JPS59219915A - Manufacture of resin molded coil - Google Patents

Abstract

PURPOSE:To remove leakage of resin, and to stabilize the electric and the mechanical characteristics of a resin molded coil by a method wherein a foam sheet or tape is wound around the inlet/outlet parts of transition wires in cooling air paths between inside coils and outside coils to form foam layers. CONSTITUTION:Because foam sheets 17 are wound around transition wires 16 at a cooling air path part between the inside coil 11 and the outside coil 12 of a low voltage coil, transition wires 26 at a cooling air path part between a high voltage coil 23 and an outside coil 28, and the respective lead out parts of terminals 27 projecting from the outer peripheral side of the outermost layer coil, when the foam sheets 17 thereof are heated at the temperature of 120 deg.C or more at resin impregnating time, the sheets foam to 3-5 times. Accordingly, because gaps at the lead out parts of the transition wires 16, 26 to insulators 15a, 15b and 15e, 15f, and gaps at the terminal parts to the outermost periphery insulating layer 36 are blocked according to foaming action of the foam layers 17, leakage of resin from the parts thereof can be checked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a resin molded coil having a cooling airway for use in electromagnetic induction equipment such as dry transformers and reactors.

[Technical background of the invention and its problems]

Recently, a mold type dry transformer has appeared as a dry transformer, which is made by impregnating and hardening resin into one piece to improve insulation properties. This molded dry type transformer is generally constructed by concentrically arranging a plurality of resin-molded coils around an iron core leg.

There are two main methods for manufacturing the coils used in molded dry type transformers: methods that use molds and methods that do not use molds, but in recent years, specifications have diversified, and productivity such as maintenance of molds has improved. Since it is economically advantageous, a so-called impregnated iso manufacturing method, in which a resin molded coil is manufactured without using a mold, is often adopted.

By the way, in the case of the impregnation type manufacturing method, since excess resin does not adhere to the coil, there is no occurrence of cracks peculiar to molded coils, and the coil can be made smaller and lighter.

However, since a low viscosity resin is used and no mold is used, there is a risk that the resin impregnated into the coil may leak out, and the key to this manufacturing method is how to prevent this.

Conventional impregnation type manufacturing methods include: (1) Immediately after taking out the coil from the impregnation tank, the coil is rotatably set in a rotary drive device and heated while being rotated to harden the resin; (2) A curing accelerator is attached in advance to the inside of the coil or to the coil insulating layer,
It is known that the coil is impregnated with resin and the curing accelerator reacts with the resin, resulting in celification.When the resin in the coil stops leaking, the coil is taken out and heated in a heating furnace to harden the resin. It is being Among these, method (1) requires work to set the coil in the rotary drive device, and has the disadvantage that it is not suitable for mass-produced models due to equipment limitations of the rotary drive device. The manufacturing method described in (2) above has been attracting attention.

Here, the manufacturing method (2) above will be explained with reference to the drawings. Figures 1 and 2 show an example of a resin molded coil with a multiple winding configuration according to a conventional manufacturing method.◎ To manufacture a resin molded coil by this conventional method, a coil frame 1 such as an insulating tube is After winding the conductor 2& to form the low voltage coil 2 and pulling out the lead wire 2b upward, a glass tape to which a curing accelerator has been applied in advance is wound around the outer periphery to form the outer periphery insulating layer 3a of the low voltage coil 2. Form. A corrugated spacer insulator 4 is placed outside the insulating layer 3a to ensure a cooling airway. After winding a glass tape to which a curing accelerator has been applied in advance on the spacer insulator 4 to form the inner peripheral insulating layer 3b, the conductor 5a is wound to form the high voltage coil 5, and the lead wire 5b is directed upward. Pull it out.

The high voltage coil 5 is formed of a plurality of winding layers with an interstage insulator 6 interposed therebetween. In addition, end insulators 7a are provided outside the upper and lower ends of each coil 2 and 5 to insulate the coil and improve mechanical strength.
, 7b is inserted, and the lower end insulator 7b is also treated with a curing accelerator in advance. Furthermore, the outermost insulating layer 3C of the high voltage coil 5 is made of glass tape treated with a curing accelerator.
form.

