RU1772831C - Welding transformer - Google Patents

Abstract

SUBSTANCE: welding transformer contains two separate 0-shaped cores 1 and 2, located at a distance from each other and magnetic shunts 3 are installed between them. Primary coils 7 are located on one of the rods of each core, coils of the secondary winding 8 span two adjacent rods of individual cores, cores 1 and 2 can be arranged parallel to each other in different planes, adjacent to one another in the same plane. 3 s P. f-ly. 3 ill.

Description

The invention relates to electrical engineering, in particular transformers with steeply falling external characteristics and can be used to power arc welding stations.

A welding transformer with increased magnetic dissipation is known, comprising a magnetic circuit, on the rods of which primary and secondary winding coils are located, and an additional coil, which functions as a current-limiting reactor, is wound on top of all windings and is connected in series to the secondary winding circuit.

The disadvantage of this welding transformer is the significant scattering field, which leads to additional losses, as well as increased consumption of winding material, which leads to an increase in the mass and dimensions of the transformer, and, consequently, an increase in their cost.

Also known is a welding transformer containing a magnetic wire and a movable magnetic shunt on a rod x

which are located on two coils of the primary and secondary windings.

This design of the welding transformer is the closest to the proposed welding transformer and is taken as a prototype of the latter

The disadvantage of the prototype is the significant length of the rods, which leads to an increase in the consumption of electrical steel, an increase in weight and dimensions.

An object of the present invention is to reduce the consumption of active materials.

Furthermore, it is an object of the present invention to limit the operational short circuit current to a level below the nominal.

The first goal is achieved in that the magnetic circuit is made in the form of two separate closed cores installed at a distance from each other and between which magnetic shunts are installed, the primary winding coils are located on one of the rods of each core, the secondary winding

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cover two adjacent core of individual cores.

The second goal is achieved in that the welding transformer has additional primary coils mounted on the second rod of each core and connected in series and counter to the primary coils.

These distinctive features are not described in similar designs of welding transformers, therefore, the proposed technical solution meets the criterion of significant differences.

In FIG. 1 is a schematic diagram of the connection of the windings of a welding transformer made in different planes. In FIG. 2 shows a schematic diagram of a welding transformer in one plane. In FIG. Figure 3 shows a schematic diagram of the connection of the windings of a welding transformer containing additional coils and a capacitor bank; in FIG. 4 - welding transformer in two Russian versions (general view); in FIG. 5 - welding transformer in one Russian version (general view).

The welding transformer contains a magnetic system made of two identical separate 0-shaped cores 1 and 2, magnetically connected to each other by moving magnetic shunts 3. In addition, the transformer contains a primary one consisting of two identical coils 7, and a secondary winding located on rods x cores 1 and 2 of the magnetic system. According to the location of the 0-shaped cores, the welding transformer has two versions: 1 design - 0-shaped cores. 1 and 2 are located one above the other in two planes (Fig. 1, 3,4); 2 execution - 0-shaped cores 1 and 2 are located one next to the other in the same plane of the ruse (Fig. 2.5). In the gap between the 0-shaped cores in the region of the pma 4 there are magnetic shunts 3 which enter and exit between these cores. The cross section of each rod and magnetic shunt is 1: 1.7-2.0, the primary winding coils 7 are connected sequentially and counterclockwise and are located one on one of the rods 5 (or 6) of each individual 0-shaped core, and the free ends form input terminals to which the alternating voltage UL is applied Coils 8 of the secondary winding cover two rods of 5 and 6 different separate 0-shaped cores, one of which contains the primary coil 7 and the other not. If the welding transformer is made in the form of 1 design, then the coils 8 of the secondary winding are located on different rods of separate

cores and are connected in series and counter. In the second embodiment, the coils 8 of the secondary windings are located on one rod and are connected in series and according to each other, and in both cases the free ends of the coils form the output terminals, from which the voltage Ua is removed. To limit the current of the operational short circuit of the primary winding to a level below the nominal by

the rod x 6 (Fig. 3) of each individual core, free from the primary winding coils, an additional two coils 9 are inserted, which are interconnected sequentially and counterclockwise.

the ends (beginning and end) of the coils of the primary and secondary windings located on adjacent rods 5 and 6 of different individual cores 1 and 2, covered on top of the secondary coil 8, are connected

between each other and form one of the terminals, to which the primary voltage Ut. The second AC terminal to which the UL voltage is applied forms the other end of the primary winding, and

between this terminal and the free terminal of the auxiliary winding, a capacitor bank is connected ..

Welding transformer operates as follows.

When the AC source is connected to the terminals of the primary winding, a magnetic flux Φ is created in the rods of the individual cores, the direction of which is conventionally shown by arrows (Fig. 1). As

there is a direct electromagnetic coupling between the primary and secondary windings, | then in the secondary winding an emf is induced, f is equal to the secondary voltage U2, which is determined by the trans

formations between these windings. When the secondary winding closes (for example, the electrode touches the metal), a current appears in the secondary winding, which creates a magnetizing force aimed at decreasing the flux F. Therefore, in the rods on which there are no primary winding coils, its direction flows opposite to F1. and, as can be seen from FIG. 1, flows in the rod x one separate

the magnet is directed downward, and the flows in the rods of another separate core are directed upward. In order to form a closed flow path, it will be closed through an air gap separating the individual cores. Men magnetic resistance

of this gap using a magnetic shunt, we change the magnetizing force of the secondary winding, and therefore the current.

The limitation of the operational current of the short circuit of the primary winding is as follows.

Due to the fact that the primary winding and the additional winding are connected in opposite directions, when idling, the voltage at the terminals of the capacitor is determined as the difference in values, the voltage across the capacitor is small, and it generates a small amount of reactive power. When the secondary winding of the welding transformer is closed, the flow in the rods where additional coils are mounted changes its direction, therefore, the voltage at the terminals of the capacitor is defined as the sum of the voltage of the network and the voltage of the additional winding. The voltage across the capacitor increases, which leads to an increase in the reactive power it generates, which compensates for the inductive reactive power consumed by the transformer from the network. Then the short circuit current decreases; which is almost purely inductive. By choosing the value of the capacitor, it is possible to reduce the current of the operational short circuit of the primary winding to a level below the nominal.

Formulas of the invention

Claims (4)

1. A welding transformer containing a magnetic circuit, on the rod x of which there are two primary and secondary winding coils, a magnetic shunt, characterized in that, in order to reduce the consumption of active materials, the magnetic core is made in the form of two separate closed cores installed at a distance from each other and between which magnetic shunts, primary winding coils are installed located on one of the rods of each core, the secondary winding coils span two adjacent rods of individual cores. 2. The transformer according to claim t, with the exception of the fact that, in order to limit the short circuit current, it has additional primary coils mounted on the second rod of each core and connected in series and counter to the coils primary winding 3. The transformer according to claim 1, characterized in that the cores are mounted parallel to each other in different planes, the secondary winding coils span each of two adjacent rods of a separate core and are connected in series and counterclockwise. 4. The transformer according to claim 1, characterized in that the cores are located adjacent to each other in the same plane, the secondary winding coils are connected in series, and according to this, both secondary winding coils are located on the same rods of the individual cores. U2 F # s.Ј % g 8 6