A short-circuit-proof current transformer

Abstract

The present invention provides a short-circuit-proof current transformer, which includes a housing and a magnetic core with primary coil terminals. The magnetic core is installed inside the housing. A through hole for the primary coil terminals to be exposed is provided on the housing. The housing includes a separable front cover and a rear cover, and also includes a fixing block. The fixing block passes through the center of the magnetic core. First terminal grooves are provided at both the front and rear ends of the fixing block. Second terminal grooves coaxial with the through hole are provided on both the front cover and the rear cover. When the front cover and the rear cover are closed with each other, the front and rear ends of the fixing block respectively abut against the inner walls of the front cover and the rear cover, and the first terminal grooves and the second terminal grooves are mutually fitted to form a space for restricting the movement of the primary coil terminals. In this solution, the terminals of the primary coil are fixed in the transformer housing by a mechanical fixing method. This fixing method is stable and reliable, simple to install, effectively avoids terminal loosening, and circumvents the short-circuit problem caused by terminal loosening.

Description

Technical Field

[0001] The present invention belongs to the technical field of current transformers, and particularly relates to a short-circuit-proof current transformer. Background Art

[0002] A current transformer is a measuring and protecting device used in a power system. Its main function is to convert high voltage or large current into low voltage and small current signals in proportion for safe measurement, metering, and monitoring. The current transformer has a primary coil (subsequently abbreviated as the primary coil) and a secondary coil (subsequently abbreviated as the secondary coil) wound around an internal magnetic core respectively and works based on the principle of electromagnetic induction. It can accurately reflect the current change on the primary side and at the same time ensure electrical isolation between the secondary circuit and the primary circuit, thus ensuring the safety of operators and the normal operation of measuring instruments and other electronic devices.

[0003] In practical applications, some current transformers install the terminals of the primary coil at the center position of the transformer housing. And to prevent the terminals of the primary coil from loosening due to mechanical vibration or other factors, glue is usually used to fix them on the transformer housing. However, the glue will gradually age during long-term use, and its adhesion performance is easily affected by temperature and humidity, which may lead to a decrease in adhesion force, and then cause the loosening of the terminals of the primary coil, increasing the risks of short circuit and poor contact. In addition, after the glue for fixing ages or the terminals of the primary coil loosen, it may also cause the fixing of the copper wire of the primary coil to be insecure, making the copper wire move freely inside the transformer. Under normal use conditions, once the copper wire of the primary coil touches the secondary coil or other conductive components, a short circuit may also occur, thus damaging the transformer. Moreover, the glue fixing requires a curing process, which takes a long time, has a low error tolerance, and is easily affected by the outside world, resulting in inaccurate fixing of the terminals. Summary of the Invention

[0004] The present invention provides a short-circuit-proof current transformer, which uses a mechanical fixing method to fix the terminals of the primary coil in the transformer housing. This fixing method is stable and reliable, simple to install, effectively avoids terminal loosening, and circumvents the short-circuit problem caused by terminal loosening.

[0005] To solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A short-circuit-proof current transformer includes a housing and a magnetic core with primary coil terminals. The magnetic core is installed inside the housing, and the housing is provided with through holes for the primary coil terminals to be exposed. The housing includes a front cover and a rear cover that can be separated from each other, and also includes a fixing block. The fixing block passes through the center of the magnetic core, and first terminal slots are provided at both the front and rear ends of the fixing block. Second terminal slots coaxial with the through holes are provided on both the front cover and the rear cover. When the front cover and the rear cover are closed together, the front and rear ends of the fixing block respectively abut against the inner walls of the front cover and the rear cover, and the first terminal slots and the second terminal slots are mutually fitted to form a space that restricts the movement of the primary coil terminals.

[0007] In the prior art, the primary coil terminals are usually fixed to the current transformer housing with glue. However, the glue is prone to aging after long-term use, resulting in the loosening or even falling off of the terminals, which undoubtedly increases the risk of short circuit in the electrical system. To avoid this problem, some technicians may consider clamping the primary coil terminals into the front cover and the rear cover respectively. For example, first clamp one primary coil terminal into the rear cover, then place the magnetic core in the rear cover, and then clamp the other primary coil terminal into the front cover, and finally close the front cover onto the rear cover.

[0008] However, the above alternative solution has the disadvantages of inconvenient installation and poor installation accuracy: Since the primary coil terminals are fixedly connected to the primary coil wound on the magnetic core, the primary coil will generate a certain pulling tendency on the terminals. Therefore, during the process of closing the front cover onto the rear cover, it is impossible to ensure that the primary coil terminals will not loosen or fall off due to the pulling of the primary coil. In addition, the line of sight is blocked during the closing process, making it difficult for the installer to accurately judge whether the internal primary coil terminals are loose. In view of this, the present invention proposes a new solution to replace the unreliability of traditional glue fixing by introducing a fixing block and a terminal slot design that cooperates with it.

