SU1128299A1 - A.c.contactor with arcless commutation - Google Patents

Abstract

AC INPUT CONTROLLER WITH ARCESSED SWITCH, containing main contacts with electromagnetic drive, transformer, two power thyristors, on and off buttons, with the main contacts and the primary winding of the transformer connected in series and bridged after disconnectedly connected by the secondary winding of the transformer and connected to the same time, they are bridged after the secondary winding of the system, which is also connected to the same time, the same time, and the same time, the same time, the same time, the same time, and the same time, the same time, and the same time, the same time, and the same time, and the same time, and the same time, and the same time, the same time, the same time, the same time, the same time, the same time, the same time, the same time, the same time, and the same time, the same time, the same time, the same time, the same time, the same time, which is used to connect the current-timed circuits of the current transformer and the primary transformer connected to the main transformer, the main contacts and the primary transformer are connected to each other. the contactor drive through the sequentially connected closing contact of the power button and the opening The contact of the off button is connected to the terminals for connecting the AC network, which is different from the fact that, in order to increase the reliability of the contactor, a pulse transformer, two electrically operated relays, two auxiliary thyristors, two rectifying bridges, storage capacitor, two. , PC circuits, isolating diodes and limiting resistors, with the primary winding of the pulse transformer connected between the main contacts and the primary winding of the transformer, the secondary winding of the pulse transformer is connected to the inputs of the first rapid bridge, one of the outputs of which is connected to the cathode of the first auxiliary thyristor and through The first and second isolating diodes are connected to the control electrodes of the power thyristors, the other output of the first rectifying bridge is connected in series through e the first limiting resistor, the disconnecting contact, the first electromagnetic relay and the third separating diode are connected to the control electrode of the first auxiliary thyristor, the anode of the first auxiliary thyristor through one of the RC circuits connected to one of the power thyristors, through another RC circuit — with the anode of another power thyristor and through a series-connected contact of the second electromagnetic relay and the second limiting resistor — with its control electrode, the inputs of the second A connecting bridge is connected to the terminals for connecting the AC mains, one directly, the other through the opening contact of the switch-on button, one of the outputs of the second bridge rectifier is connected to one of the plates of the storage capacitor and one of the terminals of the second electromagnetic relay, the other koto conclusion

Description

The swarm of the third limiting resistor, the second auxiliary thyristor and the fourth limiting resistor connected in series are connected to another plate of the storage capacitor and another, by the second transient bridge, controlled by the second auxiliary thyristor electrode

1.28299

the fifth limiting resistor connected in series and the closing contact of the first electromagnetic relay is connected to another input of the second rectifying bridge / winding of the first electromagnetic relay connected in parallel with the winding of the electromagnet of the contact actuator.

This invention relates to electrical engineering and can be used in low voltage AC contactors. .

Known contactors are alternating current with arc-free commutation of electric circuits, in which thyristors or diodes lj are connected in parallel with the contacts.

When the contacts are opened, an electric arc is formed on them and only after the current passes into the semiconductor circuit, it goes out.

The closest to the invention according to the technical essence is an AC contact with arc-free commutation, containing main contacts with an electromagnetic drive, a transformer, two Tiris powers, switch on and off buttons, with the main contacts and the primary transformer of the transformer connected in series and bridged in series. , the secondary winding of the transformer and counter-parallel-connected power thyristors, the winding of the contactor actuator electromagnet through the follower The connected make contact of the power button and the break contact of the power button are connected to the terminals for connecting the overvoltage network 2.1

In this contactor, maintenance is achieved when the thyristors are turned on at the current flow stage through the contacts, and when the latter are opened, the current devices already switched on, the current passes almost instantly and eliminates the formation of an electric arc. Possible sparking when breeding contacts.

slightly affects the wear of contacts 2,

A disadvantage of the known contactor is that during the flow of current through the closed contacts, part of the current branches into the shunt circuit and leads to significant energy losses in the thyristors, reducing their current carrying capacity in switching modes, and the need to use radiators for cooling. This reduces the reliability of the operation of the contactor and affects its size. In addition, such a contactor does not provide arc-free closure of contacts when turned on.

The aim of the invention is to increase the reliability of the apparatus operation by eliminating the turn-on arc and ensuring the operation of the thyristors only at the xcommutation current intervals.

