addition, when the cable passes through the clamping sleeve, the main body and the clamping sleeve move synchronously when the main body is vibrated, causing the clamping sleeve to move the cable synchronously. Since the relative positions of the clamping sleeve and the main body remain unchanged, the cable always maintains a coaxial state with the busbar hole of the main body. Furthermore, the expansion sleeve can produce elastic contraction and elastic expansion deformation. The expansion sleeve will ensure that the clamping sleeve always maintains the clamping force on the cable, and when the cable is pulled, the two expansion sleeves produce corresponding elastic contraction deformation, thereby increasing the clamping force of the clamping sleeve on the cable, increasing the resistance when the cable is pulled, and keeping the cable between the two clamping sleeves in a taut state, so as to achieve a high coaxiality between the cable and the busbar hole of the current transformer.

[0033] 2. In this invention, the spiral spring has elastic deformation capability, which causes the protrusion to move when the pad slides on the surface of the mounting base plate, thereby causing the spiral spring to deform. After the pad is subjected to vibration force, the spiral spring itself recovers its deformation, thereby causing the protrusion to move to the center position of the inner coil of the spiral spring in the initial state, that is, driving the pad and the body to return to the initial state.

[0034] 3. In this invention, when the main body is vibrated and moves, the drive unit is triggered to move. The drive unit drives the piston to move in the sliding cavity, so that the piston can squeeze the air in the sliding cavity, and then the piston drives the connecting rod to move, so that the floating guide wheel moves towards the inside of the fixed plate. This allows the cable wrapped around the two fixed guide wheels and the floating guide wheel to relax, so that when the main body moves, the cable on the outside of the two clamping sleeves is under great tension, which would cause the cable to pull the main body and prevent the main body from being unable to cushion the vibration by moving.

[0035] 4. In this invention, when the main body moves due to vibration, the end of the drive rod will contact the inner wall of the conical groove and generate a compressive force along the axial direction of the hollow cylinder on the inner wall of the conical groove. This causes the sliding block to move towards the support seat in the sliding cavity, thereby causing the sliding block to compress the air in the hollow cylinder, allowing the air in the hollow cylinder to enter the sliding cavity. This causes the piston to be pushed by the air, thereby causing the piston to slide in the sliding cavity and causing the floating guide wheel to move towards the inner side of the fixed guide wheel, thereby allowing the cable to be in a slack state. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of an openable current transformer according to the present invention;

[0037] Figure 2 yes Figure 1 A diagram illustrating the positional relationships from a first-person perspective.

[0038] Figure 3 yes Figure 1 A diagram illustrating the positional relationships from a second-person perspective;

[0039] Figure 4 This is a schematic diagram showing the positional relationship of the support base, fixing plate, and hollow cylinder after assembly in this invention;

[0040] Figure 5 yes Figure 4 A schematic diagram showing the positional relationship of the middle section after it has been cut open;

[0041] Figure 6 yes Figure 5 Enlarged schematic diagram of the local structure at point A;

[0042] Figure 7 This is a schematic diagram showing the positional relationship between the mounting base plate, pad plate, and body after assembly in this invention;

[0043] Figure 8 yes Figure 7 Schematic diagram of the explosive decomposition of the medium structure;

[0044] Figure 9 yes Figure 8A diagram illustrating the positional relationship from another perspective;

[0045] Figure 10 This is a schematic diagram of the structure of the expansion sleeve in this invention;

[0046] Figure 11 yes Figure 10 A diagram showing the positional relationship from another perspective.

