SU1798863A1 - Asynchronous welding generator - Google Patents

Description

The invention relates to the field of electrical engineering and energy and can be used in electric arc welding technology.

The purpose of the present invention is to remedy these disadvantages: increasing the specific power and efficiency of the generator by reducing the demagnetizing effect of the welding current of the working winding.

In FIG. 1 is a vector diagram of the currents Ip and 1 ", EMF Ep and Ec and magnetic flux in the air gap F. All electromagnetic quantities are given to the excitation winding 1 _C - the phase current of the excitation winding flows around the primary winding of the compound transformer. A current of 1 _C flows through the secondary winding of the compound transformer in the short circuit mode (we neglect the magnetizing current of the compound transformer). An operating current of 1 r flows through the secondary winding of the compound transformer. To enhance the magnetization current 1s with an increase in the operating current 1p (with an increase in the longitudinal demagnetizing reaction), the direction of the current 1p should coincide with the direction of the current - 1 _s . The angle a is determined from the diagram.

In FIG. 2 shows a diagram of the stator windings of an asynchronous welding generator. Ci, Cg, Cz - three-phase field winding laid on the stator and connected to the capacitor bank 1. Cf, Cg ', Cz' - three-phase field winding laid on the stator and supplying welding electrode 3 through the rectifier 2. The beginning of the phase of the working winding is shifted at a geometric angle a / r in the direction of rotation of the rotor relative to the beginning of the corresponding phase of the field winding, which ensures the optimal effect of compounding by current with the help of compounding transformers 4,5,6. Switches 7, 8, 9 are used to bypass the corresponding windings of transformers 45, 4, 5, 6 in the self-excitation mode of the asynchronous welding generator at idle. In FIG. 3 shows the external characteristics of the generator.

The invention is carried out on the basis of an asynchronous machine of the 4A 4A80V4UZ series, on the stator of which two windings are stacked: an excitation winding and a working winding. External characteristic 1 was obtained by shifting the same phases of the winding. excitation and working winding at an angle a80 el. degrees. External characteristic 2 was obtained at a = 150 e. hail. External characteristic 3 - at a = 180 e. hail.

The device operates as follows. The residual magnetism of the rotor, rotated by an external motor, induces an EMF in the stator excitation winding, due to which a capacitive current flows in the excitation winding, which creates a longitudinal magnetizing reaction. Under the influence of a magnetizing reaction with closed switches 7. 8, 9, the magnetic flux in the air gap increases to a nominal value, so that the EMF of the working winding reaches a nominal value. When opening, turn off. lei 7, 8, 9 and the load of the working winding of the welding electrode 3 comes the nominal mode of operation.

Experimental studies of the claimed device showed that at the optimum value of the angle a, the rated power of the asynchronous welding generator reaches a maximum, and the external characteristic takes a steeply falling shape suitable for powering the welding arc. From FIG. 3 it follows that the rated active power at a '' = 80 el. hail, (curve 1) is equal to 2760 W; rated power at a = 150 el. hail: (curve 2) is only 2040 W, and the rated power at "= 180 zl. hail, equal to 1560 watts. Efficiency at a = 80 e. hail, equal to 0.628: with a = -150 e. hail. -0.557, and with a = 180 e. hail. -0.420. From FIG. 3 it also follows that 35 external characteristic 3 is unsuitable for supplying the welding arc, because in the short circuit mode the system is demagnetized,

In the prototype there is no current compounding, i.e., for the prototype, a = 180 e. hail. It follows that in the claimed technical solution, the Specific Power is 2760/1560 more = 1.77 times, and the efficiency is 0.628 / 0.420 = 1.495 times

Claims (1)

Claim Asynchronous welding generator c. two multiphase windings on the stator, one of which is an excitation winding has terminals for connecting to a capacitor bank, the other is working and has terminals for connecting to a welding device, so that, in order to increasing specific power and efficiency, the beginning of the phases of the working winding are offset by an angle a el. hail, relative to the beginning of the same phases of the field winding in the direction of rotation of the rotor, where a = 180 ° - ($> ⁺ Vt). W At the ^{goal of the} shift between the current and the EMF of the phase of the working winding, ^ "is the angle of shift between the current and the EMF of the phase of the field winding, and the primary windings of the compounding transformer are connected to the phases of the winding'vo1® excitation, and the secondary windings of this transformer are connected to the phases of the working winding of the same name . Military Committee for Inventions and Discoveries at the State Committee for Science and Technology of the USSR 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Combine Patent, Uzhgorod, 101 Gagarin St.