An epoxy resin insulation pouring mold for a current transformer

Abstract

The utility model provides a kind of epoxy resin insulation potting mould of current transformer belongs to current transformer technical field, including mould top plate, and the both ends of mould top plate are respectively provided with pouring hole, between two pouring holes, hoisting hole is set up in the center position of mould top plate;The edge position of hoisting hole is provided with the hoisting flange fixed on mould top plate, and mounting space is set up between every pouring hole and hoisting flange, and mounting hole is set up on the mould top plate at every mounting space;Mould top plate is connected with hoisting frame by hoisting hole, hoisting flange and screw, and hoisting frame is connected with secondary winding by connecting band.The utility model can avoid support exposure to save polishing process, reduce material and amount of pouring material, improve production efficiency, save cost, and guarantee insulation performance and structural reliability by boss structure and hoisting frame.

Description

Technical Field

[0001] This utility model relates to the field of current transformer technology, and in particular to an epoxy resin insulating casting mold for current transformers. Background Technology

[0002] In power systems, current transformers, as crucial current measurement and protection devices, are widely used in power grid lines and switchgear. Their performance stability and insulation reliability directly affect the safe operation of the power system. Among them, epoxy resin casting insulation remains one of the commonly used insulation methods for transformers with voltage levels of 35kV and below due to its excellent insulation performance and mechanical strength.

[0003] In existing technologies, to ensure the positioning stability of internal components during the casting process, a lifting bracket is typically used to fix the coil assembly or winding. For example, Chinese Patent CN222365466U discloses a current transformer, including a coil assembly, an epoxy resin casting body, a P1 terminal copper busbar, and a P2 terminal copper busbar. The coil assembly includes a toroidal core, a coil winding mounted on the toroidal core, and a lifting bracket. One end of the lifting bracket has a support plate, which is fixed to the coil winding by cable ties. The other end of the lifting bracket has a lifting plate connected to the casting mold. The lifting plate has two symmetrically arranged lifting holes, and two copper inserts connected to the casting mold are provided at the corresponding two lifting holes on the lifting plate. The coil winding is connected to the P1 terminal copper busbar and the P2 terminal copper busbar by two primary leads. The coil winding, the toroidal core, and the lifting bracket are integrally cast with epoxy resin to form the epoxy resin casting body.

[0004] While the aforementioned existing technologies can improve product qualification rates to some extent, the inverted casting process for 35kV current transformers still has the following shortcomings: Currently, the secondary winding is generally directly suspended from the mold top plate using brackets. Because epoxy resin inevitably shrinks during curing, the suspension brackets at the bottom of the product are easily exposed. This problem directly results in an uneven bottom surface of the transformer. In subsequent base plate assembly processes, the protruding brackets on the bottom surface need to be ground, which not only increases labor costs and operational steps and reduces production efficiency, but may also affect the product's structural accuracy and insulation performance due to errors during the grinding process.

[0005] Therefore, how to avoid exposed brackets, reduce subsequent grinding processes, improve production efficiency, and save costs has become an urgent technical problem to be solved in the current epoxy resin casting process of 35kV current transformers. Utility Model Content

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the easy exposure of the bottom mounting bracket of the product during the epoxy resin curing process, which affects the structural accuracy and insulation performance of the product, and to provide an epoxy resin insulation casting mold for current transformers.

[0007] This utility model is achieved through the following technical solution: an epoxy resin insulation casting mold for a current transformer, comprising a mold top plate, with casting holes at both ends of the mold top plate, and a lifting hole at the center of the mold top plate between the two casting holes; a lifting flange fixed to the mold top plate is provided at the edge of the lifting hole, and an installation space is provided between each casting hole and the lifting flange, with an installation hole provided on the mold top plate at each installation space; a lifting frame is connected to the mold top plate through the lifting hole, the lifting flange and screws, and a secondary winding is connected to the lifting frame through a connecting strap.

