Combined mutual inductor and production method thereof

Abstract

The invention belongs to the field of instrument mutual inductors, particularly relates to a combined mutual inductor and a production method thereof, and provides a combined mutual inductor in order to solve the technical problem that in the prior art, due to the fact that a voltage coil is not fixed when the combined mutual inductor is manufactured, the qualified rate of the combined mutual inductor is low. The current secondary coil and the voltage iron core are fixedly connected through a first fixing piece, a second fixing piece is fixedly arranged on the voltage coil, and the second fixing piece is fixedly connected with the first fixing piece or the second fixing piece is provided with a connecting structure used for being fixedly connected with a pouring mold. The invention further provides a production method of the combined mutual inductor, the second fixing piece is fixed on the voltage coil before die assembly, and the second fixing piece is fixed with the first fixing piece or the pouring die. The voltage coil is fixed through the second fixing piece, and when an insulating material is poured into a pouring mold, the change of the insulating distance of the voltage transformer body can be avoided, so that the qualified rate of the combined transformer is improved.

Description

Technical Field

[0001] The invention belongs to the field of instrument transformers, and in particular relates to a combined transformer and a production method thereof. Background Art

[0002] At present, the metering box is mainly used to measure the electric energy and assess the line loss in the power line. The metering box consists of a combination transformer and measuring instruments and meters, among which the combination transformer is mainly used for metering. When manufacturing the combination transformer, the voltage transformer body and the current transformer body are generally placed in a casting mold, and then epoxy resin is poured into the casting mold. After the epoxy resin solidifies, the casting mold is removed.

[0003] The Chinese invention patent with the authorization announcement number CN 104485219 B and the authorization announcement date 2017.03.15 discloses a casting mold and production process for producing a cast-type combined transformer, which specifically produces a combined transformer, which includes a voltage core, a current core, an upper clamp, a lower clamp and a support member. The upper ends of the two voltage cores are respectively fixed to the two ends of the upper clamp by cable ties, and the two ends of the upper clamp are respectively provided with support members. The two support members extend toward the direction of each current core, and one end of the two support members close to each current core is respectively attached to the outer edge of each current core and is respectively fixed to the current core by cable ties. The lower ends of the two voltage cores are fixedly connected by the lower clamp.

[0004] In the casting of the above-mentioned combined transformer, since the epoxy resin has pressure and impact force on the voltage coil during casting, and the epoxy resin will expand and contract when solidifying, and at the same time, the voltage coil of the voltage transformer body is not fixed in the casting mold, it will cause the insulating paper and other structures in the voltage coil to undergo slight deformation, thereby causing the insulation spacing of the voltage transformer to change, and further resulting in a low pass rate of the combined transformer. Summary of the invention

[0005] The object of the present invention is to provide a combined mutual inductor and a production method thereof, so as to solve the technical problem in the prior art that the qualified rate of the combined mutual inductor is low due to the failure to fix the voltage coil when manufacturing the combined mutual inductor.

[0006] To achieve the above object, the technical solution of the combined mutual inductor provided by the present invention is:

[0007] A combined transformer comprises a current transformer body and a voltage transformer body, wherein the voltage transformer body comprises a voltage core and a voltage coil mounted on the voltage core, and the current transformer body comprises a current core and a current secondary coil mounted on the current core, wherein the current secondary coil and the voltage core are fixedly connected via a first fixing member, a second fixing member is fixedly provided on the voltage coil, the second fixing member is fixedly connected to the first fixing member or a connecting structure for fixedly connecting to a casting mold is provided on the second fixing member.

[0008] The beneficial effect is that the present invention is an improved invention. The voltage coil is fixed by the second fixing member, and when the insulating material is poured into the casting mold, the voltage coil can be effectively prevented from having a small movement, thereby preventing the insulation spacing of the voltage transformer body from changing, thereby improving the qualified rate of the combined transformer.

[0009] Furthermore, the number of the voltage transformer bodies is at least two, the axis of the voltage coil extends in the horizontal direction, and the second fixing member is fixedly connected to all the voltage coils at the same time.

[0010] The beneficial effect is that all voltage coils can be connected simultaneously by using one second fixing member, and the structure is simple.

[0011] Furthermore, the second fixing member includes a connecting rod and at least two arc-shaped connecting plates arranged on the connecting rod and used to be connected to the voltage coil, and the arc-shaped connecting plates are respectively connected to each voltage coil.

[0012] The beneficial effect is that the contact area between the second fixing member and the voltage coil can be increased by the arc-shaped connecting plate, thereby better fixing the voltage coil.

[0013] Furthermore, the second fixing member is a conductor, the connecting rod is an inverted "T" shaped connecting rod, the connecting rod includes a horizontal rod and a vertical rod, the arc-shaped connecting plate is arranged on the horizontal rod, one end of the vertical rod is used to extend out of the casting mold, and the other end is used to connect with the horizontal rod, the voltage coil includes a primary voltage coil, and the low-voltage end of the primary voltage coil is electrically connected to the arc-shaped connecting plate.

