SU944031A1 - Device for supply of electroplating bathes with periodic current with reverse pulse - Google Patents

Description

154) yCTPa fCTBO for POWER SUPPLY for GALVANIC BATTERIES PPGIODIODIC CURRENT with RETURN PULSE The invention relates to AC-to-asymmetric AC converters and can be primoned for supplying vanilla baths with a periodic current with reverse impuls. Devices are known for supplying galvanic H and electrolytic processing of products, in which the converted current of one phase G1 3 is used. The disadvantages of these devices are low current consumption in the direct process during the period, which leads to a loss in the performance of electrofluids. processes and does not evenly load all three phases of the industrial electrical network. These deficiencies are largely eliminated in the power supplies of electroplating baths, in which a three-phase alternating current is converted into a periodic current with a reverse pulse. The closest in technical essence is a device for supplying electroplating baths with a periodic current with a reverse pulse, containing a three-phase power transformer with primary and star-connected secondary windings, three direct current pulse thyristors, a reverse pulse thyristor, and also thyristor control units and control devices the current and reverse current pulses, thr, the cathodes of the direct current pulse thyristors and the reverse current pulse thyristor anode are combined, and our common point is connected to one them from BbDcoffiibDC leads for connection of one of the bath electrodes. In this device, the forward current is equal to 2 / 3T (240 °), and the maximally small duration of reverse current can reach 1 / 3T (120 °) 4. The disadvantages of the known device are a reduction in the effective factor chenin duration (magnitude) of the reverse pulse. In the case when, under the conditions of electrolysis, it is necessary to reduce the value (duration; reverse pulse, and the period of the flow of the direct and reverse current occurs a break (pause), leading to idle installation in this interval and to a decrease in efficiency. In addition, the pause size is greater than T / 9 (40), the cohesion strength decreases and the quality of coatings deteriorates. Another factor reducing the efficiency of this device is the additional losses in the transformer due to the influence of the zero-sequence magnetic flux arising in The goal of the invention is to increase the efficiency of the device and ensure high quality of the coating. The goal is achieved by the fact that the device for supplying galvanic baths with a periodic current with a reverse pulse, contains a three-phase power transformer with primary windings and a star connected secondary windings current pulse, a reverse current pulse thyristor, as well as thyristor control units and devices for controlling the greatness of right and reverse current pulses, with the cathodes of the direct and The current and anode thyristor of the reverse current pulse are combined and their common point is connected to one of the output terminals for connecting one of the bath electrodes, an additional direct current pulse thyristor and a switch are inserted, and the transformer is provided with an additional secondary winding connected in a star , with the free outputs of the first phase of the main secondary winding and the second phase of the additional critical winding being connected to a different output of the 11.1m output for connecting the second electrode of the bath, each of the remaining free X The leads of both secondary windings are connected to the anode of one of the corresponding direct current thyristors, the rG cathode of the reverse current pulse through the switch is connected to the anode of one of the direct current pulse thyristors. Figure 1 shows the circuit diagram of the device; in fig. 2 Phase vector voltage diagram on secondary windings; FIG. 3 shows a vecgorn voltage chart at the output of a transformer; Fig. 4-7 shows the oscillograms of the curves of variation of the periodic volatility .4.4 - ® of the impedance due to the connection of the reverse current impulse current tristor. The device consists of a three-phase transformer 1, having primary windings 2-4 and secondary windings 5-7 and 8-10, connected in two stars. The free leads of the windings 5 and 9 are connected to the electrode 11 of the bath 12, and the “ends of the windings 6, 7, 8 and 10 are connected to the anodes of the thyristors 13-16, which form a direct current pulse. The thyristor cathodes 13-16 through the measuring device 1 7 are connected to the second electrode 18 of the bath 12. To obtain a reverse current pulse, parallel to each of the thyristors 13-16, the cathode of the thyristor 2O is connected to a switching device 19, the anode of which is connected through the measuring device 21 with the electrode 18 of the bath 12. The device makes it possible to obtain a four-phase system of voltages b - IS with a phase shift equal to T / 6 (BO), which is explained by the vector diagram in FIG. 3, g, U /, ttttttii OU, Ug, Ug, c are the phase voltages of the secondary windings. This greatly reduces forward current ripple. The reverse current is obtained by the fraction of the negative half-wave of a sinusoid of one of these voltages. Since the voltage supplied to the thyristors is removed from two phases (linear voltage is not), there are no zero-sequence magnetic fluxes inherent in known devices using the zero rectifier circuit, and, accordingly, there is no additional loss in the proposed device. zero-sequence magnetic flux. Thyristors with separate control systems are used as rectifying elements. The duration of the forward and reverse periodic pulses (tpp, f gp) during the period T is controlled using known thyristor control systems. Consider the operation of the device using the example when the reverse thyristor 20 of the bca current is connected in parallel to the thyristor 14 (figure 5) . The alternating current is fed to the primary windings of the transformer 2-4. The reduced voltage d of the secondary windings forms a four-phase voltage system, which is fed to the anodes of the thyristors 13-16, the voltage rectified by these thyristors is supplied to the electrodes