In this way, the inner and outer peripheries and the lower end of the coil are covered with the insulating layers 3a to 3C treated with a curing accelerator and the lower end insulator 7b. An insulating layer 3a in which such a coil is impregnated with resin in a resin bath (not shown) and the resin is treated with a curing accelerator.
~3C and the lower end portion ``insulator 7b'' are left in the resin bath until they react with the curing accelerator and form a glue. When the resin in the insulating layers 3a to 3C and the lower end insulator 7b treated with the curing accelerator has progressed to dullness and the resin impregnated inside the coil does not flow out, the coil is pulled up from the resin bath and heated. The resin was cured by heating in a furnace to obtain a one-piece resin molded coil.

However, this conventional resin molded coil manufacturing method has the following drawbacks.

In other words, in a transformer with a large capacity, in order to reduce the heat generated in the coil, it is possible to reduce the current density by using a conductor with a large cross-sectional area, but this would make the coil itself large, so the low voltage coil 2, high voltage It is necessary to provide a cooling airway within the coil 5 as well. However, when providing cooling airways in the low-voltage coil 2 and high-voltage coil 5, the low-voltage coil 2 and the high-voltage coil 5 are divided into an inner coil and an outer coil, respectively, a cooling airway is formed between the coils, and the inner coil and outer coil are separated. shall be connected with a crossover wire via a cooling airway. For this purpose, a glass tape pre-treated with a curing accelerator is tightly wrapped multiple times around the inner circumference of the outer coil and the outer circumference of the inner coil to form an inner circumference insulating layer and an outer circumference insulating layer. However, it is necessary to prevent the resin from leaking, but this work must be done during the winding work of the coil conductor, which is a very complicated work and is not suitable as an actual manufacturing method.

Another method is to provide insulation made of non-impregnated heat-resistant board on the inner periphery of the outer coil facing the cooling airway and on the outer periphery of the inner coil, but in this case, the heat-resistant To prevent resin from leaking from the exiting and entering parts, these parts must be sealed with room-temperature vulcanized rubber or room-temperature curing resin. However, performing such work during winding work not only complicates the work, but also causes resin to leak from this part if the conductor at the transition part moves during subsequent work, increasing the defect rate. expensive.

Providing a cooling airway in the coil in this way not only involves extremely complicated work, but also prevents resin from leaking from the coil surfaces and transition parts facing the cooling airway, making it difficult to implement in the actual structure. It was not suitable and improvements and improvements were desired.

On the other hand, in the multi-wound resin molded coil of a general transformer, as shown in the wiring diagram shown in FIG. 3, after winding from the winding start end U and winding in multiple layers, the outermost layer is connected to a tap terminal T1 for voltage switching. T2. T3°T4, T5, and T6 are often provided in sequence. In this case, there is a method of bringing out the tap terminals T1 to T6 above the coil, but the insulation becomes complicated because the terminal leads must be passed over the coil and brought out. Therefore, a method is adopted in which the lead wire of the tap terminal is directly extended to the outer circumference and only that lead wire is insulated, and then attached to the terminal block, or alternatively, the tap terminal is attached directly to the conductor and the terminal is fixed with resin on the outer circumference of the coil. . However, in this case as well, similar to the transition section of the cooling airway, gaps and marks will occur where the lead wire or tap terminal exits from the coil surface, so this section should be coated with room-temperature vulcanized rubber or room-temperature curing resin in the same way as the transition section. Although sealing was used to prevent resin leakage, similar to the transition section, manual sealing methods had to be used, and there were cases where resin leaked outside from the sealed section, so improvements were desired.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned demands, and its purpose is to improve workability and to improve the transition between the inner coil and the outer coil facing the cooling air passage formed in the coil that exits in the axial direction. It is an object of the present invention to provide a method for manufacturing a resin-molded coil that is stable in electrical and mechanical properties and can prevent resin leakage from the terminal portion led out from the outer periphery of the coil.