[0014] The beneficial effect is that by setting the second fixing part as a conductor, on the one hand, the second fixing part can play the role of fixing the voltage coil; on the other hand, the second fixing part can also play the role of conducting electricity, and the end of the vertical rod extending out of the casting mold can be connected to other equipment or wires. Compared with the combined mutual inductor in the background technology, by making the second fixing part play the role of conducting electricity, the number of fixing parts used in the combined mutual inductor can be effectively reduced, making the structure simpler and reducing the cost.

[0015] Furthermore, the current transformer body also includes a current primary coil, to which a current enameled wire is electrically connected; the voltage coil includes a voltage primary coil, to which a voltage enameled wire is electrically connected; the current enameled wire and the voltage enameled wire are fixedly electrically connected; and a portion of at least one of the current enameled wire and the voltage enameled wire is bent into a spring shape.

[0016] The beneficial effect is: compared with the technical solution in the prior art of directly connecting the current enameled wire and the voltage enameled wire, by bending at least a part of the current enameled wire and the voltage enameled wire into a spring shape, the voltage enameled wire can apply a pulling force to the voltage coil, thereby avoiding a slight position change of the voltage coil, thereby further improving the qualified rate of the combined transformer.

[0017] Furthermore, the voltage enameled wire and the second fixing member are respectively arranged at two ends of the voltage coil in the axial direction.

[0018] The beneficial effect is: by respectively arranging the voltage enameled wire and the second fixing member at the two ends of the voltage coil along the axial direction of the voltage coil, on the one hand, the volume of the arc-shaped connecting plate can be reduced, and on the other hand, the voltage coil can be better fixed from both ends.

[0019] Furthermore, the number of the current transformer bodies is at least two, and the current transformer body also includes a P1 terminal or a P2 terminal for fixed connection to the casting mold, the first fixing part includes a current fixing plate connected to the current secondary coil and a voltage fixing plate connected to the side of the voltage core, and the current fixing plate includes an arc segment for connecting to the current secondary coil and a vertical segment for connecting to the voltage fixing plate.

[0020] The beneficial effects are as follows: the arc section of the current fixing plate can increase the connection area between the current fixing plate and the current secondary coil, and the vertical section of the current fixing plate can be easily connected to the voltage fixing plate.

[0021] Furthermore, the vertical section of the current fixing plate or the voltage fixing plate is provided with a long hole for the bolts to slide, and the vertical section of the current fixing plate and the voltage fixing plate are connected via the long hole and the bolts.

[0022] The beneficial effect is that the relative position of the secondary current coil and the primary current coil can be conveniently adjusted by setting the long hole.

[0023] To achieve the above object, the technical solution of the production method of the combined mutual inductor provided by the present invention is:

[0024] A production method for a combined transformer includes a mold closing step of placing a current transformer body and a voltage transformer body in a casting mold and then closing the mold, fixing the current secondary coil of the current transformer body and the voltage core of the voltage transformer body with a first fixing piece before closing the mold, fixing a second fixing piece on the voltage coil of the voltage transformer body before closing the mold, and positioning the voltage coil by fixing the second fixing piece to the first fixing piece or the casting mold.

[0025] The beneficial effect is that the present invention is an improved invention. The voltage coil is fixed by the second fixing member, and when the insulating material is poured into the casting mold, the voltage coil can be effectively prevented from having a small movement, thereby preventing the insulation spacing of the voltage transformer body from changing, thereby improving the qualified rate of the combined transformer.

[0026] Furthermore, after the mold closing step, there is also a pouring step of pouring insulating material into the pouring mold, and after the pouring step, there is also a curing step. In the curing step, the pouring mold is first placed in an oven for preheating, and then the temperature of the oven is increased several times and the mold shrinkage is compensated, and then demolding is performed. After demolding, the temperature of the oven is increased again and the demolded combined mutual inductor is sent into the oven again for curing, and then the temperature of the oven is lowered several times to complete the curing of the combined mutual inductor.

[0027] The beneficial effects are as follows: before demoulding, increasing the temperature of the oven several times and performing mold shrinkage compensation can effectively make the combined mutual inductor initially solidified and ensure that the body of the combined mutual inductor is in good condition; after demoulding, increasing the temperature of the oven again and performing multiple temperature reductions can effectively release the internal stress of the product and prevent the body of the combined mutual inductor from being affected by secondary stress, thereby improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a front view of a current transformer body of a specific embodiment 1 of the combined transformer of the present invention;

[0029] Figure 2 It is a side view of a current transformer body of a specific embodiment 1 of the combined transformer of the present invention;

[0030] Figure 3 It is a front view of the P1 terminal of the current transformer body of the specific embodiment 1 of the combined transformer in the present invention;

[0031] Figure 4 It is a side view of the P1 terminal of the current transformer body of the specific embodiment 1 of the combined transformer in the present invention;

[0032] Figure 5 It is a front view of the P2 terminal of the current transformer body of the specific embodiment 1 of the combined transformer in the present invention;

