Single-phase welding rectifier
(57) Abstract:Usage: electric arc welding with consumable electrode. Single-phase rectifier with electronic current control ensures high stability of the process when welding at low currents (15-90) that can be welded thin sheet structures (0.8 to 1.5 mm) made of carbon and alloyed steels electrodes with a diameter of 2.6-3,25 mm When welding metal large thickness increases weld quality due to the increased dynamic effects of the arc on the weld pool, increasing the depth of molding and improving the crystallization of the metal. Easy excitation and high arc stability, negligible loss of metal spatter and high energy performance, wide range of smooth regulation of current and convenience to ensure the successful application of the rectifier in a domestic environment, for plumbing work in small enterprises, in repair workshops. Single phase rectifier contains a transformer, thyristor rectifier with a control unit and recharge, phase shifting device, two threshold devices, and symmetric thyristor with a control unit and line sudais electrode short circuit arc gap.Known single-phase welding rectifier containing a transformer with two secondary windings larger and smaller voltage, a smoothing choke, two diodes and four thyristor, the connection of which with the conclusions of the transformer and the output circuit provides the obtaining of two controlled rectifier bridges with a common diagonal, implementing the device in the welding modes, battery and starter engine start car 
The disadvantages of the known rectifier can be attributed to a large size, weight and value of the smoothing inductor, connected in series in the welding circuit. This additional inductance in the welding circuit limits the rate of rise of current at short circuit arc gap. In addition, the transfer of electrode metal is accompanied by an increased spatter, since the destruction of the jumpers occurs when a large current values.The closest in technical essence to the invention is a welding rectifier  contains the transformer, full-wave thyristor rectifier, phase shifting device, the control unit thyristor rectifier, two threshold device and Mitel provides simultaneous power arc from malalbergo block recharge and thyristor rectifier, that increases the arc stability and allows to exclude from the circuit of the thyristor rectifier smoothing choke. This improves weight and dimensions of the rectifier. The proposed algorithm works rectifier provides for limiting the current in the welding circuit in case of short circuit the interelectrode gap by prohibiting the inclusion of a rectifier that prevents "freezing" of the electrode to the product when the initial excitation of the arc.The disadvantage of this straightener is the dependence of the fracture behavior of jumpers from the duration of the short circuit. In particular, if a short circuit begins and ends in one half-cycle when the thyristors, due to the inability to turn them off until the end of the half gap jumper will occur when the current value of the short circuit current of the thyristor rectifier, the value of which can be achieved amplitude value, which leads to increased spraying of the metal electrode.If the short circuit ends in one of the subsequent half-cycle, in accordance with the algorithm the current in the welding circuit is limited to the value defined miliamperes Blo is practical sustainability.The aim of the invention is the expansion of technological capabilities of the rectifier by improving process stability and reduce splashing of the metal electrode.This goal is achieved by the fact that in the known rectifier containing a transformer, full-wave thyristor rectifier, phase shifting device, the control unit thyristor rectifier, two threshold device and the power feeding entered symmetric thyristor connected to the input of the thyristor rectifier in parallel to the main secondary winding of the transformer, the control unit symmetrical thyristor and the delay line, the input of which is connected to the output of the first threshold device, and the output from the deny control unit symmetrical thyristor and the control unit thyristors of the rectifier, thus enabling inputs of the control unit symmetrical thyristor and the control unit thyristors connected to the output of the second threshold device, and the inputs of the first and second threshold devices connected to the arc gap.In Fig. 1 presents a functional diagram of the welding rectifier, Fig. 2 timing diagram of the welding current and voltage on Duhova the t transformer 1, parallel to the secondary winding 2 which is connected symmetric thyristor 3 and full-wave thyristor rectifier 4, and the additional secondary winding 5 connected to the power feed 6, the output of which is connected in parallel with the output of full-wave thyristor rectifier 4 and the arc gap 7. To arc the gap 7 is also connected to the inputs of the first 8 and second 9 threshold devices. In addition, the rectifier includes a control unit thyristors of the rectifier 10, the control unit