[0047] Reference numerals: 1. Mounting base plate; 2. Fixed guide wheel; 3. Fixed plate; 4. Clamping sleeve; 5. Spreading sleeve; 6. Body; 7. Pad; 8. Drive rod; 9. Floating guide wheel; 10. Hollow cylinder; 11. Support seat; 12. Deformation notch; 13. Stop part; 14. Second receiving cavity; 15. Pipe interface; 16. Connecting rod; 17. Waist-shaped hole; 18. Sliding block; 19. Sliding cavity; 20. Piston; 21. Conical groove; 22. Ball bearing; 23. Spring; 24. Communicating cavity; 25. Limiting pin; 26. Spiral spring; 27. Connecting hole; 28. First receiving cavity; 29. ​​Protrusion. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] like Figures 1-11As shown, this embodiment provides: a switchable current transformer, including a body 6 of the switchable current transformer. The body 6 is composed of upper and lower parts, and the upper and lower parts of the body 6 are hinged at one end and detachably connected at the other end by bolts, so that the upper and lower parts of the body 6 can be flipped along the hinge. A pad 7 is installed on the bottom of the body 6 by screws. The bottom of the pad 7 abuts against a mounting base plate 1. The mounting base plate 1 is fixedly installed in an external control cabinet by screws, so that the body 6 is installed in the control cabinet. A protrusion 29 is vertically fixed to the bottom of the mounting plate 7. A first receiving cavity 28 is opened on the top of the mounting base plate 1. The lower end of the protrusion 29 extends into the first receiving cavity 28, and a spiral spring 26 is installed in the first receiving cavity 28. The end of the outer ring of the spiral spring 26 is welded to the inner wall of the first receiving cavity 28, and the end of the inner ring of the spiral spring 26 is welded to the periphery of the protrusion 29. The spiral spring 26 is installed on the periphery of the protrusion 29 in a looping manner, so that when the body 6 is subjected to a lateral force, the body 6 will drive the pad 7 to move, and the pad 7 will synchronously move the pad 7. The protruding part 29 moves, causing it to compress the spiral spring 26. The spiral spring 26 begins to accumulate elastic potential energy. When the lateral force acting on the body 6 disappears, the elastic potential energy of the spiral spring 26 is released, enabling the protruding part 29 to move back to its initial state. That is, when the protruding part 29 moves back to its initial state, the inner ring of the spiral spring 26 is positioned in the orthographic projection area within the first receiving cavity 28. Additionally, a limiting pin 25 is coaxially and fixedly inserted through the end face of the protruding part 29, and the mounting base plate 1 has an opening for the limiting pin 25 to pass freely. The connecting hole 27 has an inner diameter larger than the outer diameter of the limiting pin 25. The lower end of the limiting pin 25 is fixedly sleeved with a stop part 13. The bottom surface of the mounting base plate 1 has a second receiving cavity 14 for the stop part 13 to pass through freely. The inner diameter of the second receiving cavity 14 is larger than the outer diameter of the stop part 13. When the body 6 is subjected to vibration, the stop part 13 will move in the second receiving cavity 14. Since the inner diameter of the second receiving cavity 14 is larger than the outer diameter of the stop part 13 and the outer diameter of the limiting pin 25 is smaller than the inner diameter of the connecting hole 27, the body 6 can move when subjected to vibration.

[0050] Spreading sleeves 5 are installed on both end faces of the main body 6 via screws. Specifically, the end of the spreading sleeve 5 that contacts the main body 6 has an annular portion that abuts against the end face of the main body 6 and is installed on the end face of the main body 6 via screws. The outer diameter of the spreading sleeve 5 decreases sequentially in the direction away from the main body 6. A clamping sleeve 4 is fixedly connected to the smallest end of the spreading sleeve 5. Multiple deformation notches 12 penetrating the inner cavity of the spreading sleeve 5 are provided around the periphery of the spreading sleeve 5. By providing deformation notches 12, the spreading sleeve 5 will undergo elastic contraction deformation when subjected to compressive force along its radial inward side, thereby enabling... The opening of the clamping sleeve 4 is narrowed, making the clamping sleeve 4 clamped. In addition, multiple deformation notches 12 are arranged in an array along the axial direction of the spreading sleeve 5, and the deformation notches 12 extend to the periphery of the clamping sleeve 4, so that the deformation amplitude of the multiple parts divided by the multiple deformation notches 12 of the spreading sleeve 5 and the clamping sleeve 4 tends to be consistent. Furthermore, a rubber layer (not shown in the figure) is provided on the inner wall surface of the clamping sleeve 4. The rubber layer makes the frictional resistance between the cable and the inner wall surface of the clamping sleeve 4 greater, thereby preventing the cable from sliding on its own inside the clamping sleeve 4 and increasing the resistance to the cable sliding inside the clamping sleeve 4 when it is pulled.

