SU1422387A1 - Contactless d.c. switch - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to switching equipment, which has counter electromotive force in direct current circuits, subject to short-term power supply wiring. The purpose of the invention is to increase the reliability of operation and reduce the power consumption of the control to restore the operability of the proximity switch. The switch is made on the basis of a type thyristor 1 connected between the load 3 and the power source. An inductance coil 6 and a transistor 5 are provided in the switch. In case of short-term dips of the supply voltage, the switch is operable by applying a pulse to the control electrode of the thyristor 1, in series with which the inductance 6 is used in the control circuit of the thyristor. stored in the switching capacitor 4 switch. 2 Il. J2 in (L

Description

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The invention of electrical engineering, and more specifically, of contactless GK-switching equipment, made on thyristors or other semiconductor devices, is intended for switching loads with a counter-EMF in direct current circuits exposed to short-time supply voltage.

The purpose of the invention is to increase the on-the-time; operation of the non-contact switch-off; chatter under conditions of short-term voltage dips and reduction of the power consumption of the control to regulate the operation of the switch.

FIG. 1 shows a circuit diagram of a contactless DC switch; in fig. 2 - times} charts that explain the operation of the switch.

A contactless DC switch contains a power thyristor 1, a switching thyristor 2, a load 3, which has a counter-EMF, a switching capacitor 4, a transistor 5, an inductor 6, the first 7 and the second 8 diodes, a resistor 9, the limiting resistor 10, control unit 11, first 12 and second 13 power buses

The cathodes of thyristors 1 and 2 are connected to bus 12, the control electrodes of thyristors 1 and 2 are connected to the outputs of control unit 11, the anode of thyristor 1 through load 3 is connected to bus 13, the anode of thyristor 2 through series, connected diode 7 and resistor 9 is connected to bus 13, capacitor 4 is connected between the anodes of thyristors 1 and 2, the base of transistor 5 is connected via resistor 10 to bus 13, the emitter of transistor 5 is connected to common point of connecting anode of transistor 2 and capacitor 4, collector of transistor 5 through coil 6 inductance is connected to the control electric the thyristor 1 electrode, and the inductor 6 and the control circuit of the thyristor 1 are shunted by a diode 8.

The switch works as follows.

Suppose that in the initial state, the thyristor 15 is open while the load 3 is turned on, and the capacitor 4 is charged before the supply voltage and has the polarity indicated in FIG. 1 "In this case, the same potential and transistor are applied to the emitter and base of the transistor 5 .5 closed At time t (Fig. 2), the voltage of the power supply source drops below the allowable Uop, at which, in the event of the presence of a counter EMF in the load, the de-energization of the thyristor 1 is de-energized and, therefore, it is turned off. At the same time, when the supply voltage decreases at the base of transistor 5, the potential decreases, and the circuit: capacitor 4, emitter-base of transistor 5, resistor 10, load 3 begins to flow and the transistor 5 opens. In this case, the current begins to flow along the circuit: capacitor 4, emitter-collector of transistor 5, inductance coil 6, control electrode of thyristor 1, power bus 12 and 13, load 3. At time t2 (Fig. 2), the supply voltage recovers. In this case, the transistor 5 is closed, however, the inductance 6 does not allow the current to disappear instantly, and through the upran-thyristor electrode 1, the diode 8 flows a reactive current of inductance 6, which contributes to the opening of the thyristor 1. Once the thyristor; 1 opens, the capacitor 4 is charged and. at time t, the circuit is again

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is in a healthy state.

Claims (1)

Formula invented A non-contact DC-breaker containing a power thyristor, a switching thyristor, a switching capacitor, a resistor, two diodes and a control unit whose outputs are connected to the control power FL of the power thymers and switching thyristors whose cathodes are connected to the first power bus, the power anode thyristor through the load is connected to the second power bus, which is connected through a successively connected resistor and the first diode of the switching thyristor anode, the switching capacitor is connected between the anodes of the power switching and switching thyristors, which contributes to the fact that, in order to increase reliability and reduce power consumption, a transistor, an inductance coil and a limiting resistor are inserted, the base of the transistor.  the second power bus, the emitter of the transistor is connected to the common switching on point of the switching thyristor anode with the control electrode of the power thyristor, and the inductance coil and the control circuit of the power and the switching capacitor, and the cyristor are shunted by the second diolector through the induction coil - the house. with the control electrode of the power thyristor, and the inductance coil and the control circuit of the power Udi  Ofl. ABOUT ex. about about t1 t2 tJ Rig. 2