symmetrical thyristor 11, prohibiting the inputs of which is connected through the delay line 12 to the output of the first threshold device 8, and enabling inputs to the output of the second threshold device 9. The output of the phase shifting device 13 is connected with the control input of the control unit thyristor rectifier 10, and the output from an additional secondary winding 5 of the transformer 1.Welding rectifier operates as follows.When applying to the input of the transformer 1, the voltage at the output of block recharge 6, and, therefore, the arc gap 7 appears open circuit voltage sufficient for the excitation of the arc (phase 1, Fig. 2). This voltage is fed to the inputs of threshold devices 8 and 9. In Oia idling, but most of the arc voltage and the threshold device 9 with the threshold voltage U02whose value is greater than the sum of the voltage drops on the jumper liquid metal and the radius of the electrode, but less than the voltage across the arc gap in the arc.At the time of the initiation of the arc by zakolachivaniya electrode on the product of the voltage across the arc gap 7 is reduced to the magnitude of the voltage drop in the departure electrode (phase 2, Fig. 2). When it reaches a value less than the threshold U01a threshold device 8 generates a signal that triggers the delay line, which at the time3prohibits the operation of the control unit thyristors of the rectifier 10 and the control unit symmetrical thyristor 11. The main thyristors of the rectifier and the symmetric thyristor 3 are in non-conductive condition. The excitation of the arc at this point in time is only possible from malalbergo block recharge 6, which provides the minimum value of the short circuit current, therefore, primerzanie" electrode to the product at the moment of contact does not occur.When the separation of the electrode from the workpiece excited maloamperny arc (phase 3, Fig. 2). Upon expiration of the duration of the ban, the delay line 3 removes blokirovki begins to flow the total current from the power feeding 6 thyristor rectifier 4 (phase 4, Fig. 2). The firing angle of the thyristors of the rectifier 4 is specified phase shifting device 13 for determining the effective value of the welding current.The second threshold device 9 voltage arc gap 7 is continuously compared with the reference voltage U02. When the droplet formation of the metal electrode and its growth arc gap is reduced, the arc voltage decreases and when it reaches the value U02the second threshold device 9 outputs a signal from the beginning of the short circuit (phase 5, Fig. 2). This signal regardless of the phase shifting device 13 includes thyristors of the rectifier 4, providing an accelerated transition to a drop of the metal electrode. At the final stage short circuit (phase 6, Fig. 2) the voltage across the arc gap 7 starts to rise and when it reaches the value U02the second threshold device 9 outputs a signal to activate symmetric thyristor 3. However, depending on the current half-cycle unlocked one of the symmetric thyristor shunt the input of the rectifier 4. The thyristors of the rectifier 4 is transferred in a non-conductive state, causing an abrupt decrease in current magnitude equal to a current of short circuit power feed 6. The gap p is nania half-cycle symmetric thyristor switches to a nonconducting state, and the thyristors of the rectifier 4 is included in the time specified phase shifting device 13 (phase 8, Fig. 2), and the process continues.The tests of the inventive welding rectifier showed that the introduction of additional elements and blocks (symmetric thyristor, the control unit symmetrical thyristor and delay lines) provides the expansion of technological capabilities of the rectifier by increasing technological stability of the welding process and reduce splashing of the metal electrode. Single-phase welding rectifier primarily for arc welding with coated electrodes, containing a transformer with multiple secondary windings, a full-wave thyristor rectifier, the power feeding phase shift unit, the control unit thyristor rectifier and two threshold device, characterized in that it introduced the symmetric thyristor connected to the input of the thyristor rectifier in parallel to the main secondary winding of the transformer, the control unit symmetrical thyristor and the delay line, the input of which is connected to the output of the first threshold device, and the output from the deny control unit si is s symmetric thyristor and the control unit thyristor rectifier connected to the output of the second threshold device, the output control unit symmetrical thyristor is connected to a control electrode of the symmetric thyristor, an additional winding of the transformer is connected to the input unit of recharge and phase shifting devices, the output of which is connected to the input of the control unit thyristor rectifier, the inputs of the first and second threshold devices connected to the outputs of the thyristor rectifier and power feed connected in parallel with each other.