[0033] Figure 6 It is a side view of the P2 terminal of the current transformer body of the specific embodiment 1 of the combined transformer in the present invention;

[0034] Figure 7 It is a front view of a current fixing plate of a current transformer body of a specific embodiment 1 of a combined transformer in the present invention;

[0035] Figure 8 It is a side view of a current fixing plate of a current transformer body of a specific embodiment 1 of a combined transformer in the present invention;

[0036] Fig. 9 It is a front view of a voltage transformer body and a second fixing member when they are connected in a specific embodiment 1 of the combined transformer of the present invention;

[0037] Fig.10 It is a side view of a voltage transformer body and a second fixing member when the voltage transformer body is connected to the specific embodiment 1 of the combined transformer in the present invention;

[0038] Fig.11 It is a front view of the second fixing member of the specific embodiment 1 of the combined mutual inductor in the present invention;

[0039] Fig.12 It is a side view of the second fixing member of the specific embodiment 1 of the combined mutual inductor in the present invention;

[0040] Fig.13 A top view of a second fixing member of a specific embodiment 1 of a combined mutual inductor in the present invention;

[0041] Fig.14 It is a front view of a voltage fixing plate of a specific embodiment 1 of a combined mutual inductor in the present invention;

[0042] Fig.15 It is a side view of a voltage fixing plate of a specific embodiment 1 of a combined mutual inductor in the present invention;

[0043] Fig.16 It is a front perspective view of a specific embodiment 1 of the combined mutual inductor of the present invention;

[0044] Fig.17 It is a side perspective view of a specific embodiment 1 of the combined mutual inductor of the present invention;

[0045] Fig.18 It is a front view of a specific embodiment 1 of the combined mutual inductor of the present invention;

[0046] Fig.19 It is a side view of a specific embodiment 1 of the combined mutual inductor of the present invention;

[0047] Fig. 20 It is a top view of a specific embodiment 1 of the combined mutual inductor in the present invention.

[0048] Explanation of the accompanying drawings: 1. P1 terminal; 2. P2 terminal; 3. Primary soft copper strip for current; 4. Secondary current coil; 5. Current enameled wire; 6. Current fixing plate; 7. Second fixing piece; 71. Connecting rod; 72. Arc-shaped connecting plate; 8. Primary voltage coil; 9. Voltage enameled wire; 10. Voltage core; 11. Voltage fixing plate, 12. Secondary voltage coil; 13. Skeleton; 14. Electrostatic screen; 15. Bottom screen; 16. Silicone rubber sleeve; 17. Mounting bracket. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with embodiments.

[0050] Specific embodiment 1 of the combined mutual inductor provided by the present invention:

[0051] The purpose of this embodiment is to provide a combined transformer that is manufactured using a casting mold, and the voltage coil and the current transformer body are fixedly connected to the casting mold. When pouring insulating material into the casting mold, by fixing the voltage coil and the current transformer body to the casting mold, it is possible to effectively avoid changes in the insulation spacing between the voltage transformer body and the current transformer body, thereby increasing the product qualification rate of the combined transformer.

[0052] like Figure 1-20 As shown, this embodiment specifically provides a combined transformer, including a current transformer body, a voltage transformer body, and a second fixing member 7 fixedly connected to the voltage transformer body. In this embodiment, there are two current transformer bodies and two voltage transformer bodies, but in other embodiments, there can be three or more current transformer bodies and two voltage transformer bodies.

[0053] like Figure 1-6 As shown, the current transformer body includes a current core, a current secondary coil 4 wrapped around the current core, a current primary coil, a P1 terminal 1 and a P2 terminal 2 connected to the current primary coil, and a current enameled wire 5. In this embodiment, the current primary coil is wound with a current primary soft copper strip 3. The current primary coil and the current secondary coil constitute a current coil.

[0054] like Figure 9-10As shown, the voltage transformer body includes a voltage core 10 and a voltage coil installed on the voltage core 10, and the voltage coil includes a voltage secondary coil, a bottom screen 15 installed outside the voltage secondary coil, a voltage primary coil 8 installed outside the bottom screen 15, and an electrostatic screen 14 installed outside the voltage primary coil 8. In this embodiment, the axis of the voltage coil extends along the horizontal defense line, the cross-section of the voltage core 10 is rectangular and the voltage core 10 forms a ring connected end to end, a buffer layer is laid on the non-winding side of the voltage core 10, and the buffer layer is arranged on the three sides of the voltage core 10 that are not directly opposite to other parts of the voltage core 10, and the side of the buffer layer away from the voltage core 10 is flush with the side of the voltage secondary coil away from the voltage core 10, and the buffer layer is close to the voltage secondary coil.

