RU2430817C2 - Inductor welding generator - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to welding hardware and may be used for producing self-contained power supplies. Two toothed stacks of generator stator are connected with thick-wall steel foundation that doubles as housing and outer magnetic core. Excitation winding terminals are connected with power supply. Power winding 3-phase terminals are connected via rectifier and current regulator with output terminals. Two toothed no-winding rotor cores are joined together by bushes that make inner magnetic core. Power winding comprises separate coils applied on every tooth of every core. Phase each branch is formed by interconnected pair of coils fitted on adjacent teeth and another pair of coils shifted through 180 electrical degrees and arranged diametrically. Number of stator teeth is multiple of 12, while that of rotor is multiple of 5 or 7.

EFFECT: expanded operating performances, simplified design.

3 cl, 5 dwg

Description

The invention relates to electrical engineering, in particular to electric machines of high frequency, and can be used in the manufacture of autonomous power sources of the welding arc.

A welding generator is known (RF patent No. 7358, op. 10.08.1998 and No. 21845, publ. 02.20.2002), containing a two-pack gear stator with a constant pitch of teeth, with a three-phase winding, each phase of which consists of parallel coil groups , gear winding two-pack rotor and field winding made of one coil. The findings of the stator winding through the rectifier and switchgear are connected to the output terminals. A distinctive feature of this generator is that each coil from the stator winding coil group covers the corresponding teeth of two packets.

The disadvantage of this welding generator is the increased consumption of wire, due to the fact that the coils of the power winding cover both packages of the stator. A significant part of the conductors embedded in the space between the packets is not active, since no EMF is induced in them at this section. One massive excitation coil also requires an increased consumption of winding wire due to the insufficient cooling surface and the need to reduce the current density in this connection, increasing the cross section of the wire to avoid overheating of the insulation.

In addition, the generator has a low speed of stabilization of the welding current, since feedback through the field coil having a large inductance is slow and lags significantly behind the rate of change of the current and voltage of the welding arc, which leads to defects in the weld.

The closest in design features to the claimed is a power source for electric arc welding (A.S. No. 754586, publ. 08/07/1980), containing two gear packages of the stator, an annular excitation coil made of one coil and placed between two packages of gear windingless rotor, and power winding. The conclusions of the phases of the power winding through the rectifier unit and the switches playing the role of a current regulator are connected to the output terminals, and the conclusions of the excitation coil are connected to the power source of the excitation circuit.

On each stator package, the same three-phase windings are placed, shifted relative to each other by 180 el. hail and connected in a common six-phase star.

The disadvantages of this power source are the high consumption of the winding wire and the distorted shape of the generated voltage, leading to an increased level of ripple of the rectified voltage, which, in turn, prevents the use of high-frequency pulse welding current regulators.

Concentration of the field winding in one coil leads to a decrease in the cooling surface and forces an increase in the cross section of the wire in order to avoid excessive overheating. In addition, the speed of stabilization of the welding current is low, since the feedback through the field coil having a large inductance is slow and lags significantly behind the rate of change of the current and voltage of the welding arc, which leads to defects in the weld.

The objective of the invention is the formation of external steep and hard characteristics while improving dynamic characteristics (welding properties), reducing the ripple of the rectified voltage, as well as increasing the degree of use of active materials and simplifying the design.

The problem is solved in that in an axial-type induction welding generator containing two serrated gear packages connected to a thick-walled steel bed serving simultaneously as a casing and an external magnetic circuit, an annular field winding whose terminals are connected to a power source, a 3-phase power winding, phase outputs which through the rectifier unit and the current regulator are connected to the output terminals, two gear non-wound gear packages of the rotor connected by bushings serving as an internal magnetic circuit, in addition, silt winding, made by superimposing on each tooth of each stator packet of separate coils, each phase branch is formed by the counter-connection of one counter-connected pair of coils located on adjacent teeth and another similar pair of coils shifted by 180 electrical degrees and diametrically located, while the number of stator teeth is a multiple of 12, and the number of rotor teeth is a multiple of 5 or 7. In this case, the field winding is made of at least two ring coils connected in parallel. The power supply of the excitation circuit is made controllable, and the current regulator is made in the form of a high-frequency pulse regulator.

