SU817928A1

SU817928A1 - Contact-free converter for power supply of galvanic bathes

Info

Publication number: SU817928A1
Application number: SU792766128A
Authority: SU
Inventors: Валерий Елисеевич Мунтян
Original assignee: Кишиневский Сельскохозяйственный Ин-Ститут Им. M.B.Фрунзе
Priority date: 1979-05-04
Filing date: 1979-05-04
Publication date: 1981-03-30

Description

Изобретение относится к преобразовательной технике и может быть использовано в качестве бесконтактного преобразователя для питания гальванических ванн периодическим током с обрат- $ ним импульсом.The invention relates to a conversion technique and can be used as a non-contact converter for supplying galvanic baths with a periodic current with a reverse pulse.

Известны устройства для питания гальванических ванн и электролитической обработки изделий периодическим асимметричным током, в которых ис- ’* пользуется однофазновыпрямительный ток’[1] и [21.Known devices for supplying electroplating baths and electrolytic treatment of products with periodic asymmetric current, in which one uses a single-phase rectifying current ’[1] and [21.

Недостатком таких устройств является потеря производительности электрохимических процессов, а также низ- 15 кфё качество гальванических покрытий.The disadvantage of such devices is the loss of productivity of electrochemical processes, as well as the low quality of electroplating coatings.

Известен источник питания гальванических ванн, использующий трех Фазный переменный ток промышленной частоты [3] . 20A known power source of plating baths using three phase alternating current industrial frequency [3]. 20

Наиболее близким к предлагаемому является бесконтактный преобразователь для питания гальванических ванн, содержащий трехфазный трансформатор, вторичные обмотки которого соединены 25 в звезду., причем обмотки одной из фаз включена встречно по отношению к обмоткам двух других фаз, четыре тиристора, три из которых соединены по схеме нулевого выпрямителя и полклю- 30 чены к вторичным обмоткам, нулевая точка которых н общая точка тиристоров образуют выводы для подключения нагрузки,а четвертый тиристор включен встречно по отношению к другим тиристорам и один из его силовых выводов соединен с общей точкой этих тиристоров, и приборы контроля величины катодного и анодного токов [4].Closest to the proposed one is a non-contact converter for supplying galvanic baths, containing a three-phase transformer, the secondary windings of which are connected 25 to the star., And the windings of one of the phases are turned in opposite to the windings of the other two phases, four thyristors, three of which are connected according to the zero rectifier and 30 are connected to the secondary windings, the zero point of which and the common point of the thyristors form the terminals for connecting the load, and the fourth thyristor is turned on counter to other t Ristori and one of its power terminals connected to the common point of these thyristors, and control devices magnitude cathode and anode currents [4].

Недостатками известного устройства являются потери энергии в силовом трансформаторе, которые возникают за счет протекания во вторичных обмотках прямых токов, создающих магнитные потоки прямой последовательности, а ток обратного·импульса создает магнитный поток обратной последовательности в одном и том же магнитном проводнике.The disadvantages of the known device are energy losses in the power transformer, which occur due to the flow in the secondary windings of direct currents that create magnetic fluxes of a direct sequence, and the current of the reverse · pulse generates a magnetic flux of the negative sequence in the same magnetic conductor.

Вследствие возникновения в магнитопроводе близких по величине магнитных потоков прямой и обратной последовательности возникает их короткое замыкание. Это приводит к сильному перегреву магнитопровода, большим потерям электроэнергии, достигающим 20-30%, искажению формы кривой прямого и обратного.тока, завалу переднего фронта обратного импульса, а (следовательно,к потерям производитель3 встречными того, супоэволяют тока в шиto ности гальванического процесса. Вышеуказанные недостатки характерны для схем трехфазного тока со вторичными токами. Кроме Шествующие устройства не получать различные формы роком диапазоне, что ограничивает |их технологические возможности .Все згго отрицательно влияет на физикомеханические свойства электролитических осадков и значительно снижает 'эксплуатационные свойства самого устройства.Due to the appearance in the magnetic circuit of magnitude close magnetic fluxes of direct and reverse sequence, a short circuit occurs. This leads to severe overheating of the magnetic circuit, large losses of electricity, reaching 20-30%, distortion of the shape of the curve of the forward and reverse currents, obstruction of the leading edge of the reverse pulse, and (therefore, losses by the producer3 counterpropagating by spontaneously emitting current in a wide galvanic process. The above disadvantages are typical for three-phase current circuits with secondary currents.In addition to the marching devices do not receive various forms in the rock band, which limits | their technological capabilities. on the physicomechanical properties of an electrolytic precipitation and significantly reduces the "performance of the device itself.