[0009] The working principle of the present invention is as follows: First, the magnetic core wound with the primary coil and the secondary coil is installed into the rear cover. During this installation process, one terminal of the primary coil needs to be installed in the second terminal slot of the rear cover first; after installation, one end of this primary coil terminal will rest against the second terminal slot, and the other end will pass through the through hole of the rear cover and extend out of the rear cover. It should be noted that the terminal located in the second terminal slot is not completely embedded in the second terminal slot, but a part of the terminal will be exposed outside the second terminal slot. Then, the fixing block is installed. Align the first terminal slot with the primary coil terminal exposed outside the second terminal slot, and then press the fixing block against the rear cover to ensure that the primary coil terminal is completely covered by the first terminal slot and the second terminal slot. After that, the other primary coil terminal is installed in the first terminal slot of the fixing block. Similarly, a part of the terminal is exposed outside the first terminal slot. Finally, align the second terminal slot on the front cover with the primary coil terminal exposed outside the first terminal slot, then cover the front cover on the rear cover and also make one end of the terminal extend out of the front cover from the through hole. Then, fix the front cover and the rear cover, so that both terminals of the primary coil are covered in the first terminal slot and the second terminal slot. Such a structure also avoids the problem of blocked line of sight during closing. Since the front and rear ends of the fixing block are against the inner walls of the front cover and the rear cover, after the front cover and the rear cover are fixed to each other, the fixing block can no longer move axially, and the fact that the primary coil terminals are fixed in the first terminal slot and the second terminal slot will further restrict the radial movement of the fixing block, thereby realizing the complete fixation of the fixing block. Since the fixing block cannot move, the primary coil terminals cannot move either. It should be noted that the secondary coil wound around the magnetic core is also equipped with secondary coil terminals. Among them, the secondary coil terminals adopt a conventional installation and fixation method, that is, before covering the front cover on the rear cover, the secondary coil terminals are first installed on the rear cover, and a part of the secondary coil terminals is exposed outside the housing for easy connection to the electrical system. Since it is a conventional design, the installation process of the secondary coil terminals will not be described in detail in the present invention.

[0010] This mechanical fixing method is not affected by environmental factors such as temperature and humidity, effectively preventing the problem of loosening of the primary coil terminals due to long-term use or changes in external conditions, ensuring that the current transformer can maintain stable performance in various environments, and avoiding the short-circuit risk caused by terminal loosening. Moreover, the design of the fixing block and the terminal slot simplifies the installation process, eliminating the need to wait for glue to cure, improving the installation efficiency, and also facilitating future maintenance and replacement operations. In addition, since the primary coil terminals are firmly fixed in the transformer housing by the fixing block, when connecting the primary coil terminals to the power system, there is no need to worry about terminal loosening caused by installation errors or excessive force during the installation process.

[0011] Preferably, copper wire placement holes are provided on the side wall of the fixed block. There are two copper wire placement holes, which are respectively located at the front and rear ends of the fixed block, and the copper wire placement holes communicate with the first terminal groove. By providing copper wire placement holes on the side wall of the fixed block, the copper wire of the primary coil can directly pass through or be placed in these holes during the installation process. This not only increases the stability of the copper wire fixation but also prevents the possibility of the copper wire freely moving inside the mutual inductor, further reducing the short-circuit risk. Moreover, this design allows for more convenient positioning and fixation of the primary coil copper wire during assembly, eliminating the need for additional binding or fixation measures, simplifying the assembly steps, and improving production efficiency.

[0012] Preferably, bearing platforms are provided on both the front cover and the rear cover. The end face size of the bearing platform is the same as the front and rear end sizes of the fixed block and is used to abut against the front and rear ends of the fixed block. The second terminal groove is provided on the bearing platform. The design of the bearing platform provides more space for the setting of the second terminal groove, facilitating the design and processing of the second terminal groove; moreover, this design also avoids the direct action of the force on the fixed block on the front cover and the rear cover, reducing the stress concentration on the outer shell and improving the service life of the outer shell.

[0013] Regarding the positioning problem of the fixed block, this solution first proposes that there is no connection structure between the end face of the bearing platform and the fixed block, and the fixed block is clamped by the bearing platform when the front cover and the rear cover are closed. In fact, after the front cover and the rear cover are closed, the fixed block restricts the movement of the primary coil terminals. Since the primary coil terminals also restrict the movement of the fixed block after being clamped with the cover body, the fixed block does not need to be fixedly installed according to the conventional design idea, that is, only a rough axial limit is required using the inner hole of the magnetic core. This solution has obvious advantages in terms of manufacturing cost and installation convenience.

[0014] Of course, after the fixed block is provided with a fixing structure, it will have other functions. In order to accurately position and install the fixed block on the bearing platform, the present invention provides the following preferred solutions:

[0015] Solution 1: A first insertion groove is provided at one end of the bearing platform facing the fixed block. First insertion blocks that are in plug-in fit with the first insertion groove are fixedly provided on the front and rear ends of the fixed block. When the first insertion block is inserted into the first insertion groove, the first insertion block and the first insertion groove are in interference fit. In this way, the design of the first insertion block and the first insertion groove ensures that the fixed block can be quickly, accurately, and firmly installed on the bearing platform along a predetermined path, thereby ensuring that the primary coil terminals are accurately installed in the first terminal groove and the second terminal groove. Among them, a semi-circular protrusion can be fixedly provided on the first insertion block to increase the friction between the first insertion block and the first insertion groove, making the fit between the first insertion block and the first insertion groove more firm.

