SU1742880A1 - Three-phase hybrid contactor - Google Patents

Abstract

Use: electrical engineering, switching equipment. Essence of the invention: when switched on, contacts 10-12 first close, connecting galvanically-openable outputs of power supply unit 13 to inputs of integrating blocks 7 ~ 9 ", which leads to smooth switching on of semiconductor switches ^ -6 on transistors. 3L * - the contact -15 is then closed in the coil 1 * of the drive circuit and the power contacts 1-3 are turned on. Disconnection of the circuit occurs in the reverse sequence of the operation of contacts 10-12 and 15. The on-off load occurs without arcing on contacts 1-3 and is not accompanied by the appearance of overvoltages, which increases the reliability of the contactor in operation. 1 il.

Description

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This invention relates to electronic switches A-6. The outputs of the source equipment and can be used LL 13 power galvanically separated

switching electrical circuits of alternating current.

The purpose of the invention is to increase the reliability of the contactor.

The drawing shows the electrical circuit of the contactor ..

The contactor contains power contacts 1-3, shunted by the corresponding semiconductor switches -6. The inputs of each semiconductor switch are connected to the outputs of the respective integrating circuits 7-9, and the inputs of the integrating circuits are connected via the corresponding auxiliary contacts 10-12. With galvanically developed outputs of the power supply 13. The input of power supply 13 is connected, for example, according to the star circuit. Power is supplied to the drive coil 1, contacts 1-3 is supplied via an auxiliary contact 15 mechanically connected to the auxiliary contacts 10-12, and contact 15 is switched on with a time delay relative to contacts 10-12.

Each semiconductor switch consists of diodes 16-19, connected according to the full-wave rectifier type circuit. one diagonal of which shunts power contacts of 1G3, s bipolar is switched on into the other diagonal

the transistor 20, the base and emitter of which

Go connected to the outputs of the integrating circuits.

Each integrated circuit 7-9 consists of series-connected resistors 22-2, with the resistors 23 and 2 shunted by a capacitor 21. The input is the free terminal of the resistor 22 and the junction point of the capacitor 21 and resistor 2. The output is the terminals of resistor 2.

The device works as follows.

In the initial state, the power contacts 1-3 and the auxiliary contacts 10-12 and 15 are open, the semiconductor switches -6 are closed. First, auxiliary contacts 10-12 are included. The integrating circuits 7-9 are applied to the voltage U of the power supply source 13, the value of which exceeds or equal to the voltage of the base-emitter of the respective transistors 20 semiconducting with one another. The capacitor 21 is charged through the resistor 22. The transistor 20 starts to open, and at the initial period of time the collector current, which is the load current in the alternating current circuit, gradually increases. Then the auxiliary contact 15j, which has an on-delay with respect to the inclusion of the auxiliary contacts 10, closes. -12, - realized in the electromechanical way. After the auxiliary contact 15 is closed, the power supply voltage is applied to the contact drive drive cat T1 1-3, after which the front closes. - Description of work at shutdown. In the initial state, the power contacts 1-3 and the auxiliary contacts 10-12 and 15 are closed, the semiconductor switches -6 are open.

First, the auxiliary contact 15 is opened and with a delay equal to the opening time of the power contacts 1-3, the auxiliary contacts 10-12 open, the capacitor 21 begins to discharge through the resistors 23 and 2k and the base-emitter junction of the transistor 20, which leads to a smooth decrease in the base current transistor 20.

Accordingly, the load current flowing through the semiconductor

 the keys i-6j smoothly decrease, the transistor 20 is fully closed and the hybrid contactor disconnects the load.

The proposed contactor provides a significant reduction in switching overvoltages and eliminates the burning of the arc, which increases its reliability.

Invention Formula

. A three-phase hybrid contactor containing in each pole power contacts, a drive coil, three rectifying bridges with alternating current leads and direct current leads, three semiconductor switches with power leads and a control input, a power supply unit with three galvanically open outputs, and To each pole of the contactor, the power contacts are bridged by the AC leads of the corresponding rectifying bridge, and the power leads of the corresponding semiconductor switch are connected to the terminals of a constant A corresponding rectifying bridge, characterized in that, in order to increase the reliability of the contactor, a control contact, three auxiliary contacts and three integrating units, each of which is equipped with an input and an output, are inserted into it, and A transistor, these auxiliary contacts are mechanically connected to the specified control contact, the control contact is connected to the drive coil, the control input of each of the specified connection semiconductor switches It is connected to the output of the corresponding integrator unit, the input of which is connected to the corresponding output of the power supply unit through the appropriate auxiliary contact.