SU957391A1

SU957391A1 - Device for asynchronous electric motor start-up (its versions)

Info

Publication number: SU957391A1
Application number: SU813238162A
Authority: SU
Inventors: Сергей Петрович Голев; Ефим Маркович Певзнер; Сергей Евгеньевич Прохоров; Андрей Георгиевич Яуре; Лазарь Исаакович Лампер; Виктор Трофимович Шарков
Original assignee: Электромашиностроительное Объединение "Динамо" Им.С.М.Кирова
Priority date: 1981-01-21
Filing date: 1981-01-21
Publication date: 1982-09-07

Description

Изобретение относится к электротехнике и может быть использовано в приводах промышленных механизмов, преимущественно крановых.The invention relates to electrical engineering and can be used in drives of industrial mechanisms, mainly crane.

Известно устройство для пуска асинхронного электродвигателя, содержащее резисторы в цепи обмотки ротора, контакторы, шунтирукхцие резисторы, команцоаппарат, выходы которого соединены с катушками контакторов ступеней ускоре- _?0ния через размыкающие контакты реле времени, катушки которых соединены с источником питания через контакты контакторов ускорения [13 .A device for starting asynchronous electric motor comprising resistors in the circuit of rotor windings, contactors, shuntirukhtsie resistors komantsoapparat, the outputs of which are connected to coils of contactors stages _{acceleration? 0} Nia through the break contacts time relay coils are connected to a power source through contacts of contactors acceleration [ thirteen .

Недостатком этого устройства является сложность в связи с тем, что количество реле времени устанавливается по числу ступеней пуска двигателя.The disadvantage of this device is the complexity due to the fact that the number of time switches is set by the number of stages of starting the engine.

Наиболее близким по технической сущ> ности к предлагаемому является устройство· для пуска асинхронного электродвигателя, содержащее П резисторов в цепи обмотки ротора, 2 и контактов, шунтирующих резисторы, η катушек контйк- > торов с замыкающими и размыкающими контактами, командоаппарат, одни выводы которого соединены с первыми выводами П катушек контакторов, а другие его выводы - с одним из выводов источника питания, второй вывод первой катушки контактора через первый замыкающий контакт соединен с другим выводом источника питания, а второй вывод каждой последующей катушки контактора соединен с другим выводом источника питания через последовательно соединенные второй замыкающий контакт предыдущей катушки контактора и свой первый замыкающий контакт, элемент задержки, одним выводом подключённый к другому выводу источника питания, последовательно соединенные третий замыкающий контакт первой катушки контактора с параллельно соединенными размыкающим контактом второй и замыкающим' контактом третьей катушки контактора [2].The closest in technical essence to the proposed one is a device for starting an asynchronous electric motor, containing P resistors in the rotor winding circuit, 2 and contacts shunting the resistors, η coils of contactors> contactors and disconnecting contacts, a command device, one of which outputs are connected with the first terminals P of the coils of the contactors, and its other terminals with one of the terminals of the power source, the second terminal of the first coil of the contactor through the first make contact is connected to the other terminal of the power source, and the second the output terminal of each subsequent coil of the contactor is connected to the other terminal of the power source through a second normally closed contact of the previous coil of the contactor and its first closing contact, a delay element connected to the other terminal of the power source by one output, the third closing contact of the first coil of the contactor connected in parallel with opening contact of the second and closing 'contact of the third coil of the contactor [2].

Однако известное устройство характеризуется сложностью и недостаточной надежностью в связи с большим количеством контактов, включенных в цепи управления контакторами. Кроме того, в устрой-5 стве применено реле времени усложненной конструкции в связи с созданием им выдержки времени как .на срабатывание, так и на отпускание Выдержка времени переключения контакторов ускорения оди- Ю какова, что приводит к затягиванию процесса пуска двигателя на повышенную частоту вращения из-за излишней задержки на промежуточной ступени механической < характеристики. ¹⁵ However, the known device is characterized by complexity and lack of reliability due to the large number of contacts included in the control circuit of the contactors. In addition, the device uses a complicated time relay in connection with the creation of a time delay for it both to trip and to release. The time delay for switching the acceleration contactors is the same, which leads to a delay in the engine starting process at an increased speed due to excessive delay in the intermediate stage of the mechanical characteristic. ^fifteen

Цель изобретения - упрощение и повышение надежности устройства.The purpose of the invention is to simplify and improve the reliability of the device.