[0016] Solution 2: A shoulder is provided in the radial direction of the support platform, and a circle of grooves is formed between the inner wall of the shoulder and the outer wall of the support platform. Male buckles are provided on the outer walls of the front and rear ends of the fixed block, and a female buckle extending along the groove is provided on the shoulder. The male buckle engages with the female buckle after being inserted into the groove. Specifically, the fixed block and the shoulder are respectively provided with male buckles and female buckles that can engage with each other. After the fixed block is installed on the support platform (the male buckle will also be inserted into the groove at this time), the male buckle and the female buckle can be fixedly engaged with each other, so that a firm connection is achieved between the fixed block and the support platform. The design of the male buckle and the female buckle provides an additional mechanical locking function. Even in a vibration or impact environment, the male buckle and the female buckle can effectively prevent the fixed block from loosening or shifting, thereby improving the stability of the overall structure and further ensuring that the primary coil terminal can be more tightly wrapped in the first terminal groove and the second terminal groove and cannot be loosened. At the same time, this snap-on design can make the connection between the fixed block and the support platform easier, reducing the installation complexity and installation time. Importantly, since the primary coil is generally made of copper wire covered with insulating material, the primary coil as a whole will have a certain degree of elasticity; after the fixing block is installed in the housing and the primary coil is placed in the copper wire placement hole, the primary coil may move due to rebound, which may cause the fixing block to fall off the support platform, thereby causing the primary coil terminal to loosen. By introducing a male and female buckle design that can be engaged with each other, a firm engagement is achieved between the fixing block and the support platform, preventing the fixing block from axial movement after installation.

[0017] It is worth mentioning that, compared with Scheme 1, Scheme 2 forms a groove by setting a shoulder in the radial direction of the support platform, and the female buckle can be set on the shoulder, so that there is no need to groove or process other structures on the support platform, thereby ensuring the mechanical strength of the support platform, enabling it to withstand greater external pressure or vibration in the radial direction, and significantly improving the overall reliability of the current transformer. In addition, this design makes full use of the radial space between the support platform and the inner wall of the shell, avoiding the additional occupation of the effective space inside the transformer, and realizing compact and efficient space utilization.

[0018] Solution 3: A wing plate portion is installed at one end of the fixing block. The wing plate portion extends outward from the fixing block to the inner wall of the housing. A second insertion slot is provided on the inner wall of the housing. Two downwardly vertically extending second insertion blocks are provided at both ends of the wing plate portion. The second insertion blocks can be inserted and fixed in the second insertion slot, and when inserted, the lower surface of the wing plate portion abuts against the magnetic core. Specifically, the wing plate portion can be installed at the front end of the fixing block, and the second insertion slot is located on the inner side wall of the rear cover. After one terminal of the primary coil is installed in the second terminal slot of the rear cover, then the non-wing plate portion end (i.e., the rear end of the fixing block) of the fixing block is installed on the primary coil terminal. The key is that during this installation process, it must be ensured that the second insertion blocks at both ends of the wing plate portion accurately insert into the second insertion slots on the inner side wall of the rear cover to achieve precise positioning and fixing of the fixing block; next, the other terminal of the primary coil is installed at the front end of the fixing block. Since the wing plate portion, the second insertion blocks, and the second insertion slots are exposed outside the magnetic core, the installation process of Solution 3 is more intuitive than that of Solution 1 and Solution 2, which can effectively improve the convenience and accuracy of installation. It is worth mentioning that the lower surface of the wing plate portion can abut against the magnetic core to effectively prevent the magnetic core from shaking. This design not only enhances the fixing effect of the magnetic core and makes the installation process more convenient, but also avoids the risk of free movement of the copper wire of the primary coil caused by the loosening of the magnetic core, improving the overall stability and safety of the mutual inductor. The interference fit between the second insertion block and the second insertion slot effectively prevents the loosening of the wing plate portion and ensures the reliability of the connection. A semi-circular engaging protrusion can be provided on the second insertion block to increase the friction between the second insertion block and the second insertion slot and ensure a firm fit between the two.

[0019] In order to prevent the wing plate portion from interfering with the smooth installation of the primary wire terminal onto the fixing block, the present invention further provides the following two preferred solutions:

[0020] Solution A: The wing plate portion includes a first wing plate and a protruding portion, a third plug-in block is fixedly provided on the first wing plate, a third plug-in slot for plugging with the third plug-in block is provided at one end of the fixed block facing the first wing plate, and when the third plug-in block is plugged into the third plug-in slot, the third plug-in block and the third plug-in slot are interference fit, the protruding portion is provided on the end face of the first wing plate away from the fixed block, and the first terminal slot and the copper wire placement hole are provided on the protruding portion. Specifically, the first wing plate and the fixed block are installed in a split-type manner, so that the first wing plate can be installed after the fixed block is installed on the supporting platform, making the installation process of the first wing plate and the fixed block more flexible. Among them, a semicircular protrusion can also be provided on the third plug-in block, so that the third plug-in block is plugged into the third plug-in slot more firmly and with greater friction, thereby preventing the fixed block from loosening from the first wing plate. It is worth mentioning that a protrusion is provided on the first wing plate, and the first terminal groove and the copper wire placement hole are provided on the protrusion, which provides a clear installation position for the primary coil terminal and effectively avoids the first wing plate from affecting the installation of the primary coil terminal.

