Short circuit prevention current transformer

Abstract

The invention provides an anti-short-circuit current transformer which comprises a shell and a magnetic core with a primary coil terminal, the magnetic core is installed in the shell, the shell is provided with a through hole allowing the primary coil terminal to be exposed, the shell comprises a front cover and a rear cover which can be separated from each other, and the anti-short-circuit current transformer further comprises a fixing block penetrating through the center of the magnetic core. The front end and the rear end of the fixing block are respectively provided with a first terminal groove, the front cover and the rear cover are respectively provided with a second terminal groove coaxial with the through hole, and when the front cover and the rear cover are covered with each other, the front end and the rear end of the fixing block abut against the inner wall of the front cover and the inner wall of the rear cover respectively. And the first terminal groove and the second terminal groove are attached to each other so as to form a space for limiting the movement of the primary coil terminal. According to the scheme, the terminal of the primary coil is fixed in the mutual inductor shell in a mechanical fixing mode, the fixing mode is stable and reliable, installation is easy, terminal looseness is effectively avoided, and the short circuit problem caused by terminal looseness is avoided.

Description

Technical Field

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

[0002] A current transformer is a measuring and protection device used in power systems. Its main function is to convert high voltage or large current into low voltage, small current signals in proportion, so as to facilitate safe measurement, metering and monitoring. The current transformer has a primary coil (hereinafter referred to as the primary coil) and a secondary coil (hereinafter referred to as the secondary coil) wound around the internal magnetic core and works on the principle of electromagnetic induction. It can accurately reflect the current changes on the primary side, while ensuring that the secondary circuit is electrically isolated from the primary circuit, thereby ensuring the safety of the operator and the normal operation of the measuring instrument and other electronic equipment.

[0003] In practical applications, some current transformers will install the terminals of the primary coil in the center of the transformer housing, and in order to prevent the primary coil terminals from loosening due to mechanical vibration or other factors, glue is usually used to fix them to the transformer housing. However, the glue will gradually age during long-term use, and its bonding properties are easily affected by temperature and humidity, which may cause the bonding force to decrease, thereby causing the primary coil terminals to loosen, increasing the risk of short circuit and poor contact. In addition, after the aging of the glue used for fixing or the loosening of the primary coil terminals, the copper wire of the primary coil may not be fixed firmly, allowing the copper wire to move freely inside the transformer. Under normal use conditions, once the copper wire of the primary coil contacts the secondary coil or other conductive parts, a short circuit may also occur, thereby damaging the transformer. Moreover, glue fixing requires a curing process, which takes a long time, has a low fault tolerance, and is easily affected by external factors, resulting in the inability to accurately fix the terminals. Summary of the invention

[0004] The present invention proposes a short-circuit proof current transformer, which fixes the terminals of a primary coil in a transformer housing by mechanical fixing. The fixing method is stable and reliable, simple to install, and effectively prevents the terminals from loosening, thereby avoiding the short-circuit problem caused by the loose terminals.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A short-circuit proof current transformer comprises a shell and a magnetic core with a primary coil terminal, the magnetic core is installed in the shell, a through hole is provided on the shell for exposing the primary coil terminal, the shell comprises a front cover and a rear cover which can be separated from each other, and a fixing block, the fixing block passes through the center of the magnetic core, the front and rear ends of the fixing block are both provided with a first terminal groove, the front cover and the rear cover are both provided with a second terminal groove which is 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 are respectively abutted against the inner walls of the front cover and the rear cover, and the first terminal groove and the second terminal groove are fitted with each other to form a space for limiting the movement of the primary coil terminal.

[0007] In the prior art, the primary coil terminal is usually fixed to the transformer housing by glue. However, the glue is prone to aging after long-term use, causing the terminal to loosen or even fall off, which undoubtedly increases the risk of short circuit in the electrical system. To avoid this problem, some technicians may consider snapping the primary coil terminal into the front cover and the rear cover respectively, for example, first snapping one primary coil terminal into the rear cover, then placing the magnetic core in the rear cover, and then snapping another primary coil terminal into the front cover, and finally closing the front cover on the rear cover.

[0008] However, the above-mentioned alternative scheme has the disadvantages of inconvenient installation and poor installation accuracy: since the primary coil terminal is fixedly connected to the primary coil wound on the magnetic core, the primary coil will have a certain pulling tendency on the terminal. Therefore, in the process of closing the front cover to the back cover, it is impossible to ensure that the primary coil terminal 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 is loose. In view of this, the present invention proposes a new solution, which replaces the unreliability of traditional glue fixing by introducing a fixing block and a terminal slot design used in conjunction with it.

