JPH0131685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transformer, and more particularly to a support structure for a leg core of a power transformer.

An example of the configuration of a coil insulation group, leg core, core support beam, electromagnetic shield, lower tank, etc. in a conventional power transformer is explained with reference to FIGS. 1 to 3. As shown in FIG. The lower tank 1 of the power transformer supports a core leg 3 via a core support beam 6, and a coil insulation group 2 is placed around the leg core 3.
A lower electromagnetic shield 4 is provided between the coil insulation group 2 and the coil insulation group 2.
and an upper electromagnetic shield 5 are inserted. As shown, both ends of the core support beam 6 are supported by the lower tank 1 to support the leg core.

As is well known, the core is made up of laminated silicon steel plates with a thickness of about 0.3 to 0.5 mm, so the leg core 3 itself does not have the strength to support its own weight, and the In the conventional structure, the above-mentioned core support beam 6 was indispensable as a structure for supporting the leg core 3, but the transformer had the disadvantage that it became larger by the core support beam.

This invention was made in consideration of the above,
The aim is to provide a compact and economical power transformer without using a core support beam, and the lower part of the leg core is integrated by bonding the core laminate. It is characterized by being constructed with a bonded core. By using a bonded core, sufficient strength is obtained to support the leg cores, and the core support beam is eliminated, making the transformer more compact and achieving the above objectives. It is something to be achieved.

The invention will now be described with reference to illustrative embodiments.

In this invention, as shown in FIG. 4, the point that the lower tank 1 supports the coil insulation group 2 and the core is the same as in the conventional system, but the leg core 7 is bonded to a laminate only in its lower layer. Since the laminated plates are bonded and integrated, it has the strength to support the leg core 7, and the leg core 8 has the same function as a core support beam. Supports the iron core 7.

As a result, core support beams are no longer required and the dimensions of the transformer are reduced accordingly.

FIG. 5 shows an embodiment in which an electromagnetic shield 4 is provided below the bonded iron core 9 in order to reduce the occurrence of eddy current loss due to the entry of leakage magnetic flux. Eddy current loss is a power loss and also causes a temperature rise and local overheating of the transformer, so it is necessary to reduce it.

FIG. 6 shows that slits 11 are provided on the lower surface of the bonded core 10 to subdivide the core width, thereby reducing the occurrence of eddy current loss due to leakage magnetic flux entry and adding the function of an electromagnetic shield to the bonded core 10. This is an example.

Note that although the above description has been made using a single-phase transformer as an example, a three-phase transformer or a multi-phase transformer can have a similar configuration to that of a single-phase transformer, and can also have improved effects.

According to the present invention, as described above, by using a bonded core in the lower part of the leg core, a core support beam is not required, the transformer is downsized, and economical efficiency and compatibility with transportation size restrictions are improved. It has the effect of

[Brief explanation of drawings]

Fig. 1 is a plan view showing the internal part of a tank of a conventional external iron type transformer, Fig. 2 is a sectional view taken along line - in Fig. 1, Fig. 3 is a sectional view taken along line - in Fig. 2, FIG. 4 is a cross-sectional view similar to FIG. 2 showing one embodiment of a power transformer according to the present invention, and FIG. 5 is a cross-sectional view similar to FIG. 4 showing another embodiment of the present invention. , FIG. 6 is a sectional view similar to FIG. 4 showing still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Lower tank, 2... Coil insulation group, 3... Leg core, 4... Lower electromagnetic shield, 5... Upper electromagnetic shield, 6... Core support beam, 7... Leg core, 8,
9, 10...Adhesive core, 11...Slit. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A power external iron type transformer, characterized in that the lower layer of the leg core interlinking with the coil insulation group is composed of a bonded core in which core laminates are bonded and integrated. 2. The power transformer as claimed in claim 1, wherein an electromagnetic shield is attached or inserted between the lower part of the leg core and the coil insulation group.