SU1414884A1 - Device for feeding electroplating baths - Google Patents

Abstract

The invention relates to equipment for feeding electroplating baths with asymmetric current and can be used in the deposition of metals and alloys. The purpose of the invention is to improve the physicomechanical properties of coatings, increasing productivity. The device consists of a three-phase step-down transformer 1 with two secondary windings 2 and 3, rectifiereVNnrv / telnye elements 4 and 5, transistors 6 and 7 of direct and reverse currents, switching thyristors 8-11, control unit 12, instrumentation 13- 15. The control unit 12 is synchronized by a comparator 16, the inputs of which are supplied with voltage from the saw-tooth generator 17. The forward and reverse currents are controlled by a resistor 18, and the frequency of the generator pulses 17 is set by a resistor 19. Electrodes 21 and 22 are placed in the bath 20. and 11, capacitors 23 and 24 are included. Improving the properties and increasing the performance is achieved by introducing locking assemblies made in the form of locking and recharging thyristors and condensation into this device. atorov. The device makes it possible to control the frequency of the converted current and the ratio between the duration of the forward and reverse pulses, increases the steepness of the pulse fronts, as a result of which the physicomechanical properties of the coatings are improved. 2 Il. i (L; cx with N (ik

Description

1141

The invention relates to equipment for powering electroplating baths | asymmetric current and can be used in the deposition of metals and alloys.

The purpose of the invention is to improve the phy- and zico-mechanical properties of coatings: and the performance of the electro-process: metal deposition.

I Figure 1 shows the principle; the diagram of the device of Figure 2 is a time diagram of signals. I The device consists of a three-phase step-down transformer 1 (industrial type) with two secondary windings 2 and 3, connected by a star, rectifying elements 4 and 5 (industrial type), thyristors 6 and 7 of forward and reverse currents, switching (locking and recharging thyristors 8–11, block 12 control, instrumentation, 13–15. The control unit 12 is synchronized by the com-operator 16 (industrial type), I connected according to the appropriate yarn circuit of the saw-tooth generator 17 (assembled according to well-known schemes on: the base of industrial parts). The duration of the forward and reverse currents is adjusted by resistor 18 and the frequency of the generator pulses 17 is set by resistor 19, Control unit 12 contains industrial design elements and is assembled according to known thyristor control circuits. In the bath 20, electrodes 21 and 22 are placed. Consistently thyristors 8 and 11 include capacitors 23 and 24.

The device works as follows.

From the output windings 2 and 3 of transformer 1, the current is applied to the rectifying elements 4 and 5. The cathode rectifier 4 and the anode of the top 5 are connected to the electrode 22 of the bath 20.

From rectifier 4, the direct current is compacted by thyristor 6 through measuring devices 13 and 15 to electrode 21 of bath 20, and from rectifier 5 ground current is switched by thyristor through measuring devices 14 and 15 to electrode 21 of bath 20.

The switching of forward and reverse currents is performed alternately by thyristors 6 and 7, with the latter being locked by thyristors 8 and

11 and the capacitors 23 and 24, respectively, to the circuit, and the recharging of the capacitors 23 and 24 is performed by the thyristors 10 and 9.

The duration of the pulses of the forward T (' and reverse T currents (Fig. 2) depends on the amplitude of the generator 17 of the saw-tooth voltage and on the voltage on the resistor 18.

When Uf, Ur (, To, Uh u (y „) Td

UrMH) and, („“,

TK t - t,

si 1

- .15 2о 25

thirty

35

40

45

50

55

where and

H - () laIs) g (lly

iH

- voltage across a resistor;

- maximum and minimum generator voltages;

R-C - the minimum duration of the pulses of the forward and reverse currents j С - capacitor capacitance; R is the load resistance; T - the period of the generator pulses.

The proposed device, in comparison with the known one, makes it possible to control the frequency of the converted periodic current and the ratio between the durations of the forward and reverse pulses, eliminating the pause between pulses, increases the steepness of the pulse fronts, thereby improving the properties of coatings and increasing productivity.

Claims (1)

Invention Formula A device for supplying galvanic baths with an asymmetric current, containing a three-phase downstream transformer with two secondary windings connected in a star, powerful elements, forward and reverse current thyristors, a thyristor control unit, instrumentation, different in that, in order to improve physicomechanical properties of coatings and metal electroplating process performance; it is equipped with locking and recharging thyristors and capacitors, while the capacitors of the They are connected to locking thyristors and connected in parallel with recharging thyristors, the thyristors of direct and reverse currents are shunted by locking thyristors, and the anode of the direct current thyristor is connected to the anode of one rectifier element, and the cathode of the reverse current thyristor - to the cathode of the other rectifier element.  fas. 2