JPS61136208A - Core type transformer core - Google Patents

Abstract

PURPOSE:To obtain a transformer core which has an excellent magnetic characteristic and can be made small-sized and lightweight, by providing a construction in which one side of the V-shape is longer than the other so that the apexes of the T-joint portion of the leg cores opposed to the side leg cores are biased to the sides opposite to the side leg cores. CONSTITUTION:A three-phase, five-leg core is provided with a construction in which only the central leg core 10 around which a winding is wound has plates 10a, 10b combined so that the sides of the V-shape are substantially equal in length, and the other leg cores 20, 30 have iron plates having widths l1-l4 combined so that the apexes of the V-shapes are biased to the central leg core 10 side. With this structure, magnetic flux sharing rate can be uniformized in the respective portions in the yoke, so that a core having an excellent magnetic characteristic can be obtained, and an outstanding effect can also be expected for making it small-sized and lightweight. Since the central leg core 10 and leg cores 20, 30 are all constructed with two pairs of iron plates which wire cut slantwise, scrap is completely prevented from being produced by cutting them out from a steel tape which was previously slit at a predetermined width.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a core for a core type transformer that reduces iron loss and also reduces the weight of the core in one dimension.

[Background of the invention]

In general, the core of a normal internal iron type three-phase five-legged transformer has a structure in which two side leg irons 3 are placed on the outside of three central leg irons 1 having windings 4, as shown in Fig. 5, for example. This structure is advantageous when it is desired to reduce the height of the core due to transportation restrictions, etc., and is often used in relatively large-capacity transformers.

The reason why such a three-phase, five-legged core can be made lower than a three-phase, three-legged core will be explained using FIGS. 5 and 6.
Now, the magnetic flux passing through each leg iron 1 is φ.

φ7. φ, and the magnetic flux passing through each yoke 2 and side leg iron 3 is φ
1, φ1. φ, these magnetic flux relationships become a vector diagram as shown in FIG. 6, and in principle KHφ, φ1 .
φ, flows only 0.58 in the leg iron (7) 1 /v'T, so if the height of the yoke 2 is D, it is 1/ of the 3-round iron core.
Reduce it to about v'3 (about 1/V of leg iron width W)"
is possible.

However, in our experiments and other studies, we found that the magnetic flux φ1. φ2. φ, are not necessarily the same,
Especially φ, kuφ2. Since a phenomenon in which φ is observed, these magnetic fluxes φ1. φ1. It is desired to equalize the distribution of φ and to reduce the height D of the yoke 2 as much as possible from the viewpoint of reducing iron loss and weight.

The magnetic flux φ flowing toward the side leg iron 3 is the magnetic flux φ2 flowing toward the other yoke 2. The reason why it is smaller than φ is that the width of the side leg iron 3 is smaller than the width of the leg iron 1, and the magnetic resistance through which the magnetic flux φ1 passes and the magnetic resistance through which the magnetic flux φ81φ passes is not the same. From the previous studies, it has also been found that the degree of this magnetic flux imbalance varies depending on the structure of the core joint.

The results of these studies will be explained below using Figures KC7, Figure 8, Figure 9, and a table.The structure in Figure 7 is a case in which the T-junction is X-shaped, and scrapless cutting is possible. Although it is economically superior, iron loss and magnetic customization are not good because the iron plates are laminated alternately in the rolling direction and the direction perpendicular to this.

Figure 8 shows a Y-shaped T-joint, and Figure 9 shows a ■-shaped structure in which the yoke 2 is divided into two in the longitudinal direction, but in these core joint structures, the rolling directions of the steel plates are all aligned. Table 1
As shown in Figure 7, the iron loss is 101 compared to the X-shaped joint structure shown in Figure 7.
The level is decreasing.

Looking at Table 1-1, the magnetic flux sharing ratio φ1/φ flowing through the side leg iron 3 and yoke 2 at that time, the Y-shaped joint structure shown in Figure 8 has an unbalanced magnetic flux compared to other joint structures. The degree of From the results of these examinations of iron loss and magnetic flux sharing ratio, the V-shaped structure shown in Figure 9 is the best for the core joint, but the magnetic flux sharing ratio of φl/φ is not necessarily sufficiently equalized. It has not become what it was.

In addition, as shown in Fig. 10, a three-phase five-leg iron core joint structure with a V-shaped T-junction includes two leg irons 1a of different widths,
At the joint between lb and the yoke 2, the joint angle θ1 of the wide leg iron 1a is set to be larger than the joint angle θ of the narrow leg iron 1b, and the length tt of the wide O leg iron 1a is set larger. There is a known example of shortening the length A of the narrow leg iron 1b, for example, Japanese Patent Laid-Open No. 58-200515. Moreover, as shown in FIG. 10(a), the width of the leg iron 1 is 1. and yoke 2
When the width t is L+)tt, a notch 5 is formed on the leg iron side which is larger than the required cross-sectional area, and as shown in 1. of FIG. 10(b). <t, the joining angle θ1.
θ.

A method of constructing an iron core by laminating iron plates while changing the iron thickness is known from Japanese Patent Publication No. 58-200515.

In this structure, when the leg iron 1 and the yoke 2 are joined, those with different hypotenuse lengths are combined alternately, and a notch 5 is always formed in the yoke having a large cross-sectional area. Therefore, the concentration of magnetic flux flowing through the leg irons 1 and yoke 2 can be alleviated, but what is the structure that takes into account the uniformity of the magnetic flux sharing ratio of φI/φ2 flowing through the side leg irons 3 and yoke 2? is not.

[Purpose of the invention]

Objective of the invention σ, T close to side leg iron in 3-phase 51111 iron core
The purpose of the present invention is to provide a high-performance transformer core that has excellent magnetic properties by improving the structure of the joints, thereby making the distribution of magnetic flux flowing through each part of the core uniform, and which is further compact and lightweight.

