RU2516438C2 - Hard tape magnetic conductor for transformer and method of making same - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to electrical engineering, magnetic conductors of electrical transformers, having a multilayer structure made of amorphous or nanocrystalline tape, and methods for production thereof. The hard tape magnetic conductor for a transformer is in form of a multilayer structure, each layer of which is formed from a predefined number of magnetic amorphous strips with an off-set gap in between, on the length of the magnetic conductor. The magnetic amorphous layer has a given geometric shape and has one lock-on connection formed by the beginning and the end of said layer. The lock-on connection is in form of a finger joint, e.g. dovetail. The method of making a hard tape magnetic conductor from an amorphous magnetic alloy involves cutting strips, treatment thereof with an adhesive compound and layering while offsetting the strips relative each other on the length of the magnetic conductor. The strips are cut by passing amorphous tape, for example through scissors, for example treated with a carbon-containing adhesive material and placed on an assembly table. A magnetic conductor with a winding is formed and the fold line and the lock-on connection are exposed to pulsed and/or high-speed heating. The amorphous magnetic strips are coated with a carbon-containing adhesive material by spraying in liquid form and/or superimposing an adhesive tape.

EFFECT: high quality of the magnetic conductor by reducing magnetic losses and increasing induction therein and easy manufacture.

3 cl, 4 dwg, 1 tbl

Description

The invention relates to magnetic cores of electrical transformers having a multilayer structure of an amorphous or nanocrystalline tape and to methods for their manufacture.

A transformer is an electrical device that is widely used to transfer alternating current energy from a primary winding to one or more secondary windings. The transformer contains at least two windings. Each of the windings is made in the form of a multi-turn design with electrical conductors, with one or more magnetic circuits connecting the windings by means of magnetic flux transmission.

Magnetic cores of an electric transformer are usually made of steel sheets with a high silicon content and a correspondingly oriented crystalline structure. The most common method of manufacturing a transformer is to assemble a magnetic circuit, regardless of the preformed winding or windings with which it will be assembled in the transformer. For this, the magnetic circuit is formed detachable, in which its sheets can be separated, making it possible to install it in the winding window. Magnetic tape connections are usually “step joint” or “step overlap” connections.

Significant advantages were provided by amorphous magnetic alloys used as the material of the magnetic core for transformers, since they are materials with lower losses compared to steel with a crystalline structure. However, the annealed amorphous metals become very brittle and, thus, they are destroyed by mechanical stress, for example, at the stage of closing the joints of the magnetic circuit. Various technologies have been developed aimed at facilitating the manufacture of a magnetic tape transformer from amorphous tapes, according to which it has joints in localized areas, which makes it possible to insert an open magnetic circuit into the window of a preformed winding. These technologies are shown, for example, in US patent No. 4789849, 4790064, 4893400, 5398402, 5398403, 5329270, 5347746, 5548887.

An analogue of the proposed technical solution is a rigid tape magnetic circuit for a power distribution transformer, made in the form of a multilayer structure, each layer of which is formed from a predetermined number of magnetic strips, having one castle connection, consisting of separate elements that are not connected to each other: tongue and groove, located perpendicular to the horizontal plane of the layers of the magnetic circuit. The lock connection of this technical solution is a latch connection. (US 3,725,832 A, H01P 27/24, April 3, 1973).

The disadvantages of this technical solution include increased magnetic losses due to the structural feature of the magnetic circuit.

The closest in technical essence to the proposed technical solution is the manufacture of a magnetic circuit by the method of joining its two halves, and the assembly is performed in inclined planes. This ensures a more uniform distribution of the butt joint of the halves of the magnetic circuit, which allows to slightly reduce magnetic losses and improve its characteristics (see, for example, “Components and Technologies” No. 8, 2006).

and technology of its manufacture.

The object of the alleged invention is a rigid tape magnetic circuit for a transformer, made in the form of a multilayer structure, each layer of which is formed from a predetermined number of magnetic strips, having one castle connection, while the magnetic layer is made of an amorphous alloy in the form of a given geometric shape and has one castle the connection formed by the beginning and end of this layer, and located parallel to its horizontal plane, and the castle connection is made in the form of a spike connection eniya such as "dovetail".

The design of the rigid tape core is made in such a way that each layer is formed from the required number of amorphous tapes and is designed to ensure optimal distribution of magnetic flux inside the tapes in the layers. The number of layers is determined by the magnetic properties of the material from which the tapes are made. The core thickness is determined by the electrical and mechanical parameters of the transformer, such as the height and cross section, as well as the frequency of the current and the rated power of the transformer.

According to the selected geometric shape (Fig. 1 and Fig. 2), a decrease in magnetic losses is ensured by creating a distributed non-magnetic gap.

Magnetic cores are rods of various sizes from strips of amorphous tape, obtained by machining glued to each other strips with a thickness of 25-30 microns.

Carbon-containing, for example, activated carbon, or amorphous carbon, or graphite, an adhesive material improves heat dissipation and reduces electromagnetic dispersion fields.

