JPS62213104A - Amorphous core transformer - Google Patents

Abstract

PURPOSE:To suppress an increase in iron loss due to stress applied to an iron core, by piling amorphous magnetic material to limit fastening pressure when the iron core is assembled. CONSTITUTION:Step parts 1b are formed by piling individual plates so that their width is different every constant thickness to make the sectional plane circle-shaped, in legs 1a of the iron core 1 which is composed of a plural number of piled individual plates made of amorphous magnetic material. And, iron core plates 2 attaining to the plane of the yoke 1c are applied to both planes of the piled plates. And, splints 3 are applied on the outside leg 1a. Wedges 4 of round rods are inserted at the step parts 1b, and bands 5 of glass fiber reinforced plastics or the like are wound there, and the iron core 1, the iron core plates 2, the splints 3, and wedges 4 are unified to fasten the legs 1a by pressure of 0.05-0.5kg/cm<2>. Hence, magnetic characteristics of the iron core can be prevented from being deteriorated due to stress.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical field to which the invention pertains) The present invention relates to an amorphous core transformer in which a plurality of single plates of amorphous magnetic material are stacked to form an MM core.

(Prior art and its problems) In general, magnetic materials are sensitive to stress or strain, so when assembling a transformer core with silicon steel strips, if the effects of this stress or strain are not taken into account, the assembled transformer It is known that the necessary characteristics cannot be obtained, and that it has a particularly negative effect on iron loss. Conventionally, when assembling a transformer core by laminating silicon steel strips, the silicon steel strips are cut into strips or picture frame shapes of an appropriate width, and then subjected to strain relief annealing. The veneers are stacked, placed between thick iron plates, etc., and tightened with bolts or the like at a pressure of 1 to 3 ky/aS.

On the other hand, amorphous magnetic materials have high magnetic permeability and low loss,
If this transformer core is assembled in an ideal configuration, the iron loss and excitation current will be small, and the iron loss will be /3~ compared to when using the highest grade silicon steel strip currently in use, such as grain-oriented silicon steel strip. /4
It is said that it can be reduced to However, amorphous magnetic materials are more sensitive to stress or strain than silicon steel strips, and the disadvantage is that even if a transformer core is manufactured using the same method as silicon steel strips, it is difficult to obtain properties that take advantage of its characteristics. . In particular, amorphous magnetic materials are manufactured in the form of thin strips with a thickness of about 30 μm, so they are often used primarily as wound cores.The rolled and formed cores are annealed by applying a magnetic field to improve their magnetic properties. It is used as However, since large transformers naturally have to be assembled by inserting an iron core into the coil, a thin plate of amorphous magnetic material is cut into a predetermined shape to make a veneer, and multiple veneers are stacked to form a so-called laminated structure. An iron core must be used. Of course, such amorphous magnetic materials for lamination are also annealed to remove strain, but such magnetically sensitive materials will deteriorate again when stress is applied during assembly. However, during assembly, it is necessary to prevent deterioration of the magnetic properties due to this increase in stress.

(Object of the Invention) An object of the present invention is to provide an amorphous core transformer in which an increase in core loss due to stress applied to the core is suppressed by limiting the tightening pressure when assembling the core by laminating amorphous magnetic materials. There is a particular thing.

(Summary of the Invention) The present invention uses a plurality of single plates made of amorphous magnetic material, and when the laminated core is tightened with pressure, stress is applied to the amorphous magnetic material in relation to this pressure, causing deterioration of magnetic properties. In particular, in view of the increase in iron loss, this tightening is intended to limit the pressure and prevent deterioration of magnetic properties, thereby providing an amorphous core transformer that reproduces properties close to those in the annealed state. be. Note that it is convenient to construct the laminated core by stacking multiple veneers of annealed amorphous magnetic material.

(Embodiments of the Invention) The present invention will be described in detail below with reference to the drawings. First, the present inventors conducted the following research to satisfy the above-mentioned requirements, and as a result, they arrived at the present invention.

First, six veneers with a thickness of 25 μm and a width of 50.5 ms were stacked and bonded, and subjected to magnetic field annealing. e78. Si9
．． The length of the strip-shaped amorphous magnetic material containing 13 at.
As shown in the figure, the four corners of each sheet were wrapped to form a quadrilateral magnetic circuit with an outer dimension of 401 m5, and the iron loss was measured without tightening. As a result, the iron loss W at 50Hz and the most used magnetic flux density of 1.3T, watt / &
9 is the number of sheets stacked on one side of the frame N(
Here, the actual number of WIWJ sheets is 6 times that of H) is 10
The iron loss W increases as the number N increases until the number of sheets N increases, but after that it remains almost constant and is approximately 0.18 watt/hg.
It is stable at a sufficiently low value. This is thought to be because the veneers, which had been slightly deformed in their free state, were stacked together, correcting the deformation due to their own weight, and conversely applying stress, which increased the iron loss W.