[0021] Solution B: The wing plate portion includes a second wing plate, and a concave stopper is provided at one end of the fixed block. The second wing plate is rotatably mounted on the concave stopper, and the rotation axis of the second wing plate is coaxial with the fixed block. Specifically, when the second plug-in block of the wing plate portion is inserted into the second plug-in slot, the direction of the fixed block is fixed, and thus the direction of the copper wire placement hole is also fixed. This requires that during the installation of the magnetic core, the position of the primary coil segment connected to the primary coil terminal also needs to be fixed to ensure that the copper wire can be installed in the copper wire placement hole. This positioning requirement brings inconvenience to the installation process. Therefore, in order to increase the degree of freedom of the magnetic core installation, a second wing plate that can rotate on the fixed block is designed, and the rotation axis of the second wing plate is coaxial with the fixed block; it is worth noting that the second wing plate is arranged in the concave stopper, and the concave stopper itself is a part opened on the fixed block, so Solution B does not need to add an additional component with a first terminal slot and a copper wire placement hole like Solution A, which effectively simplifies the design of the component and controls the cost. Although the direction of the fixing block can be adjusted before installing the first wing plate in solution A, since the position of the second plug-in slot is fixed, the direction of the first wing plate and the protrusion arranged thereon will also be fixed with the second plug-in slot, which further makes it difficult to change the direction of the first terminal slot and the copper wire placement hole on the protrusion, which will also impose certain restrictions on the installation of the magnetic core and the primary coil. After adopting solution B, the angle of the fixing block can be adjusted as needed during the installation process, so that the direction of the copper wire placement hole can be flexibly adjusted without being restricted by the direction of the wing plate. This not only improves the freedom of installation of the magnetic core and the primary coil terminal, but also simplifies the assembly process, reduces the difficulty and time of installation, and improves the overall assembly efficiency.

[0022] Preferably, terminal card slots are provided at the upper ends of the front cover and the rear cover. In this way, the secondary coil terminals can be accurately and firmly installed between the front cover and the rear cover.

[0023] In summary, for such a short-circuit-proof current transformer, the terminals of the primary coil are fixed in the transformer housing by a mechanical fixing method. This fixing method is stable and reliable, simple to install, effectively avoids terminal loosening, and circumvents the short-circuit risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 Structural schematic diagram of the short-circuit-proof current transformer described in the present invention Figure 1 ;

[0026] Figure 2 Cross-sectional view of the short-circuit-proof current transformer described in the present invention;

[0027] Figure 3 Structural schematic diagram of the rear cover in the short-circuit-proof current transformer described in the present invention;

[0028] Figure 4 Structural schematic diagram of the fixing block in the short-circuit-proof current transformer described in the present invention;

[0029] Figure 5 Structural schematic diagram of the connection structure between the fixing block and the primary coil terminal in the short-circuit-proof current transformer described in the present invention;

[0030] Figure 6 Structural schematic diagram of Embodiment 1 in the short-circuit-proof current transformer described in the present invention;

[0031] Figure 7 Structural schematic diagram of Embodiment 2 in the short-circuit-proof current transformer described in the present invention;

[0032] Figure 8 For Figure 7 partial cross-sectional view;

[0033] Figure 9 Structural schematic diagram of Embodiment A in the short-circuit-proof current transformer described in the present invention;

[0034] Figure 10 Explosion schematic diagram of the fixing block and the first wing plate in Embodiment A;

[0035] Figure 11 Structural schematic diagram of Embodiment B in the short - circuit - proof current transformer of the present invention;

[0036] Figure 12 Exploded view of the fixing block and the second wing plate in Embodiment B;

[0037] Figure 13 Structural schematic of the short - circuit - proof current transformer of the present invention Figure 2 。

[0038] In the figure,

[0039] 1 - front cover;

[0040] 2 - rear cover;

[0041] 3 - magnetic core; 31 - primary coil terminal; 32 - secondary coil terminal;

[0042] 4 - fixing block; 41 - first terminal slot; 42 - second terminal slot; 43 - first plug - in block; 44 - male buckle; 45 - female buckle; 46 - concave stop;

[0043] 5 - copper wire placement hole;

[0044] 6 - bearing platform; 61 - through hole; 62 - shoulder; 63 - first plug - in slot; 64 - groove;

[0045] 7 - terminal card slot;

[0046] 8 - wing plate part; 81 - second plug - in slot; 82 - first wing plate; 821 - second plug - in block; 8211 - semi - circular engaging protrusion; 83 - protruding part; 84 - second wing plate; 85 - third plug - in block; 86 - third plug - in slot. Detailed implementation manners

[0047] The following further explains the detailed implementation manners of the present invention with reference to the accompanying drawings. It should be noted here that the description of these implementation manners is used to help understand the present invention, but does not constitute a limitation to the present invention. In addition, the technical features involved in the various implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] Refer to Figures 1 - 5 and Figure 13As shown in the figure, a short-circuit-proof current transformer includes a housing and a magnetic core 3 with a primary coil terminal 31. The magnetic core 3 is installed inside the housing. A through hole 61 is provided on the housing for the primary coil terminal 31 to be exposed. The housing includes a separable front cover 1 and a rear cover 2. It also includes a fixing block 4. The fixing block 4 passes through the center of the magnetic core 3. First terminal slots 41 are provided at both the front and rear ends of the fixing block 4. Second terminal slots 42 coaxial with the through hole 61 are provided on both the front cover 1 and the rear cover 2. When the front cover 1 and the rear cover 2 are closed together, the front and rear ends of the fixing block 4 respectively abut against the inner walls of the front cover 1 and the rear cover 2, and the first terminal slots 41 and the second terminal slots 42 fit together to form a space that restricts the movement of the primary coil terminal 31.