Согласно первому варианту выполнения устройства указанная цель достигается _мтем, что в известном устройстве для пуска асинхронного электродвигателя, содержащем Ϊ1 резисторов в цепи обмотки ротора, 2 η контактов, шунтирующих резисторы, п катушек, контакторов с замыкающими и размыкающими контактами^' командоаппарат, одни выводы которого соединены с первыми выводами П катушек контактора, а другие его выводы соединены с одним из выводов источника питания, второй вывод первой катушки контактора через первый замыкающий контакт соединен с другим выводом источника питания, а второй вывод каждой последующей катушки контактора соединен с другим выводом источника питания че- ³⁵рез последовательно соединенные второй замыкающий контакт предыдущей катушки контактора и свой первый замыкающий контакт, элемент задержки, одним выводом подключенный к другому выво- ⁴⁰ду источника питания, И размыкающих контактов катушек контактора соединены , последовательно между собой; причем один из выводов каждого размыкающего контакта соединен с первым замыкающим ⁴⁵контактом той же катушки контактора, а другой вывод И -го размыкающего контакта соединен с другим выводом элемента задержки.According to a first embodiment of the device said object is achieved by _th fact that in the known device for starting asynchronous electric motor comprising Ϊ1 resistors in the circuit of rotor windings, 2 η contacts, shunt resistors, n coils of contactors with make and break contacts ^ 'sequencer, some conclusions which is connected to the first terminals P of the contactor coils, and its other terminals are connected to one of the terminals of the power source, the second terminal of the first contactor coil through the first make contact is connected to gim power supply terminal and the second terminal of each successive coil of the contactor is connected to the other terminal of the power source ³⁵ che Res serially connected second normally open contact previous contactor coil and a first normally open contact, a delay element, one terminal connected to another row ⁴⁰ conclusions power source , And the NC contacts of the contactor coils are connected in series with each other; moreover, one of the terminals of each NC contact is connected to the first NO contact ^{45 of} the same coil of the contactor, and the other terminal of the AND NC contact is connected to the other terminal of the delay element.

Согласно второму варианту выполне- ⁵⁰ния устройства указанная цель достигается тем, что в’ известное устройство для пуска асинхронного электродвигателя, содержащее п резисторов в цепи обмотки ротора, 2 п контактов, шунтирующих ре- 5* зисторы, п катушек контактора с замыкающими и размыкающими контактами, команде аппарат, одни выводы которого сое динены с первыми выводами П катушек контактора, а другие выводы соединены с одним из выводов источника пита·ния, второй вывод первой катушки контактора через первый замыкающий контакт соединен с другим выводом источника питания, а второй вывод каждой последующей катушки контактора соединен с другим выводом источника питания через последовательно соединенные второй замыкающий контакт предыдущей катушки контактора и свой первый замыкающий контакт, элемент задержки, одним выводом подключенный к другому выводу источника питания, последовательно соединенные третий замыкающий контакт первой катушки контактора с параллельно соединенными размыкающим контактом второй и замыкающим контактом третьей катушки контактора, введены репе с размыкающими и замыкающими контактами и П последовательно соединенных диодов, анод первого диода соединен непосредственно, аноды четных диодов - через замыкающий, а аноды всех остальных диодов - ..через размыкающий контакты реле, катод И -го диода соединен с другим выводом элемента задержки.According to a second embodiment vypolne- ⁵⁰ Nia device said object is achieved in that the 'known device for starting asynchronous electric motor comprising n resistors in the circuit of rotor windings, 2 n contacts, shunt PE 5 * ican, n contactor coils with make and break contacts , to the command, an apparatus whose one terminal is connected to the first terminals of the P coils of the contactor, and the other terminals are connected to one of the terminals of the power supply, the second terminal of the first coil of the contactor is connected to the other via the first make contact a power source, and the second terminal of each subsequent coil of the contactor is connected to another terminal of the power source through a second make contact of the previous coil of the contactor and its first make contact, a delay element connected to the other output of the power source by one pin, and a third make contact in series the first coil of the contactor with a parallel connected opening contact of the second and closing contact of the third coil of the contactor, by the opening and closing contacts and P of the series-connected diodes, the anode of the first diode is connected directly, the anodes of the even diodes - through the closing, and the anodes of all other diodes - through the relay contacts, the cathode of the nth diode is connected to another terminal of the delay element.