[0008] As the core component of the casting mold, the mold top plate has injection holes at both ends for epoxy resin injection, ensuring that the casting material can fully fill the internal space of the mold. The lifting hole at the center, together with the lifting flange at the edge, fixes the lifting frame with screws. The lifting flange creates a gap between the lifting frame and the inner plane of the mold top plate, ensuring that the lifting frame is completely embedded in the epoxy resin casting body and avoiding exposure of the lifting frame due to resin curing shrinkage. The mounting holes at the installation space use bolts to achieve a stable connection between the mold top plate and the current transformer base plate, ensuring overall assembly accuracy.

[0009] This mold fundamentally solves the problem of exposed supports in traditional systems by using a design that combines the lifting flange and the lifting frame. This eliminates the need for grinding before installing the base plate, effectively improving production efficiency. The lifting frame is embedded in the casting body to ensure insulation distance, and the symmetrical layout of the mounting holes enhances the stability of the base plate assembly. The overall structure is compact and reasonable, while reducing unnecessary material consumption and saving costs.

[0010] A further improvement of this utility model is that there are two lifting holes, which are symmetrically arranged on both sides of the top plate of the mold.

[0011] A further improvement of this utility model is that the lifting hole is a long strip structure.

[0012] A further improvement of this utility model is that the lifting frame includes an arc-shaped frame that matches the secondary winding, and the two ends of the arc-shaped frame are respectively provided with connecting frames corresponding to the lifting holes. The arc-shaped frame is connected to the mold top plate through the connecting frames, lifting holes, lifting flanges and screws.

[0013] A further improvement of this utility model is that the connecting frame has an L-shaped structure, the vertical part of the connecting frame is connected to the arc-shaped frame, and the horizontal part of the connecting frame is connected to the mold top plate through a lifting hole, a lifting flange and screws.

[0014] A further improvement of this utility model is that each of the installation spaces has two installation holes, which are symmetrically arranged on both sides of the mold top plate.

[0015] A further improvement of this utility model is that the mold top plate has a rectangular structure, and the long side of the mold top plate is parallel to the length of the lifting hole.

[0016] A further improvement of this utility model is that the pouring hole has a rectangular structure, and the long side of the mold top plate is parallel to the wide side of the pouring hole.

[0017] As can be seen from the above technical solutions, the beneficial effects of this utility model are: 1. This mold, through the lifting flange on the top plate, allows the lifting frame to form a gap with the inner plane of the top plate. Combined with the design of the shortened lifting frame, it ensures that it is completely embedded inside the epoxy resin casting, completely avoiding the phenomenon of exposed support caused by resin curing shrinkage. It eliminates the grinding process before the base plate is installed, significantly reduces manual operation steps, greatly improves production efficiency, and at the same time ensures the flatness of the bottom surface of the product, improving assembly accuracy and quality stability.

[0018] 2. This mold, through the optimized design of the boss structure on the mold top plate and the height of the lifting frame, reduces the amount of raw materials used for the lifting frame while ensuring the insulation distance of the secondary winding. Simultaneously, the boss design reduces the internal space of the mold, decreasing the consumption of epoxy resin casting material. These two measures effectively save production costs. Furthermore, the elongated lifting hole design enhances the mold's adaptability to different specifications of secondary windings, reducing the frequency of mold replacements due to changes in product specifications, further lowering equipment investment and changeover costs.

[0019] 3. This mold, through the arc-shaped frame of the hoisting frame, can fit tightly with the secondary winding, and with the stable support of the L-shaped connecting frame, ensures that the winding is accurately positioned and evenly stressed during the casting process, avoiding fluctuations in insulation performance caused by misalignment. The symmetrical arrangement of mounting holes and casting holes ensures the stability of the base plate assembly and the uniformity of epoxy resin filling, reducing defects such as bubbles and voids, making the casting body have better insulation performance, and the overall structure is more compact and reliable, which can meet the insulation and stability requirements of 35kV current transformers. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a structural schematic diagram of a specific embodiment of the present utility model.

