SU1345283A1 - Apparatus for protecting d.c.circuits from doltage changes - Google Patents

Abstract

This invention relates to electrical engineering, in particular, to relay protection. The purpose of the invention is to enhance the functionality and increase reliability by improving the automation of actuation and returning to the initial state. This is achieved by the fact that when the supply voltage increases, the voltage on the cathode of Zener diode 5 becomes greater than the voltage of stabilization. The capacitor 6 is charged, and the thyristor 8 opens. As a result, the transistors of the optocouplers 10, 11 close and form the discharge circuit of the storage capacitor 17. to the disconnect winding 15 of the polarized relay through the transistor 16. Contact group 1 disconnects the load from the power source. 1 il. from 1 00 4 JV Yu oo with

Description

The invention relates to electrical engineering and is intended to protect against overvoltage, voltage reduction and short circuits of electronic equipment, mainly computer equipment and automation, containing a large number of integrated elements

The purpose of the invention is to enhance the functionality and increase reliability by improving the actuation automation and returning to the initial state.

The drawing shows a device diagram for protecting the direct current circuits against voltage changes.

The device contains a contact group 1 of a polarized relay with a 2-winding switch, a comparison element on resistors 3 and 4, to which a threshold element at the Zener diode 5 is connected, a capacitor 6, a ballast resistance 7 in the circuit of the actuator on the thyristor 8, a buckling resistor 9, connected in series with the comparator on diodes of transistor optocouplers 10 and 11, the transistors of which are connected to the positive, bus through the ballast resistance 12, and among themselves - through the ballast resistance 13, diode 14, shunt winding 15 disconnecting the polarized relay controlled by the transistor 16 and the storage capacitor 17.

The device works as follows.

At rated voltage E "cg. resistors 3 and 4 are chosen so that the zener diode 5 does not populate into stabilization mode and the thyristor 8 is closed through the diodes of optocouplers 10 and 11 a current flows sufficient to open the transistors of optocouplers, the transistor 16 is closed, the capacitor 17 is charged through the open transistor of the optocoupler 11 and resistor 13 , through the closed contacts 1 of the polarized relay, the supply voltage is applied to the load. i

With increasing voltage E pig voltage on the cathode of Zener diode 5 becomes more stabilization voltage, capacitor 6 is charged and thyristor 8 opens, which leads to short circuit of power supply lines and shunting of load and optocouplers 10 and 11, which transistors close and form yes save

tel condenser. 17 to the coil 15 of disconnecting a polarized relay through a transistor 16. Contact Group 1 disconnects the device and the load from the power source.

 After the restoration of the voltage Enj, f, the device is switched on again and the load is carried out through the input of the control of the short-time supply of voltage U on the winding 2 of the connection. The capacitor 6 and the resistor 3 are chosen so that the device does not work for transients at the moment of switching on and short time;

Resistors 9, 12 and 13 limit the currents through the optocouplers 10 and 11. When the voltage E ~ decreases, the current through the diodes of the optocouplers 10 and 11 decreases, their transistors close, and then the device operates as in the case of a voltage Epe.

A diode 14 C protects the transistor 16 from a reverse current surge when the tripping winding 15 is activated.

Claims (1)

Invention Formula A device for protection of DC circuits against voltage changes, containing a comparator connected to the power buses, to the output of which a threshold element is connected, the actuator on the thyristor connected by the anode through a resistor to the positive power bus, and the cathode to the negative one It is tactile that, in order to expand the functional possibilities (gay and increase reliability by improving the automation of actuation and return to the initial state, it is additionally equipped with two transistor ptronami, polarized relay controlled by a transistor, a capacitor and a diode, wherein the first anode is connected via an optocoupler the resistor to the positive power line, the cathode to the anode of the second optocoupler, the collector to the base of the transistor K; the resistor to the positive power line, the emitter to the emitter of the second optocoupler. connected by the cathode and the emitter to the negative power bus through a parallel-connected winding disconnecting the polarized relay and the diode, the anode of which is connected to 31345283 the collector of the transistor, the power capacitor through the floor contact group — one plate is connected to the emitter relay, the turn-on winding of the transistor, and the second to the positive winding of which is connected to the negative wiring connected to the power supply bus and control input.