JPH02123711A - Foil-wound transformer - Google Patents

Abstract

PURPOSE:To provide a lead wire characterized by low loss at a lead part and flexibility by providing a metal sheet which is connected to a copper sheet of a lead part, and providing an insulating sheet which is overlapped on said metal sheet and wound around an iron core. CONSTITUTION:A copper sheet 3 has the same length as the width of a metal sheet 1 or the length shorter than said width. A part of a strand insulated cable 2 where the insulating layer is removed is brazed to the copper sheet 3. Thus a lead part is obtained. Then, the end part of the copper sheet 3 at the lead part is connected to the end part of the metal sheet by pressure welding or welding. Since the strand insulated cable 2 and the copper sheet 3 are securely connected by the welding, the reliability of the conductor connecting part is improved. Since the strand insulated cable 2 has flexibility, excessive force is hard to be applied to the bonding part between a winding and the lead wire. In this constitution, eddy current loss at the lead wire is less, and a foil wound transformer having the lead wire structure characterized by flexibility is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a foil-wound transformer having a sheet-like winding in which a metal sheet and an insulating sheet are overlapped and wound around an iron core.

(Prior Art) Foil-wound transformers have a good winding space factor, so they can be made smaller and lighter. It has already been put to practical use in relatively low voltage, small capacity transformers of several kilovolts and several hundred kilowatts. Recently, in view of its excellent advantages, higher voltage,
Expanding its application to large capacity transformers is being researched. However, when applying a foil-wound transformer to a large capacity transformer, there are the following problems.

(Problems to be solved by the invention) The lead wire extraction structure in the conventional foil-wound transformer is
As shown in the enlarged view of the figure, a rod-shaped lead wire 40 made of aluminum, copper, etc. is drawn out from the metal sheet 1 by brazing or low-temperature pressure welding. However, in the case of the lead wire 40 having such a structure, eddy current is generated due to the magnetic flux emitted from the coil in the part indicated by A in FIG. This has the disadvantage that the temperature of the lead insulator increases, which impairs the life of the lead insulator. In addition, because the conventional rod-shaped lead wire 40 has high rigidity, it cannot follow the movement of the winding when vibrations that occur during operation of the transformer or electromagnetic mechanical force that occurs during a short circuit are applied to the winding. There was a risk that excessive stress would be applied to the connection between the lead wire 40 and the metal sheet 1, resulting in damage.

Published Patent Publication No. 59-191309.59-19131 as an improved lead wire that solves the above problems.
1 etc. In Japanese Patent Application Laid-open No. 59-191309, a slit 50 is provided in a rod-shaped lead wire 40 in order to reduce eddy current due to leakage magnetic flux, as shown in FIG. Because of this high temperature, there remains the problem that the connection is weak against mechanical stress. Furthermore, as shown in FIG. 6, Japanese Patent Application Laid-Open No. 59-191311 applies pressure from the outside after inserting the wire insulated cable 2 into the hollow conductor 30, connects the wire insulated cable 2 and the hollow conductor 30 by crimping, and further The hollow conductor 30 and the metal sheet 1 are connected by brazing or pressure welding. In this method, a conductor is further placed over the outside of the bare wire insulated cable 2 having the necessary cross-sectional area, so the external dimensions of the lead wire become large and a tool is required for crimping. Further, the surface after crimping becomes uneven, which is disadvantageous in terms of insulation, and there are also problems in that it is difficult to connect the lead wire and the metal sheet.

The present invention was proposed in order to solve the above-mentioned drawbacks of the lead wire structure of the conventional foil-wound transformer, and its purpose is to reduce loss in the lead portion and provide structural flexibility. An object of the present invention is to provide a foil-wound transformer having a lead wire structure.

[Structure of the invention]

(Means and effects for solving the problem) The foil-wound transformer of the present invention is constructed by electrically fixing a copper sheet to a strand insulated cable made by twisting insulated unit strands together by brazing. A metal sheet that is bonded to the copper sheet of the output lead so as to be electrically connected to the end, and an insulating sheet that is overlapped with the metal sheet and wound around the iron core. As a result, the bare wire insulated cable and the copper sheet are reliably connected by welding, etc., which improves the reliability of the conductor connection part, and since the wire insulated cable has flexibility, the winding and lead Since no unreasonable force is applied to the joint with the bushing, and because a coated bare wire insulated cable is used, the output lead can be connected directly to the bushing without having to join the connection lead wire and the output lead in the middle. It is also possible to do so.

