JPH01122109A - Molded winding - Google Patents

Abstract

PURPOSE:To decrease the radial size between a high voltage winding and a low voltage winding and to reduce the size and weight of a molded transformer by composing the high voltage winding of a plurality of coils, and independently providing insulators at the respective coils. CONSTITUTION:A high voltage winding 2 is formed by connecting in series 5 coils 21-25, and the coils 21 are formed as a winding called 'strip coils' formed by radially laminating and winding aluminum strips whole holding an insulating film therebetween. Since insulators 4 are independently provided at the coils 21-25, its width may be slightly larger than the height as the axial size of the coil. Accordingly, since the width of the film is smaller in a step of manufacturing the insulators 4, the film is not wrinkled, and the film is not wrinkled in a step of winding the coils 21-25 of the high voltage winding. Thus, the size of the whole winding can be reduced, and a core is also reduced due to its far-reaching effect, and the size and weight of a molded transformer are decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molded winding including a high-voltage winding of a molded transformer that is often used as a power receiving transformer in a consumer.

(Prior art) In recent years, molded transformers whose windings are molded with epoxy resin, etc., have begun to be widely used. Compared to oil-immersed transformers, these molded transformers have features such as flame retardancy, small size, light weight, and low noise. have.

Figure 3 is a sectional view showing an example of the winding configuration of a conventional molded transformer, in which 1 is a low voltage winding, 2 is a high voltage winding, 3 is a molded resin for the high voltage winding, and 5 is a low voltage winding 1 and a high voltage winding. This is an air section between the high-voltage winding 2 and the high-voltage winding wires 21, 22, 23, 24 .
25 wire rings are connected in series, and each wire wire is made of a thin aluminum conductor with a thickness of about 0.1 ms+, which is radially connected through a polyethylene insulating film with a thickness of about 110 l1. It is formed by winding and laminating,
The low voltage winding is formed by laminating and winding insulated rectangular conductors in the radial and height directions. The air portion 5 serves as an insulating space for the high voltage winding and the low voltage winding, and at the same time serves as a cooling duct for cooling both windings.

The number of wire rings constituting the high-voltage winding varies depending on the capacity of the molded transformer, etc., but in any case it is only a few, and there are also types of low-voltage winding other than those mentioned above.

The height of the winding in these structures varies greatly depending on the capacity of the molded transformer, but some are as large as about 1.5 m.

FIG. 4 is a sectional view showing the winding structure of a molded transformer, in which a high voltage winding 2A and a low voltage winding 1A are integrated with an insulator 4A formed by winding and laminating an insulating film made of the same material as the above-mentioned insulating film. It has a molded configuration. A transformer has a small capacity but a high voltage, so the current in the high-voltage winding is small, so its conductor is a thin round wire. The actual size of the round wire is actually much thinner than the size of the round wire shown in FIG. The size of this transformer is approximately 200 mm in height, which is the axial dimension of the low voltage winding.

[Problem that the invention seeks to solve]

In the winding configuration of the molded transformer shown in Figure 3, the space 5 has the two functions of insulation and cooling as described above, but the air insulation performance is low and the allowable electric field strength is only 3K at most.
V/am, which is a much smaller value than the allowable electric field strength of the mold resin, which is about 30 to 50 kV/ms. Therefore, the radial dimension of this air portion 5 is determined mainly from the dimension for maintaining insulation strength. On the other hand, in the case of a small-capacity molded transformer where a sufficient winding cooling effect can be obtained by cooling only either the inner or outer diameter side of the winding for both the low-voltage and high-voltage windings. If the configuration shown in Figure 3 is adopted, the dimensions of the air space 5 between the windings must be maintained to maintain insulation strength, so the dimensions, weight, and losses will deviate from the optimal design as a molded transformer. Both of these factors increased, resulting in an unreasonable design.

In order to solve this problem, the high-voltage winding is directly wound on the low-voltage winding through an insulating film of sufficient material and dimensions to provide insulation strength corresponding to the voltage of the high-voltage winding. It is possible to consider a method of eliminating the air portion by adopting this structure. This method is used for transformers used for high voltage measurements as shown in Figure 4, but in this case the height of the winding is small, around 200mm, so the work of winding the insulating film is difficult. Although this does not cause any problems, in the case of a molded transformer like the one shown in Figure 3, as mentioned above (the height of the winding is around 1 m or more, it is necessary to insulate with a width that covers the height of the winding). When winding a film around a low-voltage winding wire, since the insulating film is wide, it is difficult to maintain the winding tension uniformly, and the film may wrinkle partially during the winding process. When the high-voltage winding is wound on each wire ring, the tension applied to the coil conductor during winding of the wire tightens the film, causing further wrinkles.

