SU1457054A1 - Arrangement for protecting three-phase electric installation from two-phase operation - Google Patents

Abstract

This invention relates to the field of electrical engineering, in particular, to relay protection of a three-phase electrical installation. The purpose of the invention is to increase the reliability of protection and expand the range of controlled load currents. The goal is achieved by the fact that with the help of three measuring transducers 4-6 and three transistor switches 7-9, if any of the network phases is broken, the current disappears. This closes the corresponding transistor key, cht (5 leads to a decrease in current through the light-emitting diodes of the optocouplers 15, 16 and the closure of their photo thyristors. The power supply circuit of the winding of the electromagnetic comparator 10 is broken, and the electrical installation 12 is disconnected from the network 1 or S.

Description

ten

one

 The invention relates to electrical engineering, in particular, to protection devices against operation on two phases of three-phase electrical installations, in particular asynchronous and synchronous electric motors, electromagnets, and the like. ;

The aim of the invention is to increase the reliability of protection and expand the range of monitored currents.

load.

The drawing shows the circuit diagram of the assembly device. The device contains current phase transformers 1-3, the windings of which 15 are connected to the corresponding inputs of measuring transducers 4-69 transistor switches 7-9, whose inputs are connected in a unidirectional chain with the corresponding outputs of measuring transducers, and the emitter-collector circuits of the outputs are interconnected in series - unidirectional circuit of a kidney, electromagnetic contactor 10, power contacts 11 of which are included in the phase wires of a three-phase electrical installation 12, a chain connected to the supply network and co-hundred and control mixture consisting of the Start button; 30 13, included in series with

button and winding of the electromagnetic contactor 10, two oppositely connected photo thyristor optocouplers 15 and 16, connected by one of the clamps to the common point of the Start and Stop buttons, and the other to the closing block contact 17 of the electromagnetic contactor, is connected MTT..l. t t

14570542

including electrical installation 12 in a three-phase network. Phases flow load currents that induce a proportional EMF in the windings of phase transformers 1-3 current. On-and-off coils of phase current transformers are rectified on a two-half-time bridge circuit in a pulsircord with a frequency of 100 Hz, signals that are shifted by 60 zlah between themselves and applied to the inputs of transistor switches 7-9. The output emitter-collector circuits of transistor switches are connected to a series-unidirectional chain with light-emitting diodes of optocouplers -15 and 16, the current from the operating current source 18 passes through, the photo thyristors of optocouplers 15 and 16 open and sequentially with block contact 17 of the electromagnetic contactor 10 are shunted start button.

When any of the network phases breaks, it disappears, which causes the corresponding transistor switch to close, a sharp decrease in current through the light-emitting diodes of optocouplers 15 and 16 and their photothyristors to close, the power supply circuit of the electromagnetic contactor 10 is broken and the electrical installation 12 is disconnected from the network.

20

25

35

Claims (1)

Invention Formula Device for the protection of three-phase electrical installation o-work on two phases, containing phase transformariil IU1 invjx W ixw.Г-, “;;; and to lp lera current with leads to enable to the common point of the Start button and about 40 electromagnetic contactor, the power contacts of which are connected to the terminals for connection with the phase conductors of the three-phase electrically conductive cable, - the supply source of the operating current, torus, LED optocoupler included in 45 parallel to the winding of the electrical-unidirectional circuit, the cathode of the LED of the optocoupler 15 , y IX l. j. g the coils of the electromagnetic contactor 10, the operating current source 18, the input of which is connected arally to the coil of the electromagnetic contact connected to the negative terminal of the operating current source 18, and the anode of the optical diode 16 to the collector jQ of the transistor switch 7 ,. The positive terminal of the source 18 operating current is connected to the emitter of the transistor EO key 9.. $ 5 The device works as follows. When the start button is pressed, the electromagnetic contactor 10 is activated, a magnetic contactor connected to the terminals for connecting to the supply network a chain consisting of the Stop control button - connected in series with the Start button and the winding of the electromagnetic contactor, one terminal of the closing contact block of which is connected to the common point of the Start button and windings electromagnetic contactor, two photo-thyristor counter-parallel connected optocouplers connected. between the common point of the buttons and 35 Invention Formula   parallel winding zlekt a magnetic contactor connected to the terminals for connecting to the supply network a chain consisting of the Stop control button - connected in series with the Start button and the winding of the electromagnetic contactor, one terminal of the closing contact block of which is connected to the common point of the Start button and windings electromagnetic contactor, two photo-thyristor counter-parallel connected optocouplers connected. between the common point of the buttons and A stop and a blocking contact of the electromagnetic contactor, one of the light emitting diodes is connected by a cathode to the minus terminal of the operating current source, and the anode to the cathode of the second light emitting diode of the other Iroro optocoupler, so as to improve the reliability of protection and expansion range of monitored load currents, three measuring transducers are entered into it, the inputs of which are connected to the corresponding The windings of phase current transformers and three transistors, each input of which is soy, are connected to the output of the corresponding measuring transducers in a unidirectional chain, and the emitter-collector circuits of the outputs of the transistor switches are connected in a single unidirectional chain connected to the anode of the second light-emitting diode. diode, and the other - to the positive terminal of the source of operating current.