[0055] like Figure 7-8 As shown in Figures 14-17, in order to solve the problem that the current secondary coil 4 of the current transformer body is difficult to fix, which causes the insulation spacing of the current transformer body to change, and then causes the product qualification rate to decrease, in this embodiment, the current secondary coil 4 and the voltage core 10 are fixedly connected by a first fixing member, and the first fixing member includes a current fixing plate 6 arranged on the current secondary coil 4 and fixedly connected to the current secondary coil 4, and a voltage fixing plate arranged on the voltage core 10 and fixedly connected to the voltage core 10, the voltage fixing plate is a vertical fixing plate vertically arranged on the voltage core 10, the current fixing plate 6 includes an arc segment connected to the current secondary coil 4 and a vertical segment connected to the voltage fixing plate, and the arc segment of the current fixing plate 6 is fixedly connected to the current secondary coil 4 through a heat shrinkable tape, the voltage fixing plate is fixedly connected to the voltage core 10 through a heat shrinkable tape, the vertical segment of the current fixing plate 6 is provided with a long hole for the bolt to slide, and the voltage fixing plate is provided with a corresponding through hole, and the vertical segment of the current fixing plate 6 and the voltage fixing plate are fixedly connected by fixing bolts passing through the long holes.

[0056] The combined mutual inductor further comprises a second fixing member 7 for fixing the voltage secondary coil, one end of the second fixing member 7 is used to be fixedly connected to the casting mold, and the other end of the second fixing member 7 is fixedly connected to the electrostatic screen 14. In this embodiment, Figure 9-13 As shown, the second fixing member 7 is a conductor, and the second fixing member 7 includes two arc-shaped connecting plates 72 for being fixedly connected to the electrostatic screen 14 and an inverted "T"-shaped connecting rod 71 for fixing the two arc-shaped connecting plates 72. The inverted "T"-shaped connecting rod 71 includes a horizontal bar and a vertical bar. The horizontal bar is used to connect the arc-shaped connecting plates 72. One end of the vertical bar is connected to the horizontal bar, and the other end is used to connect with other equipment or wires. When pouring insulating material into the casting mold, a threaded hole is provided at one end of the vertical bar away from the horizontal bar and extends out of the casting mold. A baffle or other stopping structure is installed on the vertical bar through the threaded hole, so that the vertical bar can be stopped with the casting mold, thereby realizing the fixed connection between the second fixing member 7 and the casting mold.

[0057] The voltage coil is fixed by the second fixing member 7, and when the insulating material is poured into the casting mold, the voltage coil can be effectively prevented from undergoing slight movement, thereby preventing the insulation spacing of the voltage transformer body from changing, thereby improving the qualified rate of the combined transformer; when the insulating material is poured into the casting mold, the buffer layer can play a buffering role, prevent the voltage transformer body from moving, and ensure the insulation spacing of the voltage transformer body, thereby further improving the qualified rate of the combined transformer; the arc-shaped connecting plate 72 can increase the contact area between the second fixing member and the voltage coil, thereby better fixing the voltage coil; by arranging horizontal bars and vertical bars, all the voltage coils can be connected by a second fixing member, and the structure is simple; compared with the combined transformer in the background technology, by making the second fixing member play a conductive role, the number of fixing members used in the combined transformer can be effectively reduced, making the structure simpler while reducing the cost. This invention relates to a method for fixing the current secondary coil 4 and the voltage core 10 through a first fixing member, so that the position of the current secondary coil 4 can be effectively fixed, thereby fixing the position of the current primary coil and the current secondary coil 4, thereby ensuring the insulation distance between the current primary coil and the current secondary coil 4, increasing the voltage when partial discharge occurs in the combined mutual inductor, and improving the qualified rate of the product; the arc-shaped end of the current fixing plate 6 can increase the contact area between the current fixing plate 6 and the current secondary coil 4, thereby better fixing the current secondary coil 4; wrapping the current fixing plate 6 and the voltage fixing plate with a heat shrinkable tape is convenient to operate and has a simple structure, and when pouring high-temperature insulating material into the casting mold, the heat shrinkable tape can ensure that the position of the current fixing plate 6 and the voltage fixing plate does not change, thereby ensuring that the position of the current secondary coil 4 does not change; by setting a long hole, the relative position of the current secondary coil 4 and the current primary coil can be conveniently adjusted.

[0058] In order to facilitate the fixing of the current transformer body, Figure 1 and 9 As shown, a voltage enameled wire 9 having one end fixedly connected to the electrostatic screen 14 is provided on the electrostatic screen 14, and the other end of the voltage enameled wire 9 is fixedly connected to an end of the current enameled wire 5 away from the current primary coil, and the voltage enameled wire 9 is conductively connected to both the voltage primary coil and the current enameled wire 5, and a portion of at least one of the current enameled wire 5 and the voltage enameled wire 9 is bent into a spring shape. In this embodiment, one end of the current enameled wire 5 is bent into a spring shape.