Furthermore, in the process of resin molding these, resin is impregnated between the films, but since the width of the film is wide, the resin may not be sufficiently impregnated into the middle between the laminated films, leaving gaps, or when winding. Since the resin is not sufficiently impregnated into the wrinkled portion of the insulating film, there is a high possibility that voids will be formed in this portion as well. This air gap that exists between the low-voltage winding and the high-voltage winding becomes a fatal defect in terms of insulation performance.In other words, the relative dielectric constant of the molding resin is 5.3, while that of air is l, so the electric field strength is Since the electric field strength in the void is inversely proportional to the relative dielectric constant, the electric field strength in the void is 5.3 times greater than that in the mold resin.On the other hand, as mentioned above, the insulation strength of the void is about one-tenth that of the mold resin. Partial discharge occurs in this gap. At first, this partial discharge occurs only in the gap, so its effect is small, but it gradually erodes the resin and eventually develops into a complete dielectric breakdown. Therefore, in an insulation structure in which resin is molded to ensure insulation strength with a solid insulator, it is necessary to eliminate voids as much as possible.

For this reason, from the standpoint of cooling the windings, even if the low-voltage winding and high-voltage winding could be integrally molded in resin, there was no choice but to provide the air portion 5 to ensure insulation strength due to the above-mentioned insulation structure. .

This invention reduces the radial dimension between the high-voltage winding and the low-voltage winding by configuring the insulation structure between the high-voltage winding and the low-voltage winding only with solid insulators, thereby reducing the size of the molded transformer. An object of the present invention is to provide a molded transformer that is small in weight and highly efficient.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention includes a low-voltage part having a cylindrical shape, an insulating material made by winding an insulating film around the outer diameter side of the low-voltage part and laminating it in the radial direction. In a molded winding having a structure in which a high voltage winding wound on the outer diameter side of an insulator is integrally molded with resin, the high voltage winding is spaced apart from each other by a predetermined interval in the axial direction of the low voltage part. It consists of a plurality of wire rings arranged in an arrangement, and the insulator is provided independently for each of these wire rings.

[Effect]

In the configuration of this invention, in order to independently wind an insulating film between each wire ring of the high voltage winding and the low voltage section, the width dimension of the insulating film is slightly larger than the height dimension of the wire wire. Since the width of the insulating film is small when winding the insulating film or when winding the wire ring on top of the insulating film, the winding tension becomes uniform and wrinkles do not occur in the insulating film. . In addition, because the width of the insulating film is small and the wire rings are spaced apart, it is easy for the resin to enter between the insulating films when molding the resin. It is possible to prevent the generation of gaps between the insulating films wound and laminated between the low voltage section and the high voltage winding.

〔Example〕

The present invention will be explained below based on examples. FIG. 1 is a sectional view showing a winding structure according to an embodiment of the present invention. l is a low-voltage winding, 2 is a high-voltage winding, 3 is a molded resin, 4 is an insulator made by winding and laminating polyester film (about 50 μm thick) insulating film, and 8 is a glass which is also the winding frame of the low-voltage winding. This is an insulating cylinder made by impregnating cloth with epoxy resin.

In this figure, the low-voltage winding 1 is a cylindrical winding that is continuously wound in the axial direction using an insulating cylinder 8 as a winding frame, and the high-voltage winding 2
is a series connection of five wire rings 21 to 25, and these wire rings 21 are windings called strip coils, which are formed by laminating and winding aluminum strips in the radial direction while sandwiching an insulating film. be.

Since the insulator 4 is provided independently for each of the wire rings 21 to 25, its width may be slightly larger than the height dimension, which is the axial dimension of the wire wire. Since the width of the film is small, the insulating film does not wrinkle during the manufacturing process, and the insulating film also does not wrinkle during the process of winding each coil of the high-voltage winding on top of the insulating film.

Figure m2 shows another embodiment of the present invention.

This embodiment is applied when the capacity of the molded transformer increases and at least either the high voltage winding or the low voltage winding needs to be cooled with air layers on both the outer diameter side and the inner diameter side. The low voltage winding 1 is the same as the conventional structure shown in FIG. 3, and the cooling of the high voltage winding 2 toward the outer diameter side is the same as the structure shown in FIG. In this figure, 5B is an air section, 8B is an insulating cylinder, and 9 is a ground electrode made by pasting aluminum foil on this insulating cylinder 8B.