[0009] The working principle of the present invention is: first install the magnetic core wound with the primary coil and the secondary coil into the back cover. During this installation process, one of the terminals of the primary coil needs to be installed in the second terminal slot of the back cover first; after installation, one end of the primary coil terminal will be supported in the second terminal slot, and the other end will pass through the through hole of the back cover and extend out of the back 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 install the fixing block, align the first terminal slot with the primary coil terminal exposed outside the second terminal slot, and then press the fixing block against the back cover to ensure that the primary coil terminal is completely covered by the first terminal slot and the second terminal slot. After that, install the other primary coil terminal in the first terminal slot of the fixing block. Similarly, 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 close the front cover on the rear cover and make one end of the terminal extend out of the front cover from the through hole, and 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 obstructed vision when the covers are closed. Since the front and rear ends of the fixing block are against the inner walls of the front cover and the rear cover, when the front cover and the rear cover are fixed to each other, the fixing block can no longer move axially, and the primary coil terminal is fixed in the first terminal slot and the second terminal slot, which will further limit the radial movement of the fixing block, thereby completely fixing the fixing block. If the fixing block cannot move, then the primary coil terminal cannot move either. It should be noted that the secondary coil wound on the magnetic core is also equipped with a secondary coil terminal, wherein the secondary coil terminal adopts a conventional installation and fixing method, that is, before the front cover is closed on the rear cover, the secondary coil terminal is first installed on the rear cover, and a part of the secondary coil terminal is exposed outside the outer shell to facilitate connection with the electrical system. Since it is a conventional design, the installation process of the secondary coil terminal is no longer repeated in the present invention.

[0010] This mechanical fixing method is not affected by environmental factors such as temperature and humidity, and effectively prevents the primary coil terminal from loosening 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 risk of short circuit caused by loose terminals. Moreover, the design of the fixing block and terminal slot simplifies the installation process, eliminating the need to wait for the glue to cure, improving installation efficiency and facilitating future maintenance and replacement operations. In addition, the primary coil terminal is firmly fixed in the transformer housing by the fixing block, so when the primary coil terminal is connected to the power system, there is no need to worry about the terminal loosening due to errors in the installation process or excessive force.

[0011] Preferably, a copper wire placement hole is provided on the side wall of the fixed block, and two copper wire placement holes are provided and are respectively located at the front and rear ends of the fixed block, and the copper wire placement holes are connected to the first terminal slot. By providing copper wire placement holes on the side wall of the fixed block, the copper wire of the primary coil can be directly passed through or 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 mutual inductor, further reducing the risk of short circuit. Moreover, this design allows the primary coil copper wire to be positioned and fixed more conveniently during assembly, without the need for additional binding or fixing measures, thereby simplifying the assembly steps and improving production efficiency.

[0012] Preferably, the front cover and the rear cover are both provided with a support platform, the end surface size of the support 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 slot is provided on the support platform. The design of the support platform provides more space for the setting of the second terminal slot, which is convenient for the design and processing of the second terminal slot; and the design also avoids the force on the fixing block directly acting on the front cover and the rear cover, reduces the stress concentration on the shell, and improves the service life of the shell.

[0013] Regarding the positioning of the fixed block, this solution first proposes that there is no connection structure between the end face of the support platform and the fixed block, and the support platform clamps the fixed block when the front cover and the rear cover are closed. In fact, when the front cover and the rear cover are closed, the fixed block limits the movement of the primary coil terminal. Since the primary coil terminal is clamped with the cover body, it will in turn limit the movement of the fixed block. Therefore, the fixed block does not need to be fixed and installed according to conventional design ideas, that is, it can be roughly axially limited by using the inner hole of the magnetic core. This solution has obvious advantages in terms of manufacturing cost and installation convenience.

[0014] Of course, the fixed block will have other functions after the fixed structure is set. In order to enable the fixed block to be accurately positioned and installed on the supporting platform, the present invention provides the following preferred solutions:

[0015] Solution 1: A first plug-in slot is provided at one end of the supporting platform facing the fixed block, and a first plug-in block plugged into and matched with the first plug-in slot is fixedly provided on the front and rear ends of the fixed block, and 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. In this way, the design of the first plug-in block and the first plug-in slot ensures that the fixed block can be quickly, accurately and firmly installed on the supporting platform along a predetermined path, thereby ensuring that the primary coil terminal is accurately installed in the first terminal slot and the second terminal slot. Among them, a semicircular protrusion can be fixedly provided on the first plug-in block to increase the friction between the first plug-in block and the first plug-in slot, so that the first plug-in block and the first plug-in slot are more firmly matched.