The reduction in the consumption of the winding wire and at the same time the reduction of the ripple of the rectified voltage is ensured by the fact that the stator winding is made of coils, each of which covers only one tooth and on only one package.

The reduction in wire consumption occurs by reducing the average length of the coil. Firstly, the length of the frontal parts of the coils is significantly reduced, since the path from the groove to the adjacent one is obviously shorter than the path from the same groove to the third. Secondly, the intersection of the frontal parts of the stator winding coils and the need to extend the frontal parts to round the intersection points are eliminated.

Reducing the ripple of the rectified voltage is achieved by the fact that the coil covers only one tooth and does not cover a single opening of the stator groove, as well as the compensation of even harmonics by the counter-connection of the coil groups.

Reducing the flow rate of the wire to the field winding is achieved by making it from two or three separate coils installed at intervals, which improves cooling of the winding and makes it possible to reduce the cross section of the wire.

The increase in speed is achieved by independent supply of the field winding from an adjustable power source and the use of a high-frequency pulse regulator of the welding current.

Figure 1 shows a two-pack induction welding generator, a longitudinal section;

Figure 2 shows a two-pack induction welding generator, a cross section (A-A);

Figure 3 shows a scan of the winding of one stator package, with the image of the connection circuit of the coils containing S = 12 teeth of the stator and R = 5 teeth of the rotor;

Figure 4 shows the electrical circuit of the generator with stepwise regulation of the welding current;

Figure 5 shows the electrical circuit of the generator with smooth regulation of the welding current;

Induction welding generator (Fig.1, 2) contains two gear stator packages 1 and 2, the gear surface of which is facing the working gap. Each of the stator packets contains S = 12 (S1 ÷ S12) teeth (Fig. 3) located around a circle with a constant pitch. Stator packages 1 and 2 are connected by a thick-walled tubular bed 3, which is the external magnetic circuit of the axial machine. Opposite the stator packs 1 and 2, two gear rotor packs 4 and 5 are installed, the gear surface of which faces the working gap. Each of the rotor packages contains R = 5 (R1 ÷ R5) teeth located around the circle with a constant pitch. Rotor packages 4 and 5 have the ability to rotate inside the stator packages 1 and 2 with a small air working gap. The rotor bags 4 and 5 are mounted on the dowels on two massive steel bushings 6 and 7, respectively, which are mounted on the dowels on a common shaft 8 and are tightly interconnected by end surfaces, forming an internal magnetic circuit, also conducting axial magnetic flux. The shaft 8 rotates in two bearing shields 9 and 10, attached to a thick-walled tubular bed 3, which performs, in addition to the function of an external magnetic circuit, the function of a generator housing.

The proposed inductor generator differs from the prototype in the arrangement of both windings available in the generator: the stator power winding and the field winding.

The power winding 11 consists of two power windings 12 and 13, respectively laid in the grooves of the stator packets 1 and 2. Moreover, each of the power windings 12 and 13 consists of coils L = 12 (L1 ÷ L12) (figure 3) and is superimposed on each tooth S1 ÷ S12 of each stator packet 1 and 2, respectively, of a separate coil L1 ÷ L12. Every two coils L located on adjacent teeth S are interconnected in the opposite direction. To suppress even harmonics, the phase branch 14 is formed by a counter-connection, for example, of the first pair of coils L1 and L2 with the second similar counter-coupled pair of coils L7 and L8 shifted by 180 electric degrees in the magnetic field relative to the first pair. In addition, to compensate for the unevenness of the air gap, said second pair of coils is located as diametrically remote as possible from the stator bore relative to the first.

The minimum number S of stator teeth in the proposed generator, which allows to obtain a 3-phase winding with a phase zone of 60 electrical degrees and one parallel branch, is S = 12. The minimum number of teeth R of the rotor is equal to R = 5 or R = 7. This set of teeth S and R forms the elementary sector of the generator with minimum generated power. A multiple increase in elementary sectors makes it possible to obtain several parallel branches in each phase and increase power. Accordingly, the number R of rotor teeth and S of the stator increases by a factor of one. In the inventive generator, the power winding can be performed according to one of the following options: two branches with S = 24 teeth of the stator and R = 10 or R = 14 teeth of the rotor, three branches with S = 36 teeth of the stator and R = 15 or R = 21 teeth rotor, four branches with S = 48 teeth of the stator and R = 20 or R = 28 teeth of the rotor. A greater number of parallel branches corresponds to a generator of greater power.

