JPH01259514A - Iron-core reactor with gap - Google Patents

Abstract

PURPOSE:To prevent local heating by reducing an eddy current by forming a slit extending transversely across a silicon steel plate of a yoke at a position located outside the outer diameter dimension of a block iron core. CONSTITUTION:A slit 41 is cut in from an opposing side end of a yoke 4 to a block iron core 1 to a given height directed transversely across the yoke 4. The height of the slit 41 extending from the side end of a silicon steel plate of the yoke 4 located on the side of the block iron core 1 is determined by a magnetic flux density distribution. Accordingly, although an eddy current 7 tends to flow through the surface layer silicon steel plate of the yoke 4 owing to a fringing magnetic flux 22 and a leakage magnetic flux 61 from a winding 6, the eddy current 7 is interrupted by the slit 41 and divided into several groups. Thus, the eddy current 7 is reduced. Therefore, local heating due to the eddy current 7 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a gapped iron-core reactor, and more particularly to a gapped iron-core reactor with an improved iron core structure.

[Prior Art] In general, a gapped core reactor consists of a gapped main core, which is constructed by alternately stacking a radial block core in which silicon steel plates are arranged radially and spacing pieces, and is magnetically coupled to the main core. The iron core is made up of a yoke and a yoke.

A conventional gapped iron core reactor of this type is shown in FIGS. 6 and 7.

FIG. 6 shows a three-legged main core 3 with gaps in which a plurality of block cores 1 and gap pieces (not shown) are alternately stacked to form gaps 2b, and a winding 6 is wound around each main core 3. The figure also shows an iron core structure in which the main iron cores 3 are magnetically coupled by a yoke 4 via a gap 2a formed by a gap piece (not shown).

Further, FIG. 7 shows a core structure similar to that shown in FIG. 6 described above, in which return membranes 5 are arranged on both sides of the main core 3 around which the winding 6 is wound, and yokes 4 are arranged at both ends. A gap 2a is also formed between the main iron core 3 and the yoke 4 by a gap piece (not shown).

In either case, these cores are housed in a container, and the container is filled with an insulating cooling medium such as insulating oil to form a gapped core reactor.

When looking at the magnetic coupling portion between the main core 3 and the yoke 4 of this type of gapped core type reactor, that is, the sectional view taken along the line AA in FIGS. 6 and 7, it is as shown in FIG. In other words, in addition to the main magnetic flux 21, there is a
A fringing phenomenon occurs due to the gap 2a or gap 2b between each block iron core 1, and a fringing magnetic flux 22 is generated. Since each block core 1 is formed in a radial shape with silicon steel plates arranged radially, the fringing magnetic flux 22 between each block core 1 is
There is no particular problem because it invades along the laminated layers. However, in the case of yoke 4, the fringing magnetic flux 2 is perpendicular to the laminated outer surface.
2 invades. In addition, the leakage magnetic flux 61 from the winding 6 also leaks from the yoke 4.
Penetrates perpendicularly to the outer surface of the laminate. In particular, when the amount of magnetic flux penetrating these yokes 4 increases due to the recent increase in the capacity of glue accruals, the eddy current 7 flowing on the end surface of the yoke 4 facing the block core 1 increases as shown in FIG. increase, causing local overheating and increasing losses.

In this respect, the conventional gapped iron core reactor is
As shown in the figure, the laminated thickness of the rectangular silicon steel plates constituting the yoke 4 is made larger than the outer diameter of the block core 1, and
As shown in FIG. 2, the gap 2a between the yoke 4 and the block core 1 was made small to reduce the fringing magnetic flux 22 that perpendicularly enters the laminated surface of the yoke 4. Also, the 1980s
As described in Japanese Patent Publication No. 22819, an additional block may be provided on a part of the yoke, which is stacked in the same direction as the layered direction of the yoke. An iron core structure has been proposed in which a block end core is disposed in the block end core, and the block end core is formed of rectangular silicon steel plates so as to stand perpendicular to the stacking direction of the yoke.