Кроме того, .элемент задержки снабжен регулятором времени, шунтируемым И последовательно соединенными- замыкающими контактами катушек контакторов. На фиг. 1 изображена схема включения резисторов' в цепь ротора электродвигателя; на фиг. 2 - схема первого варианта устройства; на фиг. 3 - схема второго варианта устройства.In addition, the delay element is equipped with a time regulator, shunted And connected in series by the closing contacts of the contactor coils. In FIG. 1 shows a diagram of the inclusion of resistors' in the rotor circuit of an electric motor; in FIG. 2 is a diagram of a first embodiment of a device; in FIG. 3 is a diagram of a second embodiment of the device.

Устройство для пуска асинхронного электродвигателя 1 содержит резисторы 2 (фиг. 1) в цепи обмотки его ротора, командсаппарат 3 (фиг. 2), выходы которого соединены с одними выводами катушек 4-6 контактора соответственно, элемент 7 задержки, который состоит из тиристора 8, параллельно которому подключен однопереходный транзистор 9 через диод 10 и резисторы 11-13, конденсатора 14 и резисторов 15, подключенных к электродам транзистора»9. Замыкающие контакты 16 первой катушки контактора соединяют второй вывод катушки 4 с источником питания и второй вывод катушки 5 с замыкающим контактом 1 7 второй,катушки контактора, подключенного к источнику питания 5. Другой замыкающий контакт 17 соединяет катушку 6 контактора с замыкающим контактом 1 8 третьей катушки контактора; подключендA device for starting an induction motor 1 contains resistors 2 (Fig. 1) in the circuit of the winding of its rotor, a command device 3 (Fig. 2), the outputs of which are connected to one terminal of the coils 4-6 of the contactor, respectively, a delay element 7, which consists of a thyristor 8 parallel to which a single-junction transistor 9 is connected through a diode 10 and resistors 11-13, a capacitor 14 and resistors 15 connected to the electrodes of the transistor "9. The closing contacts 16 of the first coil of the contactor connect the second terminal of the coil 4 to the power source and the second terminal of the coil 5 with the making contact 1 of the second second coil of the contactor connected to the power source 5. Another making contact 17 connects the coil 6 of the contactor to the closing contact 1 of the third coil 8 contactor; connected

957391 6 ного к источнику питания. Размыкающие контакты 16 и 17 контакторов включены последовательно и замыкают второй вывод катушки 4 контактора с анодом тиристора 8 элемента 7 задержки. 5957391 6 to the power source. The NC contacts 16 and 17 of the contactors are connected in series and close the second output of the coil 4 of the contactor with the anode of the thyristor 8 of the delay element 7. 5

Во втором варианте устройства (фиг. 3) катушка 19 реле одним выводом подключена к первому выводу катушки 4, а другим выводом - к цепочке из последовательно соединенных замыкающего контакта 16·^ и параллельно соединенных размыкающего контакта 17 и замыкающего контакта 18. Контакты 20 реле соединяют диоды 21, подключенные к входу элемента. 7 задержки, с замыкающими контактами 16-18.. ΙίIn the second variant of the device (Fig. 3), the relay coil 19 is connected to the first output of the coil 4 by one output and to the chain of the make-up contact 16 · ^ and the parallel-connected make-contact 17 and the make-up contact 18. The relay contacts 20 connect diodes 21 connected to the input of the element. 7 delays, with make contacts 16-18 .. Ιί

Устройство работает следующим образом.The device operates as follows.

В первом варианте устройства для пуска двигателя 1 подают напряжение на обмотку статора. В цепи обмотки ро- 20 тора электродвигателя 1 введены резисторы 2 так, что контакты 16-18 контакторов отключены. Двигатель 1 развивает наименьший пусковой момент .In the first embodiment of the device for starting the motor 1, voltage is applied to the stator winding. Resistors 2 are introduced in the winding circuit of the rotor 20 of the electric motor 1 so that the contacts 16-18 of the contactors are disconnected. Engine 1 develops the smallest starting torque.