[Summary of the invention]

In order to achieve such an object, the present invention provides an inner coil by providing end insulators on the outside of the upper and lower ends of a wound layer formed by winding a conductor, and providing insulators with poor resin impregnation on the inner and outer peripheries. In addition, after providing a wave-shaped insulator on the outer periphery of this inner coil to form a cooling airway extending in the axial direction, end insulators are placed outwardly at the upper and lower ends of the wound layer formed by winding a conductor around the outer periphery. and an insulating material with poor resin impregnation on the inner and outer peripheries, and an insulating layer treated with a curing accelerator on the outermost insulating material to form a side coil, and the inner coil and the outer side After attaching a curing accelerator to the end insulator at the lower end of the coil, which has a foam layer wound with a foam material that foams when heated, at the entrance/exit part of the crossover wire facing the cooling airway between the coils, The coil is impregnated with resin in a tank, and when the resin impregnated into the outermost insulating layer and the end insulator reacts with a curing accelerator and becomes dull, the coil is taken out from the resin tank and heated to harden. It is a feature.

[Embodiments of the invention]

The method for manufacturing a resin molded coil according to the present invention will be described below with reference to FIGS. 4 and 5. FIG. 4 is a plan view of a resin molded coil according to an embodiment of the present invention, and FIG. 5 is a longitudinal sectional view taken along line A--A in FIG. 4. That is,
In order to manufacture the resin molded coil in this example, as shown in FIGS. 4 and 5, a heat-resistant nonwoven fabric (for example, Nippon Vilene) that is easily impregnable is placed on a non-impregnable winding frame 8 such as an epoxy insulating tube. Product name: HC5408), a buffer layer 9a made of a buffer material such as glass cloth is provided, and a conductor 10 is wound around the outer periphery of the buffer layer 9a to form an inner coil 1 of a low-voltage coil consisting of at least one winding layer (7. Lead line 11a
pull it upwards. On the winding layer of this inner coil 11,
An end insulator 14a made of an easily impregnable material such as rock wool or thick non-woven fabric is disposed outwardly at the lower end.

14b is provided. Further, a buffer layer 9b made of the same material as described above is provided on the outer periphery of the inner coil 1), and a non-impregnable material (for example, GA board manufactured by Nippon Aroma Co., Ltd.,
The insulator 15a is provided by winding GAH or DuPont (product name: Nomex 410 type). In this case, the overlapping part of the wire 16 and the insulator 15a at the end of the winding of the inner coil 11 of the low-voltage coil is as shown in FIG.
As shown in FIG. 7, a foam sheet that foams when heated (for example, a foam sheet manufactured by Nitto Denko) is wound around the portion of the connecting wire 16 corresponding to the overlapping portion of the wires 5a to provide a foam layer 117, and then the buffer f@ 9b is provided, and an insulator 15a made of a non-impregnated material is superimposed thereon.

Further, a cut 18 is provided in a portion of the insulator 15a corresponding to the crossing wire 16, so that the overlapping portion of the insulator 15th is completely in contact with the insulator 15a. After the insulator 15a is provided in this manner, the overlapping portion of the insulator 15a and the cut portion leading to the cut 9018 are fixed with adhesive tape 19, as shown in FIG. Next, a corrugated insulator 20 is provided around the outer periphery of this insulator 15a to form a cooling airway passing through in the axial direction, and an insulator 15b made of the same non-impregnable material as described above is provided thereon. Furthermore, a buffer layer 9C made of the same material as described above is provided around the outer periphery of this insulator 15b, and a conductor 1θ is wound thereon to form the outer coil 12 of the low-voltage coil. Edge insulators 14g and 14b are provided above and outside the lower end of the circuit layer. In this case, the crossover portion 9 of the crossover wire 16 from the inner coil 11 to the outer coil 12 is formed as follows. That is, FIG. 9 shows the transition line from the inner coil 11 to the outer coil 12, and the transition line corresponds to the overlapped portion of the insulator 15b provided on the outer periphery of the corrugated insulator 20. After a foam layer 17 is provided by winding a foam sheet around 16 as shown in FIG. 7, a buffer layer 9c is provided. Further, a cut 18 is provided in a portion of the insulator 15b corresponding to the connecting wire 16, as described above, so that the overlapping portions of the insulator 15b are completely in contact with each other. After the insulator 15b is provided in this way, the overlapping 9 parts of the insulator 15b and the notch part reaching the 99 opening 18 are fixed with adhesive tape 19, as in the case of FIG. FIG. 10 is a cross-sectional view showing an outline of the transition portion of the crossover wire 16 from the inner coil 11 to the outer coil 12 in the cooling airway section formed by the corrugated insulator 20.

