RU2106711C1 - Shell-type magnetic core - Google Patents

Abstract

FIELD: electrical engineering, transformers and other electrical gears. SUBSTANCE: proposed shell-type magnetic core is wound from one ferromagnetic tape having extended continuous section that forms internal cylinder in process of winding, having extended window section in midpart that forms yoke in process of winding and having extended continuous section with holes for cooling agent that forms external cylinder in process of winding. EFFECT: facilitated manufacture, improved functional characteristics. 1 cl, 4 dwg

Description

 The invention relates to electrical transformers and other electrical devices, in particular to the designs of their magnetic circuits.

Known magnetic circuit (AS USSR N 936047, class H 01 F 3/04), made of a continuous ferromagnetic tape with an insulating coating, wound on a rib with an excess of 180 ^o . A disadvantage of the analogue is the deformation of the tape at the inflection points, which reduces the electromagnetic characteristics of the core and complicates the manufacturing technology.

 Closest to the technical nature of the claimed device is the magnetic core of the transformer (AS USSR N 1332395, class H 01 F 27/30), containing a magnetic system with cores made in the form of hollow cylinders of the same height, placed concentrically relative to each other, and a ring-shaped yoke with flanges at the ends located on the ends of the cores, with windings located in the cavity formed by the cylinders and yokes. The disadvantage of the prototype is the presence of continuous gaps between the rods and yokes, which leads to an increase in the magnetization current of the transformer and the occurrence of eddy currents at the joints of the charged packages of the magnetic circuit. To avoid the formation of eddy currents in these places and the associated increase in additional losses, and even “fire in steel”, insulating gaskets are used, but this, in turn, increases the gap and the open-circuit current.

 The aim of the invention is to eliminate these disadvantages.

 This goal is achieved by the fact that the magnetic core is made of twisted one tape, having in the initial part an extended continuous section, which forms an inner cylinder during winding, in the middle part with an extended section window, which forms a yoke during winding, and in the last part an extended continuous section with openings for a cooling agent forming an external cylinder during winding.

 In FIG. 1 shows the inventive magnetic circuit; in FIG. 2 - blank tape with stamped windows for winding the magnetic circuit; in FIG. 3 - the position of the roll tape after winding the rod; in FIG. 4 - blank with a trapezoidal window.

 In FIG. 1: 1 - magnetic core, 2 - transformer winding coils located on the core of the magnetic core, 3 - windows in the yoke of the magnetic core, 4 - clips, 5 - pressure device, 6 - welding seam.

 The magnetic core is made in the form of a spiral coil of ferromagnetic roll tape 1, the initial part of which “a” (Fig. 2) has no slots and forms a “a” rod after winding (Fig. 1, 2). Then the core winding is suspended, and two half-frames of insulating material are put on the formed round rod “a”, which are fastened together and, rotating the resulting cylinder relative to the rod, are wound on it in the usual way. The rotation of the cylinder is done manually or from the simplest mechanism. After the windings are finished and (if necessary) the insulating layer between them, winding of the remaining roll tape is resumed. After winding the middle part "b" (Fig. 1, 2, 3), having an extended notch, two horizontal yokes of the magnetic circuit are formed in the form of "disks", limiting the core from above and below, and after winding the third part "c", with windows 3 , a vertical, in the form of a hollow cylinder, yoke "in" is formed (Fig. 1), limiting the magnetic circuit from the sides. After the winding of the tape is completed, the clips 4 are put on the top and bottom of the magnetic circuit, and a pressure device 5 is inserted into the axial hole to seal the layers of the obtained core 5. In some cases, the end of the tape can be fixed with a welding seam 6.

 The second option is designed for winding high-power power transformers, where large wires are required. The winding coils in this case are made in advance, before the start of the winding of the magnetic circuit. In this method, after winding part “a” of the magnetic circuit, the tape in the upper part “b” of the workpiece is cut and the core winding continues for some time until the remaining “appendix” of part “b” is laid. Now the core is a cylinder with small thickenings at the edges (several turns of tape) and nothing prevents putting on it pre-made windings on top, reinforcing them, then joining the cut parts of the upper tape “b” of the workpiece and continuing to wind the core together with the installed windings before using the entire tape blank. In this case, one of the many turns of the tape in the upper yoke will have one gap, but this circumstance will not have a significant effect on the core. If necessary, to compensate for this error, you can slightly increase the width of the upper part "b" of the workpiece (Fig. 2).

 In another embodiment of the core, in order to further reduce the weight of the magnetic core, the middle part of the preform has a trapezoidal window, which allows the cross section of the horizontal part “b” of the yoke to be the same over the entire length / radius / (Fig. 4).

 The proposed device is characterized by a high degree of use of materials. The outer part of the magnetic circuit “c” during air cooling can play the role of a casing that reliably protects the windings from mechanical damage. When winding, the waste became small, because the cutout in part "b" of the workpiece (Fig. 2) can be used for the manufacture of other, smaller cores, other products. A transformer with such a core is characterized by a small amount of magnetic flux scattering and a low idle current. The design is extremely simple and technologically advanced, all operations of stamping, core winding and windings, welding are easily mechanized and automated.

Claims (2)

 1. Armored magnetic core mainly for transformers, made of electrical steel in the form of two coaxial cylinders connected by annular yokes, characterized in that the magnetic core is made of twisted one tape, having in the initial part an extended solid section forming an inner cylinder during winding, and in the middle parts with an extended window - a section forming when yoke is wound, and in the last part - an extended continuous section with holes for a cooling agent, forming an external cylinder during winding.  2. The magnetic circuit according to claim 1, characterized in that the window in the middle part of the tape is made in a trapezoidal shape.

Images