SU838813A1 - Relay-thyristor change-over switch - Google Patents

Description

(54) RELAY-TYRISTOR SWITCH

I

The invention relates to electrical engineering and can be used, for example, in devices for automatic control of swing, reciprocating mechanisms, etc., where a time delay is required when disconnecting and disconnecting elements.

Known switching devices with a delay for disconnecting, containing thermal time relays, thyristors and electromechanical relays with mutually interlocked contacts 1j.

However, these devices have a complex structure and low reliability due to the large number of switching elements; greater instability of the time delay for switching off, determined by the parameters of the thermal relays; greater inertia of the circuit, determined by the number of consecutive com mutations; the inability to control the amount of time delay.

The closest to the proposed one is a thyristor switch consisting of two thyristors, load resistors and switching capacitor 2.

The disadvantage of these thyristor switches is the absence of a time delay when switching the switches' shoulders, which prevents the use of these three-step switches. Together with the electromagnetic relays in automatic control devices, different mechapisms are used.

The purpose of the invention is to ensure stable adjustable delay at the relay-triac switches.

The goal is achieved by the fact that in a thyristor relay switch containing two thyristors, in each power circuit of which a current of an electromagnetic relay is connected, a switching capacitor connected between the thyristor anodes and a terminal for connecting a DC power source, a switching capacitor It is made in the form of two capacitors connected in series, and the common point of these capacitors is connected to the terminal for connecting the positive pole of the DC power source.

FIG. 1 is a diagram of a thyristor relay switch for the case of controlling the switching on of three executive circuits;

in fig. 2 - cyclogram, where, LJg, Ug voltage loads.

The circuit contains two thyristors 1 and 2, in the power circuits of which are included the windings of electromagnetic relays 3 and 4. Between the anodes of thyristors 1 and 2 there are two capacitors 5 and 6 included. The executive circuits of loads 7-9 include the contacts of electromagnetic relays 3 and 4, respectively 3 3, 3 and 4, 4, 4. The inputs 10, 11 of the switch are thyristor control terminals 1 and 2.

In the initial state, the thyristors I and 2 are closed, the capacitors 5 and 6 are discharged. When a control signal Jex.t arrives at one of the switch inputs (for example, at input 10), thyristor 1 is opened, capacitor 5 is charged, relay 3 is activated, and closes the load circuit 7. The circuit changes to a steady state. When a signal Jex is applied.) Thyristor 2 opens at input 11, relay 4 operates and closes load circuit 8, simultaneously disconnecting load 7. Capacitor 5 charged is connected in parallel to thyristor 1 via capacitor 6, whose resistance is zero at the moment of switching and open thyristor 2. The voltage on the anode of the thyristor 1 of the relay 3 remains for some time switched on due to the flow of the discharge current of the capacitor 5. to its winding. The delay time for switching off is determined by the magnitude of the resistance of the winding of relay 1 and the capacitance of capacitor 5. After the control signal is applied to input 11, the circuit changes to the second steady state, i.e. the right shoulder of the switch is open, and the left is closed. On the delay time for switching off the relay 3, i.e. when both relays are turned on, loads 7 and 8 are disconnected and load 9 is supplied. When the delay time has elapsed, load 9 is disconnected and load 8 is supplied. After a delay time, load 9 is disconnected and load 8 receives power. When applying the next signal to input 10. , the circuit "overturns, opens the thyristor 1, switches on the relay 3 and disconnects the load 8. The charged capacitor 6 is connected in parallel to the thyristor 2 through the capacitor 5, whose resistance 8 is zero and the open thyristor 1. Ex. The life on the anode of the thyristor 2 becomes negative and it is locked. After the thyristor is closed, the relay 4 remains switched on due to the flow of the discharge current of the capacitor 6 through the relay 4 winding. condition. On the delay time for switching off the relay 4, i.e. when both relays are turned on, the loads 7 and 8 are disconnected and the load 9 is energized. After the delay time has elapsed, the load 9 is switched off, the load 7 is turned on.

The invention provides a simplification of automatic control devices for various actuators in which a stable response time delay is required.

Claims (2)

1. Technical description and operating instructions of the machine PZM-2, PZM2.0000000TU. 2. Chopin L. A. Contactless electrical automation devices. Publishing house "Energy, 1967, p. 425, fig. 10-15. ex fo to Sx.11 y to i to 0 - b