JPS5875815A - Leaf winding - Google Patents

Abstract

PURPOSE:To improve the cooling efficiency through the reduction of the contact heat resisance between a leaf conductor and an insulating sheet by forming a soft layer therebetween. CONSTITUTION:An aluminum leaf conductor 12 and an insulating polyester sheet 3, together with an extremely thin polyethylene sheet 15 interposed therebetween, are wound on the outside of an iron core 1 to form a low-voltage winding 4 and a high-voltage winding 5. Annular cooling ducts 6 are incorporated in these windings, and a coolant 14 is cooled by a cooler 8 and circulated by a pump 7 through coolant-collecting pipes 10, insulating pipes 11 and the ducts 6. By thus constituting the windings, the adhesion between the aluminum sheet and the insulating polyester sheet is improved to reduce the contact heat resistance. Therefore, the number of the necessary cooling ducts can be reduced to allow the transformer to be more compact.

Description

[Detailed Description of the Invention] The present invention relates to a foil-wrapped winding used in a foil-wound transformer, etc. Since the foil-wound winding has a good space factor of the conductor, it has less dust and quantification than a linear one. ! However, K, which is aiming for higher voltage and larger capacity, has a cooling duct built into the cooling winding, and a refrigerant with excellent insulating properties is supplied to reduce the heat generated from one winding loss. This conventional foil-wrapped coil is used in a foil-wound transformer as shown in the GT diagram and FIG. A winding layer 2 made of aluminum, which is a conductor, and an insulating sheet 3 made of polyester film are layered and wound on the outside to form a low-thickness winding body 4 and a high-thickness winding body 5. An annular cooling duct 6 is built into these rolls. There is a gap in this cooling duct. Freon R-114+ FC-7
The duct is filled with a refrigerant 14 such as No. 5, and is circulated through the duct by a pump 7 to remove the heat generated within the foil-wrapped body. The refrigerant 14, whose temperature has increased by absorbing heat, is cooled by cooling water 9 in an external cooler 8 and sent into the cooling duct again.O The liquid collecting pipe IO is made of metal such as stainless steel, and the cooling Since an insulated pipe 11 is used to connect the duct, the liquid collecting pipe 10 is connected to the tank 12.
〇On the other hand, the cooling duct and the winding are at almost the same potential because the cooling duct is wrapped inside the winding, and the insulation between them and the outside is sealed in the tank. 8F and 13 gases for insulation.

In some cases, insulating oil is used in place of this insulating gas.In addition, in Fig. 1, the bushings for pulling the lead wires out of the tank, which are not directly related to the present invention, are omitted. It is. This type of foil-wound transformer is called a separate foil-wound transformer because the circulation circuit through which the refrigerant flows for cooling and the insulator 13 for insulation are completely separated. It has advantages such as being able to be smaller and lighter and having high insulation reliability.

However, the foil-wound wire used in the conventional separate-type foil-wound transformer shown in Figures 1 and 2 is simply a foil-like conductor and an insulating sheet that are overlapped and wound together. It was not possible to increase the adhesion between the conductor and the insulating sheet, and a large contact thermal resistance existed between the sheets. This decrease in apparent thermal conductivity causes a large temperature difference between the rolls, and the drawback is that cooling ducts must be installed very tightly in order to keep the temperature rise within the rolls below a certain value. Ta.

The present invention has been made in consideration of the above circumstances, and its object is to provide a foil-wrapped body with low contact thermal resistance between a foil-like conductor and an insulating sheet.

The present invention produces the above-mentioned material by installing a soft layer between the foil conductor and the insulating sheet, or by using a thermoplastic resin such as polyester, polyethylene, or polycarbonate as the insulating sheet and softening it by heating to produce a roll. By forming a soft layer, this foil-wrapped body improves the adhesion between the foil-like conductor and the insulating sheet, reduces the contact thermal resistance of the foil-wrapped body, and thereby improves cooling efficiency. .

Hereinafter, some embodiments of the present invention will be described based on the drawings.

Figure 544 is a diagram showing a part of the foil-wrapped body according to the embodiment of the present invention.As can be seen from Figure 0, there is a gap between the aluminum foil conductor 2 and the insulating polyester sheet j at room temperature. The adhesiveness between the aluminum ζ sheet and the insulating polyester sheet is good because the polyester sheet 15 is wrapped around the stretch of polyethylene, which is softer than Al Denko Kumu foil or polyester sheet. Tonashi.

A foil-wound body with low contact thermal resistance can be obtained.

FIG. 4 is a diagram showing a part of a foil-wrapped body according to another embodiment of the present invention. As can be seen in the figure, the aluminum sheet 2 and the insulating sheet 16 made of polycarbonate thermoplastic resin
are overlapped to form a roll. Since the insulating polycarbonate sheet is once heated and softened at the time of manufacture, the contact surface with the Al2 sheet is in good contact with the expansion, and the contact thermal resistance (4h) is always small.

As explained above, if the foil-wound body according to the present invention is used in a foil-wound transformer or the like, it is possible to reduce the contact thermal resistance between the foil-like conductor and the insulating sheet. It is possible to cool the coil without installing it, and furthermore, it is possible to reduce the size of a device such as a transformer using the coil.

[Brief explanation of the drawing]

Figure 41 is a diagram showing a conventional foil-wound transformer using a foil-wound body;
Figure g2 is a partially enlarged view of the foil-wrapped body, Figures 3 and 4.
The figure shows an embodiment of the foil-wrapped body according to the present invention. 0 2... Foil conductor, 3... Insulating sheet, 15...
- Soft layer, 16... thermoplastic resin. Agent: Patent attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2

Claims (2)

[Claims] (1) A foil-wound body 0 formed by overlapping and winding a foil-like conductor and an insulating sheet, characterized in that a soft layer is provided between the foil-like conductor and the insulating sheet. (2) The foil-wrapped body 0 according to claim S, paragraph 1, characterized in that the soft layer is a polyethylene sheet. (3) The soft layer is made by heating and softening the surface of an insulating sheet made of thermoplastic resin. The foil-wrapped body according to claim 1, characterized in that the foil-wrapped body is formed by