11 n 18 baths 12. For C

Etc. one

metal is precipitated. Thyristor, 13 opens at time 0, t, etc. In tjy -1, the reverse pulse acts, the maximum duration of which is Cp5P. 1 T / (60). The control of the magnitude of the reverse impulse (the duration of the return impulse) within this interval is carried out by the control system, and its name. t the moment of opening thyristor 2О. If under the conditions of electrolysis it is necessary to increase the duration of the reverse pulse over T / 6 (increase the reverse current), but not more than T / 3 (12O), then the thyristor 15 is closed, and in the interval a reverse pulse acts, the maximum duration of which is .I P the need to increase the duration of the reverse pulse over T / 3 closes the thyristors 15 and 16 and in the gap -tj the reverse pulse acts, the maximum length of which can be sent to T / 2 (18O ° h). Thus, the reverse current can be smoothly changed from zero maximum value, minimized (no more than T / 6) break (pause) between the forward and reverse pulses. Similar or other forms of periodic current can be obtained by connecting the thyristor 2O in parallel to the thyristor 13 (figure 4), the thyristor 15 (FIG. 6) and the thyristor 16 (Fig. 7). To eliminate short circuits as a result of the possible imposition of forward and reverse current pulses, the triggering signals supplied to the control electrodes of the thyristors are out of phase with the voltages applied to the thyristor anodes .

This device allows to increase the efficiency of the transformer and to obtain various forms of the periodic current curve, as well as to change in a wide range the length of the cut (from zero to T / 2) and forward (from T / 2 to T) current pulses.

Formula Yabobretenn

A device for feeding galvanic baths with a periodic current with reversal; a three-phase power transformer with primary and star-connected o6MOiws, three forward voltage sensors, a reverse current thyristor, as well as thyristor control devices for the forward current pulse control modules, and the current cathode voltage codes, and the current cathode voltage control circuits, and the current cathode voltage control circuits, and the direct current pulse voltage regulator. My current pulse and the anode of the reverse current pulse thyristor are connected to their common point connected to one of the output pins to connect one of the bath electrodes, which is full. In particular, with a circuit for increasing the efficiency and providing high quality coatings, an additional direct current pulse wristwinder switch was inserted into it, and the transformer was equipped with an additional secondary (H1 connected to a star winding, and the free terminals of the first phase of the main secondary The windings and the second phase of the additional secondary winding are connected to a different output viewport for connecting the second electrode of the bath, each of the remaining free terminals of the secondary windings is connected to a ode respective one of the thyristors direct current pulse and the cathode of the reverse pulse tirist tszha through switch connected to the anode of a thyristor current pulse npsiMoro.

Sources of information taken into account in the examination

1. USSR author's certificate number 168569, cl. C 23 B 5 / O4, 1964.

2. USSR author's certificate number 377439, cl. From 23 to 5/68, 1973.

3. Authors certificate of the USSR NS 461978, cl. From 23 to 5/68, 1973.

4. Avts Cold Certificate of the USSR No. 649110, cl. H 02 M 7/12, 1974.

P

Puj.l 12

no

Claims (1)

Claim A device for supplying galvanic baths with a periodic current with a reverse pulse, comprising a three-phase power transformer with primary and secondary windings connected to a star, three thyristors of a direct current pulse, a thyristor of a reverse current pulse, as well as thyristor control units and control devices for direct and reverse pulse values current, and the cathodes of the thyristors of the direct current pulse and the anode of the thyristor of the reverse current pulse are combined and their common point is connected to one of the output terminals for connecting one and h bath electrodes, characterized in that, in order to increase the efficiency and ensure high quality coatings, an additional direct current thyristor and a switch are introduced into it, and the transformer is equipped with an additional secondary winding connected to a star, and the free terminals of the first phase of the main secondary the windings and the second phase of the additional secondary winding are connected to another output terminal for connecting the second electrode of the bath, each of the remaining free terminals of both secondary a coil connected to the anode of a direct current pulse corresponding thyristor and the thyristor cathode of the reverse current pulse through the switch connected to the anode of a thyristor direct current pulse.