[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 three: A wing plate portion is installed at one end of the fixed block, and the wing plate portion extends outward from the fixed block to the inner wall of the shell, and a second plug-in slot is provided on the inner wall of the shell. The two ends of the wing plate portion are provided with second plug-in blocks extending vertically downward, and the second plug-in block can be plugged and fixed in the second plug-in slot, and the lower surface of the wing plate portion rests on the magnetic core when plugged in. Specifically, the wing plate portion can be installed at the front end of the fixed block, and the second plug-in slot is located on the inner wall of the rear cover. After one terminal of the primary coil is installed in the second terminal slot of the rear cover, the non-wing plate end of the fixed block (that is, the rear end of the fixed block) is installed on the primary coil terminal. The key is that during this installation process, it is necessary to ensure that the second plug-in blocks at both ends of the wing plate portion are accurately inserted into the second plug-in slot on the inner wall of the rear cover, so as to achieve accurate positioning and fixation of the fixed block; next, the other terminal of the primary coil is installed at the front end of the fixed block. Because the wing plate portion, the second plug-in block and the second plug-in slot are exposed outside the magnetic core, the installation process of Scheme 3 is more intuitive than that of Schemes 1 and 2, and can effectively improve the convenience and accuracy of installation. It is worth mentioning that the lower surface of the wing plate portion can be 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 primary coil copper wire due to loosening of the magnetic core, thereby improving the overall stability and safety of the mutual inductor. The interference fit between the second plug-in block and the second plug-in slot effectively prevents the loosening of the wing plate portion and ensures the reliability of the connection. A semicircular snap-fit ​​protrusion can be provided on the second plug-in block to increase the friction between the second plug-in block and the second plug-in slot to ensure that the two can fit firmly.

[0019] In order to prevent the wing plate from hindering the primary wire terminal from being smoothly installed on 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, the upper ends of the front cover and the rear cover are both provided with terminal slots, so that the secondary coil terminal can be accurately and firmly installed between the front cover and the rear cover.

[0023] In summary, such a short-circuit-proof current transformer uses a mechanical fixing method to fix the terminals of the primary coil in the transformer housing. This fixing method is stable and reliable, easy to install, and effectively avoids terminal loosening and avoids short-circuit risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 The structure diagram of the short-circuit protection current transformer of the present invention is shown in FIG. Figure 1 ;

[0026] Figure 2 is a cross-sectional view of the short-circuit protection current transformer of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the rear cover in the short-circuit proof current transformer of the present invention;

[0028] Figure 4 It is a structural schematic diagram of a fixed block in the short-circuit proof current transformer of the present invention;

[0029] Figure 5 It is a schematic diagram of the connection structure between the fixed block and the primary coil terminal in the short-circuit proof current transformer of the present invention;

[0030] Figure 6 This is a structural schematic diagram of Example 1 of the short-circuit protection current transformer of the present invention;

[0031] Figure 7 This is a structural schematic diagram of Embodiment 2 of the short-circuit proof current transformer of the present invention;

[0032] Figure 8 for Figure 7 A partial cross-sectional view of

[0033] Fig. 9 This is a schematic diagram of the structure of the embodiment A of the short-circuit proof current transformer of the present invention;

[0034] Fig.10 It is an exploded schematic diagram of the fixing block and the first wing plate in Example A;

[0035] Fig.11 This is a structural schematic diagram of Embodiment B of the short-circuit proof current transformer of the present invention;

[0036] Fig.12 This is an exploded schematic diagram of the fixing block and the second wing plate in Example B;

[0037] Fig.13 The structure diagram of the short-circuit protection current transformer of the present invention is shown in FIG. Figure 2 .