FIELD: electric arc welding processes and equipment, possibly manual electric arc welding by means of coated electrode that may be in different spatial positions.
SUBSTANCE: welding is realized by means of modulated electric current at separate regulation of pulse and pause duration of welding electric current. During pause additional pulses with amplitude equal to that of main pulses, frequency no less than 50 Hz, duration (0.5 - 2) ms are applied on small welding current 5 - 30 A. Heat power of welding current is automatically realized according to action of welding operator due to changing parameters of main pulses depending upon fluctuation of mean voltage of electric arc from predetermined value at relatively small change of arc gap (2 - 2.5)V.
EFFECT: lowered contrast degree of irradiation of electric arc during pulse and pause, enhanced quality of welded joint, possibility for controlling heat power of electric arc according to desire of welding operator, improved topography of welded seam.
5 cl, 5 dwg, 5 ex
FIELD: electric welding processes and equipment, namely regulated power source for manual electric arc welding, possibly in workshops, in domestic or industrial condition.
SUBSTANCE: inlet of bridge type diode rectifier is connected with one section of secondary winding of transformer. Two gangs of capacitors are connected in parallel with diodes of one arm of bridge type rectifier and with one outlet of said section. Smoothing choke with split windings is connected between arms of bridge type rectifier. Secondary winding of transformer includes additional booster section to which two thyristors are connected. Said thyristors are controlled by means of pulse-phase control system. The last includes double-threshold comparator whose inlet is connected with outlet of power source and whose outlet is connected with inlet for interlocking pulses of pulse-phase control system.
EFFECT: possibility for proving smooth regulation of welding electric current in desired range.
FIELD: welding processes and equipment, namely method for controlling manufacturing equipment providing pulse feed of welding wire to electric arc zone.
SUBSTANCE: method comprises steps of applying signal to adaptive system for controlling mechanism for pulse feed of welding wire. During automatic mode in said system control signal source is operated. Source of control signal is in the form of pickup for measuring welding wire force in guiding duct of welding hose and feed stroke pickup. Pulse is generated at time moment when welding wire achieves in guiding duct energy corresponding to optimal acceleration of welding wire motion. Pulse repetition frequency is set by adjustment of force pickup, by speed of feed mechanism and by stroke set by welding wire feed stroke pickup.
EFFECT: simplified control circuit, regulation of stroke of welding wire feed and therefore of size of drops of electrode metal transferred to welding bath.
FIELD: mechanical engineering; welding.
SUBSTANCE: invention relates to two-stage electric arc welding sets and methods of their operation. Proposed set includes quick-acting impulse supply source 10 with controller 130 for implementing first and second welding processes in space between part to be welded W and welding wire E moved in direction towards part W. During first stage first current signal waveform is used, and during second stage, second current signal waveform. Circuit is provided to change over first and second welding processes. Change-over circuit includes counter 212 to count signals during first and second processes, and circuit 190 to change over from one welding process to other welding process at moment when counted signals in carried out welding process reach preset value for this process. Invention provides quality gas-shielded welding by consumable electrode with changing over of welding process with transfer of metal owing to surface tension, or process of welding at constant stress with jet transfer to other process of welding.
EFFECT: enlarged operating capabilities.
87 cl, 4 dwg
FIELD: welding manufacturing processes, namely system for inspecting state of welding zone, possibly used in all branches of machine engineering.
SUBSTANCE: welding control system includes welding apparatus and apparatus for monitoring welding zone state. The last is provided with device for displaying image of welding zone, at least one filter arranged in front of display device or inside it, device for illuminating welding zone by means of UV irradiation. Said filter is band type filter for passing irradiation in vicinity of predetermined wavelength of UV irradiation.
EFFECT: enhanced reliability of welding process.
34 cl, 6 dwg
FIELD: welding jobs.