[0059] By setting one end of the voltage enameled wire 9 on the electrostatic screen 14 and bending a part of at least one of the current enameled wire 5 and the voltage enameled wire 9 into a spring shape, on the one hand, it is convenient to connect the primary coil of the current transformer body with the secondary coil of the voltage transformer body. At the same time, since the current enameled wire 5 or the voltage enameled wire 9 can be stretched, the current transformer body can be conveniently placed at different positions in the casting mold; on the other hand, the spring-shaped current enameled wire 5 or the voltage enameled wire 9 can apply a pulling force to the voltage coil. On the premise that the combined transformer already includes the second fixing member 7 and the first fixing member, the spring-shaped current enameled wire 5 or the voltage enameled wire 9 can also further fix the voltage coil, thereby improving the qualified rate of the combined transformer. In this embodiment, the voltage enameled wire 9 and the second fixing member 7 are respectively arranged at the two ends of the voltage coil along the axial direction of the voltage coil. By setting the voltage enameled wire 9 and the second fixing member 7 at the two ends of the voltage coil along the axial direction of the voltage coil, on the one hand, the volume of the arc-shaped connecting plate can be reduced, and on the other hand, the voltage coil can be better fixed from both ends.

[0060] Specific embodiment 2 of the combined mutual inductor provided by the present invention:

[0061] The purpose of this embodiment is to provide a combination transformer with different numbers of voltage transformer bodies. The main difference between this embodiment and specific embodiment 1 is that: in this embodiment, there are three voltage transformer bodies and three current transformer bodies, and there are also three second fixing members. Each second fixing member fixes each voltage coil on the first fixing member respectively.

[0062] Specific embodiment 3 of the combined mutual inductor provided by the present invention:

[0063] The purpose of this embodiment is to provide a different second fixing member. The main difference between this embodiment and specific embodiment 1 is that in this embodiment, the arc-shaped connecting plate connected to the upper part of the voltage coil is not included, and the second fixing member is two "I"-shaped connecting rods, one end of the two connecting rods is respectively fixedly connected to the two sides of the vertical fixing plate, and the other end is respectively fixedly connected to the two sides of the voltage coil.

[0064] Specific embodiment 4 of the combined mutual inductor provided by the present invention:

[0065] The purpose of this embodiment is to provide a second fixing member made of non-conductive material. The main difference between this embodiment and specific embodiment 1 is that in this embodiment, a conductive structure for connecting the voltage coil to the outside world is separately provided as in the background technology, and the second fixing member only serves to fix the voltage coil.

[0066] Specific embodiment 5 of the combined mutual inductor provided by the present invention:

[0067] The purpose of this embodiment is to provide a current enameled wire and a voltage enameled wire that are not bent into a spring shape. The main difference between this embodiment and specific embodiment 1 is that in this embodiment, in the direction along the axis of the voltage coil, the length of the arc-shaped fixing plate is the same as the length of the voltage coil, and the current enameled wire and the voltage enameled wire do not need to provide tension. Therefore, the current enameled wire and the voltage enameled wire are not bent into a spring shape.

[0068] Specific embodiment 6 of the combined mutual inductor provided by the present invention:

[0069] The purpose of this embodiment is to provide a different setting method for the voltage enameled wire and the second fixing member. The main difference between this embodiment and specific embodiment 1 is that in this embodiment, the arc-shaped connecting plate is connected to the middle of the voltage coil, and the voltage enameled wire is connected to one end of the voltage coil.

[0070] Specific embodiment 7 of the combined mutual inductor provided by the present invention:

[0071] The purpose of this embodiment is to provide a combination transformer with different numbers of current transformer bodies. The main difference between this embodiment and specific embodiment 1 is that: in this embodiment, the number of current transformer bodies is three, the number of voltage transformer bodies is also three, and each pair of voltage transformer bodies and current transformer bodies are connected by a first fixing member.

[0072] Specific embodiment 8 of the combined mutual inductor provided by the present invention:

[0073] The purpose of this embodiment is to provide a different connection method of the current fixing plate and the voltage fixing plate. The main difference between this embodiment and specific embodiment 1 is that in this embodiment, the current fixing plate and the voltage fixing plate are welded together.

[0074] Specific embodiment 9 of the combined mutual inductor provided by the present invention:

[0075] The purpose of this embodiment is to provide another different connection method between the current fixing plate and the voltage fixing plate. The main difference between this embodiment and specific embodiment 1 is that: in this embodiment, a long hole is provided on the voltage fixing plate, and the current fixing plate and the voltage fixing plate are fixedly connected through the long hole and bolts.

[0076] Specific embodiment 1 of the production method of the combined mutual inductor provided by the present invention:

[0077] The purpose of this embodiment is to provide a production method for a combined transformer, which utilizes a casting mold, a first fixing member, and a second fixing member to effectively fix the voltage coil and the current transformer body, thereby improving the product quality of the combined transformer, ensuring the measurement accuracy of the combined transformer, increasing the voltage of the combined transformer when partial discharge occurs, and improving the qualified rate of the product.

[0078] To achieve the above purpose, this embodiment is mainly divided into the following steps:

[0079] S1. Make the current transformer body

[0080] When making the current transformer body, it can be divided into the following four steps:

[0081] 1. The current core used in the current secondary coil is wrapped according to the following process: the outer diameter of the core shell is wrapped with a layer of 1mm thick insulating cardboard of the same height as the core shell, and the interface is fixed with electrical tape → two layers of yellow crumpled paper half-folded one layer → white cloth tape half-folded one layer → electrical tape half-folded one layer.