After configuring the inner coil 11 and outer coil 12 of the low-voltage coil in this way, a buffer layer 9d and an insulator 15c made of the same material as described above are provided around the outer periphery of the outer coil 12, and the overlapping portion of the insulator 15c is Adhesive chi-j'1
Fix it at υ according to 9. In this case, the insulating layer formed around the outer periphery of the low-voltage coil may be a wound glass tube treated with a curing accelerator in the same manner as in the past. Next, a wave-shaped insulator 22 for forming a cooling airway passing through in the axial direction is placed around the outer circumference of the insulator 15c, and an insulator 15d similar to that described above is provided on top of the insulator 22, and the overlapping portion is attached to an adhesive chip f19. After fixing with
form. A coil lead wire (
The winding start portion 23a is pulled out upward and the conductor 29 is wound, and end insulators 14m and 14b are provided above and outside the lower end of the winding layer. Further, an interlayer insulator 25 with good resin impregnation property (for example, HC5408 manufactured by Nihon Vilene Co., Ltd.) is provided around the outer periphery of this wound layer, and a conductor 29 is wound thereon and outside the upper and lower ends of the wound layer. End insulators 14m and 14b are provided on both sides to constitute the inner coil 23 of the high-voltage coil consisting of two winding layers. This inner coil 23
A buffer layer 9f and an insulator 15e made of the same material as described above are provided on the outer periphery of the object 30, and a wave-shaped insulator 30 ball is placed thereon.
and a buffer layer 9g are provided in this order. In this case, the configurations of the wire 16 from the inner coil 23, the wave-shaped insulator 30 of the insulator 15e1, and the insulator 15f are the same as in the case of the low-voltage coil.

Then, the conductor 29 is wound around the outer periphery of the buffer layer 9g in two layers with interlayer insulating material 25 interposed therebetween, and the lead wire 28a thereof is pulled out upward, and end insulators 14a, 14b are placed outside the upper and lower ends of each wound layer. constitutes the outer coil 28.

In this case, the terminal portion 27 is drawn out from the outermost layer of the outer coil, and the detailed structure of this portion is shown in FIG. 11. That is, as shown in FIG. 11, a terminal 27 is connected to a conductor 29, a glass tape treated with a curing accelerator is wound around this terminal 27 to form an insulating layer 31, and then the conductor on the insulating layer 31 is connected. A foamed layer 17 is provided by winding a foamed sheet around the connecting portion with 29. Then conductor 2
A non-impregnable reinforcing insulator 32 is applied to a portion of the terminal 27 including the connection portion with the conductor 27, and the conductor 29 is wound thereon, and the terminal 27 is sequentially attached in the same manner until the lead wire 28h is reached. Next, an insulating material 33 with good impregnability, such as rock wool, is provided around the outer periphery of the conductor 29 to a thickness corresponding to the thickness of the protrusion of the terminal 27 including the connection part with the conductor 29, so that the surface is almost uniform. After that, an easily impregnable material such as a glass tape or a nonwoven tape is wound to form an insulating layer 34. After providing an insulator 35 made of a non-impregnable thin sheet material on this insulating layer 34, a glass tape previously treated with a curing accelerator is wound while adjusting the outer periphery to form an insulating layer 36.
Manufacture coils. In order to provide a buffer layer on the conductor, the crossover wire 16.degree. 26 is wound with glass tape, non-woven tape, etc. treated with a curing accelerator to form an insulating layer.

The end insulator 14b at the bottom of the coil configured in this way is immersed in a solution containing a curing accelerator in a solvent, and after the curing accelerator is attached to the end insulator 14b, it is pre-dried, and the solvent, etc. evaporate.

After that, the coil is stored in a resin vat in a vacuum tank and impregnated with low viscosity, for example, epoxy resin, and when the insulator part to which a curing accelerator has been attached in advance reacts with the impregnated resin and becomes dull, the resin An integrated resin molded coil is obtained by taking out the coil from the tank and completely curing the inside of the coil in a dryer or the like.

