JPS5834742Y2 - Henseiki - Google Patents

Description

[Detailed description of the invention] This invention uses a high thermal conductivity sheet and a semi-hardened insulating sheet to prevent air gaps between the iron core and the coil attached to the iron core. The idea is to provide a dry type transformer with excellent heat dissipation by heating a hardened insulating sheet to melt it and filling it between an iron core and a coil.

Conventional transformers have been constructed as shown in FIGS. 1 and 2.

That is, a secondary coil 2 and a secondary coil 3 are wound around an iron core 1 in a shape formed by laminating E and I-shaped laminated iron plates, and the secondary coil 2 and secondary coil 3 and the iron core 1 An insulating sheet 4 was used for insulation from the coils 2 and 3, and a shunt core 5 was inserted between each coil 2 and 3 to form a leakage flux type transformer.

Organic materials such as polyester films, aromatic polyamide films, and pressboards have been used as the insulating sheets 4, and impregnating agents such as varnish have been used to fix them.

In such a configuration, a gap 6 inevitably occurs between the coils 2, 3 and the insulating sheet 4, or between the insulating sheet 4 and the iron core 1, even if some varnish or the like is present.

The thermal conductivity of this organic insulating material and air is 10' each.
~10' cal 7cm, sec, C and 10
'cal 7cm, sec.

C, and a large thermal resistance exists between the coils 2 and 3 and the iron core 1.

As a result, the Joule heat generated in the coils 2 and 3 is not effectively dissipated, so that the temperature of the coils 2 and 3 increases sharply.

Therefore, it is necessary to use a thick wire diameter with low resistance as the copper wire constituting the coils 2 and 3.
As the coils 2 and 3 become larger, it becomes necessary to enlarge the iron core 1, and the transformer also becomes significantly larger and weighs more. The amount of iron material used was also increased, which was a significant disadvantage in terms of cost.

The present invention eliminates the above-mentioned drawbacks of the prior art.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

Reference numeral 7 denotes a square-shaped iron core constructed by laminating E- and I-shaped laminated iron plates.A primary coil 9 and a secondary coil 10 are wound around a central magnetic leg 8 of this iron core 7.

The opposing surfaces of the iron core 7 and the coils 9, 10 have a thermal conductivity of 10" to 10"cal 7cm, sec,
A sheet 11 of high thermal conductivity material such as ceramic having a value of C is inserted between the sheet 11 of high thermal conductivity material and the coils 9 and 10, and a material that is melted by heating is semi-hardened.
An insulating material sheet 12 made of this sheet is inserted.

Note that 13 is a shunt core inserted between the coils 9 and 10.

This insulating material sheet 12 is placed over the coils 9 and 10 and heated under pressure, thereby melting the insulating material sheet 12 and filling the surfaces of the coils 9 and 10 with the insulating material without leaving any voids.

Note that this insulating material sheet 12 is also arranged on the iron core 7 side,
After being assembled as a dry transformer, it may be heat treated.
This configuration is more effective.

This insulating material sheet 12 is made of glass cloth, silicone, etc.
It is semi-cured by impregnating it with phenol, epoxy, polyester, polyurethane, etc.

This silicone, phenol, epoxy, polyester,
The thermal conductivity of polyurethane etc. is 3.5 to 7.5 x 10
'cal 70m, SeC, although it is in the range of C, it is not expensive, but 1O-9cal 7cm, sec,
It is expensive compared to air in C.

In addition, there is a high thermal conductivity material sheet 11 in close contact with the insulating material sheet 12, and the heat of the coils 9 and 10 is transferred to the iron core 7, thereby improving heat dissipation.

In other words, the thermal resistance between the coils 9, 10 and the iron core 7 is significantly lower than that of a conventional dry transformer, and as a result, the heat generated in the coils 9, 10 is reliably transferred to the iron core 7, which has a lower temperature rise value. As a result, the average temperature rise value of the coils 9 and 10 becomes smaller.

Therefore, if a dry type transformer is designed with the same wire diameter, the heat resistance classification of the insulating material can be lowered, and if the heat resistance classification remains the same, the wire diameter can be reduced to create a smaller transformer.

According to experiments, the cross-sectional area of conventional primary and secondary coils is 3
The average temperature rise value of the coil of the dry type transformer of the present invention, which was reduced by 0%, was lower than the average temperature rise value of the coil of the conventional dry type transformer.

In addition, this makes it possible to use a dry transformer with a weight of approximately 1.
It can be made 2% lighter, and the amount of copper and iron used can be reduced by 10-12%.

Since the dry type transformer of the present invention is configured as described above,
Since the heat generated in the coil is effectively transferred to the iron core, the temperature rise in the coil can be kept low, and the copper wire that makes up the coil can be made with a thin wire diameter, making it possible to downsize the coil. As the coil becomes smaller, the iron core becomes smaller, allowing the transformer to be significantly smaller, and less copper and iron materials are used to make up the transformer, making effective use of resources and reducing costs. In addition, the insulating material can be easily wrapped in sheet form, and the workability of assembly is good, so it is of great practical value.

[Brief explanation of drawings]

Fig. 1 is a front view of a conventional transformer, Fig. 2 is a sectional view of the main parts thereof, and Fig. 3 is a perspective view showing an embodiment of the transformer of the present invention.
FIG. 4 is a sectional view of the main part. 7... Iron core, 9, 10... Coil, 1
1... High thermal conductivity material sheet, 12...
Insulation sheet.

Claims (1)

[Scope of utility model registration request] In a dry type transformer in which a coil is attached to an iron core through an insulator, a sheet of high thermal conductivity material is placed between the coil and the iron core, and a A transformer in which at least one side is coated with an insulating material sheet that is melted by heating to completely eliminate voids.