SU1038387A1 - Device for supplying electroplating baths with asymmetric current - Google Patents

Abstract

A GALVANIC BATTERY FOR POWER SUPPLY ASYMMETRIC CURRENT, containing a three-phase power, step-down transformer, in which the secondary winding of the third phase is turned on in relation to the windings of the other two phases, four thyristors, three of which are connected according to the one-period wiring and anode, I connected a three-phase switch. transformer, and the common connection point of the cathodes - to the device controlling the cathode current, the fourth thyristor, connected in series with the device controlling the anode current, on An anti-parallel circuit from the thyristor of the cathode current of the first phase and the cathode current control device, the thyristor control system, characterized in that, in order to increase the efficiency of the device, it is equipped with two uncontrollable valves, the anodes of which are combined and connected to the windings - the beginning of the first and the end of the third phase, and the cathodes, respectively, to the ends of the secondary winding of the second phase, and the thyristic (L rom, the anode of which is connected to the beginning of the secondary winding of the second phase, and the cathode to the common connection point of the thyristor cathodes current 00 CX) oe 00

Description

The invention relates to electroplating and can be used for feeding electroplating baths with asymmetric current of industrial frequency in silvering processes, copper casting, cadmium plating and degreasing. A device for feeding electroplating baths with a periodic current with a reverse pulse containing a three-phase step-down transformer is provided. Г Ij However, this device does not fully use the power of the transformer, as in the useful electrolytic deposition Only two phases are involved in the metal, and the third phase is used to create a reverse current, which serves only to destroy the passivation film formed during the cathodic process. The network load is uneven, since the two phases of the cathode target are loaded with the operating current of the coating, and the third phase is insignificant inverse current. All these drawbacks are about low device efficiency. The closest to the proposed technical essence and the achieved result is a device for supplying electroplating baths with an asymmetric current, containing a three-phase power downconverter, in which the secondary winding of the third phase is turned on in relation to the windings of two other phases, four thyristors, three of which are connected according to a single-period rectifying scheme and anodes are connected to the secondary windings of a power transformer, and the common connection point of the cathodes is connected to a device for controlling cathodic current, the fourth thyristor, connected in series with the anode current control device, is connected anti-parallel to the circuit from the cathode current thyristor of the first phase and the cathode current control device, thyristor control system 2. A disadvantage of the known device is low efficiency due to the fact that the converter does not provide for use of the second half-wave voltage of the second phase of the power transformer. The purpose of the invention is to increase. Efficiency of the device. The goal is achieved by the fact that a device for powering galvanized baths with an asymmetric current contains a power downconverter for which the secondary winding of the third phase is turned on in relation to the windings of the other two phases, four thyristors, three of which are connected in p6 half-wavelength rectification and anodes are connected to the secondary windings of a power transformer, and the common thyuronic connection point to the cathode current control device, the fourth thyristor connected in series with the control device anode current, connected to the counter-parallel circuit from the thyristor of the cathodic current of the first phase and the cathode current control device, the thyristor control system, is equipped with two uncontrolled valves, the anodes of which are combined and connected to the windings - the beginning of the first and the end of the third phases, and the cathode, respectively - to the ends of the secondary winding of the second phase, and the thyristor, - the anode of which is connected to - the beginning / secondary winding of the second phase, and the cathode to the common connection point of the cathodes of the thyristors of the cathode current. FIG. 1 is a schematic diagram of the deviceJ in FIG. 2 is a graphical representation of the curve of the received current. The device for powering the galvanic baths with asymmetric current contains a three-phase power-down transformer 1, the secondary windings 2-. 4 of which are connected to thyristors 5-9 and uncontrolled gates 10 and 11, with two windings 2 and 4 connected to thyristors 5.8 according to the one-half-time rectifier circuit, and winding 3 is connected to the diagonal of a full-wave bridge rectifier whose input is Anodes of uncontrolled valves 10 and 11, connected to the beginning of winding 2 and the end of winding 4, and output cathodes of thyristors b and 7, connected to cathodes of thyristors 5 and 8, common connection point, connected to device 12 of cathode current control, anode current thyristor 9 consistently with United with the device 13 of the anode current control and connected anti-parallel to the circuit of the thyristor 5 of the cathode current of the first phase and the device 12 of the control of the cathode current. Thyristors 5-9 are included from control units 14-18, respectively. The free leads of devices 12 and 13 are connected together and connected to the anode 19 of the galvanic bath, and the cathode 20 is connected to the common connection point of the anodes of the uncontrollable valves 10 and 11, the beginning of the winding 2 and the end of the winding 4. The device for supplying the galvanic baths with asymmetric current works as follows . Voltage: three-phase AC mains is supplied to the primary windings of the power transformer 1. The reduced voltage of the required value from the secondary windings 2-4 is applied to the thyristors 5-8 and uncontrolled gates 10 and 11. The resulting

from secondary windings 2 and 4, rectified half-wave current of two phases through thyristors 5, 8 and full-wave current from secondary winding 3 through thyristors 6, 7 and uncontrollable valves 10 and 11 feeds the galvanic bath in the cathode Direction, and the current obtained from the secondary winding 2 through the thyristor 9, with a duration of one third of the half-period at the time of the absence of the cathode current, feeds the van in the anode direction.

The pulses formed in blocks 14-17, including thyristors 5-8, respectively, are synchronized with the voltage of the phase circuits in which the thyristors are included, and the pulses formed in block 18 of the control, including the thyristor 9, are synchronized with the voltage of the second phase winding.

The proposed device makes it possible to additionally remove the useful power from the transformer by rectifying the full-wave bridge rectifier and using it in the cathode rectifier, the direction of the second half-wave of the secondary voltage. winding of the second phase, which increases the efficiency of the transformer and the device as a whole to 70-72% compared to 60% of the existing one, and also improves the shape of the curve of the resulting current.

The use of the proposed device for feeding electroplating baths with asymmetric current allows to intensify the silvering and cadmium plating process in 4, copper plating in b, and the degreasing process - by 2-3 times with good qualities of electroplated coatings.

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Claims (1)

DEVICE FOR POWER SUPPLY OF ELECTRIC BATH-HOUSES ASYMMETRIC CURRENT, containing power three-phase. a step-down transformer, in which the secondary winding of the third phase is turned in opposite to the windings of the other two phases, four thyristors, three of which are connected according to the half-wave rectification scheme with anodes, are connected to the secondary windings of the power transformer, and the common cathode connection point is connected to the cathode current monitoring device the fourth thyristor, connected in series with the anode current control device, is connected counter-parallel to the circuit from the first phase cathode current thyristor and the cathode current control device, thyristor control system, characterized in that, in order to increase the efficiency of the device, it is equipped with two uncontrolled valves, the anodes of which are combined and connected to the windings - the beginning of the first and end of the third phase, and the cathodes, respectively - to the ends of the secondary winding of the second phase, and the thyristor . rum, the anode of which is connected to the beginning of the secondary winding of the second phase, and the cathode to the common connection point of the cathodes of the cathode current’s thyristors.