1. Таким образом, известное устройство имеет низкий КПД и недостаточно хорошую форму кривой прямого и обрат. ного токов.1. Thus, the known device has a low efficiency and not a good shape of the curve of the forward and reverse. currents.

Цель изобретения - повышение КПД и улучшение формы.кривой прямого и обратного, токов.The purpose of the invention is improving efficiency and improving the shape of the forward and reverse curves, currents.

Указанная цель достигается тем, что бесконтактный преобразователь для питания гальванических ванн снабжен дополнительными трансформатором и тиристором, причем тиристор включен в схему нулевого выпрямителя и соединен с нулевой точкой указанной звезды вторичных обмоток через дополнительную обмотку, включенную встречно по отношению к указанным вторичным обмоткам двух других фаз, первичная обмотка дополнительного трансформатора подключена параллельно первичной обмотке одной из фаз основного трансформатора, а его вторичная обмотка подключена одним концом к нулевой точке звезды вторич'ных обмоток основного трансформатора и выполнена со скользящим контактом, к которому подключен второй вывод четвертого тиристора.This goal is achieved by the fact that the non-contact converter for supplying galvanic baths is equipped with additional transformer and thyristor, and the thyristor is included in the zero rectifier circuit and is connected to the zero point of the indicated star of the secondary windings through an additional winding connected counterclockwise to the indicated secondary windings of two other phases, the primary winding of the auxiliary transformer is connected in parallel with the primary winding of one of the phases of the main transformer, and its secondary winding is connected connected at one end to the zero point of the star of the secondary windings of the main transformer and is made with a sliding contact to which the second output of the fourth thyristor is connected.

На фиг·. 1 представлена принципи- альная схема устройства; на фиг. 2 формы кривых токов. лIn FIG. 1 is a schematic diagram of a device; in FIG. 2 forms of curved currents. l

Устройство состоит из тиристоровThe device consists of thyristors

1-5, приборов б и7 контроля анодного и катодного токов, трехфазного трансформатора 8, в котором концы вторичных обмоток 9 и 10 и начала обмоток 11 и 12 соединены нулевым проводом 13 с катодом 14, а другие их концы через тиристоры 1-4 соединены с анодом 15 ванны 16.Вторичная обмотка 17 . однофазного трансформатора 18 подключена концом к катоду 14, а началом ч<ЗРез скользящий контакт 19 к тиристору 5 так, что отрицательный полюс тирйстора соединен с анодом 15 ванны. Первичная обмотка 20 однофазного тран-55 сформатора 18 подключена параллельно обмотке 21 трехфазного трансформатора 8.1-5, devices b and 7 for monitoring the anode and cathode currents, a three-phase transformer 8, in which the ends of the secondary windings 9 and 10 and the beginning of the windings 11 and 12 are connected by a neutral wire 13 to the cathode 14, and their other ends are connected through thyristors 1-4 to the anode 15 of the bathtub 16. The secondary winding 17. single-phase transformer 18 is connected end to cathode 14, and the beginning of h <3> Sliding contact 19 to thyristor 5 so that the negative pole of the thyristor is connected to the anode 15 of the bath. The primary winding 20 of a single-phase trans-55 transformer 18 is connected in parallel with the winding 21 of the three-phase transformer 8.