[0022] Figure 2 This is a schematic diagram of the structure of the mold top plate and the lifting flange in a specific embodiment of this utility model.

[0023] Figure 3 yes Figure 2 Top view of the top plate of the intermediate mold and the lifting flange.

[0024] Figure 4 This is a schematic diagram of the structure of the mold top plate in a specific embodiment of this utility model.

[0025] Figure 5 This is a structural schematic diagram of the hoisting frame according to a specific embodiment of the present utility model.

[0026] In the diagram: 1. Mold top plate; 101. Pour hole; 102. Lifting hole; 103. Mounting hole; 104. Mounting space; 2. Lifting flange; 3. Lifting frame; 301. Arc frame; 302. Connecting frame; 4. Secondary winding. Detailed Implementation

[0027] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0028] Now refer to Figures 1-5The following is a description of a specific embodiment: The epoxy resin insulating casting mold for a current transformer according to this utility model includes a mold top plate 1. Casting holes 101 are respectively provided at both ends of the mold top plate 1. A lifting hole 102 is provided at the center of the mold top plate 1 between the two casting holes 101. A lifting flange 2, fixed to the mold top plate 1, is provided at the edge of the lifting hole 102. An installation space 104 is provided between each casting hole 101 and the lifting flange 2. An installation hole 103 is provided on the mold top plate 1 at each installation space 104. The mold top plate 1 is connected to the base plate of the current transformer via the installation hole 103 and bolts. A lifting frame 3 is connected to the mold top plate 1 via the lifting hole 102, the lifting flange 2, and screws. The lifting frame 3 is connected to a secondary winding 4 via a connecting strap.

[0029] As the core component of the casting mold, the mold top plate 1 has casting holes 101 at both ends for epoxy resin injection, ensuring that the casting material can fully fill the internal space of the mold. The lifting hole 102 at the center, together with the lifting flange 2 on the edge, fixes the lifting frame 3 with screws. The lifting flange 2 makes the lifting frame 3 form a gap with the inner plane of the mold top plate 1, ensuring that the lifting frame 3 is completely embedded in the epoxy resin casting body, avoiding the lifting frame 3 from being exposed due to resin curing shrinkage. The mounting hole 103 at the installation space 104 realizes a stable connection between the mold top plate 1 and the current transformer base plate through bolts, ensuring the overall assembly accuracy.

[0030] This mold solves the problem of exposed supports in traditional molds by combining the lifting flange 2 and the lifting frame 3. It eliminates the need for grinding before the base plate is installed, which can effectively improve production efficiency. The lifting frame 3 is embedded in the casting body to ensure the insulation distance. The symmetrical layout of the mounting holes 103 enhances the stability of the base plate assembly. The overall structure is compact and reasonable, while reducing unnecessary material consumption and saving costs.

[0031] Specifically, refer to Figure 2 and Figure 3 There are two lifting holes 102, which are symmetrically arranged on both sides of the mold top plate 1.

[0032] Two symmetrically arranged lifting holes 102 correspond to the connection positions on both sides of the lifting frame 3, ensuring that the lifting frame 3 is subjected to balanced force on the mold top plate 1, and preventing the secondary winding 4 from shifting due to unilateral force. The symmetrical structure ensures that the secondary winding is always in the center position of the mold during the casting process, guaranteeing that the epoxy resin is evenly distributed around the winding.

[0033] This mold improves the installation stability of the lifting frame 3 and the secondary winding 4 through the above-mentioned symmetrical layout design, reduces the shaking or displacement of the winding during casting, ensures uniform thickness of the casting body, reduces the risk of insulation performance fluctuations caused by winding position deviations, and further ensures product quality consistency.

[0034] Specifically, refer to Figure 5 The lifting frame 3 includes an arc-shaped frame 301 that matches the secondary winding 4. The two ends of the arc-shaped frame 301 are respectively provided with connecting frames 302 corresponding to the lifting holes 102. The arc-shaped frame 301 is connected to the mold top plate 1 through the connecting frames 302, the lifting holes 102, the lifting flanges 2 and screws.