[0038] In the figure,

[0039] 1-Front cover;

[0040] 2- Back 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-recessed stopper;

[0043] 5-hole for placing copper wire;

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

[0045] 7-Terminal slot;

[0046] 8-wing plate portion; 81-second plug-in slot; 82-first wing plate; 821-second plug-in block; 8211-semicircular engaging protrusion; 83-protruding portion; 84-second wing plate; 85-third plug-in block; 86-third plug-in slot. DETAILED DESCRIPTION

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

[0048] Reference Figure 1-Figure 5 and Fig.13As shown, a short-circuit proof current transformer comprises a shell and a magnetic core 3 with a primary coil terminal 31, the magnetic core 3 is installed in the shell, a through hole 61 is provided on the shell for exposing the primary coil terminal 31, the shell comprises a front cover 1 and a rear cover 2 which can be separated from each other, and a fixing block 4, the fixing block 4 passes through the center of the magnetic core 3, the front and rear ends of the fixing block 4 are both provided with a first terminal groove 41, the front cover 1 and the rear cover 2 are both provided with a second terminal groove 42 which is coaxial with the through hole 61, when the front cover 1 and the rear cover 2 are covered with each other, the front and rear ends of the fixing block 4 are respectively abutted against the inner walls of the front cover 1 and the rear cover 2, and the first terminal groove 41 and the second terminal groove 42 are fitted with each other to form a space to limit the movement of the primary coil terminal 31.

[0049] In the prior art, the primary coil terminal 31 is usually fixed to the transformer housing by glue. However, the glue is prone to aging after long-term use, causing the terminal to loosen or even fall off, which undoubtedly increases the risk of short circuit in the electrical system. In order to avoid this problem, some technicians may consider snapping the primary coil terminal 31 into the front cover 1 and the rear cover 2 respectively, for example, first snapping one primary coil terminal 31 into the rear cover 2, then placing the magnetic core 3 in the rear cover 2, and then snapping another primary coil terminal 31 onto the front cover 1, and finally closing the front cover 1 onto the rear cover 2.

[0050] However, the above-mentioned alternative scheme has the disadvantages of inconvenient installation and poor installation accuracy: since the primary coil terminal 31 is fixedly connected to the primary coil wound on the magnetic core 3, the primary coil will have a certain pulling tendency on the terminal. Therefore, in the process of covering the front cover 1 to 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 covering process, making it difficult for the installer to accurately judge whether the internal primary coil terminal 31 is loose. In view of this, the present invention proposes a new solution, which replaces the unreliability of traditional glue fixing by introducing a fixing block 4 and a terminal slot design used in conjunction with it.

[0051] The working principle of the present invention is: first install the magnetic core 3 wound with the primary coil and the secondary coil into the back cover 2. During the installation process, one of the terminals of the primary coil needs to be installed in the second terminal groove 42 of the back cover 2 first; after installation, one end of the primary coil terminal 31 will be supported in the second terminal groove 42, and the other end will pass through the through hole 61 of the back cover 2 and extend out of the back cover 2. It should be noted that the terminal located in the second terminal groove 42 is not completely embedded in the second terminal groove 42, but a part of the terminal will be exposed outside the second terminal groove 42. Then install the fixing block 4, align the first terminal groove 41 with the primary coil terminal 31 exposed outside the second terminal groove 42, and then place the fixing block 4 against the back cover 2 to ensure that the primary coil terminal 31 is completely covered by the first terminal groove 41 and the second terminal groove 42. After that, install another primary coil terminal 31 in the first terminal groove 41 of the fixing block 4. Similarly, part of the terminal is exposed outside the first terminal groove 41. Finally, align the second terminal groove 42 on the front cover 1 with the primary coil terminal 31 exposed outside the first terminal groove 41, then cover the front cover 1 on the rear cover 2 and make one end of the terminal extend out of the front cover 1 from the through hole 61, and then fix the front cover 1 and the rear cover 2, so that both terminals of the primary coil are covered in the first terminal groove 41 and the second terminal groove 42. Such a structure also avoids the problem of obstructed vision when covering. Since the front and rear ends of the fixing block 4 are against the inner walls of the front cover 1 and the rear cover 2, when 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 primary coil terminal 31 is fixed in the first terminal groove 41 and the second terminal groove 42, which will further limit the radial movement of the fixing block 4, thereby completely fixing the fixing block 4. The fixing block 4 cannot move, and then the primary coil terminal 31 cannot move either. It should be noted that the secondary coil wound on the magnetic core 3 is also equipped with a secondary coil terminal 32, wherein the secondary coil terminal 32 adopts a conventional installation and fixing 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 shell to facilitate connection with the electrical system. Since it is a conventional design, the installation process of the secondary coil terminal 32 is no longer repeated in the present invention.