[Summary of the invention]

The present invention relates to a transformer core consisting of a side leg iron with no winding wound thereon and a leg iron having a winding formed by dividing the yoke into two parts in a V shape. It has a configuration in which one side of the V shape is lengthened so that the apex is shifted toward the opposite leg iron side.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be described in which iron plates 10a and 10b are combined so that only the central leg iron 10, which is connected to the three-phase transformer shown in FIG. 1, has approximately the same length of the V-shaped end sides. The other leg irons 20 and 30 have a structure in which iron plates having different widths t1 to t4 are combined so that the apex of the V shape is biased towards the center leg iron 10 side.

In this construction method, for example, as shown in FIG. 1(b), the leg iron 20 facing the side leg iron is an iron plate 20a.

It is divided into two by 20b, but since the iron plate width of 20a is wider than 20b, the iron plate width is 1. The magnetic flux φ1 included in the iron plate width t, and the magnetic flux φ included in the iron plate width t are also
If φ, >φ2, this magnetic flux will flow into the yoke 2. From these things, the iron plate width for leg irons 20a and 20b is 1. , 1. By changing , the distribution of magnetic flux flowing through the yoke changes, and conventionally φ1 < φ8. φ, the phenomenon that becomes φ,
It becomes possible to set it as medium φ, medium φ. Since the magnetic flux sharing ratio in each part of the yoke can be made uniform, it is possible to create an iron core with excellent magnetic properties*ti, and it also has the advantage of being compact and lightweight, which is required for a 3-phase, 5-legged iron core. That's something to look forward to.

In order to make the magnetic flux flowing through the leg irons 20 and 30 uniform in the yoke 2 in this way, four types of iron plates are required as shown in FIG. 1(C). ') The width of the iron plate for machining 20a and 20b is 11
) t, , 30a, 30b, t.

> t4, the degree of unbalance of the magnetic flux flowing through the yoke 2 is minimized. The center leg iron 10 and the leg irons 20 and 30 are both diagonally cut iron plates 10a, 10b and 20a, 20b, 3.
Since it is composed of 0a and 30b, it also has the advantage of not producing any scrap by cutting them through a copper strip that has been slit to a predetermined width in advance.

FIG. 2 shows another embodiment of the present invention, which shows a flat surface of a single-phase four-leg iron core, with iron plates 20a, 20b, 30a, and 30b divided into two leg irons 20 and 30 on which windings are wound, and windings. The figure shows a structure made up of unwound side leg irons 3 and two leg yokes 2 each.

Even with this configuration, the iron plate width of the leg irons 20 and 30 is 1. ＞Lx
, Ls>! -4, it is possible to make the magnetic flux amounts φ1 and φ passing through the yoke 2 the same, and the effects of the present invention are no different from those described above with reference to FIG.

FIG. 3 shows another embodiment of the present invention, showing the same parts as FIG. The difference is that they are integrated. In the leg iron 40, the vertices of the hv-shaped portion are not aligned in a straight line, and t.

>Ax, ts >tI, and the pieces are stacked while being turned upside down.

Even in this construction method, the magnetic flux flowing through the leg iron 40 is T
After flowing to the top of the joint, it is diverted to the yoke 2, but tI
>At-As>74.

Furthermore, the magnetic flux flowing through the yoke 2 near the side leg iron 3 increases.

As a result, it is possible to set the φ1 to φ and the medium φ, and it is possible to equalize the magnetic flux share in each part of the core.

FIG. 4 shows another embodiment of the present invention, showing the same parts as FIG. 2, except that the iron plate of the leg iron 40 around which the winding is wound is integral.

Even in this construction method, by controlling the length of the oblique side of the leg iron 40, it is possible to equalize the magnetic flux φ1゜φ flowing through the yoke 2, and the effect of the present invention can be seen in FIG. It's no different from what I said.

〔Effect of the invention〕

As described above, according to the inner iron type transformer core of the present invention, it is possible to make the distribution of magnetic flux flowing through each part of the core uniform, and it is possible to achieve excellent magnetic properties and further miniaturization and weight reduction. .

[Brief explanation of the drawing]

FIGS. 1(a), (b), and (C) are plan views of a three-phase, five-legged core showing one embodiment of the present invention, and FIG. 2 is a plan view of a single-phase, four-legged core showing another embodiment of the present invention. 3 and 4 are plan views showing other embodiments of the present invention, and FIG. 5 is a plan view showing a conventional three-phase 5
FIG. 6 is a plan view showing the leg core, and FIG. 6 is a vector diagram showing the magnetic flux relationship of each part of the core, and FIGS. 7 and 8. Figure 9 is a plan view showing the joint structure of a three-phase, five-legged core;
Figures 0 (a) and 0 (b) are plan views showing an example of a three-phase five-leg core joint structure in which the T-junction is V-shaped. 1,) a, lb, 10, 10a, 10b, 20° 20a
, 20b, 30, 30a, 30b, 40・-leg iron, 2・
... Yoke, 3... Side leg iron, 4... Winding wire, 5... Notch part.

Claims (1)

[Claims] 1. Trapezoidal iron cores with both ends cut diagonally are used as side leg irons, which are inserted into these side leg irons to form windings, and a plurality of leg irons with V-shaped tips are arranged above and below. In the configuration where the yoke protrudes to completely divide the yoke, the one placed in the center of the group of leg irons has two sides of the V-shaped end having approximately equal lengths,
The inner iron type transformer core that faces the other side leg iron is characterized in that the lengths of the two sides of the V-shaped end are changed so that the apex of the V-shape of the leg iron is shifted toward the opposite side leg iron side.