[Problems to be Solved by the Invention] Conventional gapped iron core reactors have taken measures against the fringing magnetic flux 22 as described above, but as shown in FIG. In this method, a substantial effect cannot be expected unless the yoke 4 is made at least as large as the inner diameter of the winding 6, which increases the weight of the yoke 4 and makes it expensive. Put it away.

Furthermore, in the method of reducing the gap 2a between the yoke 4 and the main core 3 as shown in FIG. 12, the gap 2b between the block cores 1 must be increased in order to obtain a gap length determined by the overall impedance. In some cases, the gap 2b is too large and a new block core must be added, or the leakage magnetic flux 6 from the winding 6
1 could not be expected, and the results were not satisfactory. Furthermore, the methods disclosed in Japanese Utility Model Application Publication No. 60-22'819 and Japanese Patent Application Publication No. 60-217615 result in a complex structure and an expensive gapped core reactor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a gapped iron core reactor which has a simple structure and prevents local overheating of the yoke and increase in loss.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a yoke disposed at both ends of a main core with a gap wound with one winding to prevent fringing magnetic flux and leakage from the winding. Forms slits that disperse eddy currents caused by magnetic flux.

The slit is characterized in that it is formed in the silicon steel plate in the surface layer at the end in the stacking direction located at least outside the outer diameter of the gapped main core so as to extend in the width direction of the silicon steel plate.

[Function] Since the gapped iron-core reactor according to the present invention has the above-described configuration, eddy currents flow in the silicon steel plate on the surface layer at the end of the yoke in the stacking direction due to fringing magnetic flux and leakage magnetic flux due to the winding. Since this eddy current is divided by the slits formed in the width direction of the silicon steel plate and its absolute value becomes small, local heating can be prevented and loss can be reduced.

In addition, the depth of the slit is limited to the surface silicon steel plate located outside the outer diameter of the gapped main core, so it has no negative effect on the main magnetic flux flowing from the gapped main core to the yoke. Never.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a front view of a single-phase gap iron core reactor according to an embodiment of the present invention, and FIG. 5 is a plan view of FIG. 4.

The gapped main core 3 is configured by alternately stacking a plurality of block cores 1 and insulating gap pieces (not shown) to have a gap 2b, and has a winding 6 wound thereon. Return legs 5 are arranged side by side on the sides of the gapped main core 3, and yokes 4 are arranged at both ends of the gapped main core 3 with gaps 2a interposed therebetween to form an iron core structure. This entire structure is housed in a container filled with an insulating cooling medium to form a gapped iron core reactor.

As can be seen from FIG. 5, the lamination direction of the iron core 4 is perpendicular to the line connecting the return legs 5, and a slit 41 is formed in the silicon steel plate of the surface layer at the end in the lamination direction. . The details of this slit 41 will be explained using FIG. 1 and FIG. 2.

1 corresponds to a sectional view taken along the line B--B in FIG. 4, and FIG. 2 is an enlarged view of the main part of FIG. 4.

As shown in FIG. 1, the number of laminated silicon steel plates in the yoke 4 is determined so that it is slightly thicker than the outer diameter of the block core 1 of the gapped main core 3.
A slit 41 with a depth corresponding to the surface layer of the silicon steel plate at the end in the stacking direction located outside the outer diameter dimension of
is provided. This slit 41 is the block iron core 1
The cutting starts from the opposite end of the yoke 4 and is cut to a predetermined height in the width direction of the yoke 4. The height of this slit 41 will be described later, but the position of the slit 41 is preferably near the straight line in the stacking direction of the yoke 4 passing through the center of the block core 1, and is located at a position as shown in FIG.

Next, the height of the slit 41 will be explained with reference to FIG. This FIG. 10 shows the magnetic flux density distribution in the silicon steel plate on the laminated surface among the silicon steel plates constituting the yoke 4.
The vertical axis indicates the width of the silicon steel plate from the block iron core 1 side. Therefore, as can be seen from the figure, the magnetic flux density in the silicon steel plate is highest at a location slightly away from the block iron core 1, and thereafter decreases as the width increases. Correspondingly, the slit 41 is cut from the end of the silicon steel plate constituting the yoke 4 on the block core 1 side according to this magnetic flux density distribution, and its height is determined.