[0082] By wrapping with insulating cardboard, yellow crumpled paper and white cloth tape, the buffer can be increased to prevent stress during the coil winding process, which will affect the performance parameters of the current core; wrapping with electrical tape can effectively fix the buffer material to prevent the product's performance from being unqualified due to stress on the core during the secondary coil winding process.

[0083] 2. Wind the secondary coil according to user requirements. After the accuracy test is qualified, install a silicone rubber glass fiber sleeve of corresponding length on the secondary coil, weld the secondary insert, and wrap the secondary coil according to the following process: half-fold polyester film → press shielding wire (the beginning of the shielding wire is reliably fixed with electrical tape, the shielding wire is about 50mm long, and the lead wire is φ0.8 enameled wire) → half-fold semiconductor crepe paper (20mm away from the secondary tap) → half-fold yellow crepe paper; then fix the arc-shaped fixing plate to the outside of the secondary coil with heat shrink tape.

[0084] By installing a silicone rubber fiberglass casing, the primary winding can be effectively prevented from discharging and puncturing the secondary coil; the polyester film can enhance the insulation strength of the secondary coil to prevent puncture; the pressed shield wire and the semiconductor corrugated paper can help form an equipotential ring outside the secondary coil to prevent puncture, and the yellow corrugated paper can prevent dust; the arc-shaped fixing plate can adjust the position of the secondary coil by cooperating with the vertical fixing plate.

[0085] 3. Select the copper tape of corresponding specifications according to the technical specifications, wind it into the primary coil on the specified mold, put the wrapped secondary coil on the copper tape, and weld the copper tape to the corresponding terminal;

[0086] By soldering the copper strip to the terminals, it helps to fix the primary coil of the current.

[0087] 4. Cut 500mm long 1.8×2.8mm current enameled wire and fold it into a spring shape with the help of a cylinder with an outer diameter of 10mm and use it as the current enameled wire. After the paint on both ends is polished clean, one end is welded to the outermost copper strip of the current primary coil. Then, the body is wrapped according to the following process: place the cut DMD insulation paper in the center between the turns → half-fold the white cloth tape and tightly wrap it → three layers of yellow crepe paper and half-fold it → half-fold the semiconductor crepe paper (when wrapping the semiconductor crepe paper, press the welded current enameled wire reliably between the layers of semiconductor crepe paper, and no breakage is allowed).

[0088] By folding the 1.8×2.8mm current enameled wire into a spring shape, it helps to connect with the voltage enameled wire and support the positioning of the voltage secondary coil. The DMD insulating paper can prevent primary turn breakdown. The white cloth tape and yellow wrinkled paper act as buffers. The semiconductor wrinkled paper can balance the potential of the current primary coil.

[0089] S2. Make the voltage transformer body

[0090] When making the voltage transformer body, it can be divided into the following four steps:

[0091] 1. Wrap one layer of highland barley paper and 5 layers of 0.1mm thick PMP insulating paper on the winding side of the voltage core. Select the corresponding specifications of enameled wire according to the requirements of the drawing to complete the coil winding. The voltage secondary coil is wrapped with three layers of 0.1mm thick PMP insulating paper and fixed with double-sided tape; Wrap the non-winding side of the voltage core according to the following process: scrape off the insulation layer at the R corner of the core → put the copper foil with the core shielding lead welded close to that place → wrap the insulating tape to press the copper foil → the core is not directly connected to the other parts of the core Pad the outer three sides with a layer of 3mm thick polyurethane high-density sponge of appropriate size, and make sure that the non-winding side is perfectly overlapped with the secondary wire package when wrapped with the polyurethane high-density sponge → Wrap it with a layer of electrical tape, and wrap the entire shielded wire with a layer of semiconductor crepe paper (no warping is allowed). Wrap the non-winding side and the winding side with electrical tape and semiconductor paper → Leave room for lead welding to the ground insert (weld a shielded lead with a length of about 160mm to the end of the original grounding lead, and weld another grounding insert to the end).

[0092] Wrapping the winding side of the voltage core with highland barley paper and 0.1mm thick PMP insulating paper can play a buffering and insulating role; wrapping the voltage secondary coil with 0.1mm thick PMP insulating paper can prevent breakdown; scraping off the insulation layer of the core and welding the shielding lead can form an equipotential ring to reliably ground the core, thereby preventing breakdown; 3mm thick polyurethane high-density sponge plays a buffering role; electrical tape seals and fixes the polyurethane high-density sponge; semiconductor corrugated paper and shielding wires can form an equipotential ring to prevent breakdown.

[0093] 2. Cut the corresponding copper foil according to the size of the skeleton as the bottom screen (the bottom screen must not form a closed loop, and the sharp corners and burrs must be polished clean), cut 100mm of Ф0.59 enameled wire, remove the insulating paint (about 10mm) in the middle and both ends, and weld the adapter wire to the center of the bottom screen (copper foil), with the welding point in the middle of the adapter wire; stick the bottom screen to the outside of the skeleton with double-sided tape, and cover it with a layer of 25mm wide semiconductor crepe paper;

[0094] The bottom screen and the semiconductor corrugated paper on the outside of the skeleton can form an equipotential ring to prevent primary and secondary breakdown, and the enameled wire serves to connect the two coils.