SUBSTANCE: invention relates to welding, particularly to the method of welding metal products and to welding apparatus. The welding apparatus incorporates the short-arc welding system and allows the electrode to move towards the structure to be welded and to adjust the arc length. The welded seam produced by the short-arc welding meets the requirements of API 5L for pipe welding of at least X80 class, the arc length in welding not exceeding 0.3 inch. The system additionally comprises a power source with a regulator to create current pulse to feed power to electrode to fuse the self-protected electrode and a section of smooth metal transfer with low current that follows behind the end of fusing pulse during which fused electrode gets connected with the structure being welded.
EFFECT: welding pipelines together.
43 cl, 18 dwg, 3 tbl
FIELD: welding jobs.
SUBSTANCE: invention covers the method and device of machine arc welding in active gases that features intermittent alternation of the stages and arc discharge and short-circuiting, and can be used for producing seams in whatever spatial positions, for example, in welding the pipelines joints. At the stage of arc discharge bath damping is provided for by stabilising the voltage in two automatic control cycles. The first of them stabilises the voltage of arc proper, while the second stabilises the medium welding voltage. At the short-circuit stage bath damping is provided for by reducing electro dynamic effects onto the bath via reduction in sizes of transferred drops, which is reached thanks to bringing the frequency of pulsed effects into agreement with the natural frequency of drop formation by generating the current fall that initiates the transfer process, and the subsequent short-circuit current peak that allows the drop to detach from the electrode. The device primary power circuit outputs and high-voltage backfeed circuits are integrated and connected, via the current pickup, to external terminals. The current pickup output is connected to the microprocessor controller first measuring input. The voltage pickup output is connected to the microprocessor controller first measuring output. The first control output of microprocessor controller is connected to the controlled input of thyristor rectifier unit. The second control output of microprocessor controller is connected to the control input of the fist magnetic starter. The output of the operating conditions control unit is connected to the data input of microprocessor controller. The device low-voltage backfeed circuit is made up of the following components connected in series, i.e. transformer third output, second magnetic starter, second diode rectifier and controlled throttle. The output of low-voltage backfeed circuit is connected to the current pickup input. The fourth control input of microprocessor controller is connected to the controlled input of the second magnetic starter. The third control output of microprocessor controller is connected with the controlled input of controlled throttle. The output of the external feedback communication voltage pickup is connected to the third measuring input.
EFFECT: control of fused metal bath to produce high-quality welded seam.
6 cl, 6 dwg
SUBSTANCE: invention relates to a method and device for consumable-electrode arc welding and can be used in manual or machine welding of joints of main and industrial pipelines, as well as other metal structures in different industries. When welding, transfer of electrode metal is controlled during the short circuit period. Before the short circuit, welding current is bridged and reduced to zero. Then during the short circuit period, welding current is varied proportionally to electrical conductivity of the liquid metal jumper. At the end of the short circuit, welding current is once again reduced to zero. After the short circuit, bridging is stopped and arcing is induced at the peak level of welding current, which during arcing, is gradually reduced to a base level. The device has a direct current power supply, throttle, current sensor, control unit, electrode, stabilitron, delay line and N diodes, connected in series and accordingly. The throttle has an impregnable magnetic core and a split winding.
EFFECT: prevention of metal sputtering during the short circuit period.
3 cl, 3 dwg
SUBSTANCE: tandem welding system comprises spaced apart electrodes for movement with same speed and jointly making weld joints. A data storage device stores measured data for each electrode when making a weld joint. The device carries out a process, which includes selection of measured data for each electrode, corresponding to the electrode passing through a control position and comparison of selected measured data of several spaced out electrodes for calculation of the weld joint parametre of the tandem welding system in the control position.
EFFECT: increased operational reliability.
38 cl, 8 dwg
FIELD: electrical engineering, welding.
SUBSTANCE: arc is fed by pulsed welding current with parametres that allow arcing in dynamic mode. Arc, in above conditions, features high physical stability given a concentrated heat feed into welded product. Proposed method provided for control over heat feed by smoothly varying pulse repetition frequency and preset current pulse amplitude through variation of power supply voltage and stepwise variation of pulse duration in inverse proportion to departure of mean voltage at arc from preset voltage.
EFFECT: through penetration, formation of keyhole-type pilot hole and root pass in various positions of weld pool.
3 dwg, 1 ex