При замыкании контакторов командоагь25 парата 3 напряжение через первую катушку 4 контактора и размыкающие контакты 1 6 и 17 поступает на вход элемента 7 задержки. Конденсатор 14 заряжается в течение времени, определяемого величи— jq нами сопротивления резисторов 11, 12, 13 и 15, и его разряд осуществляется через эмиттер и базу включившегося однопереходного транзистора 9 и управляющий электро»-катод тиристора 8, последний включается, замыкая цепь катушки 4 контактора. Контактор первой ступени пуска срабатывает с выдержкой времени, шунтируя своими контактами 16 часть резиоторов 2. Двигатель 1 переходит на еле— дующую ступень пуска с меньшей величиной сопротивления в цепи обмотки ротора электродвигателя. Одновременно переключается контакт 16 в цепи катушки 4, подключая ее непосредственно к источ-_<5нику питания, а в цепи катушки 5, подключая ее к элементу 7 задержки. По истечении времени заряда конденсатора 14 и при срабатывании тиристора 8 катушка 5 контактора подключается к источнику питания, замыкаются контакты 17., шунтируя следующую часть резисторов 2 и подготавливая цепь включения контактора к следующей ступени пуска. Катушка 6 контакторов включается аналогично.When the contactors are closed, command 25 of unit 3, the voltage through the first coil 4 of the contactor and the NC contacts 1 6 and 17 is supplied to the input of the delay element 7. The capacitor 14 is charged for a time determined by the jq resistance of resistors 11, 12, 13, and 15, and its discharge is carried out through the emitter and the base of the switched-on single-junction transistor 9 and the control electro-cathode of the thyristor 8, the latter turns on, closing the circuit of the coil 4 contactor. The contactor of the first start-up stage operates with a delay time, by shunting with its contacts 16 part of the resonators 2. Motor 1 switches to the next start-up stage with a lower resistance value in the winding circuit of the electric motor rotor. At the same time, contact 16 is switched in the coil 4 circuit, connecting it directly to the power source _<5 , and in the coil 5 circuit, connecting it to the delay element 7. After the charging time of the capacitor 14 and when the thyristor 8 is triggered, the contactor coil 5 is connected to a power source, contacts 17 are closed, bypassing the next part of the resistors 2 and preparing the contactor switching circuit for the next starting stage. The coil 6 of the contactors is switched on in the same way.

Для создания оптимального по величи- ⁵⁵не задержки времени переключения резисторов в цепи обмотки ротора замыкающие контакты 16—1 8 контакторов под* ключены к резистору 15, изменяя его сопротивление на каждой ступени пуска двигателя.To create an optimal magnitude ⁵⁵ does not delay the switching of resistors in the rotor winding circuit closing contacts 16-1 8 * contactors under key K resistor 15, changing its impedance at each engine start-up stage.

Для повышения надежности включения контакторов при переключении контактов в цепи питания их катушек последние могут быть замкнуты конденсаторами или диодами, с помощью которых производится поддержание магнитного поля в катушке при кратковременном перерыве питания.To increase the reliability of switching on the contactors when switching contacts in the power supply circuit of their coils, the latter can be closed by capacitors or diodes, with the help of which the magnetic field in the coil is maintained during a short interruption in power supply.

Во втором варианте устройства (фиг. 3) катушка 4 контактора первой ступени пуска подключается к элементу 7 задержки через диоды 21. Контакты 16 контактора подключают катушку 4 к источнику питания, шунтируя элемент 7 задержки, и включает катушку 19 реле, которое своим контактом 20 замыкает цепь включения катушки 5. Контактор последующей катушки включится после переключения контактора предыдущей катушки и реле 19. Реле 13 служит для создания задержки на подключение катушек контакторов к элементу 7 .задержки.In the second embodiment of the device (Fig. 3), the coil 4 of the contactor of the first start-up stage is connected to the delay element 7 via diodes 21. The contacts 16 of the contactor connect the coil 4 to the power source, bypassing the delay element 7, and turns on the relay coil 19, which closes with its contact 20 coil switching circuit 5. The contactor of the subsequent coil will turn on after switching the contactor of the previous coil and relay 19. Relay 13 is used to create a delay for connecting the coils of contactors to the delay element 7.

Таким образом, предлагаемое устройство позволяет производить переключение ступеней пуска двигателя более простыми техническими средствами и по упрощенной схеме управления, в связи с чем снижает—· ся его стоимость и повышается надежность. Установка выдержки времени от дель но для каждой ступени позволяет сократить общее время пуска двигателя и соов* ветственно повысить производительность приводимого механизма.Thus, the proposed device allows you to switch the start-up stages of the engine with simpler technical means and according to a simplified control scheme, in connection with which its cost is reduced and reliability is increased. The setting of the time delay from delno for each stage allows one to reduce the total time for starting the engine and, accordingly, to increase the productivity of the driven mechanism.