[0049] In the prior art, the primary coil terminal 31 is usually fixed to the current transformer housing with glue. However, the glue is prone to aging after long-term use, resulting in terminal loosening or even falling off, which undoubtedly increases the risk of short circuit in the electrical system. To avoid this problem, some technicians may consider clamping the primary coil terminals 31 into the front cover 1 and the rear cover 2 respectively. For example, first clamp one primary coil terminal 31 into the rear cover 2, then place the magnetic core 3 in the rear cover 2, then clamp the other primary coil terminal 31 onto the front cover 1, and finally close the front cover 1 onto the rear cover 2.

[0050] However, the above alternative solution has the disadvantages of inconvenient installation and poor installation accuracy: Since the primary coil terminal 31 is fixedly connected to the primary coil wound around the magnetic core 3, the primary coil will exert a certain pulling tendency on the terminal. Therefore, during the process of closing the front cover 1 onto the rear cover 2, it is impossible to ensure that the primary coil terminal 31 will not loosen or fall off due to the pulling of the primary coil. In addition, the line of sight is blocked during the closing process, making it difficult for the installer to accurately judge whether the internal primary coil terminal 31 has become loose. In view of this, the present invention proposes a new solution, by introducing a fixing block 4 and a terminal slot design used in cooperation with it, to replace the unreliability of traditional glue fixation.

[0051] The working principle of the present invention is as follows: First, the magnetic core 3 wound with the primary coil and the secondary coil is installed into the rear cover 2. During this installation process, one terminal of the primary coil needs to be installed in the second terminal slot 42 of the rear cover 2 first; after installation, one end of the primary coil terminal 31 will rest against the second terminal slot 42, and the other end will pass through the through hole 61 of the rear cover 2 and extend out of the rear cover 2. It should be noted that the terminal located in the second terminal slot 42 is not completely embedded in the second terminal slot 42, but a part of the terminal will be exposed outside the second terminal slot 42. Then, the fixing block 4 is installed. The first terminal slot 41 is aligned with the primary coil terminal 31 exposed outside the second terminal slot 42. Subsequently, the fixing block 4 is abutted against the rear cover 2 to ensure that the primary coil terminal 31 is completely covered by the first terminal slot 41 and the second terminal slot 42. After that, the other primary coil terminal 31 is installed in the first terminal slot 41 of the fixing block 4. Similarly, a part of the terminal is exposed outside the first terminal slot 41. Finally, the second terminal slot 42 on the front cover 1 is aligned with the primary coil terminal 31 exposed outside the first terminal slot 41. Subsequently, the front cover 1 is closed on the rear cover 2 and one end of the terminal also extends out of the front cover 1 from the through hole 61. Then, the front cover 1 and the rear cover 2 are fixed, so that both terminals of the primary coil are covered in the first terminal slot 41 and the second terminal slot 42. Such a structure also avoids the problem of blocked sight during closing. Since the front and rear ends of the fixing block 4 are abutted against the inner walls of the front cover 1 and the rear cover 2, after the front cover 1 and the rear cover 2 are fixed to each other, the fixing block 4 can no longer move axially. And the fact that the primary coil terminal 31 is fixed in the first terminal slot 41 and the second terminal slot 42 will further restrict the radial movement of the fixing block 4, thereby realizing the complete fixation of the fixing block 4. Since the fixing block 4 cannot move, the primary coil terminal 31 also cannot move. It should be noted that the secondary coil wound on the magnetic core 3 is also provided with a secondary coil terminal 32. Among them, the secondary coil terminal 32 adopts a conventional installation and fixation method, that is, before the front cover 1 is closed on the rear cover 2, the secondary coil terminal 32 is first installed on the rear cover 2, and a part of the secondary coil terminal 32 is exposed outside the housing for easy connection to the electrical system. Since it is a conventional design, the installation process of the secondary coil terminal 32 will not be described in detail in the present invention.

[0052] This mechanical fixing method is not affected by environmental factors such as temperature and humidity, effectively preventing the problem of loosening of the primary coil terminal 31 due to long-term use or changes in external conditions. It ensures that the current transformer can maintain stable performance in various environments and avoids the short-circuit risk caused by terminal loosening. Moreover, the design of the fixing block 4 and the terminal slot simplifies the installation process, eliminating the need to wait for glue curing, improving the installation efficiency, and facilitating future maintenance and replacement operations. In addition, since the primary coil terminal 31 is firmly fixed in the transformer housing by the fixing block 4, there is no need to worry about terminal loosening caused by installation errors or excessive force when connecting the primary coil terminal 31 to the power system.

[0053] In addition, referring to Figure 4 As shown, two copper wire placement holes 5 are provided on the side wall of the fixing block 4, and are respectively located at the front and rear ends of the fixing block 4. The copper wire placement holes 5 communicate with the first terminal slot 41. By providing the copper wire placement holes 5 on the side wall of the fixing block 4, the copper wire of the primary coil can directly pass through or be placed in these holes during the installation process. This not only increases the stability of the copper wire fixation but also prevents the possibility of the copper wire moving freely inside the transformer, further reducing the short-circuit risk. Moreover, this design allows for more convenient positioning and fixation of the primary coil copper wire during assembly, eliminating the need for additional tying or fixing measures, simplifying the assembly steps, and improving the production efficiency.