[0035] The arc-shaped frame 301 of the lifting frame 3 fits snugly against the outer peripheral wall of the secondary winding 4, and the two are tightly fixed by a connecting strap to prevent the winding from shaking during the casting process. The connecting frames 302 at both ends of the arc-shaped frame 301 correspond to the lifting holes 102 and lifting flanges 2 of the mold top plate 1, and are fixed by screws to ensure that the overall position of the lifting frame 3 is stable and embedded in the casting body. The compatibility between the arc-shaped structure and the winding ensures maximum contact area and improves the reliability of fixation.

[0036] This mold enhances the connection strength and reduces the risk of winding misalignment through the fitting design of the arc frame 301 and the winding. The cooperation between the connecting frame 302 and the lifting flange 2 further ensures that the lifting frame 3 is completely embedded in the casting body to avoid exposure, while ensuring the insulation distance, reducing subsequent processing steps and improving the product qualification rate.

[0037] Specifically, refer to Figure 5 The connecting frame 302 has an L-shaped structure. The vertical part of the connecting frame 302 is connected to the arc-shaped frame 301, and the horizontal part of the connecting frame 302 is connected to the mold top plate 1 through the lifting hole 102, the lifting flange 2 and the screw.

[0038] The vertical part of the L-shaped connecting frame 302 is connected to the arc-shaped frame 301 to form a stable support structure; the horizontal part is connected to the mold top plate 1 through the lifting hole 102 and the lifting flange 2, which shortens the overall height of the lifting frame 3, reduces the amount of material used, and makes it easier to control the distance between the lifting frame 3 and the inner plane of the mold top plate 1, ensuring that it is completely embedded in the casting body. The mechanical design of the L-shaped structure disperses the gravitational load of the winding and improves the lifting stability.

[0039] This mold reduces the consumption of raw materials for the lifting frame 3 through the above-mentioned L-shaped structure design, thereby lowering costs; the shortened height, combined with the design of the lifting flange 2, further avoids the exposed support, while enhancing the load-bearing capacity of the lifting frame 3 and improving the reliability and safety of the overall structure.

[0040] Specifically, refer to Figure 4Each of the mounting spaces 104 has two mounting holes 103, which are symmetrically arranged on both sides of the mold top plate 1.

[0041] The two symmetrical mounting holes 103 in each mounting space 104 are connected to the base plate of the current transformer by bolts, so that the stress points of the base plate on the mold top plate 1 are evenly distributed, avoiding tilting or loosening of the base plate due to single-point stress. The symmetrical layout ensures the fit between the base plate and the bottom surface of the casting body and reduces the assembly gap.

[0042] The mold design improves the connection stability between the base plate and the mold top plate 1, preventing the base plate from loosening during transportation or use and ensuring the overall structural strength of the current transformer; uniform stress distribution reduces the risk of deformation after the base plate is assembled, further improving the reliability of the product.

[0043] Specifically, refer to Figure 4 The mold top plate 1 has a rectangular structure, and the long side of the mold top plate 1 is parallel to the length of the lifting hole 102.

[0044] The long side of the rectangular mold top plate 1 is parallel to the length direction of the lifting hole 102, so that the length of the lifting hole 102 makes full use of the space of the mold top plate 1 and can accommodate the longer secondary winding 4; the compact layout reduces the overall volume of the mold, reduces the amount of epoxy resin filling, and facilitates the storage and handling of the mold.

[0045] The above design optimizes the use of internal space in the mold, reduces the consumption of casting materials, and saves production costs; reasonable size matching improves the mold's adaptability to windings of different lengths, enhances production flexibility, and at the same time reduces the mold's footprint and improves the utilization rate of workshop space.