Claims

However, the known device is characterized by complexity and lack of reliability due to the large number of contacts made in the control circuit of the contactors. In addition, the device used a time relay of a complicated construction in connection with creating time delays for both actuation and release. The switching time of the acceleration contactors is the same, which leads to a delay in the engine start process for an increased time. for the latency at the intermediate stage of the mechanical characteristic. The purpose of the invention is to simplify and increase the reliability of the device. According to the first embodiment of the device, this goal is achieved by the fact that in a known device for starting an asynchronous electric motor containing Δ resistors in the rotor winding circuit, 2 n contacts, shunt resistors, π coils, contactors with closing and opening contacts / control unit, all of which are connected The first leads of the contactor's pushes and the other of its pins are connected to one of the power supply terminals; the second lead of the first contactor coil is connected to the other through the first closing contact a second power supply terminal, and the second output of each subsequent contactor coil is connected to a different output of the power source through a serially connected second closing contact of the previous contactor coil and its first closing contact, a delay element, one output connected to the other output of the power source, P disconnecting contacts the contactor is connected in series with each other, with one of the conclusions of each opening contact connected to the first closing contact of the same coil contact Ora, and the other output of the nth disconnecting cycle is connected to another output of the delay element. According to the second embodiment of the device, said target achieves with the fact that, in a known device for starting an asynchronous electric motor, containing n resistors in the rotor winding circuit, 2 n contacts, shunting resistors, n coils of contactor with short-circuit and breaker contacts, com- mand device, one of the terminals of which is connected (1s with the first terminals of the P catchers of the contactor, and the other terminals are connected to one of the source terminals, the second terminal of the first coil of the contactor is connected to the other terminal via the first closing contact The power supply and the second output of each subsequent contactor coil is connected to another output of the power source through the second make contact of the previous contactor coil and its first make contact, a delay element connected to the other side of the power source sequentially connected to the third make contact of the first coil a contactor with a second contact opened in parallel with a second contact and a closing contact for the third coil of a contactor; contacts and последовательно series-connected diodes, the anode of the first diode is connected directly, the anodes of even diodes through the closing, and the anodes of all other diodes through a dielectric KotiTaKTb relay, the cathode of the -th diode is connected to another output of the delay element. In addition, the delay element is equipped with a time controller, which is bridged by N series-connected contact contacts of the coils of the contactors. FIG. Figure 1 shows a circuit for incorporating resistors into the rotor circuit of an electric motor; in fig. 2 is a diagram of the first embodiment of the device; in fig. 3 is a diagram of a second embodiment of the device. A device for starting an asynchronous motor 1 contains resistors 2 (Fig. 1) in the winding circuit of its rotor, command unit 3 (Fig. 2), the outputs of which are connected to one of the terminals of the contactor coils 4-6, respectively, delay element 7, which consists of a thyristor 8 , in parallel, KOfopoKiy is connected to a unijunction transistor 9 through diode 10 and resistors 11-13, capacitor 14 and resistors 15 connected to the electrodes of the transistor. The closing contacts 16 of the first coil of the contactor connect the second lead of the coil 4 to the power source and the second lead of the coil 5 to the closing contact 17 of the second coil of the contactor connected to the power supply 5. The other close contact 17 connects the coil 6 of the contactor to the lock of the third coil contactor; connected to a power source. The opening contacts 16 and 17 of the contactors are connected in series and close the second output of the coil 4 of the contactor with the anode of the thyristor 8 of the delay element 7. In the second version of the device (Fig. 3, the coil 19 of the relay is connected by one output to the first output of coil 4, and the other output is connected to a chain of series-connected closing contact 16 and parallel-connected disconnecting contact 17 and closing contact 18 Contacts 20 of the relay connect diodes 21 Connected to the input of the element. 7 delay, with closing contacts 16-18 The device operates as follows: In the first version of the device for the nycka of the engine 1, the voltage is applied to the stator winding.In the rotor winding circuit of the electric motor 1 Resistors 2 are turned off so that contacts 16-18 of contactors are disconnected. Motor 1 develops the smallest starting torque. When the contactors of command and control 3 contactors are closed, the voltage across the first contact 4 of the contactor and the break contacts 1 6 and 17 goes to the input of the delay element 7. 14 is charged for a time determined by the resistance values of the resistors 11, 12, 13 and 15, and is discharged through the emitter and the base of the included single-junction transistor 9 and the control electro-cathode of the thyristor 8, the latter turning on closure c nb 4 contactor coil. The contactor of the first stage of the puoka triggers with a time delay, shunting with its contacts 16 a part of the resiators 2. Engine 1 goes to a barely starting stage with a lower resistance value in the rotor winding circuit of the electric motor. At the same time, the contact 16 in the coil circuit 4 is switched, connecting it directly to the power source, and in the coil circuit 5, connecting it to the delay element 7. After the charging time of the capacitor 14 has expired and when the thyristor 8 is triggered, the coil 5 of the contactor is connected to the power source, contacts 17 are closed, shunt the next part of the resistors 2 and prepare the contactor switch-on circuit to the next start level. The coil 6 of contactors is included in the same way. In order to create an optimal time delay for switching resistors in the rotor winding circuit, the closing contacts 16-1 of the 8 contactors are connected to the resistor 15, changing its resistance at each stage of the engine start. To increase the reliability of the contactors when switching contacts in the power supply circuit of their coils, the latter can be closed by capacitors or diodes, by means of which the magnetic field in the coil is maintained during a short power interruption. In the second version of the device (Fig. 3), the coil 4 of the first-stage contactor is connected to the delay element 7 via diodes 21. The contactor contacts 16 connect the coil 4 to the power supply, shunt the delay element 7, and turn on the relay coil 19, which by its contact 2O closes the circuit for turning on the coil 5. The contactor of the subsequent coil turns on after switching the contactor of the previous coil and the relay 19. Relay 13 serves to create a delay on connecting the coils of the contactors to the delay element 7. Thus, the proposed device makes it possible to switch the engine starting stages using simpler technical means and a simplified control scheme, and therefore reduces its cost and reliability 1. Setting the time delay separately for each stage can reduce the total engine start time and, accordingly, improve the performance of the driven mechanism. Claim 1. Device for starting an asynchronous electric motor containing C cutters in the rotor winding circuit, 2 And contacts of shunt resistors, noK-f-coil coils with closing and opening contacts, command device, one terminals of which are connected to the first pins of the contactor coils, and its other leads are connected to one of the power supply leads, the second lead of the first contactor coil is connected to the other lead of the power supply through the first closing contact, and the second lead is connected to ntaktora connected to the other terminal of source nwTaHVffl via series connected, a second normally open contact fr dydushey contactor coil and its first zamykak shy contact the delay member, one pin for prison at the other end to a power source, characterized in that, with a chain of simplicity; and increase the reliability of the device, And the opening contacts of the coils of the contactor are connected in series with each other, 5 and one of the conclusions of each opening contact is connected to the first closing contact of the same coil of the contactor, and the other output of the C-th opening contact to another output of the delay element.