[0052] This mechanical fixing method is not affected by environmental factors such as temperature and humidity, and effectively prevents the primary coil terminal 31 from loosening 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 risk of short circuit caused by loose terminals. Moreover, the design of the fixing block 4 and the terminal slot simplifies the installation process, eliminating the need to wait for the glue to cure, improving installation efficiency, and facilitating future maintenance and replacement operations. In addition, the primary coil terminal 31 is firmly fixed in the transformer housing by the fixing block 4, so when the primary coil terminal 31 is connected to the power system, there is no need to worry about the terminal loosening due to errors in the installation process or excessive force.

[0053] In addition, refer to Figure 4 As shown, a copper wire placement hole 5 is provided on the side wall of the fixed block 4, and two copper wire placement holes 5 are provided and are respectively located at the front and rear ends of the fixed block 4, and the copper wire placement holes 5 are connected to the first terminal slot 41. By providing the copper wire placement holes 5 on the side wall of the fixed block 4, the copper wire of the primary coil can be directly passed through or 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 mutual inductor, further reducing the risk of short circuit. Moreover, this design allows the primary coil copper wire to be positioned and fixed more conveniently during assembly, without the need for additional binding or fixing measures, thereby simplifying the assembly steps and improving production efficiency.

[0054] In addition, refer to Figure 3 As shown, a support platform 6 is provided on both the front cover 1 and the rear cover 2. The end surface size of the support platform 6 is the same as the front and rear end size of the fixing block 4 and is used to abut against the front and rear end of the fixing block 4. The second terminal groove 42 is provided on the support platform 6. The design of the support platform 6 provides more space for the setting of the second terminal groove 42, which is convenient for the design and processing of the second terminal groove 42; and the design also avoids the force on the fixing block 4 from directly acting on the front cover 1 and the rear cover 2, reduces the stress concentration on the shell, and improves the service life of the shell.

[0055] Regarding the positioning of the fixed block 4, this solution first proposes that there is no connection structure between the end face of the support platform 6 and the fixed block 4, and the support platform clamps the fixed block 4 when the front cover 1 and the rear cover 2 are closed. In fact, when the front cover 1 and the rear cover 2 are closed, the fixed block 4 limits the movement of the primary coil terminal 31. Since the primary coil terminal 31 will in turn limit the movement of the fixed block 4 after being clamped with the cover body, the fixed block 4 does not need to be fixed and installed according to conventional design ideas, that is, it can be roughly axially limited by using the inner hole of the magnetic core. This solution has obvious advantages in terms of manufacturing cost and installation convenience.

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

[0057] Example 1: Reference Figure 6 As shown, a first plug-in slot 63 is provided at one end of the support platform 6 facing the fixed block 4, and a first plug-in block 43 plugged and matched with the first plug-in slot 63 is fixedly provided on the front and rear ends of the fixed block 4. When the first plug-in block 43 is inserted into the first plug-in slot 63, the first plug-in block 43 and the first plug-in slot 63 are interference-fitted. In this way, the design of the first plug-in block 43 and the first plug-in slot 63 ensures that the fixed block 4 can be quickly, accurately and firmly installed on the support 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 semicircular protrusion can be fixedly provided on the first plug-in block 43 to increase the friction between the first plug-in block 43 and the first plug-in slot 63, so that the first plug-in block 43 and the first plug-in slot 63 are more firmly matched.

[0058] Example 2: Reference Figure 7 and Figure 8 As shown, a shoulder 62 is provided in the radial direction of the support platform 6, a circle of grooves 64 is formed between the inner wall of the shoulder 62 and the outer wall of the support platform 6, male buckles 44 are provided on the outer walls of the front and rear ends of the fixed block 4, and a female buckle 45 extending along the groove 64 is provided on the shoulder 62, and the male buckle 44 is engaged with the female buckle 45 after being inserted into the groove 64. Specifically, the fixed block 4 and the shoulder 62 are respectively provided with male buckles 44 and female buckles 45 that can be engaged with each other. After the fixed block 4 is installed on the support platform 6 (at this time, the male buckle 44 will also be inserted into the groove 64), the male buckle 44 and the female buckle 45 can be fixedly engaged with each other, so that a firm connection is achieved between the fixed block 4 and the support platform 6. The design of the male buckle 44 and the female buckle 45 provides an additional mechanical locking function. Even in a vibration or impact environment, the male buckle 44 and the female buckle 45 can effectively prevent the fixing block 4 from loosening or shifting, thereby 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 groove 41 and the second terminal groove 42 and cannot be loosened. At the same time, this snap-on design can make the connection between the fixing block 4 and the support platform 6 easier, reducing the installation complexity and installation time. Importantly, since the primary coil is generally made of copper wire coated with insulating material, the primary coil as a whole 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 the support platform 6, thereby causing the primary coil terminal 31 to loosen. By introducing the design of the male buckle 44 and the female buckle 45 that can be engaged with each other, a firm engagement is achieved between the fixing block 4 and the support platform 6, preventing the fixing block 4 from axial movement 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 Figure 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 wire terminal from being smoothly installed on the fixing block 4, the present invention further provides the following two embodiments:

[0062] Example A: Reference Fig. 9 and Fig.10 As shown, the wing plate portion 8 includes a first wing plate 82 and a protrusion 83. A third plug-in block 85 is fixedly arranged on the first wing plate 82. A third plug-in slot 86 for plugging and matching with the third plug-in block 85 is arranged at one end of the fixed block 4 facing the first wing plate 82. When the third plug-in block 85 is plugged into the third plug-in slot 86, the third plug-in block 85 and the third plug-in slot 86 are interference-fitted. The protrusion 83 is arranged on the end surface of the first wing plate 82 away from the fixed block 4. The first terminal slot 41 and the copper wire placement hole 5 are arranged on the protrusion 83. Specifically, the first wing plate 82 and the fixed block 4 are in a split installation form, so that the first wing plate 82 can be installed after the fixed block 4 is installed on the supporting platform 6, making the installation process of the first wing plate 82 and the fixed block 4 more flexible. Among them, the third plug-in block 85 may also be provided with a semicircular protrusion, so that the third plug-in block 85 and the third plug-in slot 86 are plugged in more firmly and with greater friction, thereby preventing the fixing block 4 from loosening from the first wing plate 82. It is worth mentioning that a protrusion 83 is provided on the first wing plate 82, and the first terminal slot 41 and the copper wire placement hole 5 are provided on the protrusion 83, which provides a clear installation position for the primary coil terminal 31, and effectively prevents the first wing plate 82 from affecting the installation of the primary coil terminal 31.

[0063] Example B: Reference Fig.11 and Fig.12As shown, the wing plate portion 8 includes a second wing plate 84, and a concave stop 46 is provided at one end of the fixing block 4. The second wing plate 84 is rotatably mounted 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 plug-in block 821 of the wing plate portion 8 is inserted into the second plug-in 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, which requires that during the installation process of the magnetic core 3, the position of the primary coil segment 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 degree of freedom of installation of the magnetic core 3, a second wing plate 84 that can rotate on the fixed block 4 is designed, and the rotation axis of the second wing plate 84 is coaxial with the fixed block 4; it is worth noting 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 fixed block 4, so embodiment B does not need to add a component with a first terminal groove 41 and a copper wire placement hole 5 as in embodiment A, which effectively simplifies the design of the component and controls the cost. Although the direction of the fixed block 4 can also be adjusted before installing the first wing plate 82 in embodiment A, since the position of the second plug-in slot 81 is fixed, the direction of the first wing plate 82 and the protrusion 83 arranged thereon will also be fixed with the second plug-in slot 81, so it is further caused that the direction of the first terminal groove 41 and the copper wire placement hole 5 on the protrusion 83 is difficult to change, which will also cause certain restrictions on the installation of the magnetic core 3 and the primary coil. After adopting embodiment B, the angle of the fixing block 4 can be adjusted as needed during the installation process, 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 portion 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, refer to Figure 3 As shown, the upper ends of the front cover 1 and the rear cover 2 are both provided with terminal slots 7. 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, refer to Figure 4 As shown, the fixing block 4 is a hollow structure. The hollow structure can facilitate the installation of the terminal copper wire and provide more operating space for the copper wire installation. In addition, the hollow structure can enhance the heat dissipation effect and effectively reduce the overall weight of the transformer.

[0066] In summary, such a short-circuit-proof current transformer uses a mechanical fixing method to fix the terminals of the primary coil in the transformer housing. This fixing method is stable and reliable, easy to install, and effectively avoids terminal loosening and avoids short-circuit risks.

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

Claims

1. A short-circuit proof current transformer, comprising a housing and a magnetic core with a primary coil terminal, wherein the magnetic core is installed in the housing, the housing is provided with a through hole for exposing the primary coil terminal, and the housing comprises 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: The side wall of the fixing block is provided with a copper wire placement hole, two copper wire placement holes are provided 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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