In this way, in the present invention, buffer layers 9a to 9g made of easily impregnable insulating material are provided in the conductor winding layers constituting the low-voltage coil and the high-voltage coil, and the inner coil 23 and the outer coil constituting the high-voltage coil are A glabellar insulator 25 made of an easily impregnable insulating material is provided between the 28 conductor winding layers, and each conductor winding of the inner coil 11.23 and outer coil 12.28 forming a low voltage coil and a high voltage coil, respectively. An end insulator 14 made of a material with good impregnability is provided outwardly at the upper and lower ends of the layer.
Since the coils 14a and 14b are provided, if the coil is housed in a resin tank and resin is injected, the resin will be satisfactorily impregnated from the axial direction and the upper and lower ends of the coil. In this case, the degree of resin impregnation varies depending on the degree of vacuum, pressure, and time during resin impregnation, but according to experiments, it is 10 degrees.

CP epoxy resin], 4.5 kg/c after injecting into the resin bath in the vacuum tank of 1111 I4g
It was found that even a stack with a diameter of 7001 m was sufficiently impregnated with resin when pressurized for 30 minutes at a.

On the other hand, insulators 15a to 15f made of a non-impregnable material are provided on the circumferential surfaces of the inner and outer coils of the low-voltage coil and the high-voltage coil on the side facing the cooling airway, and the overlapping portions are covered with adhesive tape (for example, Permacell 213, glass Since this part is sealed with adhesive tape, etc., the resin impregnated inside the coil will not leak to the outside. In addition, a terminal 27 protrudes outward on the outer peripheral surface of the outermost layer coil.
An insulating layer is formed by winding an insulating material in the form of a tape, and an insulating layer 35 made of a non-impregnated material and an insulating layer 34 and 36 formed by winding Lastezo, which has been treated with a curing accelerator in advance, are provided. The resin will not leak from any place other than the gap between the protruding portions of the terminals 27. That is, the insulating layer 35 made of a non-impregnable material has its wrap portion wrapped around the insulating layer 36 made of a glass stage treated with a curing accelerator.
Not only is it held down by the resin, but it also reacts with the resin in the resin bath and dulls to form a sealing layer together with the non-impregnable insulating layer 35, so there is no resin leakage from this part. Furthermore, if the lower end of the coil is left in a resin bath for a certain period of time after being impregnated with resin, the curing accelerator attached to the end insulator 14b provided at the lower end will accelerate the reaction with the resin, and the inside of the coil will be The resin impregnated in the area quickly dulls and forms a sealing layer, eliminating resin leakage from this area.

In addition, the crossing wire 16 and the high voltage coil 23 in the cooling airway section between the inner coil 11 and the outer coil 12 of the low voltage coil are
and a crossing wire 26 in the cooling airway section between the outer coil 28 and the outer coil 28;
Each lead-out portion of the terminal 27 protruding from the outer peripheral surface of the outermost coil is wrapped with a foam sheet 17 (for example, an epoxy resin foam adhesive sheet manufactured by Nitto Denko).
When this foamed sheet 17 is heated to a temperature of 120° C. or higher during resin impregnation, it will foam 3 to 5 times. Therefore, the insulator 15a.

The gaps at the lead-out portions of the crossover wires 16 and 26 for the connecting wires 15b, 15e, and 15f and the gaps at the terminal portions for the outermost insulating layer 36 are closed by the foaming action of the foam layer 17, so that resin leakage from these portions can be prevented.

By the way, I made a model coil with the above-mentioned configuration, and after pre-drying it at 100°C for 15 hours, I coated it with epoxy resin Ep.
828 (manufactured by Shell) as an acid anhydride curing agent HN-2200
(manufactured by Hitachi Chemical).

The coil was impregnated with vacuum pressure and pressure at 80°C, and after the resin was soaked up to the top of the coil, it was left in the resin bath for 1 to 2 hours.The coil was then taken out from the resin bath and impregnated with the resin for 120 to 150 hours.
When the coil was cured in a drying oven at ℃, a stable resin-molded coil with good insulation properties was obtained without resin leakage.

In the above embodiment, a case of a cylindrical multi-wound structure has been described, but it goes without saying that a resin molded coil can also be manufactured in the same manner as described above for a prismatic multi-wound structure. Furthermore, in the embodiment described above, the case where the terminal 27 is directly connected to the conductor 29 and led out to the outer periphery of the coil is explained.
Even when the conductor 29 is bent and used as a terminal lead to be connected to a terminal block outside the coil, if a foam sheet is wrapped around the protruding part of the terminal lead from the coil in the same way as for the transfer wire, this part can be easily The gap can be marked as 5 in the same way as above. Furthermore, there are cases where a lead comes out from the lower end of the coil in low-voltage coils, etc., but even in this case, it can be fixed by wrapping a foam sheet around the part where the lead comes out, as described above.
Resin leakage from this outlet can be prevented.

