RU2448384C1 - Transformer - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: transformer comprises primary windings (1), enveloping winding bars (2). Upper and lower yokes (3) are electrically insulated and magnetically join upper and lower ends of winding bars (2), inner outputs of which are connected to outputs of the transformer by wires (4), passing via ends of winding bars (2). Short-circuited turns (5) are introduced, which cover toroids of winding bars and providing for compensation of perpendicular magnetisation of winding bars by currents of wires (4).

EFFECT: improved characteristics and expanded field of MTS, MTC, MTM transformer by increasing permissible load currents.

1 dwg

Description

The invention relates to electrical engineering and can be used in electromagnetic transformers.

и

, направленные вдоль сердечника. Снижение рабочего значения H_c в электромагните нежелательно, т.к. это уменьшает его тяговое усилие. Кроме этого, уменьшение R₂ до нуля увеличило бы ток I₁ обмотки, подключенной к источнику напряжения, до разрушающего ее значения.Known valve electromagnet AC (Taev IS Electrical apparatuses. General theory. M .: Energy, 1977, pp. 234, 250), containing a core covered by a winding and a short-circuited coil. A short-circuited coil of an electromagnet either has an electrical resistance R ₂ >> 0, or covers only part of the core cross section, dividing H _with components shifted in phase relative to each other

and

directed along the core. A decrease in the operating value of H _c in an electromagnet is undesirable, since this reduces its traction. In addition, reducing R ₂ to zero would increase the current I _{1 of the} winding connected to the voltage source to a value that destroys it.

The closest technical solution is the MTS / MTC / MTM transformer (Vafin Sh.I., Kazakov VV, Kazakov OV, Nemtsev GA. New classic transformers with optimized block design. Description and theoretical justification. G- l "Energy of Tatarstan", No. 4, 2008, p.25), containing: a core formed by vertical rods, the upper ends of which are magnetically connected through the upper yoke, and the lower - through the lower yoke; while the ends of the rods are electrically isolated from the yoke; primary windings covering the rods; moreover, the rods are wound in the form of rolls of enameled tape of a ferromagnetic material with high electrical conductivity and combine the function of the secondary windings or their parts. The loop of the wire connecting the output of the transformer with the inner end of the tape of the rod-winding and passing through its end, covers a vertical section of the toroid formed by the turns of the rod-winding. EMF of one turn of the vertical and horizontal sections of the rod is approximately equal to e, i.e. E ₂ = N ₂ · k _U · e >> e = E ₃ , where: E ₂ and N ₂ - EMF and the number of turns of the core-winding; k _U = (D _ext. + 2D _ext.) / (3D _Ext. + 3D _ext.), D _ext. and D _ext. - outer and inner diameters of the core-winding; E ₃ - EMF loop wire. Therefore, the total current I ₃ = i _{3 of the} loop is not limited to the counter emf of the E ₃ loop and is equal to the load current of the transformer i ₂ = I ₂ / N ₂ , i.e. I ₃ = i ₃ = i ₂ = I ₂ / N ₂ . Thus, the toroid of the rod and the loop of the connecting wire are the core and primary winding of the current transformer. Since this transformer does not have a secondary winding circuit, the magnetic field strength of this current transformer, perpendicular to the intensity N _{from the} magnetic field of the main transformer, is equal to N _t = I ₃ / l _t = I ₂ / (N ₂ l _t ) and when I ₃ >> I _µt can cause perpendicular saturation of the rod, repeatedly reducing its magnetic permeability µ in the direction of H _c ; here: l _t = π · (D _{ext .} + D _int. ) / 2 is the average length of the magnetic circuit of the toroid, I _µt is the equivalent magnetization current. A similar problem arises even if the connecting wire is passed through a horizontal through hole in the middle of the winding rod. This does not allow to produce high-quality MTS / MTC / MTM transformers with a lower transformation ratio, since limits the increase in the output current I ₂ / N ₂ of the transformer load.