[0054] In addition, referring to Figure 3 As shown, bearing platforms 6 are provided on both the front cover 1 and the rear cover 2. The end face dimensions of the bearing platforms 6 are the same as the front and rear end dimensions of the fixing block 4 and are used to abut against the front and rear ends of the fixing block 4. The second terminal slot 42 is provided on the bearing platform 6. The design of the bearing platform 6 provides more space for the setting of the second terminal slot 42, facilitating the design and processing of the second terminal slot 42; moreover, this design also avoids the force on the fixing block 4 directly acting on the front cover 1 and the rear cover 2, reducing the stress concentration on the housing and increasing the service life of the housing.

[0055] Regarding the positioning problem of the fixing block 4, this solution first proposes that there is no connection structure between the end face of the bearing platform 6 and the fixing block 4, and the fixing block 4 is clamped by the bearing platform when the front cover 1 and the rear cover 2 are closed. In fact, after the front cover 1 and the rear cover 2 are closed, the fixing block 4 restricts the movement of the primary coil terminal 31. Since the primary coil terminal 31 also restricts the movement of the fixing block 4 after being clamped with the cover body, the fixing block 4 does not need to be fixedly installed according to the conventional design idea, that is, only a rough axial limit is required using the inner hole of the magnetic core. This solution has obvious advantages in terms of manufacturing cost and installation convenience.

[0056] Of course, after the fixing block 4 is provided with a fixing structure, it will have other functions. In order to enable the fixing block 4 to be accurately positioned and installed on the bearing platform 6, the present invention provides the following several embodiments:

[0057] Embodiment 1: Refer to Figure 6 As shown, at one end of the bearing platform 6 facing the fixing block 4, a first insertion slot 63 is provided. On the front and rear ends of the fixing block 4, first insertion blocks 43 that are inserted into and cooperate with the first insertion slot 63 are fixedly provided. When the first insertion block 43 is inserted into the first insertion slot 63, the first insertion block 43 and the first insertion slot 63 are in interference fit. In this way, the design of the first insertion block 43 and the first insertion slot 63 ensures that the fixing block 4 can be quickly, accurately and firmly installed on the bearing platform 6 along a predetermined path, thereby ensuring that the primary coil terminal 31 is accurately installed in the first terminal slot 41 and the second terminal slot 42. Among them, a semi-circular protrusion can be fixedly provided on the first insertion block 43 to increase the friction between the first insertion block 43 and the first insertion slot 63, making the cooperation between the first insertion block 43 and the first insertion slot 63 more firm.

[0058] Embodiment 2: Refer to Figure 7 and Figure 8 As shown, on the radial direction of the bearing platform 6, a shoulder 62 is provided. A groove 64 is formed between the inner wall of the shoulder 62 and the outer wall of the bearing platform 6. On the outer walls of the front and rear ends of the fixing block 4, male fasteners 44 are provided. On the shoulder 62, female fasteners 45 extending along the groove 64 are provided. After the male fastener 44 is inserted into the groove 64, it is engaged with the female fastener 45. Specifically, male fasteners 44 and female fasteners 45 that can be engaged with each other are respectively provided on the fixing block 4 and the shoulder 62. After the fixing block 4 is installed on the bearing platform 6 (at this time, the male fastener 44 will also be inserted into the groove 64), the male fastener 44 and the female fastener 45 can be fixedly engaged with each other, so that a firm connection is achieved between the fixing block 4 and the bearing platform 6. The design of the male fastener 44 and the female fastener 45 provides an additional mechanical locking function. Even in a vibrating or impact environment, the male fastener 44 and the female fastener 45 can effectively prevent the fixing block 4 from loosening or shifting, improving the stability of the overall structure, and further ensuring that the primary coil terminal 31 can be more tightly wrapped in the first terminal slot 41 and the second terminal slot 42 without loosening. At the same time, this snap-fastening design can make the connection between the fixing block 4 and the bearing platform 6 more convenient, reducing the installation complexity and installation time. Importantly, since the primary coil is generally made of copper wire coated with insulating material, the whole primary coil will have a certain elasticity; after the fixing block 4 is installed in the housing and the primary coil is placed in the copper wire placement hole 5, there may be a situation where the primary coil moves due to rebound, which may cause the fixing block 4 to fall off from the bearing platform 6, thereby causing the problem of loosening of the primary coil terminal 31. By introducing the design of male fasteners 44 and female fasteners 45 that can be engaged with each other, a firm engagement is achieved between the fixing block 4 and the bearing platform 6, preventing the fixing block 4 from moving axially after installation.

[0059] It is worth mentioning that, compared with Example 1, Example 2 forms a groove 64 by setting a shoulder 62 in the radial direction of the support platform 6, and the female buckle 45 can be set on the shoulder 62, so that there is no need to groove or process other structures on the support platform 6, thereby ensuring the mechanical strength of the support platform 6, enabling it to withstand greater external pressure or vibration in the radial direction, and significantly improving the overall reliability of the current transformer. In addition, this design makes full use of the radial space between the support platform 6 and the inner wall of the shell, avoids additional occupation of the effective space inside the transformer, and realizes compact and efficient space utilization.