〔Effect of the invention〕

As described above, according to the present invention, edge parts are provided outside the upper and lower ends of the wound layer formed by winding four bodies, and an insulating material with poor resin impregnation properties is provided on the outer periphery of the wound layer. After providing a wave-shaped insulator on the outer circumference of the inner coil to form a cooling airway extending in the axial direction, a conductor is wound around the outer circumference of the inner coil to form an inner coil. An end insulator is provided on one side, and an insulator with poor resin impregnation is provided on the inner and outer peripheries of the insulator, and an insulating layer treated with a curing accelerator is provided on the outermost insulator. A coil is provided with a foam layer by winding a foam layer that foams when heated around the entrance/exit part of the crossing wire facing the cooling airway between the inner coil and the outer coil, and a hardening accelerator is applied to the end insulator at the lower end of the coil. (After the coil is attached, the coil is impregnated with resin in a resin tank, and when the resin impregnated into the insulating layer and the end insulator reacts with the curing accelerator and becomes dull, the coil is removed from the resin tank.) Therefore, a foam layer is formed by wrapping a foam sheet or tape around the entrance and exit portion of the crossing wire in the cooling airway between the inner coil and the outer coil. When the coil is heated and cured, this foam layer foams and closes the gap in the 9 parts, so that a resin molded coil with stable electrical and mechanical properties without impairing resin impregnation and without resin leakage can be obtained. In addition, there is no instability caused by work during the coil manufacturing process, and additional benefits such as a reduction in mental burden can also be obtained.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a resin molded coil manufactured by a conventional manufacturing method, Fig. 2 is a side view showing a partial longitudinal section of the same coil, Fig. 3 is a wiring diagram showing a general high voltage coil, and Fig. 4 is a plan view of a resin molded coil produced by the manufacturing method of the present invention,
FIG. 5 is a longitudinal sectional view taken along the line A-A in FIG. 4, FIGS. 6 to 9 are structural explanatory diagrams showing details of the coil transfer section in the same embodiment, and FIG. 10 is a similar diagram of the transfer section. FIG. 11 is an enlarged cross-sectional view showing the structure of a terminal portion led out from the outermost coil in the same embodiment. 8... Winding frame, 10.29... Conductor, 9a to 9g...
・Buffer layer, 1 No. Inner coil, 12 Outer coil, 14 a, 14 b One end insulator, 15 a to 1
5f...Non-impregnated insulator, 16.26...Cover wire, 17...Foamed layer, 20.22.30...Wave-shaped insulator, 23...Inside (Ill coil, 28...Outer coil, 27...Terminal, 3.1, 34, 35.
...Insulating layer, 32... Insulator. Applicant's agent Patent attorney Takeshi Suzue Guo 4 Diagram 7 Figure 5 Figure 6 Figure 10

Claims (1)

[Claims] End insulators are provided outside the upper and lower ends of a wound layer formed by winding a conductor, and insulators with poor resin impregnation are provided on the inner and outer peripheries to form an inner coil. After providing a wave-shaped insulator that forms a cooling airway that exits in the direction, a conductor is wound around the outer periphery of the wound layer, and end insulators are provided outside the upper and lower ends of the wound layer, and the inner and outer peripheries are impregnated with resin. an insulating material having a poor quality, and furthermore, an insulating layer treated with a curing accelerator is provided on the outer peripheral insulating material to form an outer coil, and a bridge 9 facing the cooling airway between the inner coil and the outer coil is provided. A coil is provided with a foam layer by winding a foam material that foams when heated around the entrance and exit portion of the wire, and after a curing accelerator is attached to the end insulation at the lower end of the coil, it is impregnated with resin in a resin bath. Then, when the resin impregnated into the outermost insulating layer and the end insulating material reacts with a curing accelerator and becomes dull, the coil is taken out from the resin bath and cured by heating to produce a resin molded coil. Method.