By having the slit 41 formed as described above, the slit 41 does not interfere with the main magnetic flux 21 flowing from the block core 1 as shown in FIG. In particular, this is because the depth of the slit 41 is limited to be outside the outer diameter of the block core 1. Further, the slit 41 acts on the fringing magnetic flux 22 and the leakage magnetic flux 61 of the winding 6 as shown in FIG. In other words, due to these magnetic fluxes, an eddy current 7 as shown in FIG. 9 tries to flow through the silicon steel plate on the surface layer of the yoke 4, but the eddy current 7 is divided by the slit 41 as shown in FIG. The current is divided into groups and the current value is reduced. Therefore, local overheating due to eddy currents is prevented.

FIG. 3 shows an enlarged view of the main parts of a gapped iron-core reactor according to another embodiment of the present invention. A slit 41 is formed in the same manner as shown in FIG. According to this embodiment, the eddy current flowing through the yoke 4 is divided into smaller pieces, the current value becomes smaller, and local heating is further prevented.

As can be seen from the explanations of the above examples, when forming slits, the height, depth, number, position, etc. of the slits are determined depending on the local heating that is occurring and the extent to which it is suppressed. It's good to do that. However, regarding the depth, it should be located outside the outer diameter of the block core 1 so as not to affect the main magnetic flux 21 shown in FIG. It is best to decide the number of silicon steel plates in the surface layer that will form the slits while taking into account the difference between the two.

[Effects of the Invention] As explained above, the present invention disperses eddy current in the yoke due to fringing magnetic flux and leakage magnetic flux from the winding at a depth located outside the outer diameter of the block iron core. By forming a slit that extends in the width direction of the silicon steel plate of the yoke, the current value of the eddy current caused by the above-mentioned magnetic flux can be reduced without any negative effect on the main magnetic flux flowing from the block iron to the yoke. This can prevent local heating and loss of 1 person.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing the main parts of a gapped iron-core reactor according to an embodiment of the present invention, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a gapped core reactor according to another embodiment of the present invention. A front view showing the main parts of an iron core reactor, Figures 4 and 5 are a front view and a plan view of the gapped iron core reactor shown in Figure 1, and Figures 6 and 7 are a conventional gapped iron core reactor. , FIG. 8 is a sectional view taken along line A-A in FIGS. 6 and 7, FIG. 9 is an enlarged view of the main part of FIG. 6, FIG. 10 is a magnetic flux density distribution characteristic diagram, and FIGS. FIG. 12 is a partial sectional view showing the main parts of different conventional gapped core reactors. 1...Block core, 2a, 2b...
Gap, 3... Main core with gap, 4...
... Yoke, 6 ... Winding, 7 ... Eddy current, 21 ... Main magnetic flux, 22 ... Fringing magnetic flux, 41, 42 , 43...Slit, 61...Leakage magnetic flux. Fig. 1 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 4 Dan Fig. 8 Fig. 9 Fig. 10.

Claims (2)

[Claims] 1. A main core with a gap is formed by stacking the blocks while forming a gap between the cores, a winding is wound around the outer periphery of the main core with a gap, and a silicon steel plate is attached to both ends of the main core with a gap through a gap. In a gap core type reactor configured by arranging laminated yokes, the silicon steel plate in the surface layer at the end in the stacking direction of the yoke located outside the outer diameter dimension of the gap main core is coated with the above silicon steel plate. A gapped core reactor characterized by having a slit extending in the width direction from the side opposite to the gapped main core. 2. 2. The gapped core according to claim 1, wherein the slit is made up of a plurality of slits arranged side by side, and the height in the width direction decreases as the slit moves away from the center of the gapped main core. shaped reactor.