Устройство дает возможность получать выпрямленный ток трех фаз и об- , ’60 ратный импульс за счет доли однополупериодного выпрямительного тока однофазного трансформатора (фиг. 2), а также трехфазного выпрямительного тока. Длительность обратного и прямо- 65 го импульсов в течение одного периода т регулируется с помощью известных систем управления. В качестве выпрямительных элементов используются тиристоры с раздельными системами управления. 'The device makes it possible to obtain a rectified current of three phases and a reverse ’60 pulse due to the fraction of a half-wave rectifier current of a single-phase transformer (Fig. 2), as well as a three-phase rectifier current. The duration of the reverse and direct 65 pulses during one period m is regulated using known control systems. Thyristors with separate control systems are used as rectifier elements. ''

Устройство работает следующим образом.The device operates as follows.

Напряжение трехфазного переменно.го тока подается на первичные обмотки 20-23 понижающих трансформаторов 8 и 18. Пониженное напряжение со вторичных обмоток 9-12 трансформатора 8 трехфазного тока подается на тиристоры 1-4 и полученный от них выпрямительный ток трех фаз питает гальваническую ванну 16. За это время в течение части Ърпериода Т происходит электролитическое осаждение· металла на катоде 14.The voltage of the three-phase alternating current is supplied to the primary windings 20-23 of the step-down transformers 8 and 18. The reduced voltage from the secondary windings 9-12 of the three-phase current transformer 8 is supplied to the thyristors 1-4 and the rectifier current of three phases obtained from them feeds the galvanic bath 16. During this time, during part of the period T, electrolytic deposition of the metal on the cathode 14 takes place.

Напряжение от обмотки 17 однофазного трансформатора 18 через скользящий контакт 19 попадает на тирйстор 5 и далее на анод 15, при этом ток обратного импульса в течение определенной части периода Т течет в анодном направлении (фиг. 2).Амплитудное значение тока анодного импульса Гу регулируется скользящим контактом 19.The voltage from the winding 17 of the single-phase transformer 18 passes through the sliding contact 19 to the thyristor 5 and then to the anode 15, while the reverse pulse current flows in the anode direction for a certain part of the period T (Fig. 2). The amplitude value of the current of the anode pulse Gu is regulated by the sliding pin 19.

Тиристоры включаются подачей на их управляющие электроды запускающих импульсов, синхронных с напряжением вторичных обмоток трансформаторов.Thyristors are switched on by supplying triggering pulses to their control electrodes synchronous with the voltage of the secondary windings of the transformers.