Another object of the alleged invention is a method of manufacturing a rigid magnetic tape from magnetic 1 amorphous alloy, comprising cutting the strips, processing them with adhesive, forming them into layers with the strips shifted relative to each other along the length of the magnetic circuit, while the strips are cut by passing an amorphous tape through scissors for example, drum, treat them with carbon, for example, activated carbon, or amorphous carbon, or graphite, with adhesive material, lay on an assembly table, the magnetic core preform is compacted and sealed, for example, in a U-shaped heated matrix by lowering the heated punch, connected to the windings and fixed the bend lines and the lock connection by pulse and / or high-speed heating, and carbon-containing, for example, activated carbon, is applied to amorphous magnetic strips, or amorphous coal, or graphite, by spraying in liquid form and / or applying adhesive tape.

An amorphous tape (Fig. 3), unwound from roll 1, passes through the pulling rollers 3 and enters the flying scissors 4, which are two drums rotating in opposite directions with a cutting edge of a given geometric shape. Cut strips of a given length go to the desktop 5. The required length is provided by changing the speed of rotation of the drums of flying shears.

Carbon-containing adhesive material is applied in liquid form to the upper surface of the strip 6. Next, the next strip is superimposed on it and so on until a layer of the required thickness is formed. Stripes on the desktop are formed with an offset along the length, using installed at an angle relative to the vertical axis of the stop 7.

Under the formed layer is a heated U-shaped matrix 8. When lowering the heated punch 9 into the matrix, a close-packed preform of the magnetic circuit of a given size is formed. The matrix and punch are heated to accelerate the drying of adhesive material.

Another method of manufacturing a magnetic circuit is possible, which is as follows. Rolls of amorphous 1 and adhesive 2 tapes are unwound from coilers in such a way that an adhesive tape is located between the amorphous alloy tapes. Next, the formed layer is fed to the drums of flying shears according to the above technology.

The windings are put on open magnetic cores (Fig. 4), after which their ends are closed. Then the fold lines and lock joints are subjected to pulsed and / or high-speed heating, which allows you to remove elastic stresses and fix them.

Example:

Magnetic conductors of the PL type 16 × 32 × 65 with a size of 99.5 × 58.0 × 32 mm were made of an amorphous tape 25 ± 3 μm thick, between which there was a carbon-containing material. The magnetic core blank was formed and compacted in a U-shaped heated matrix and a punch, transformer windings were put on it and the lock connection was closed. The fold lines and the lock connection of the magnetic circuit were fixed by pulsed heating.

According to the proposed method, an experimental transformer was manufactured. Comparative tests were conducted with characteristics of similar types, the magnetic cores of which are made of electrical steel and amorphous material.

The table shows comparative data on the main characteristics of transformers, the magnetic circuits of which are made of electrical and amorphous steel (2), amorphous material (3 - prototype) and 4 - the proposed design). Losses in transformers were determined by the wattmeter method. Determination of induction was carried out by the method of a voltmeter - ammeter.

Table No. p / p Product Saturation Induction, T Working induction, T Loss, W / kg one Material properties measured on an annular tape magnetic core Amorphous Electrical Steel 1,56 - 0.20 Electrical Steel Grade 3416 1.90 - 1.20 2 Core magnetic core Amorphous Electrical Steel 1,56 1.30 0.60 Electrical Steel Grade 3416 1.90 1,60 2.40 3 Braided magnetic core Amorphous Electrical Steel 1,56 1.30 0.30 four The magnetic circuit of the proposed design Amorphous Electrical Steel 1,56 1.35 0.25

As can be seen from the table, the proposed design of the magnetic circuit, reduced magnetic losses, increased working induction compared to the prototype (3), and a transformer made from it has a higher efficiency.

The application of the proposed design of a rigid tape magnetic circuit and the method of its manufacture can improve the quality of the magnetic circuit by reducing magnetic losses and increase the working induction, as well as significantly simplify the technology of its manufacture, due to the fixation of the fold lines and lock joints by pulse and / or high-speed heating.

Claims (3)

1. A rigid tape magnetic circuit for a transformer, made in the form of a multilayer structure, each layer of which is formed from a predetermined number of magnetic amorphous strips with an offset gap along the length of the magnetic circuit, characterized in that the magnetic layer is made of an amorphous alloy in the form of a given geometric shape, has one castle connection formed by the beginning and end of this layer. 2. A rigid tape magnetic circuit for a transformer according to claim 1, characterized in that the locking connection is made in the form of a spike connection, for example, "dovetail". 3. A method of manufacturing a rigid tape magnetic core from a magnetic amorphous alloy, comprising cutting strips, forming them into layers with strips shifting relative to each other along the length of the magnetic circuit, characterized in that the strips are cut by passing an amorphous tape through scissors, for example, drum, placed on the assembly table, form and compact the blank of the magnetic circuit, for example, in a U-shaped heated matrix by lowering the heated punch, connect it to the windings and fix the fold lines and the lock connection s pulse and / or rapid heating.

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