[0095] 3. Put the frame onto the outside of the voltage secondary coil, select the enameled wire of corresponding specifications according to the requirements of the drawing to complete the winding of the voltage primary coil. During the winding process, two and a half layers of PMP insulating paper are used for insulation, and the overlapping length of the insulating paper is greater than 20mm.

[0096] PMP insulation paper uses two and a half layers with an overlap length greater than 20mm, which can form good insulation.

[0097] 4. After the accuracy check of the primary voltage coil is completed, it needs to be wrapped: three layers of 0.05 thick PMP insulating paper → wrapped with electrostatic screen → the original primary wire is led out and welded on the electrostatic screen → the supporting structure is bonded to the electrostatic screen → 100mm long 1.8×2.8mm voltage enameled wire (paint removed) is welded to the electrostatic screen on both sides → wrapped with half a layer of heat shrink tape (tighten and do not allow the supporting structure to be loose) → one layer of self-adhesive tape and half a layer of semiconductor crepe paper; use heat shrink tape to wrap the vertical fixing plate and fix it on the voltage core.

[0098] PMP insulating paper can form good insulation to prevent breakdown; the primary wire lead-out and welding on the electrostatic screen can balance the voltage and form an equipotential ring; the support structure is bonded to the electrostatic screen, and 1.8×2.8mm enameled wire is welded on both sides to adjust the main insulation distance. Heat shrink tape and self-adhesive tape can effectively fix the support to form a buffer; semiconductor corrugated paper can balance the voltage and form an equipotential ring; heat shrink tape wrapping and fixing the vertical fixing plate helps to cooperate with the arc fixing plate to adjust the insulation distance of the secondary coil of the current body.

[0099] S3, drying

[0100] Place the voltage and current devices in a vacuum drying tank for drying for ≥12 hours; place the casting mold in a 95°C oven for preheating for no less than 6 hours.

[0101] The body of the device is sent to a vacuum drying tank for drying, which can effectively remove moisture and improve local discharge; the casting mold is preheated in a 95℃ oven to prevent moisture from returning to the body of the device due to the temperature difference between the mold and the body of the device.

[0102] S4, mold installation and mold closing

[0103] After preheating the casting mold, take out the casting mold, wipe the inner cavity of the casting mold clean, apply the release agent, take out the voltage and current transformer bodies, hoist the voltage transformer body into the casting mold, fix the primary terminal of the current transformer body in the inner cavity of the casting mold, and then connect the 1.8×2.8mm current enameled wire welded on the outside of the primary coil of the current transformer body to the voltage enameled wire through copper stranded wire, and then use tin soldering. The current transformer body is positioned by the arc-shaped fixing plate 6 and the vertical fixing plate 11, and the mold is closed after adjusting the insulation distance.

[0104] In the mold installation step, wiping the inner cavity of the casting mold can effectively remove impurities and dirt; applying a mold release agent can facilitate demolding of the finished product; the 1.8×2.8mm enameled wire welded on the outside of the primary coil of the current transformer body is welded to the voltage enameled wire, which can generate tension on the primary coil of the voltage transformer body, making it easier to fix the position of the primary coil of the voltage transformer body. The arc-shaped fixing plate and the vertical fixing plate can effectively fix the position of the secondary coil of the current transformer body, thereby ensuring primary and secondary main insulation and improving product partial discharge.

[0105] S5. Pouring

[0106] Place the casting mold in a 95°C oven for preheating for no less than 6 hours; then pour the 7500 epoxy resin mixture, and after pouring, place the casting mold in an oven for initial curing.

[0107] Preheating the casting mold can ensure the temperature difference between the body and the mixture, and ensure the appearance of the product.

[0108] S6. Curing

[0109] The curing process of the casting mold in the oven for initial curing is: 80℃×5h→90℃(1h after mold shrinkage compensation) until curing→110℃×(2~6)h; then demoulding (completed within 1h), and then sent to the oven for post-curing again after demoulding. The curing process is: 130℃×8h→120℃×2h→cooling down by 20℃ every 2h→40℃×2h→turn off the oven heating→cool to room temperature;

[0110] The initial curing process is divided into three stages of heating to effectively cure the product and give it a good appearance; the post-curing process uses step-by-step cooling to effectively release the internal stress of the product, preventing the device body from being affected by secondary stress and reducing product quality.

[0111] S7, Silicone Case Set

[0112] After curing, the casting body (combined transformer body) is covered with a silicone rubber sleeve. The epoxy resin casting body and the silicone rubber are bonded with TJ-2011-R1X silicone sealing adhesive, and the silicone rubber joints are grouted with Zhonglan Chenguang GD-405 grouting adhesive. When bonding the rubber sleeve, evenly apply the silicone rubber adhesive to ensure tight bonding. After bonding, no gaps are allowed between the epoxy resin casting body and the rubber sleeve; evenly apply the grouting adhesive at the grouting joints, which should be beautiful. There should not be too many grouting joints. Wait for curing and install the fixed bracket.