Given that in the induction welding generator there are two identical power windings of the stator packets 1 and 2, they can be connected in series or in parallel to work on a common output. Thus, the total power of the proposed 2-pack generator is composed of the capacities generated by each power winding of the stator package 1 and 2.

If you do not connect the power windings of the packages, but bring them through separate regulators to separate terminals, then you can use the proposed generator as a power source simultaneously and independently of 2 welding stations.

The excitation winding 15 of the generator is divided into two or three ring coils 16, 17 and 18, which are installed in the space between the rotor packages 4 and 5. Coils 16, 17 and 18 are fixedly mounted to the frame 3, each at three points spaced one from the other on angle of 120 ° by means of rods 19 and insulating grips 20.

The findings of the field winding 15 are connected to the power supply unit 21 of the excitation circuit, which is made in the form of a controlled constant voltage source 22. The findings of the phases of the power winding 11 are connected through series-connected rectifier unit 23 and current regulator 24 to the output terminals 25 of the generator. The rectifier unit 23 contains 3-phase rectifiers 26, and their number corresponds to the number of branches of the power winding 11 of the generator. The current controller 24 can be made in the form of controlled keys 27 (Fig. 4), in this case, the number of branches of the power winding 11 of the stator should be more than one, or be a high-frequency pulse controller (electronic rheostat, chopper) 28, made according to one of the known circuits and designed for the rated current of the generator (figure 5). The number of parallel branches in this case can be any.

The operation of the device.

The generator operates as follows. An independent power unit 21 supplies voltage to the field coil 15, which generates magnetic flux in the generator. When the gear rotor 4 and 5 rotate, the magnetic flux pulsates and induces an alternating voltage in the power windings of the 12 and 13 stator packets 1 and 2. The frequency of the alternating voltage, for example, in the case with S = 48 teeth on the stator and R = 20 teeth on the rotor at speed rotor rotation of 2200 rpm is 733 Hz. The increased frequency of the welding current caused by this voltage favorably affects the welding properties of the generator. The current is rectified by 3-phase rectifiers 26 and through closed switches 27 is supplied to the output terminals for welding. In this case, step-by-step regulation is carried out by creating current ranges, by connecting through a switch 27 a different number of parallel branches, in combination with smooth regulation within each range, by changing the excitation current. To implement this option, the number of parallel branches in the stator winding 11 should be more than one. To reduce the number of contacts of the range switches, the parallel branches are connected after the rectifiers installed in each branch.

For smooth regulation of the welding current, the current controller 24 is a high-frequency pulse controller (electronic rheostat, chopper), made according to one of the known schemes and designed for the rated current of the generator. The number of parallel branches can be any (figure 5). An independent power source 21 supplies voltage to the field winding 15 composed of 2 or 3 coils, respectively 16, 17 and 18. In this case, the field current is not regulated and is always constant in magnitude. The current generated in the stator winding 11 is rectified by the rectifier unit 24 and is fed to the input of the high-frequency pulse regulator 28, from the output of which it is supplied to the welding.

Claims (3)

1. An axial-type inductor welding generator, containing two stator gear packages connected to a thick-walled steel frame serving simultaneously as a body and an external magnetic circuit, an annular field winding, the terminals of which are connected to a power source, a 3-phase power winding, the phases of which are connected through a rectifier the unit and the current regulator are connected to the output clamps, two toothed gearless gear packages of the rotor connected by bushings serving as an internal magnetic circuit, characterized in that the power winding in is complete by superimposing on each tooth of each stator packet of separate coils, each phase branch is formed by the counter-connection of one counter-connected pair of coils located on adjacent teeth and another similar pair of coils shifted by 180 electrical degrees and diametrically located, the number of stator teeth being a multiple of 12, and the number of teeth of the rotor is a multiple of 5 or 7. 2. The generator according to claim 1, characterized in that the field winding is made of at least two ring coils connected in parallel. 3. The generator according to claim 1, characterized in that the current regulator is made in the form of a high-frequency pulse regulator.

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