This goal is achieved in that the AC contactor with arc-free commutation contains the main contacts with an electromagnetic drive, a transformer, two power, thyristors, on and off buttons, the main contacts and the primary winding of the transformer are connected in series and bridged: in series with the secondary winding of the transformer and anti-parallel power thyristors, the winding of the electromagnet of the contactor drive through serially connected closing The on / off button and the disconnecting contact of the off button are connected to the terminals for connecting the AC mains, a pulse transformer, two electromagnetic relays, two auxiliary thyristors, two rectifying bridges, a storage capacitor, two SC circuits, isolating diodes and limiting resistors, The primary winding of the pulse transformer is connected between the main contacts and the primary winding of the transformer, the secondary winding of the pulse transformer is connected to the inputs of the first rectifier telny bridge, one of the outputs of which is connected to the cathode of the first. auxiliary thyristor and through the first and second isolating diodes with control electrodes of power thyristors, another output of the first rectifying bridge through the first limiting resistor connected in series, disconnecting the contact of the first electromagnetic relay and the third isolating diode connected to the control electrode of the first auxiliary thyristor, anode the first auxiliary thyristor through one of the RC circuits is connected to the anode of one of the power thyristors, through the other RC circuit to the anode of the other forces the second thyristor and the serially connected make contact of the second electromagnetic relay and the second limiting resistor — with its own controlled electrode; the inputs of the second arcing bridge are connected to the terminals for connecting the AC network, one directly, the other through the opening of the switch-on button, one of The outputs of the second bridge are connected to one of the terminals. the capacitor capacitor plates and one of the winding pins of the second electromagnetic relay, the other of which is connected via a third limiting resistor in series, the second auxiliary thyristor and the fourth limiting resistor connected to the other capacitor of the storage capacitor and the other output of the second high-speed bridge, control (equal the electrode of the second auxiliary thyristor through a series-connected fifth limiting resistor and the closing contact of the first electromagnet The main relay is connected to another input of the second rectifying bridge, the winding of the first electromagnetic relay is connected parallel to the winding of the electromagnet, the contactor drive. The drawing shows a schematic diagram of the contactor. The contactor contains an on button 1, an off button 2, the first relay 3 in the winding control circuit electromagnet 4. The contact circuit contains its own contacts 5, a pulse transformer 6, a voltage transformer 7, the secondary winding of which is connected in series with the counter-parallel connected , a pair of thyristors 8. A thyristor control circuit 8 is connected to a circuit of diodes 9, an auxiliary mains power thyristor 10, controlled from the anode circuit through contacts 11 of the second relay 12 and a resistor 13. From the contacts circuit 5, the auxiliary thyristor 10 is controlled by a pulse transformer 6 through the upper bridge 14, a resistor 15, the zener diode 16 and the contacts 17 of the first relay 3. The voltage separation circuit in the circuit of the thyristor is used for RC 18 and 19. The relay 12 is supplied from the network through a rectifying bridge 20, resistors 2 1 and 22, a storage capacitor 23, an auxiliary thyristor 24 controlled from the anode circuit through the contacts 25 of the relay 3 and a resistor 26. The operation of the contactor is carried out in the following way. When turned on by pressing button 1, power is supplied to the winding of the relay 3, winding of the electromagnet 4 of the contactor. The paired contacts of the button 1 are open. Relay 3 operates faster than the electromagnet of the contactor and turns on the auxiliary thyristor 24 with its closing contacts 25, as a result, the precharged capacitor 23 is discharged to relay 12 and turns it on. In this case, the closing contacts 11 are closed in the control circuit of the triggering thyristor 10 and one of the shunt thyristors 8 is turned on, to which a positive voltage offset is applied. The load current begins to flow through the thyristor, and after closing the contacts 5 without switching on the arc goes into the contact branch. After the capacitor 23 is discharged, the relay 12 is turned off and the control to the thyristors 8 is not exercised. Thus, the thyristors 8 with closed contacts 5 do not flow around the TOKOM. The duration of operation of the thyristor OB 8 is controlled by the moment when the control signal is removed from the instrument control circuit and is ensured by a constant discharge time of the capacitor 23 through resistors 21 and 22 and the relay winding 12. With the contacts 5 closed, the current in the primary winding of the transformer 7 creates an emf secondary winding, the value of which is sufficient for the inclusion of thyristors 8i However, they are not included due to the absence of a control signal on the control electrodes of the thyristors. When the contactor is disconnected after pressing button 2, the relay 3 and the coil of the electromagnet 4 of the contact are de-energized. Since the relay 3 operates faster than the contactor, the contacts 17 in the secondary circuit of the pulse transformer 6 are closed and the pulses from the secondary winding of the transformer 6, rectified by bridge 14, will open through the disconnecting contacts 17 of the relay and the separation diode to 10. thyristors 8 have a voltage induced by the b junction of transformer 7, then through dividers 18 and 19, JMoe is provided with a bias across thyristor 10 and it will turn on each half-cycle and beat at the input thyristor This means that the thyristors in the shunt branch will be included for one or two half-periods until the contacts are disconnected 5. The duration of the flow of part of the branch from the main current circuit (8-10% Lx) 9; 6 is small and thyristors do not have time to heat up above the temperature of the permissible value. When the contacts open, the 5-current in the contact circuit starts to decrease, and the current in the thyristor circuit increases. Magnetizing amperes. : the turns of the primary winding of the transformer 7 are reduced, the flux in the core, respectively, also decreases, creating an additional EMF in the secondary winding, which contributes to the current flowing into the shunt branch. Subsequently, the current flows through the thyristor and at the first natural zero crossing is interrupted as in the absence of current in the contact circuit from the pulse transformer 6 the control signal does not flow to the control of the auxiliary thyristor 10. Thus, the switched circuit is disconnected. The greatest efficiency with the use of the proposed apparatus can be achieved as a result of its installation in switchgear if frequent switching of currents is necessary. The resource of operation of such devices amounts to hundreds of thousands of operations (Enable — random pause — disconnect) nominal currents without forming an electric arc. . The advantage of the technical and economic indicators of the proposed solution in comparison with the known ones lies in the increased service life of this contactor, which is equal to its mechanical resource. .