The objective of the invention is to increase the load capacity of the transformer.

The technical result is achieved in that in a transformer containing primary windings, winding rods, upper and lower yokes, electrically isolated and magnetically connecting the upper and lower ends of the winding rods, the internal terminals of which are connected to the transformer outputs by wires passing through the ends of the winding rods In addition, short-circuited demagnetizing coils are introduced, covering the toroids of the winding rods and neutralizing their perpendicular magnetization.

The drawing shows a fragment of a transformer in section.

The transformer contains:

1 - primary windings,

2 - winding rods,

3 - upper and lower yokes,

4 - wires

5 - short-circuited demagnetizing coils.

The upper and lower yokes 3 are electrically isolated and magnetically connect the upper and lower ends of the rods-windings 2. The wires 4 pass through the ends of the rods-windings 2 and connect the internal terminals of the rods-windings 2 with the outputs of the transformer. Short-circuited demagnetizing coils 5 cover the toroids of the winding rods 2.

The transformer operates as follows.

When you connect an alternating voltage U ₁ network with a cyclic frequency ω to the terminals of the primary winding 1 of the transformer with the number of turns N ₁ , in a closed magnetic circuit containing the rods-windings 2 and yoke 3, the magnetic flux f _slave. = U ₁ / (ωN ₁ ), proportional to the ampere turns I ₁ = i ₁ · N _{1 of the} primary winding, uniform in horizontal section S _{c of the} rod 2 and inducing in the secondary winding 2 with the number of turns N _{2 the} voltage U ₂ = k _U ωN F ₂ where k _U = (D _ext. + 2D _ext.) / (3D _ext. + 3D _ext.), D _ext. and D _ext. - outer and inner diameters of the rod 2.

The second magnetic circuit perpendicular to the flux Ф _slave. , which reduces the permeability of the core by its perpendicular magnetization, is formed by a toroid of the rod 2 and is covered by a loop of wire 4 and a short-circuited coil 5, the electrical resistance of which is R _kz << R ₂ , where R ₂ is the total electrical resistance of the secondary winding, the role of which is performed by the rod-coil, wire 4 and transformer load. Due to the small value of R _{kz, the} total current I _{4 of the} connecting wire 4 becomes equal to the total current I _{3 of the} short-circuited coil 5, and the magnetic field strength of the unwanted magnetic circuit N _t = (I ₃ -I ₄ ) / l _t is close to zero; where l _t = π · (D + D _{ext ext..)} / 2 - the average length of the rod circumference of the toroid.

Thus, the introduction of a short-circuited coil 5, covering the toroid of the rod 2, completely eliminates the perpendicular magnetization of the rod 2, while maintaining a high magnetic permeability of the core regardless of the load current of the transformer MTS / MTC / MTM.

The transformer can be made of the same materials from which the prototype is made. For example, the rods of winding 2 and yoke 3 can be wound with calibrated tapes of enamelled polyimide from 99.998-99.999% electrolytic iron produced by electro-magnetic refining at the Kyshtym copper electrolyte plant or at Industrial metal powders (India) pvt. Itd. and having the following characteristics: resistivity ρ _{26 ° C} = 0.0947 μOhm · m; relative magnetic permeability µ = 100000 ... 120000; saturation induction In _max = 2.66-2.70 T; coercive force H _with <0.2 A / m; width calibration error - not more than ± 0.25 microns; the thickness of the polyimide 4-sided insulation d _and = 3 microns, the metal thickness of one layer of the tape d _W = 50 microns.

The transformer can have all the designs inherent in the prototype, and can replace all types of measuring and power transformers.

Claims (1)

A transformer containing primary windings covering the winding rods, the upper and lower yokes, electrically isolated and magnetically connecting the upper and lower ends of the winding rods, the internal terminals of which are connected to the transformer outputs by wires passing through the ends of the winding rods, characterized in that It is additionally introduced short-circuited demagnetizing coils, covering toroidal rods-windings.