2. A device for starting an asynchronous electric motor containing P resistors in the rotor winding circuit, 2 p contacts, shunting resistors, C coils 5 of the contactor with closing and opening. main contacts, one command of one terminal of which is connected to the first terminals of the P coils of the contactor, and its other terminals are connected to one of the 20 terminals of the power supply, the second output of the first coil of the contactor is connected to the other end of the power supply, and the second output of each subsequent coil D5 of the contactor is connected to another output of the source. power through a series-connected second closing contact of the previous coil of the contactor and its first closing contact, a retainer element, one terminal connected to another terminal of the power source,

Consequently, the third closing contact of the first coil of the contactor is connected with the second contact of the second contact and the closing contact of the third coil of the contactor connected in parallel, characterized in that, in order to simplify and increase the reliability of the device, a relay with opening and closing contacts and C-series diodes are inserted into it, the first diode is connected directly, the anodes of the even diodes through the closing, and the anodes of all the other diodes through the disconnecting relay, the cathode of the Pth diode En with a different output delay element.

3. The device according to PP. 1 and 2, characterized in that, in order to increase its speed, the delay element is provided with a time regulator shunted by P series-connected contact contacts of the coils of the contactors.

. Information sources. Considered in the examination

1.Alekseev, Yu.V. and others. Crane electrical equipment. M., Energie, 1979 p. 197-200.

2. USSR author's certificate number 94048, cl. H 02 R 1/34, 1951.