[0051] Support seats 11 are installed on both sides of the mounting base plate 1 corresponding to the two ends of the main body 6 along the axial direction. A fixed plate 3 is connected to the upper end of the support seat 11. Two fixed guide wheels 2 are vertically rotatably connected to the upper surface of the fixed plate 3 through mounting bearings. The horizontal line connecting the two fixed guide wheels 2 is parallel to the axial direction of the main body 6. A sliding cavity 19 is opened in the fixed plate 3. A piston 20 is coaxially engaged in the sliding cavity 19. The piston 20 slides freely horizontally in the sliding cavity 19. A connecting rod 16 is fixed to the end face of the piston 20. One end of the connecting rod 16 that protrudes from the top surface of the fixed plate 3 is rotatably connected to a floating guide wheel 9. The floating guide wheel 9 is located between the two fixed guide wheels. Between 2, the top surface of the fixed plate 3 is provided with an oblong hole 17 for the connecting rod 16 to pass freely. The cable is passed around a fixed guide wheel 2 away from the body 6, then around a floating guide wheel 9, then around a fixed guide wheel 2 adjacent to the body 6, and then through the clamping sleeve 4. After passing through the clamping sleeve 4, the cable passes through the busbar hole of the body 6, and then through another clamping sleeve 4. It then passes around two fixed guide wheels 2 and floating guide wheels 9 on the other side in sequence, so that the cable passes through the busbar hole of the body 6. When the cable moves towards the inside of the fixed plate 3 through the floating guide wheel 9, the cable can be relaxed.

[0052] A hollow cylinder 10 is horizontally fixed to the wall of the support base 11. A sliding block 18 is coaxially engaged inside the hollow cylinder 10, allowing it to slide freely within the cylinder. The sliding block 18 and the inner wall of the hollow cylinder 10 form a communicating cavity 24. A spring 23 is horizontally installed inside the communicating cavity 24, with its two ends elastically abutting against the sliding block 18 and the inner wall of the communicating cavity 24, respectively. A pipe interface 15 is provided on the wall of the hollow cylinder 10, and an air pipe is installed on the pipe interface 15. The end of the air pipe furthest from the hollow cylinder 10 is installed on a fixed plate. 3. The sliding block 18 is connected to the inner cavity of the sliding cavity 19. A conical groove 21 is coaxially formed on the side end face of the sliding block 18 facing the body 6. The inner diameter of the conical groove 21 increases sequentially in the direction away from the support seat 11. A drive rod 8 is horizontally connected to the wall of the body 6. The end of the drive rod 8 away from the body 6 passes into the conical groove 21. The outer diameter of the drive rod 8 is smaller than the minimum inner diameter of the conical groove 21. When the body 6 moves due to vibration, the end of the drive rod 8 will contact the inner wall of the conical groove 21 and generate a force along the axial direction of the hollow cylinder 10 on the inner wall of the conical groove 21. The squeezing force causes the sliding block 18 to move towards the support seat 11 within the sliding cavity 19, thereby squeezing the air inside the hollow cylinder 10. This allows the air inside the hollow cylinder 10 to enter the sliding cavity 19, and the piston 20 is pushed by the air, causing the piston 20 to slide within the sliding cavity 19. This causes the floating guide wheel 9 to move towards the inside of the fixed guide wheel 2, allowing the cable to be in a slack state. One end of the drive rod 8, which passes through the conical groove 21, is rotatably fitted with a ball bearing 22. The ball bearing 22 rolls in contact with the inner wall of the conical groove 21, and the ball bearing 22 rolls on the inner wall of the conical groove 21, so that the wear between the end of the drive rod 8 and the inner wall of the conical groove 21 is small, and at the same time, it prevents the inner wall of the conical groove 21 from being worn too much. The hollow cylinder 10 has an annular protrusion that is turned inward at the opening. The annular protrusion is used to limit the sliding of the sliding block 18 in the hollow cylinder 10. The annular protrusion limits the movement of the sliding block 18 away from the support seat 11, thereby preventing the sliding block 18 from coming out of the hollow cylinder 10.

[0053] The working principle of this embodiment is as follows:

[0054] The cable is routed around a fixed guide wheel 2 furthest from the main body 6, then around a floating guide wheel 9, and then around a fixed guide wheel 2 adjacent to the main body 6. The cable then passes through a clamping sleeve 4, and after passing through the clamping sleeve 4, it passes through the busbar hole of the main body 6, then exits through another clamping sleeve 4. It then passes around two fixed guide wheels 2 and a floating guide wheel 9 on the other side in sequence, thus allowing the cable to pass through the busbar hole of the main body 6. The operator pulls the cable manually to straighten it on the spreading sleeve 5 and clamping sleeve 4. When pulling, external tools can be used to widen the two spreading sleeves 5, allowing the two... The expansion sleeve 5 can generate elastic expansion deformation along its radial outer side, which in turn causes the clamping sleeve 4 to also be in an expanded state. This makes the resistance when the cable slides in the clamping sleeve 4 smaller. After the cable passes through, the expansion sleeve 5 is released, and the expansion sleeve 5 recovers through its own elastic deformation, which causes the expansion sleeve 5 to change from elastic expansion deformation to elastic contraction deformation, and causes the clamping sleeve 4 to clamp the cable. The inner wall of the clamping sleeve 4 is provided with a rubber layer, which makes the frictional resistance between the cable and the inner wall surface of the clamping sleeve 4 larger, thus preventing the cable from sliding on its own in the clamping sleeve 4 and increasing the resistance when the cable is pulled in the clamping sleeve 4.

[0055] When the main body 6 is subjected to vibration, the stop part 13 will move within the second receiving cavity 14. Since the inner diameter of the second receiving cavity 14 is larger than the outer diameter of the stop part 13, and the outer diameter of the limiting pin 25 is smaller than the inner diameter of the connecting hole 27, the main body 6 can move when subjected to vibration. When the main body 6 is subjected to a lateral force, the main body 6 will drive the pad 7 to move, and the pad 7 will simultaneously drive the protrusion 29 to move, causing the protrusion 29 to compress the spiral spring 26. The spiral spring 26 will begin to accumulate elastic potential energy. When the lateral force acting on the main body 6 disappears, the elastic potential energy of the spiral spring 26 is released, enabling the protrusion 29 to move to the initial state, that is, the position of the inner ring of the spiral spring 26 in the first receiving cavity 28 in the initial state. Thus, when the external control cabinet is subjected to a large impact and vibrates, the vibration is transmitted to the main body 6, and the protrusion 29 compresses the spiral spring 26. The coil spring 26 buffers the main body 6, allowing it to return to its initial state after vibration disappears. Furthermore, since the relative positions of the clamping sleeve 4 and the main body 6 remain unchanged, the cable always maintains coaxiality with the busbar hole of the main body 6. The spreading sleeve 5 undergoes elastic contraction and expansion deformation, ensuring the clamping sleeve 4 maintains a clamping force on the cable. When the cable is pulled, the two spreading sleeves 5 undergo corresponding elastic contraction deformation, increasing the clamping force of the clamping sleeve 4 on the cable, thus increasing the resistance when the cable is pulled. This keeps the cable taut between the two clamping sleeves 4, ensuring high coaxiality between the cable and the busbar hole of the current transformer main body 6. This ensures that the cable and busbar hole remain coaxial even when the main body 6 is vibrated and moves. Maintaining coaxiality helps ensure uniform current distribution, thereby reducing magnetic field inhomogeneity and improving measurement accuracy. Especially under high-frequency or high-current conditions, cable eccentricity can cause uneven magnetic field distribution, leading to measurement errors.

