SU1004039A1 - Welding current generator self-excitement system - Google Patents

Description

(54) WELDING GENERATOR SELF-EXCITATION SYSTEM

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The invention relates to welding production, in particular, to self-excitation systems of a welding generator.

A known system of self-excitation of a welding generator, comprising an excitation winding and a set of uncontrolled valves, intended to be connected between the circuits of the generator and the excitation winding 1.

A disadvantage of the known system is the low quality of the generator excitation, which ultimately reduces the quality of welding.

A known self-excitation system for a welding generator, comprising an excitation winding, a current transformer and a voltage transformer with armor-type cores, the secondary windings of both transformers are connected in series, and the primary windings are designed to be connected to the output circuits of the generator, and a block of uncontrolled gates connected between the secondary windings of transformers and generator winding. This device, due to the presence of current transformers and voltage, makes it possible to improve the excitation quality of generator 2.

However, to provide the necessary sensitivity of a self-excited circuit at low welding currents, the primary winding of the current transformer must contain several (3-7) primary turns. At high welding currents, since the frequency of the current flowing through the primary winding of the current transformer is several hundred hertz, and the primary winding of the transformer has a certain inductance, the current in this phase is much less than the current in the three-phase generator system, appears uneven current distribution in the valve rectifier unit, the excitation power increases, the efficiency of the generator decreases.

The aim of the invention is to increase the system efficiency and welding quality by eliminating the asymmetry of the currents in the output circuits of the generator.

Claims (2)

The goal is achieved by the fact that in a self-excited system of a welding generator containing an excitation winding, a current transformer and a voltage transformer, the secondary windings of both transformers are connected in series, the primary windings are intended to be included in the generator output circuits, and a block of uncontrolled valves connected between the secondary windings of transformers and excitation windings of the generator, the secondary winding of the current transformer is made in the form of several, according to the number of generator phases wound in one direction coils, wherein each coil separately from each other is included in sootvetstvuyushaya phase generator, with one of them turned opposite the others. The drawing shows a circuit diagram of a self-excited excitation system of a welding generator. The self-excitation system contains an excitation winding 1, a current transformer 2 with O-type cores 3 and a voltage transformer 4. The primary windings of a current transformer 2 and a voltage transformer are designed to be connected to the output circuits of the generator 5, and their secondary windings 6 and 7 are connected in series and through a block of uncontrolled valves 8-10 are connected to the excitation winding 1. The primary winding of the current transformer 2 is made as several, according to the number of phases of the generator 5, wound in one direction coils 11-13. Each coil is separately connected to the corresponding phase A, B or C of the generator 5. Moreover, winding 13 is opposite to the other windings H and 12. Such connection of the coils in the transformer core produces a double flux compared to a conventional single-phase current transformer. Therefore, the number of primary turns of the coil of such a transformer is at least less than in the prototype. Transformer 4 serves to excite the generator at idle. Then it is ONLY one through rectifier 8 that feeds the field winding. Since in the circuit both the voltage transformer 4 and the current transformer 2 with their secondary windings feed the excitation winding with single-ended current pulses, during the pauses between these current pulses the electromagnetic energy accumulated in the excitation winding 1 is discharged by the current flowing through the rectifier. The above implementation of the current transformer and the new inclusion of its primary windings in the output circuits of generator 5 allows, in comparison with the prototype, to increase the efficiency of the system and the quality of welding. The invention The samsa excitation system of a welding generator, a porridge excitation winding, a current transformer and a voltage transformer, the secondary windings of both transformers are connected in series, the primary windings are intended to be included in the output circuits of the generator, and a block of uncontrolled valves connected between the secondary windings of transformers and generator excitation winding, distinguished by the fact that, in order to increase the system efficiency and welding quality by eliminating the asymmetry of the currents in the output x chains generator, the primary winding of the current transformer is designed as a multiple, the number of phases of the generator, wound in one direction the coils, wherein each coil is separately .from other sootvetstvuyushaya included in the phase generator, with one of them turned opposite the others. Sources of information taken into account in the examination 1. Zaruba I. I. and others. Welding in carbon dioxide. Gostekhizdat, Kiev, 1960, p. 202, 203, fig. 66 2. USSR author's certificate number 266974, cl. At 23 K 9/00, 07/03/67 (prototype).