SU1746529A1 - Non-contact three-phase network commutator - Google Patents

Abstract

The invention relates to electrical engineering and can be used for contactless switching of a three-phase load of any nature. The purpose of the invention is to increase the reliability of the switch. The contactless switch of three-phase circuits contains in each switching phase a thyristor 1, 2, 3, and a diode 4, 5, 6, connected in anti-parallel between the input 7.8, 9 and output 10,11,12 pins, a three-phase transformer 13, primary windings of which are connected to the input of the switch, three optocouplers 14, 15.16, the light emitters of which are connected in series according to between the buses 17, 18 of the control, and three resistor chains 19-24, the primary windings of the three-phase transformer 13 are connected in a star, the end of the secondary winding of phase A of the transformer 13 is connected n through the photodetector of the first optocoupler 14 and the first resistor circuit 19,20 with the control electrode of the thyristor 3 phase C, the secondary winding of phase B of the transformer 13 is connected through the photodetector of the second optocoupler 15 and the second resistor circuit 21, 22 of the phase A of the thyristor 1 The end of the secondary winding of phase C of the transformer 13 is connected via the photoreceiver of the third optocoupler 16 and the third resistor circuit 23, 24 to the control electrode of the thyristor 2 of phase B, and the phase terminals A. in, C of the switch output are connected to the beginnings of the secondary capacitors In current phase, respectively, C A three-phase transformer yl 13.2. ch y

Description

The invention relates to electrical engineering and can be used for contactless switching of a three-phase load of any nature.

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

FIG. 1 shows a circuit diagram of a contactless switch for three-phase circuits; in fig. 2 - time diagrams that show his work.

The switchboard contains in each switching phase thyristors 1-3 and diodes 4-6, connected in parallel to the input 7-9 and output 10-12 pins, a three-phase transformer 13, the primary windings of which are connected in a star and connected to the input pins 7-9 a switch, and three optocouplers 14-16, the light emitters of which are connected in series according to the tires 17 and 18 of the steering. The end of the secondary winding of phase A of the transformer 13 is connected via the photoreceiver of the optocoupler 14 and resistors 19 and 20 to the control electrode of the thyristor 3 phase C, the end of the secondary winding of phase B of the transformer 13 is connected through the photoreceiver of the optocoupler 15 and resistors 21 and 22 o of the control electrode of the thyristor 1 of the phase A. The end of the secondary winding of phase C of the transformer 13 is connected via the photoreceiver of the optocoupler 16 and resistors 23 and 24 to the control electrode of the thyristor 2 of phase B, and the terminals 10-12 of the switch A1, B1, C1 output terminals are connected to the beginnings of the secondary windings respectively The phase, SA 13 three-phase transformer.

Contactless switch three-phase circuits as follows.

The switched three-phase voltage is applied to the switch 7-9 and simultaneously to the primary windings of the three-phase transformer 13. The secondary windings of the transformer 13 through the photoreceivers of the optocouplers 14-16 and the resistors 19, 23 and 21 are connected to the control electrodes of the thyristors 3, 2 and 1. If There is no control voltage on buses 17 and 18, then the light emitters of optocouplers 14–16 are de-energized, the resistance of the photodetectors is high. the current through the control electrodes of thyristors 1-3 is absent, the thyristors are closed, the voltage at the outputs 10-12 of the switch output is zero.

To turn on the switch, the voltage on buses 17 and 18 is applied and the current through the light emitters of the optocouplers 14-16 begins to flow, the photodetectors unlock, the voltage from the secondary windings of the transformer is supplied to the control

thyristor electrodes 1-3, whereby due to the indicated connections of the beginnings and ends of the windings of the transformer 13, each thyristor 1-3 is controlled by a half-wave sinusoid, which is ahead of the voltage phase of the thyristor by 60 al. hail. (Fig. 2), which provides the supply voltage to the load of the switch 13 without a cutoff, i.e. phase A controls phase C, B-A, C-B.

In the diagram (Fig. 2): A, B, C is the voltage of the phases A, B, C ,;

iua, UyB, Uyc - voltage on the control electrodes of the thyristors of these phases. The offered contactless switch is more reliable in operation, provides voltage supply to the load without cut-off, does not have galvanic connection of control circuits to the switched network, the start is carried out by a low-power signal

direct current.

Claims (1)

A non-contact switch of three-phase circuits containing oppositely connected thyristor and a diode. In each phase connected between input and output terminals, the first terminals of the first and second resistors are connected to the control electrode of the thyristor, and the second terminal of the first resistor is connected to an anode, a three-phase transformer, the primary windings of which are connected to the input of the switch, due to the fact that, in order to increase reliability, three optocouplers are introduced, whose light emitters connected in series according to the control buses, the primary windings of the three-phase transformer are connected to the star, the end of the secondary winding of phase A is connected via the photodetector of the first optocoupler with the second output of the second phase C resistor, the end of the secondary winding of phase B of the transformer is connected through the photodetector of the second optocoupler with the second output of the second phase resistor A, the end of the secondary the phase C windings of the transformer are connected via the photodetector of the third optocoupler with the second output of the second phase B resistor, and the phase terminals A. B, C of the switch output are connected to the beginnings of the secondary windings respectively phases B, C, A of a three-phase transformer. i I I I MM i ui I w i U i rW2