[0060] Example 3: Reference Figures 9 - 12 As shown, a wing plate portion 8 is installed at one end of the fixed block 4, and the wing plate portion 8 extends outward from the fixed block 4 to the inner wall of the shell, and a second plug-in slot 81 is provided on the inner wall of the shell. The two ends of the wing plate portion 8 are provided with a second plug-in block 821 extending vertically downward, and the second plug-in block 821 can be plugged and fixed in the second plug-in slot 81, and when plugged, the lower surface of the wing plate portion 8 abuts against the magnetic core 3. Specifically, the wing plate portion 8 can be installed at the front end of the fixed block 4, and the second plug-in slot 81 is located on the inner wall of the rear cover 2. After one terminal of the primary coil is installed in the second terminal slot 42 of the rear cover 2, the non-wing plate portion 8 end of the fixed block 4 (i.e., the rear end of the fixed block 4) is installed on the primary coil terminal 31. The key is that during this installation process, it is necessary to ensure that the second plug-in blocks 821 at both ends of the wing plate portion 8 are accurately inserted into the second plug-in slot 81 on the inner wall of the rear cover 2, so as to achieve accurate positioning and fixation of the fixed block 4; next, the other terminal of the primary coil is installed at the front end of the fixed block 4. Because the wing plate portion 8, the second plug-in block 821 and the second plug-in slot 81 are exposed outside the magnetic core 3, the installation process of Example 3 is more intuitive than that of Example 1 and Example 2, which can effectively improve the convenience and accuracy of installation. It is worth mentioning that the lower surface of the wing plate portion 8 can be against the magnetic core 3 to effectively prevent the magnetic core 3 from shaking. This design not only enhances the fixing effect of the magnetic core 3 and makes the installation process more convenient, but also avoids the risk of free movement of the primary coil copper wire due to loosening of the magnetic core 3, thereby improving the overall stability and safety of the mutual inductor. The interference fit between the second plug-in block 821 and the second plug-in slot 81 effectively prevents the loosening of the wing plate portion 8 and ensures the reliability of the connection. A semicircular snap-fit ​​protrusion 8211 can be provided on the second plug-in block 821 to increase the friction between the second plug-in block 821 and the second plug-in slot 81 to ensure that the two can fit firmly.

[0061] In order to prevent the wing plate portion 8 from hindering the primary terminal from being smoothly installed on the fixing block 4, the present invention further provides the following two embodiments:

[0062] Example A: Reference Figure 9 andFigure 10 As shown, the wing plate portion 8 includes a first wing plate 82 and a protruding portion 83. A third insertion block 85 is fixedly arranged on the first wing plate 82. One end of the fixing block 4 facing the first wing plate 82 is provided with a third insertion slot 86 that is in insertion fit with the third insertion block 85. When the third insertion block 85 is inserted into the third insertion slot 86, the third insertion block 85 and the third insertion slot 86 are in interference fit. The protruding portion 83 is arranged on the end surface of the first wing plate 82 facing away from the fixing block 4. The first terminal groove 41 and the copper wire placement hole 5 are arranged on the protruding portion 83. Specifically, the first wing plate 82 and the fixing block 4 are installed in a split form, so that the first wing plate 82 can be installed after the fixing block 4 is installed on the bearing platform 6, making the installation process of the first wing plate 82 and the fixing block 4 more flexible. Among them, a semi-circular protrusion can also be arranged on the third insertion block 85, so that when the third insertion block 85 is inserted into the third insertion slot 86, the insertion is more firm and the friction is greater, avoiding loosening between the fixing block 4 and the first wing plate 82. It is worth mentioning that the protruding portion 83 is arranged on the first wing plate 82, and the first terminal groove 41 and the copper wire placement hole 5 are arranged on the protruding portion 83, which provides a clear installation position for the primary coil terminal 31 and effectively avoids the influence of the first wing plate 82 on the installation of the primary coil terminal 31.

[0063] Embodiment B: Refer to Figure 11 and Figure 12As shown in the figure, the wing plate part 8 includes a second wing plate 84. One end of the fixing block 4 is provided with a concave stop 46. The second wing plate 84 is rotatably installed on the concave stop 46, and the rotation axis of the second wing plate 84 is coaxial with the fixing block 4. Specifically, when the second insertion block 821 of the wing plate part 8 is inserted into the second insertion slot 81, the direction of the fixing block 4 is fixed, and thus the direction of the copper wire placement hole 5 is also fixed. This requires that during the installation process of the magnetic core 3, the position of the primary coil section connected to the primary coil terminal 31 also needs to be fixed to ensure that the copper wire can be installed in the copper wire placement hole 5. This positioning requirement brings inconvenience to the installation process. Therefore, in order to improve the freedom of installation of the magnetic core 3, a second wing plate 84 that can rotate on the fixing block 4 is designed, and the rotation axis of the second wing plate 84 is coaxial with the fixing block 4. It should be noted that the second wing plate 84 is arranged in the concave stop 46, and the concave stop 46 itself is a part opened on the fixing block 4. Therefore, in Embodiment B, there is no need to additionally add a component with a first terminal slot 41 and a copper wire placement hole 5 like in Embodiment A, effectively simplifying the design of the component and controlling the cost. Although in Embodiment A, the direction of the fixing block 4 can also be adjusted before installing the first wing plate 82, since the position of the second insertion slot 81 is fixed, the directions of the first wing plate 82 and the protruding part 83 provided thereon will also be fixed with the second insertion slot 81, so it further causes the directions of the first terminal slot 41 and the copper wire placement hole 5 on the protruding part 83 to be difficult to change, so it will also impose certain restrictions on the installation of the magnetic core 3 and the primary coil. After adopting Embodiment B, during the installation process, the angle of the fixing block 4 can be adjusted as needed, so that the direction of the copper wire placement hole 5 can be flexibly adjusted without being restricted by the direction of the wing plate part 8. This not only improves the freedom of installation of the magnetic core 3 and the primary coil terminal 31, but also simplifies the assembly process, reduces the installation difficulty and time, and improves the overall assembly efficiency.