In this figure, the ground electrode 9 has a ground potential by pulling out a ground lead from the upper end or the lower end and electrically connecting this ground lead to a frame for tightening the iron core (not shown). Aluminum foil was used as the material for the electrode 9 as described above, but conductive carbon paper or metal mesh may be used instead, but the structure must not form an L-turn around the iron core 11 and at the same time the high voltage winding Since it is installed between 2 and low voltage winding l,
It must be designed to prevent overheating due to eddy currents generated by leakage magnetic flux.

Since the ground insulation strength of the high voltage winding 2 on the low voltage winding 1 side is ensured by the insulation structure between the ground electrode 9 and the high voltage winding 2, the air portion 5B has little to do with insulation. Since the radial dimension of the air portion 5B is only required for cooling, the radial dimension between the low voltage winding 1 and the high voltage winding 2 can be reduced.

Cooling of the inner diameter side of the high-voltage winding is achieved by the heat flow from the high-voltage winding passing through the insulator 4, the ground electrode 9, and the insulating cylinder 8B, and touching the air portion 5B, where the heat is transferred to the air. The thermal conductivity of the object 4 and the insulating tube 8B is not much different from that of the molded resin, and the distance from the inner diameter side of the high-voltage winding including these to the air portion 5B is a little larger than that in Fig. 3, but Since the temperature drop during heat transfer from the solid to the air is much larger than the temperature drop, the cooling effect from the inner diameter side of the high voltage winding 2 in this embodiment is significantly different from the conventional configuration shown in Fig. 3. There is no such thing.

〔Effect of the invention〕

As described above, this invention provides an insulating film for insulating between the high-voltage winding and the low-voltage part at each position of each wire ring of the high-voltage winding. In order to avoid wrinkles in the insulating film caused by winding it around the outer diameter of the insulation film, and also to avoid wrinkles in the insulating film when winding the wire on the wound insulation film layer, the resin is During impregnation, sufficient resin is impregnated between the insulation films, ensuring highly reliable insulation properties. Therefore, it is now possible to adopt a configuration in which the high-voltage winding and low-voltage winding are integrally molded. As a result, the dimensions of the entire winding can be reduced, which has the ripple effect of making the core smaller and reducing the size and weight of the molded transformer.

Furthermore, in order to cool at least one of the high-voltage winding and the low-voltage winding, an air layer is required on both the inner diameter side and the outer diameter side. If integral molding is not possible, by providing a grounding electrode that is molded integrally with the high-voltage winding, the high-voltage winding can be molded separately from the low-voltage winding, but the insulation inside the high-voltage winding can be separated from the ground electrode. Since the gap between the high-voltage winding and the low-voltage winding can be provided only for cooling the winding, the dimensions of this air section can be reduced. Therefore, this invention can be applied not only to relatively small-capacity molded transformers in which high-voltage windings and low-voltage windings can be integrally molded, but also to large-capacity molded transformers. This resulted in size reduction, weight reduction, and cost reduction for products with a range of specifications.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of an embodiment of the present invention, FIG. 2 is a sectional view of a winding configuration of another embodiment, FIG. 3 is a sectional view of a conventional winding configuration, and FIG. 4 is a sectional view of a conventional winding configuration. FIG. 2 is a cross-sectional view of a winding configuration of a molded transformer. 1.18...Low voltage winding, 2,2A...High voltage winding, 2
1.22, 23.24.25... Line wheel, 3.3A・-
・Mold resin, 4.4A...Insulator, 5.5B,・
...Air part, 8.8B...Insulating cylinder, 9...Grounding electrode, 11. IIA... Iron core.

Claims (1)

[Claims] 1) A low-pressure part having a cylindrical shape, an insulator formed by winding an insulating film around the outer diameter side of this low-pressure part and laminating it in the radial direction, and an outer diameter side of this insulator. In the molded winding, the high-voltage winding is integrally molded with resin, and the high-voltage winding is formed of a plurality of wires arranged in the axial direction of the low-voltage part at predetermined intervals. 1. A molded winding wire comprising rings, and the insulator is provided independently for each of these wire rings. 2) The molded winding according to claim 1, wherein the low voltage portion is a low voltage winding. 3) The molded winding according to claim 1, wherein the low voltage portion is a ground electrode.