Next, in the same way, 20 veneers on each side are assembled into the above-mentioned coil, non-magnetic plates are stacked, and pressure is gradually applied. The relationship between the pressing force Pay/cm' and the loss w and watt/Ay. is shown in Figure 4. Here, curve A is iron loss.

Curve B is hysteresis loss and curve 0 is eddy current loss.

Of course, the sum of hysteresis loss and thin current loss is iron loss, but
The fact that the eddy current loss is not related to the applied force and is almost constant indicates that the veneer is not affected by anything other than stress. Also, the hysteresis loss, and therefore the iron loss, is the applied force of 0.5
The increase rate is high up to kg/am (,0,5&da76m
It stabilizes when it exceeds , but it still increases almost linearly.

From this result, it is essential to reduce the tightening pressure in order to prevent an increase in iron loss in the core assembled by laminating amorphous magnetic materials, and the general target is 50 H2,1.
, the iron loss at 3T is 0.23 watt/kjl
1Ij To suppress it to 4 degrees or less, the tightening pressure should be 0 from Figure 4.
．． It is necessary to keep it below 5kg/ays. Of course, tightening pressure is necessary to maintain the shape of the iron core, so O-05k
If a clamping pressure of 9/C to 0.5 da/em is applied to the iron core, the desired purpose can be achieved.

Next, a specific configuration of a transformer in which such a tightening force is applied to the core will be shown. In Fig. 1, reference numeral 1 denotes an iron core made of a plurality of laminated veneers made of amorphous magnetic material, and its leg 1cL is made by laminating veneers of different widths at regular thickness intervals to form a stepped portion 1b in order to approximate a circular cross section. It is formed. Then, apply a core contact plate 2 long enough to reach the surface of the yoke IC to both sides of the stack, and apply a contact plate 3 to the outer leg 1α.
A round bar wedge 4 is placed between the stepped portions 1b, and a band 5 made of, for example, fiber-reinforced plastic is wrapped around the iron core 1. Iron core backing plate 2. Toki 3. Wedge 4 is integrated and leg 1 cL is 0.
05~0.5 kg Tighten with 76% pressure. At this time, the outer surface of the wood 3 is rounded, and one piece of wood 3 is used for each 5% band, but care must be taken so that each band 5 tightens the iron core 1 with uniform pressure. Of course York IC
Although this part is not shown in the figure, tighten it with a band in the same way as leg 15c. With such a configuration, a transformer having an iron core made of an amorphous magnetic material can be obtained.

Note that the density of the amorphous alloy (1+lθ-B-81 series) is approximately 'ty/Cm, so the laminated veneer is
When considering the thickness, due to the weight of the laminated veneer, the lower layer veneer has a thickness of 3
A pressure of 50 g/c♂ is applied. Therefore, when increasing the size of the transformer and increasing the thickness of the core, it is preferable to make the core vertical, as shown in FIG. 1, and to further reduce the influence of its own weight by using a suspended structure.

(Effects of the Invention) As described above, according to the present invention, amorphous magnetic materials are stacked to form a laminated iron core, and this iron core has a thickness of 0.05k.
By tightening with g/c pressure, the magnetic properties of the core are prevented from deteriorating due to stress.
The desired characteristics can be obtained and the effect is great.

[Brief explanation of drawings]

1 to 4 show an embodiment of an amorphous core transformer according to the present invention, FIG. 1 is a perspective view showing a part of the core of the amorphous core transformer, and FIG. 2 is a measurement of iron loss of amorphous magnetic material. Figure 3 is a curved liJ diagram showing the relationship between the number of laminated cores and iron loss, Figure 4 is a dimensional diagram of the sample used in
The figure is a curve diagram showing the relationship between the clamping pressure and loss of the laminated core. Figure 1

Claims (1)

[Scope of Claims] 1) In an amorphous core transformer having a laminated core assembled by stacking a plurality of veneers of amorphous magnetic material, the laminated core has a weight of 0.05 kg/cm^2 to 0.05 kg/cm^2.
An amorphous iron core transformer characterized by tightening with a pressure of 5 kg/cm^2. 2) The amorphous core transformer according to claim 1, wherein the laminated core is assembled by stacking annealed amorphous magnetic materials.