[0056] When the main body 6 moves due to vibration, the end of the drive rod 8 will contact the inner wall of the conical groove 21 and exert a compressive force on the inner wall of the conical groove 21 along the axial direction of the hollow cylinder 10. This causes the sliding block 18 to move towards the support seat 11 in the sliding cavity 19, thereby causing the sliding block 18 to compress the air in the hollow cylinder 10. This allows the air in the hollow cylinder 10 to enter the sliding cavity 19, and causes the piston 20 to be pushed by the air. This causes the piston 20 to slide in the sliding cavity 19, and causes the floating guide wheel 9 to move towards the inside of the fixed guide wheel 2. This allows the cable to be in a slack state. In this way, when the main body 6 moves due to vibration, the cable is relaxed, thereby preventing the main body 6 from pulling on the cable and causing the cable to interfere with the movement of the main body 6. This reduces the buffering damping effect of the main body 6 when it is vibrated.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A switchable current transformer, comprising a switchable current transformer body (6), characterized in that, Also includes: A pad (7) is detachably connected to the bottom of the body (6). The bottom of the pad (7) is connected to the mounting base plate (1). The pad (7) slides freely on the top surface of the mounting base plate (1). A reset assembly is provided on the mounting base plate (1), and the reset assembly is used to generate a damping force on the sliding of the pad (7) on the top surface of the mounting base plate (1); There are two expansion sleeves (5), which are respectively connected to the two axial end faces of the body (6). The outer diameter of the expansion sleeve (5) decreases in sequence in the direction away from the body (6). The smallest end of the outer diameter of the expansion sleeve (5) is fixed with a clamping sleeve (4). Multiple deformation notches (12) penetrating the inner cavity of the expansion sleeve (5) are opened around the periphery of the expansion sleeve (5). The mounting base plate (1) is equipped with support seats (11) on both sides of the axial ends of the body (6). The upper end of the support seat (11) is connected to a fixing plate (3), and the top of the fixing plate (3) is provided with a relaxation component. The relaxation assembly includes two fixed guide wheels (2) that are vertically rotatably connected to the upper surface of the fixed plate (3). The horizontal line connecting the two fixed guide wheels (2) is parallel to the axis of the body (6). A sliding cavity (19) is provided in the fixed plate (3). A piston (20) is coaxially engaged in the sliding cavity (19). The piston (20) slides freely horizontally in the sliding cavity (19). A connecting rod (16) is fixedly connected to the end face of the piston (20). A floating guide wheel (9) is rotatably connected to one end of the connecting rod (16) that protrudes from the top surface of the fixed plate (3). The floating guide wheel (9) is located between the two fixed guide wheels (2). A waist-shaped hole (17) is provided on the top surface of the fixed plate (3) for the connecting rod (16) to pass freely. The support base (11) is provided with a drive unit for driving the piston (20) to move in the sliding cavity (19). The driving unit includes a hollow cylinder (10) fixed to the wall of the support base (11). A sliding block (18) is coaxially engaged inside the hollow cylinder (10). The sliding block (18) slides freely inside the hollow cylinder (10), and the sliding block (18) and the inner wall of the hollow cylinder (10) form a communicating cavity (24). A spring (23) is horizontally installed inside the connecting cavity (24). The two ends of the spring (23) elastically abut against the sliding block (18) and the inner wall of the connecting cavity (24) respectively. An air pipe is installed on the wall of the hollow cylinder (10). The end of the air pipe away from the hollow cylinder (10) is installed on the fixing plate (3) and is connected to the inner cavity of the sliding cavity (19). A conical groove (21) is coaxially opened on the side end face of the sliding block (18) facing the body (6). The inner diameter of the conical groove (21) increases sequentially in the direction away from the support seat (11). The wall of the body (6) is horizontally connected to a drive rod (8). The end of the drive rod (8) away from the body (6) is inserted into the conical groove (21). The outer diameter of the drive rod (8) is smaller than the minimum inner diameter of the conical groove (21).

2. The switchable current transformer according to claim 1, characterized in that, The reset assembly includes a protrusion (29) fixed to the bottom of the pad (7). The top of the mounting base plate (1) has a first receiving cavity (28). The protrusion (29) extends downward into the first receiving cavity (28). A spiral spring (26) is installed in the first receiving cavity (28). The inner ring of the spiral spring (26) is fixedly sleeved around the periphery of the protrusion (29), and the outer ring end of the spiral spring (26) is fixed to the inner wall of the first receiving cavity (28).

3. A switchable current transformer according to claim 2, characterized in that, The protrusion (29) is coaxially fixedly provided with a limiting pin (25). The mounting base plate (1) is provided with a connecting hole (27) for the limiting pin (25) to pass freely. The inner diameter of the connecting hole (27) is larger than the outer diameter of the limiting pin (25). The lower end of the limiting pin (25) is fixedly sleeved with a stop part (13). The bottom surface of the mounting base plate (1) is provided with a second receiving cavity (14) for the stop part (13) to pass freely. The inner diameter of the second receiving cavity (14) is larger than the outer diameter of the stop part (13).

4. The switchable current transformer according to claim 1, characterized in that, Multiple deformation notches (12) are arranged in an axial array along the spreading sleeve (5), and the deformation notches (12) extend to the periphery of the clamping sleeve (4).

5. A switchable current transformer according to claim 1, characterized in that, The inner wall of the clamping sleeve (4) is provided with a rubber layer.

6. A switchable current transformer according to claim 1, characterized in that, One end of the drive rod (8) that passes into the conical groove (21) is rotatably fitted with a ball (22), and the ball (22) makes rolling contact with the inner wall of the conical groove (21).

7. A switchable current transformer according to claim 1, characterized in that, The hollow cylinder (10) has an inwardly turned annular protrusion at its opening, which is used to limit the sliding of the sliding block (18) inside the hollow cylinder (10).

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