JPS638097Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to the application of magnetic fluid, and particularly to a transformer in which the magnetic fluid is formed as part of a magnetic path.

As an example of this type of transformer, the one shown in Fig.
114716). In the figure, 1 is the iron core, 2 is the coil, and 3
4 is a container, and 4 is a magnetic fluid filled in the space between the iron core 1 and coil 2 housed in the container 3 and the container 3. Compared to conventional transformers, such as oil-immersed transformers in which the core and coil are immersed in insulating oil, and dry type transformers in which there is a complete void around the core and coil, this transformer has the following advantages: The gap between the iron core and the coil is filled with a magnetic fluid made by colloidally dispersing fine magnetic powder in an insulating liquid, increasing the effective magnetic path and improving magnetic properties. Because it has better thermal conductivity than oil, it was possible to downsize the transformer.

However, the magnetic fluid that is directly interposed between the coil conductor and the iron core, which is generally at the same potential as the ground, has low insulation resistance and has been unstable in terms of insulation resistance.
Although there was no problem at relatively low voltages in coil conductors using insulated wires coated with enamel, there was a risk of dielectric breakdown in coils to which high voltages were applied.

This invention was made to eliminate the drawbacks of the conventional ones as described above, and by molding the coil adjacent to the magnetic fluid with resin, it can be used in high voltage circuits. It is an object of the present invention to provide a transformer in which a magnetic fluid is used as at least a part of a magnetic path.

An embodiment of this invention will be described below with reference to the drawings. In FIG. 2, the same symbols as in FIG. 1 indicate the same or corresponding parts, and 2 is a coil of a transformer;
21 is the primary coil, 22 is the secondary coil, and 23 is the resin insulation layer. A conductor is wound a plurality of times to form a primary coil 21, and a conductor is further wound thereon with an insulating layer interposed therebetween to form a secondary coil 22.
These bare coils were immersed in epoxy resin, injected under vacuum, and further impregnated under pressure. Thereafter, the coil 2 molded with the epoxy resin insulating layer 23 was obtained by heating and curing. This contained no voids within the coil. The coil 2 was inserted into the iron core 1 and assembled into the container 3. The spaces between the coil 2 and the iron core 1 and between them and the container 3 were filled with a magnetic fluid in which fine magnetic powder was colloidally dispersed in electrical insulating oil (JISC2320 No. 2 oil). The transformer constructed in this manner could be used safely even in applications where extremely high voltages were applied. In addition, in the above embodiment, an epoxy resin was used as the mold resin for forming the resin insulating layer 23 of the coil, but other insulating resins such as polyester resin and phenol resin may be used in the same manner as in the above embodiment. It has the effect of

As described above, according to this invention, a coil whose outer periphery is molded with insulating resin,
Since it is in a magnetic path containing magnetic fluid, it can fully exhibit the characteristics of magnetic fluid even in transformers to which high voltage is applied, and has the effect of obtaining a safe and high-quality product.

[Brief explanation of the drawing]

Figure 1 is a front sectional view showing a conventional transformer;
The figure is a front sectional view showing an embodiment of the transformer according to this invention. In the figure, 1 is the iron core, 2 is the coil, 21 is the primary coil, 22 is the secondary coil, 23
3 is a resin insulating layer, 3 is a container, and 4 is a magnetic fluid. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) In a transformer having a coil and a magnetic path interlinked with the coil and containing a magnetic fluid at least in part, at least in a portion where the coil is in contact with the magnetic fluid, A transformer characterized by being molded with resin. (2) The transformer according to claim 1, wherein the resin used to mold the coil is an epoxy resin. (3) The transformer according to claim 1 or 2, wherein the magnetic fluid is a colloidal dispersion of magnetic fine particles in electric insulating oil.