[0064] In addition, referring to Figure 3 As shown in the figure, terminal card slots 7 are provided at the upper ends of both the front cover 1 and the rear cover 2. In this way, the secondary coil terminal 32 can be accurately and firmly installed between the front cover 1 and the rear cover 2.

[0065] In addition, referring to Figure 4 As shown in the figure, the fixing block 4 is of a hollow structure. The hollow structure can facilitate the installation of the terminal copper wire, providing more operating space for the copper wire installation. And the hollow structure can enhance the heat dissipation effect and also effectively reduce the overall weight of the current transformer.

[0066] In summary, for such a short-circuit current-proof current transformer, the terminals of the primary coil are fixed in the current transformer housing by a mechanical fixing method. This fixing method is stable and reliable, simple to install, effectively avoids terminal loosening, and circumvents the short-circuit risk.

[0067] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principle and spirit of the present invention, various changes, modifications, substitutions, and variations to these embodiments still fall within the protection scope of the present invention.

Claims

1. A short-circuit proof current transformer, comprising a housing and a magnetic core with a primary coil terminal, the magnetic core being installed in the housing, the housing being provided with a through hole for exposing the primary coil terminal, the housing comprising a front cover and a rear cover which can be separated from each other, characterized in that: It also includes a fixing block, which passes through the center of the magnetic core, and the front and rear ends of the fixing block are both provided with a first terminal groove, and the front cover and the rear cover are both provided with a second terminal groove coaxial with the through hole, when the front cover and the rear cover are covered with each other, the front and rear ends of the fixing block respectively abut against the inner walls of the front cover and the rear cover, and the first terminal groove and the second terminal groove are fitted together to form a space to limit the movement of the primary coil terminal.

2. The short-circuit-proof current transformer according to claim 1, characterized in that: A copper wire placement hole is arranged on the side wall of the fixing block, two copper wire placement holes are arranged and are respectively located at the front and rear ends of the fixing block, and the copper wire placement holes are communicated with the first terminal groove.

3. The short-circuit-proof current transformer according to claim 2, characterized in that: The front cover and the rear cover are both provided with a supporting platform, the end surface size of the supporting platform is the same as the front and rear end size of the fixing block and is used to abut against the front and rear end of the fixing block, and the second terminal groove is provided on the supporting platform.

4. The short-circuit-proof current transformer according to claim 3, characterized in that: There is no connection structure between the end surface of the supporting platform and the fixed block, and the supporting platform clamps the fixed block when the front cover and the rear cover are closed.

5. The short-circuit-proof current transformer according to claim 3, characterized in that: A first plug-in slot is arranged at one end of the supporting platform facing the fixed block, and first plug-in blocks plugged into the first plug-in slot are fixedly arranged on the front and rear ends of the fixed block. When the first plug-in block is inserted into the first plug-in slot, the first plug-in block and the first plug-in slot are interference-fitted.

6. The short-circuit-proof current transformer according to claim 3, characterized in that: A shoulder is provided in the radial direction of the supporting platform, a circle of groove is formed between the inner wall of the shoulder and the outer wall of the supporting platform, male buckles are provided on the outer walls of the front and rear ends of the fixing block, and a female buckle extending along the groove is provided on the shoulder. The male buckle is inserted into the groove and engages with the female buckle.

7. The short-circuit-proof current transformer according to claim 3, characterized in that: A wing portion is installed at one end of the fixed block, and the wing portion extends outward from the fixed block to the inner wall of the shell. A second plug-in slot is arranged on the inner wall of the shell. Second plug-in blocks extending vertically downward are arranged at both ends of the wing portion. The second plug-in block can be plugged and fixed in the second plug-in slot, and the lower surface of the wing portion abuts against the magnetic core when plugged in.

8. The short-circuit-proof current transformer according to claim 7, characterized in that: The wing plate portion includes a first wing plate and a protruding portion, a third plug-in block is fixedly arranged on the first wing plate, a third plug-in slot for plugging with the third plug-in block is arranged at one end of the fixed block facing the first wing plate, and when the third plug-in block is plugged into the third plug-in slot, the third plug-in block and the third plug-in slot are interference fit, the protruding portion is arranged on the end surface of the first wing plate facing away from the fixed block, and the first terminal slot and the copper wire placement hole are arranged on the protruding portion.

9. The short-circuit-proof current transformer according to claim 7, characterized in that: The wing plate portion includes a second wing plate, one end of the fixed block is provided with a concave stop, the second wing plate is rotatably mounted on the concave stop, and the rotation axis of the second wing plate is coaxial with the fixed block.

10. The short-circuit-proof current transformer according to claim 1, characterized in that: The upper ends of the front cover and the rear cover are both provided with terminal slots.

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