[0113] After the curing, the casting body is covered with a silicone rubber sleeve, which can effectively prevent water and dust, and improve the environmental tolerance of the product; TJ-2011-R1X silicone sealing adhesive can be used to effectively bond the rubber sleeve and the casting body; Zhonglan Chenguang GD-405 jointing adhesive can be used to effectively bond the gaps to prevent small gaps from affecting product quality.

[0114] The production method of the combined transformer in the present invention fixes the voltage coil by a second fixing member, and when pouring the insulating material into the casting mold, it can effectively avoid the voltage coil from having a small movement, thereby avoiding the insulation spacing of the voltage transformer body from changing, thereby improving the qualified rate of the combined transformer; in the curing step, before demolding, the temperature of the oven is increased several times and the mold is compensated for shrinkage, which can effectively make the combined transformer initially solidified and ensure that the body of the combined transformer is in good condition; after demolding, the temperature of the oven is increased again and the temperature is lowered several times, which can effectively release the internal stress of the product, prevent the body of the combined transformer from being affected by secondary stress, thereby improving the product quality.

[0115] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A combined transformer, comprising a current transformer body and a voltage transformer body, wherein the voltage transformer body comprises a voltage core and a voltage coil mounted on the voltage core, the current transformer body comprises a current core and a current secondary coil mounted on the current core, the current secondary coil and the voltage core are fixedly connected by a first fixing member, characterized in that: A second fixing member is fixedly arranged on the voltage coil, and the second fixing member is fixedly connected to the first fixing member or the second fixing member is provided with a connecting structure for being fixedly connected to the casting mold.

2. The combined mutual inductor according to claim 1, characterized in that: The number of the voltage transformer bodies is at least two, the axes of the voltage coils extend in the horizontal direction, and the second fixing member is fixedly connected to all the voltage coils at the same time.

3. The combined mutual inductor according to claim 2, characterized in that: The second fixing member includes a connecting rod and at least two arc-shaped connecting plates arranged on the connecting rod and used to be connected to the voltage coil, and the arc-shaped connecting plates are respectively connected to each voltage coil.

4. The combined mutual inductor according to claim 3, characterized in that: The second fixing member is a conductor, the connecting rod is an inverted "T" shaped connecting rod, the connecting rod includes a horizontal rod and a vertical rod, the arc-shaped connecting plate is arranged on the horizontal rod, one end of the vertical rod is used to extend out of the casting mold, and the other end is used to connect with the horizontal rod, the voltage coil includes a primary voltage coil, and the low voltage end of the primary voltage coil is electrically connected to the arc-shaped connecting plate.

5. The combined mutual inductor according to any one of claims 1 to 3, characterized in that: The current transformer body also includes a current primary coil, to which a current enameled wire is electrically connected; the voltage coil includes a voltage primary coil, to which a voltage enameled wire is electrically connected; the current enameled wire and the voltage enameled wire are fixedly electrically connected; and a portion of at least one of the current enameled wire and the voltage enameled wire is bent into a spring shape.

6. The combined mutual inductor according to claim 5, characterized in that: The voltage enameled wire and the second fixing member are respectively arranged at two ends of the voltage coil in the axial direction.

7. The combined mutual inductor according to any one of claims 2 to 4, characterized in that: The number of the current transformer bodies is at least two, and the current transformer body also includes a P1 terminal or a P2 terminal for fixed connection to the casting mold. The first fixing part includes a current fixing plate connected to the current secondary coil and a voltage fixing plate connected to the side of the voltage core. The current fixing plate includes an arc segment for connecting to the current secondary coil and a vertical segment for connecting to the voltage fixing plate.

8. The combined mutual inductor according to claim 7, characterized in that: The vertical section of the current fixing plate or the voltage fixing plate is provided with a long hole for the bolts to slide, and the vertical section of the current fixing plate and the voltage fixing plate are connected through the long hole and the bolts.

9. A method for producing a combined transformer, comprising a step of placing a current transformer body and a voltage transformer body in a casting mold and then closing the mold, and before closing the mold, fixing the current secondary coil of the current transformer body and the voltage core of the voltage transformer body with a first fixing member, characterized in that: Before closing the mold, a second fixing piece is fixed on the voltage coil of the voltage transformer body, and the voltage coil is positioned by fixing the second fixing piece to the first fixing piece or the casting mold.

10. The method for producing a combined mutual inductor according to claim 9, characterized in that: After the mold closing step, the method further includes a pouring step of pouring insulating material into the pouring mold. After the pouring step, the method further includes a curing step. In the curing step, the pouring mold is first placed in an oven for preheating, and then the temperature of the oven is increased several times and the mold shrinkage is compensated, and then demolding is performed. After demolding, the temperature of the oven is increased again and the demolded combined mutual inductor is sent back into the oven for curing, and then the temperature of the oven is lowered several times to complete the curing of the combined mutual inductor.

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