JPS5866316A - Iron core for three-phase transformer - Google Patents

Abstract

PURPOSE:To form a junction section with less loss by a method wherein the notches of a yoke section steel plate connected to the opposite end sections of a central-leg steel plate are formed with scalene triagnles hving obtuse angles at apex angles. CONSTITUTION:In a both leg section steel plate 12, the opposite end sections are formed in padestal shape having tilt angles of nearly 45 deg.. The upper and lower sections of the yoke section steel plate 12 are formed in pedestal shape having tilt angles of nearly 45 deg. at the opposite end sections and are provided with scalene-triangular notches 12a having obtuse angles at apex angles at the position slightly going toward one end side from the central section. In a central leg steel plate 13, the shape of the opposite end sections is formed with the same shape as that of the nothces 12. Firstly, these steel plates are combined as shown in solid lines to compose a set of laminated plate. Next, these steel plates are combined into the shape inverting the solid line section and the other set of laminated plate is composed as shown in dashed lines. Then the steel plates are alternately combined as shown in solid and dashed lines by the number of required steel plates for lamination. This constitution connects the steel plates 12 and 13 by completely agreeing the notches 12a with the opposite end sections of the steel plate 13. Therefore, the flow of magnetic flux between the yoke section and the central leg becomes smooth.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-phase transformer core made of laminated grain-oriented silicon steel sheets.

FIG. 1 shows a typical example of a three-phase transformer core made of conventional grain-oriented silicon steel plate T' laminated. In the same figure, reference numeral 1 is a steel plate with both legs formed into a trapezoid with both ends having an inclination angle of approximately 45°, and 2 is a steel plate with both ends formed into a trapezoid with an inclination angle of approximately 45°. Upper and lower yoke steel plates having an isosceles triangular notch 2afe with an apex angle of 90° at ゜=t, ), 3 have both ends partially aligned with the above notch t12a, and 45 on both gR. The central leg steel plate is formed into an asymmetrical chevron shape with an angle of inclination of °. When constructing a steel core using these steel plates, first place these steel plates into the first land a).
They are combined as shown by the solid line to form one set of laminates, and then the solid line parts are combined in a reversed form to form another set of laminates as shown by the broken line in Figure 1(a). By stacking the required number of laminated plates in an alternate combination as shown by solid lines and broken lines, a so-called overlap-bonded three-phase transformer core in which the joints of the laminated plates are alternately located is obtained.

In the conventional three-phase transformer core shown in Fig. 1, the yoke steel plate 2
In the construction where the direction of magnetic flux near the joint between the steel plate A and the center leg steel plate B coincides with the rolling direction of the steel plate, the notch 2a of the steel plate of the yoke part is
is shaped like an isosceles triangle with two sides having an inclination angle of 45°, and therefore an apex angle of 90°.
As shown in detail in FIG. 1(b), in order to mechanically hold the center leg, the joints between the yoke steel plates 2 and the center leg steel plates 3 are alternately shifted left and right. It is necessary to multiply by 1,
As a result, both ends of the center leg steel plate 6 are cut out at the yoke part @2
It is not possible to completely match the angle a, and a gap g is created at both corners. For this reason, the magnetic resistance at the joint between the central leg and the yoke, which affects the characteristics of the three-phase transformer core, increases locally at the gap g, impeding the smooth flow of magnetic flux. In particular, the excitation current and iron loss increase.

Also, from the standpoint of effective use of materials, in the conventional core configuration shown in the first example, the notch 2a of the yoke steel plate and the cut-off portions at both ends of the center leg steel plate were large, resulting in poor yield.

The purpose of the present invention is to compensate for the drawbacks of the above-mentioned conventional examples, improve the core characteristics, and provide a three-phase transformer core by laminating grain-oriented silicon steel sheets, which is a problem in terms of production such as material yield. It's in particular.

In order to achieve the above object, in the present invention, the notch l! By forming a scalene triangle with an obtuse apex angle, it is possible to form a joint with low edge loss without using a gear metal that locally increases magnetic resistance as in the conventional example shown in Fig. 1. This is the next thing.

Hereinafter, all embodiments of the present invention will be explained with reference to FIG. 2. In FIG. It is formed into a trapezoid with an angle of inclination of approximately 45° and its central part!
- Slightly closer to 4111, apex angle -
is an obtuse angle, and the inclination angles α and β of the two sides are α≠β. The upper and lower yoke steel plates 12 have a scalene triangular notch 12at-, and 13 has the same shape at both ends as the above notch @12a. The center leg is made of steel plate. When constructing these steel plate rainbow cores, first, these steel plates are combined as shown by the solid line in FIG. 2(a) to form a set of laminated plates, and then the solid line portions are combined in a shape in which #! Another set of laminates is constructed as indicated by the broken line in Figure 2 (IL). Hereinafter, the required number of sheets are alternately combined and laminated as shown by the solid lines and broken lines, and the joints of each layer are alternately located, so-called lap joints to form a three-phase transformer core.

The reason for this configuration is that the yoke steel plate 12 and the center leg steel plate 13 only have the positions of the apexes of their joints alternately shifted left and right, and the notch 1112a of the yoke steel plate and the center leg steel plate Joined with both ends perfectly aligned h ~ 1st
In the conventional construction shown in the figure, the notch in the yoke steel plate and both ends of the center leg steel plate do not shift left or right, causing gaps at the corners.

Therefore, the magnetic resistance of the joint is reduced, and the flow of magnetic flux between the yoke and the central leg becomes smoother.

No. 211g (the apex angle of the scalene triangle shown in b3 is 95°)
It is appropriate to set the apex angle to ~115°), and the apex angle # is made to be an obtuse angle of this L).Compared to the conventional example, the notch @ 12a of the steel plate of the yoke part and the center leg steel plate are The cut-off portions on both ends are smaller, improving material yield, and cutting off @
The life of the press die that punches 12ai will also be longer.

Further, in order to smooth the flow of magnetic flux at the joint and improve the core characteristics, the best results can be obtained when the inclination angle (α or β) of each side of the scalene triangle is set to 45° in total.

If the present invention is implemented as described above, the magnetic resistance at the joint between the yoke and the center leg will be reduced compared to the conventional example shown in Fig. 1, and the combination of one type of steel plate will have excellent magnetic properties. In terms of production, the material yield is improved, and the life of the press die for punching out the notches in the steel plate of the yoke is extended.〇

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are detailed drawings of the tatami part of a conventional façade made of grain-oriented silicon steel plates. 11: both leg steel plates, 12: yoke steel plate, 12a: notch in yoke steel plate, 13: center leg steel plate, #: apex angle of scalene triangle, σ, β: slope of two sides of scalene triangle Kaku Agent Patent Attorney Susuki 1) Toshi Yukio 1

Claims (1)

[Scope of Claims] 1. A steel plate for both legs having a trapezoidal shape with both ends having an inclination angle of approximately 45°, and a central portion having a trapezoidal shape with both ends having an inclination angle of approximately 45°. upper and lower yoke steel plates having scalene triangular notches with obtuse apex angles at positions slightly closer to one end; and central leg steel plates having both ends having shapes that match the notches. The three-phase transformer iron is made by laminating the laminated plates that are combined to form an S shape, with the joints of the laminated plates alternately inverted and stacked. The apex angle of the above scalene triangle is 95. The three-phase transformer core 03 according to claim 1, which has an angle of 45° to 115°; Three-phase transformer iron IcN as described.