private

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Claims (1)

; * AC-CONTROLLER WITH ARC-FREE COMMUNICATION, containing the main contacts with an electromagnetic 'drive, a transformer, two power thyristors, on and off buttons, the main contacts and the primary winding of the transformer connected in series and shunted in series by the secondary winding of the transformer and the opposite parallel-connected power -, Ristorami, electromagnet winding with water contactor through. sequentially connected make contact of the power button and disconnect the contact of the shutdown button is connected to the outputs for connecting an AC network, characterized in that, in order to increase the reliability of the contactor, a pulse transformer, two electromagnetic relays, two auxiliary thyristors, two rectifier bridges, a storage capacitor, two . , ifC-circuits, decoupling diodes and limiting resistors, with the primary winding of the pulse transformer connected between the main contacts and the primary winding of the transformer, the secondary winding of the pulse transformer connected to the inputs of the first rectifier bridge, one of the outputs of which is connected to the cathode of the first auxiliary thyristor and through the first and the second time knitting diodes - with control electrodes of power thyristors, another output of the first rectifier bridge through series-connected first the limiting resistor, the breaking contact of the first. electromagnetic relay and the third disconnecting diode is connected to the control electrode of the first auxiliary thyristor, the anode of the first auxiliary thyristor through one of the RC circuits connected to the anode of one of the power thyristors, through the other RC circuit - with the anode of another power thyristor and through a series-connected make contact of the second electromagnetic relay and the second limiting resistor - with its control electrode, the inputs of the second rectifier one hundred are connected to the conclusions of the day of connecting the AC network, one directly, the other through the opening contact of the power button, one of the outputs of the second bridge rectifier is connected to one of the plates of the storage capacitor and to one:: ID terminals of the winding of the second electromagnetic relay, another output which is 11.28299 a swarm through which a third limiting resistor, a second auxiliary thyristor and a fourth limiting resistor are connected in series to a different plate of the storage capacitor and another .. m at the output of the second rectifier bridge, the control electrode of the second auxiliary thyristor is connected through the fifth limiting resistor and the make contact of the first electromagnetic relay in series with the other input of the second rectifier bridge. winding of the first electromagnetic ·. The relay is connected in parallel with the coil of the contactor drive electromagnet.