JPH05109547A - Iron core type reactor with gap - Google Patents

Abstract

PURPOSE:To provide an iron core type reactor with a gap which prevents occurrence of excess compressive stress at the central part of a yoke iron core so as to reduce noises. CONSTITUTION:The end face of blank at both ends in the laminating direction 4a of a yoke iron core 4 having rectangular profile formed by laminating silicon steel bands and at least one end of blank's surface are coated with an insulating material 9. As a result, a difference in temperature distribution caused by irregular distribution of magnetic flux at both ends in the laminating direction 4a and a central part 4b of the yoke iron core 4 is eliminated, so occurrence of compressive force due to a difference in thermal expansion is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cored reactor with a gap, and more particularly to improvement of a yoke core.

[0002]

2. Description of the Related Art As a reactor used for a shunt reactor or the like, a cored reactor with a gap is generally used. This core-reactor with a gap has a circular cross-section that is formed by stacking a plurality of magnetic gaps between a plurality of block cores formed by stacking silicon steel strips to stack them through a plurality of magnetic gaps. An iron core with a core is formed, and a yoke iron core having a rectangular cross section, which is also formed by laminating silicon steel strips, is arranged below the core, and a winding is wound around the core with a gap.

By the way, in the iron core type reactor with a gap constructed as described above, one of the major problems is reduction of noise generated from the reactor body. The factors of noise can be roughly classified into those due to mechanical vibration and those due to magnetostriction. What is due to mechanical vibration?
This is a phenomenon in which a magnetic attraction force acts between the block cores above and below the gap by the magnetic flux passing through the gap, and noise is generated due to the vibration caused by the magnetic attraction force. Therefore, it is necessary to have a structure in which the yoke core and the block core are integrally and firmly tightened via the gap. On the other hand, due to magnetostriction, it consists of magnetostrictive noise generated due to the flow of magnetic flux in the iron core, and magnetostrictive noise that further increases as a result of applying an unreasonable compressive force to the iron core inside blank at that time, especially the latter effect. large. For this purpose, it is conceivable to appropriately set the magnetic flux density and to adopt an iron core structure that does not apply unreasonable compressive stress to the iron core inner blank during tightening and during operation. Here, looking at the magnetic flux density in the yoke core, as shown in FIG. 3, the core core with a gap 1 having a circular cross section to the yoke core 4 having a rectangular cross section.
Since the magnetic flux flows through, the magnetic flux density is high in the central portion 4b in the stacking direction of the yoke cores and the magnetic flux density is low in both end portions 4a.
Therefore, one of the major characteristics of the cored reactor with a gap is that the temperature difference due to the generated loss causes a difference in thermal expansion between the central portion 4b and both end portions 4a as shown in FIG.

[0004]

In the cored reactor with a gap, the central portion 4b of the yoke core 4 tends to extend in the blanking direction because of the uneven magnetic flux distribution of the yoke core 4 as described above. Both end portions 4a of the above work to prevent it, and eventually, the blank of the central portion 4b of the yoke iron core 4 is compressed and the magnetostrictive noise often increases. As a means for preventing this, there is a means for relaxing the tightening pressure of the yoke core in the stacking direction so that the central part of the yoke core can be extended easily, but it is difficult to control the tightening force and is not practical.

In view of the above points, an object of the present invention is to provide an iron core reactor with a gap, which prevents generation of an unreasonable compressive stress in the central portion of the yoke iron core during operation, and which has reduced noise. To do.

[0006]

DISCLOSURE OF THE INVENTION The present invention is a cored reactor with a gap formed by combining a cored leg with a gap having a circular cross section and a yoke core with a rectangular cross section formed by laminating silicon steel strips. It is characterized in that both ends in the stacking direction are covered with an insulator.

[0007]

As a result, the difference in the temperature distribution due to the non-uniformity of the magnetic flux distribution between the two ends of the yoke core in the stacking direction and the central part is made substantially uniform, and the compression force due to the difference in thermal expansion is prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a case of a single-phase three-leg iron core, in which a plurality of block iron cores 1a formed by laminating silicon steel strips are connected via a magnetic gap 2 made of an insulating gap member. Are stacked to form an iron core leg 1 with a circular cross section, and a winding 3 is wound around the iron core leg 1 with a gap. Above and below this iron core leg 1 with a gap, upper and lower yoke cores 4 and 5 are arranged with a rectangular cross section in which silicon steel strips are laminated so as to sandwich it, and upper and lower tightening plates 6 The iron core leg with a gap 1 by the tightening stud 7 through
The upper and lower yoke cores 4 and 5 are integrally tightened.
In the present invention, as shown in FIGS. 2 (a) and 2 (b), the punched plates at both ends of the upper and lower yoke cores 4 and 5 (only the upper yoke core 4 is shown in the drawing) in the stacking direction. The end surface of the blank, the surface of the blank, or both are covered with an insulator.

With this configuration, during operation, the difference in the temperature distribution due to the non-uniformity of the magnetic flux distribution between both ends and the central part of the yoke core 4 in the stacking direction is not uniform.
As shown by the arrow, the blanks of the respective sections of the yoke iron core 4 extend evenly to prevent the generation of unreasonable compressive stress due to the difference in thermal expansion.

In the above embodiment, the case of the single-phase three-leg iron core has been described, but the present invention similarly applies to other three-phase three-leg iron cores (including winding core yokes) and three-phase five-leg iron cores. Applicable. Further, the present invention can be applied to the side leg portion even for the side leg portion.

[0012]

As described above, according to the present invention, there is provided a core iron reactor with a gap formed by combining a core iron leg with a gap having a circular cross section and a yoke iron core with a rectangular cross section formed by laminating silicon steel strips. The difference in the temperature distribution due to the uneven magnetic flux distribution between the both ends of the yoke core in the stacking direction and the central part, by covering the end surface of the punched plate at the both ends of the stacking direction of Therefore, it is possible to prevent the generation of an unreasonable compressive stress in the central portion of the yoke iron core during operation, and to obtain a cored reactor with a gap that further reduces noise.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part showing an embodiment of the present invention, in which (a) is a plan view and (b) is a front view.

FIG. 3 is a plan view showing a yoke core of a conventional core-core reactor with a gap.

FIG. 4 is a front view showing a temperature distribution of a yoke core.

[Explanation of symbols]

1 ... Gap iron core leg 1a ... Block iron core 2 ... Gap 3 ... Winding 4,5 ... Yoke iron core 4a ... Yoke iron core both ends 4b ... Yoke iron core central part 9 ... Insulator 10 ... Temperature distribution

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01F 37/00 Z 8935-5E

Claims (1)

[Claims] 1. An iron core reactor with a gap formed by combining an iron core leg with a circular cross section with a gap and a yoke iron core with a rectangular cross section formed by laminating silicon steel strips, in which both ends of the yoke core in the laminating direction are removed. An iron core reactor with a gap, characterized in that at least one of the end face of the plate and the surface of the blank is covered with an insulator.