[0046] Specifically, refer to Figure 4 The pouring hole 101 has a rectangular structure, and the long side of the mold top plate 1 is parallel to the wide side of the pouring hole 101.

[0047] The wide side of the rectangular gating hole 101 is parallel to the long side of the mold top plate 1, so that the opening direction of the gating hole 101 is consistent with the extension direction of the internal space of the mold, which facilitates the epoxy resin to flow into the mold quickly and evenly from both ends and reduces the generation of air bubbles. The wide side design increases the cross-sectional area of ​​the gating hole 101, improves the gating efficiency, and ensures that the gating material can fully fill all corners of the mold.

[0048] This mold design accelerates the injection speed of epoxy resin, shortens the casting time, and improves production efficiency; the uniform casting effect reduces air bubbles and voids, ensures the insulation performance and mechanical strength of the cast body, and improves product quality stability.

[0049] In one embodiment, reference Figure 2and Figure 3 The lifting hole 102 is a long strip structure.

[0050] The elongated lifting hole 102 allows for adjustment of the installation position of the lifting frame 3 according to the specifications of the secondary winding 4, accommodating secondary windings 4 of different sizes or structures. This eliminates the need to change molds and meets the production needs of various products. The elongated hole design provides sufficient adjustment space, ensuring that the relative position of the lifting frame 3 and the winding 4 is always optimal.

[0051] The design of this mold enhances its versatility, reduces the frequency of mold replacement due to changes in product specifications, and lowers equipment investment costs; the flexible adjustment function improves production adaptability, shortens changeover time, and indirectly improves production efficiency.

[0052] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A current transformer epoxy resin insulation casting mold, comprising a mold top plate (1), characterized in that, The mold top plate (1) has pouring holes (101) at both ends, and a lifting hole (102) is provided at the center of the mold top plate (1) between the two pouring holes (101). A lifting flange (2) is provided at the edge of the lifting hole (102) and fixed to the mold top plate (1). An installation space (104) is provided between each pouring hole (101) and the lifting flange (2). An installation hole (103) is provided on the mold top plate (1) at each installation space (104). The mold top plate (1) is connected to a lifting frame (3) through the lifting hole (102), the lifting flange (2) and screws. The lifting frame (3) is connected to a secondary winding (4) through a connecting strap.

2. The epoxy resin insulating casting mold for a current transformer according to claim 1, characterized in that, There are two lifting holes (102), which are symmetrically arranged on both sides of the mold top plate (1).

3. The epoxy resin insulating casting mold for a current transformer according to claim 2, characterized in that, The lifting hole (102) is a long strip structure.

4. The epoxy resin insulating casting mold for a current transformer according to claim 3, characterized in that, The lifting frame (3) includes an arc-shaped frame (301) that matches the secondary winding (4). The two ends of the arc-shaped frame (301) are respectively provided with connecting frames (302) corresponding to the lifting holes (102). The arc-shaped frame (301) is connected to the mold top plate (1) through the connecting frames (302), the lifting holes (102), the lifting flange (2) and the screws.

5. The epoxy resin insulating casting mold for a current transformer according to claim 4, characterized in that, The connecting frame (302) has an L-shaped structure. The vertical part of the connecting frame (302) is connected to the arc frame (301), and the horizontal part of the connecting frame (302) is connected to the mold top plate (1) through the lifting hole (102), the lifting flange (2) and the screw.

6. The epoxy resin insulating casting mold for a current transformer according to claim 1, characterized in that, Each of the mounting spaces (104) has two mounting holes (103), which are symmetrically arranged on both sides of the mold top plate (1).

7. The epoxy resin insulating casting mold for a current transformer according to claim 3, characterized in that, The mold top plate (1) has a rectangular structure, and the long side of the mold top plate (1) is parallel to the length of the lifting hole (102).

8. The epoxy resin insulating casting mold for a current transformer according to claim 4, characterized in that, The pouring hole (101) is rectangular, and the long side of the mold top plate (1) is parallel to the wide side of the pouring hole (101).

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