(Example) An example of the present invention will be specifically described below with reference to FIG. A plurality of unit fronts 84 having an insulating layer 5 on the surface are twisted together, the insulator is peeled off at the end of the bare wire insulated cable 2 on which the insulator 6 is rolled, and then one part of the insulator layer 5 on the cable surface is twisted. Remove the parts by filing or sandblasting.

The portion of the stranded insulated cable 2 from which the insulation layer has been removed is brazed to a copper sheet 3 having the same length as or less than the width of the metal sheet 1 as shown in FIG. 1 to form a lead portion.

After that, as shown in Fig. 2, the copper sheet 3 of the lead part
The end portion is connected to the end portion of the metal sheet 1 by pressure welding or welding.

In this way, the bare wire insulated cable 2 can be reliably welded.
Since the copper sheet 3 is connected to the winding wire, the reliability of the conductor connection part is improved, and since the bare wire insulated cable 2 has flexibility, it is difficult to apply excessive force to the joint part between the winding wire and the lead. Further, since the coated wire insulated cable 2 is used, it is also possible to directly connect the output lead to the bushing without joining the connection lead wire and the output lead midway.

The above is an example of connecting one bare wire insulated cable 2 to the copper sheet 3, but it is also possible to connect a large number of bare wire insulated cables 2 to the copper sheet 3 in parallel as shown in Fig. 3. It is possible. The connection may be made by brazing the wires one by one onto the copper sheet 3.

The area where the insulation layer of the bare wire insulated cable 2 is removed is only the part where the brazing is to be performed.Since the bare wire insulated cable 2 is a stranded wire, all of the insulation layer can be removed by straightly brazing one place on the outer circumference of the cable. The strands of wire are electrically connected to the copper sheet 3. Further, the metal sheet 1 and the copper sheet 3 can also be joined by ultrasonic welding.

〔Effect of the invention〕

As described above, the foil-wound transformer of the present invention uses a wire insulated cable as the lead, and once brazed to the copper sheet, it is easy to connect to the metal sheet, and the wax current product in the lead is small. Due to its flexibility, it is possible to connect a lead to a coil with a structure that is resistant to mechanical stress, and the necessary minimum lead external dimensions are required, and the surface is relatively smooth, making it an expensive lead in terms of insulation. be able to.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, FIG. 2 is a front view of the vicinity of the output lead showing brazing or pressure welding, and FIG. 3 is a perspective view showing another embodiment of the present invention. FIG. 4 is a perspective view showing a lead-out structure of a general foil-wound transformer, and FIGS. 5 and 6 are perspective views showing other conventional lead-out structures, respectively. 1...Metal sheet 2...Element wire insulated cable 3...Copper sheet 4...Unit element wire 5...
Insulating layer 6... Insulator agent Patent attorney
Nori Chika Kenji Yushiro Kaneto)゛go°1. Mashi Daiko Maruken Diagram σ Diagram Diagram Diagram δ Diagram

Claims (5)

[Claims] (1) An output lead portion formed by electrically fixing a wire insulated cable made by twisting insulated unit wires to a copper sheet by brazing, and an end portion attached to the copper sheet of this output lead portion. A foil-wound transformer includes a metal sheet that is bonded to be electrically connected, and an insulating sheet that is overlapped with the metal sheet and wound around an iron core. (2) The foil-wound transformer according to claim 1, wherein the copper sheet and the metal sheet are joined by pressure welding. (3) The foil-wound transformer according to claim 1, wherein the copper sheet and the metal sheet are joined by ultrasonic welding. (4) The foil-wound transformer according to claim 1, wherein the copper sheet and the metal sheet are joined by brazing. (5) Claim 1, characterized in that the brazing length of the wire insulated cable and the copper sheet is made shorter than the height of the copper sheet, and the wire insulated cable and the side end of the copper sheet are insulated. The foil-wound transformer described.