Claims

The invention relates to a conversion technique and can be used as a contactless converter for supplying electroplating baths with a periodic current with a reverse pulse. Devices are known for feeding electroplating baths and electrolytic treatment of products with periodic asymmetric currents, in which single-phase current currents 1 and 2 are used. The disadvantage of such devices is the loss of performance of electrochemical processes, as well as the low quality of electroplating. A power source of electroplating baths is known, using a three-phase alternating current with a frequency of 3 W. The closest to the present invention is a contactless converter for powering electroplating baths containing a three-phase transformer, the secondary windings of which are connected into a star, the windings of one of the phases being connected opposite to the windings of the other two phases, four thyrisors, three of which are connected according to the zero recirculation circuit mitel and half-connected to the secondary windings, the zero point of which is the common point of the thyristors form the terminals for connecting the load, and the fourth thyristor is turned on opposite to other thyristors Frames and one of its power terminals are connected to the common point of these thyristors, and instruments for monitoring the magnitude of the cathode and anode currents 4. The disadvantages of the known device are the energy losses in the power transformer, which occur due to the flow in the secondary windings of direct currents that create magnetic direct sequence flows, and the reverse-pulse current creates a negative-sequence magnetic flux in the same magnetic conductor. Due to the occurrence of direct and inverse magnetic field currents of similar magnitude in the magnetic flux of the forward and reverse sequence, their short circuit occurs. This leads to a strong overheating of the magnetic circuit, a large loss of electric power, reaching 20-30%, distortion of the shape of the forward and reverse currents, blockage of the leading edge of the reverse pulse, and, consequently, losses in the performance of the galvanic process. Your indicated drawbacks are characteristic of three-phase current circuits with all secondary currents. In addition, the existing devices do not allow obtaining various current forms in a wide range, which limits their technological capabilities. All Wo affects the physical and mechanical properties of electrolytic precipitates and significantly reduces the operational properties of the device itself. .. Thus, the known device has a low .KPD and not a good enough shape of the curve of direct and front currents. The purpose of the invention is to increase the efficiency and improve the shape of the forward and reverse curves, currents. This goal is achieved by the fact that a contactless converter for powering electroplating baths is equipped with an additional transformer and thyristor, the thyristor being included in the zero rectifier circuit and connected to the zero point of the indicated star of the secondary windings through an additional winding connected in opposite with respect to the specified secondary windings of the other two phases, the primary winding of an additional transformer is connected in parallel to the primary winding of one of the phases of the main transformer, and its secondary winding is connected at one end to the zero point of the star of the secondary windings of the main transformer and is made with a sliding contact to which the second output of the fourth thyristor is connected. In FIG. 1 is a schematic diagram of the device; in fig. 2 forms of curved currents. The device consists of thyristors 1-5, devices b and 7 -control of anodic and cathodic currents, a three-phase transformer 8, in which the ends of the secondary windings 9 and 10 and the beginning of the windings 11 and 12 are connected by the neutral wire 13 to the cathode 14, and their other ends through thyristors 1-4 are connected to the anode 15 of the bath 16. The secondary winding 1 of the single-phase transformer 18 is connected end to the cathode 14, and the beginning through the sliding contact 19 to the thyristy Y 5 so that the negative pole of the thyristor is connected to the anode 15 of the bath Primary winding 20 single phase tra. The transformer 18 is connected in parallel to the winding 21 of a three-phase transformer 8. The device makes it possible to obtain a consistent three-phase current and a reverse pulse due to the share of a single-field periodical rectifier current of a single-phase transformer (Fig. 2), as well as a three-phase rectifying current. The duration of the inverse and forward pulses T for one period T is regulated by means of known control systems. Thyristors with separate control systems are used as rectifying elements. The device works as follows. The voltage of the three-phase alternating current is supplied to the primary windings1 and 20-23 step-down transformers 8 and 18. The reduced voltage from the secondary windings 9-12 of the transformer 8 three-phase current is supplied to the thyristors 1-4 and the rectifying current of three phases received from them feeds the electroplating bath 16. During this time, electrolytic deposition occurs during a part of the Cp period; metal at the cathode 14. The voltage from the winding 17 of the single-phase transformer 18 through the sliding contact 19 hits the thyristor 5 and further to the anode 15, while the reverse pulse current flows during a certain part of the period T in the anode direction (Fig. 2). Amplitude the value of the anode current tTq is controlled by a sliding contact 19. The thyristors are turned on by supplying control pulses to their control electrodes that are synchronous with the voltage of the secondary windings of the transformers. A non-contact converter for supplying electroplating baths, comprising a three-phase transformer, the secondary windings of which are connected to a star, the winding of one of the phases being connected oppositely to the windings of the other two phases, four thyristors, three of which are connected according to the zero rectifier circuit and connected to secondary windings, the zero point of which and the common point of the thyristors form terminals for connecting the load, the fourth thyristor is switched on opposite to other thyristors and one of them The power terminals are connected to the common point of these thyristors, and devices controlling the magnitude of the cathode and anodic currents, characterized in that, in order to increase the efficiency and improve the shape of the forward and reverse currents, it is equipped with an additional transformer and thyristor, and the thyristor is included in the zero rectifier and i is connected to the zero point of the specified star of the secondary windings through an additional winding connected in opposite with respect to the specified secondary windings of the other two fa: 5, the primary winding of an additional transformer Matora is connected in parallel to the primary winding of one of the phases of the OS