SU1575161A2 - Device for protection of supply source from overcurrents - Google Patents

Abstract

The invention relates to electrical engineering, can be used in power sources. The goal is to extend the functionality by providing timer functions. The goal is achieved by the fact that the proposed device can operate in three modes: I - electronic safety mode, II - timed timer mode for load shedding, III - timed timer mode to hold the load under voltage. In mode 1, pins 14, 15 and 17, 18 are closed. When the output current exceeds the set value, transistor 2 goes out of voltage, the output voltage decreases, the base current of transistor 1 decreases, and its avalanche-like blocking occurs. When this generator starts to generate, providing periodic unlocking of the transistor 1 with a high duty cycle, so that the average current wt. When the overload disappears, transistor 1 is turned on again, and the generation fails. In mode II, the switch 13 is set to the "timer" position, contacts 14, 15 and 17, 18 are broken. When the charging current falls below a critical value, the collector current of transistor 2 will drive transistor 1 out of saturation state, which will lead to an avalanche-like process of closing transistors 1 and 2. The time delay for disconnecting the load is determined by the capacitance of the capacitor 8 and the resistance of its charge circuit. In mode III, the switch is set to the "timer" position, as in mode II. When button 12 is pressed, a trigger pulse through capacitors 11 and 8 creates a timer circuit trigger circuit. Transistors 1 and 2 turn on. When the charge current of capacitor 8 becomes less than critical, then an avalanche-like process of locking transistors 1 and 2 will occur, as was described in the previous modes. Diode 9 serves to discharge the capacitor 8 after disconnecting the voltage on the load 7. 1 sludge.

Description

The invention relates to electrical engineering, can be used in power sources, and is an improvement of the invention according to the author.

№ 1367005.

The goal is to extend the functionality by providing timer functions.

The drawing shows a diagram of the device.

The device contains a locking transistor 1 connected to the power supply power bus, a control transistor 2 connected by a collector to the base of transistor 1, and an emitter through a resistor 3 to a common bus and a start-up pulse generator made on a single junction transistor 4, a capacitor 6. The load 7 is connected between the common bus and the collector terminal of transistor 1.

The first and second bases of the transistor t are connected respectively to the emitter and collectors of transistor 2. The emitter of transistor k is connected to a resistor 5 and a capacitor 6, the second

the output of which is connected to the first base of the unijunction transistor k, Additionally, in the device-entered capacitor 8 with diode 9 is parallel to the RC circuit on the resistor 10 and capacitor 11, the closing button 12 and the switch 13 with two opening and closing contacts, 15, 16, 17, 18, wherein the capacitor 8 and the diode 9 are connected in series

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their common connection point is connected to the base of the control transistor 2, the anode of the diode 9 is connected to the common bus, the free output of the capacitor 8 to the collector of the locking transistor 1 and to one of the RC circuit terminals 10, 11, the other terminal of which through the closing button 12 and the closing contact 15, 16 of the switch 13 is connected to the emitter of the locking transistor 1, the first disconnecting contact 1 and 15 of the switch 13 is connected between the emitter of the locking transistor 1 and the resistor 5 of the start-up pulse generator, and the second disconnecting contact 17 and 18 is turned on between the base of the control transistor 2 and the collector of the gate transistor 1 "

The device can operate in any of the three modes.

I Mode 4 electronic fuse (EP). Switch 13 is in position (EP), as shown in the diagram. In this mode, its pins 1, 15 and 17, 18 are closed. When the supply voltage is applied, the transistor turns on, ensuring that the transistor 1 is turned on, a voltage appears on the load 7 that unlocks the transistor 2, as a result of which the transistor 1 turns on reliably and the generator does not work.

When increasing the output current above the set value, the transistor goes out of saturation, the output

the voltage decreases, the base current of the transistor decreases, its avalanche-like closing occurs. In this case, the start-up generator begins to generate, providing periodic unlocking of the transistor 1 with a high duty cycle, so that the average current is small. When the overload disappears, transistor 1 again. "Turns on and generation fails.

IIWorking the device in tamer mode with time delay for load shedding.

In this mode, the switch 13 is set to the Timer position, while the contacts 1, 15 and 17 18 are broken. The first contacts disconnect the pulse start generator circuit, and the second disconnect the capacitor 8.

The voltage on the load 7 will be maintained as long as the charging current of the capacitor 8, flowing through the base-emitter junction of transistor 2 and the resistor 3 keeps the locking transistor 1 in the open state. When the charge current decreases below the critical value, the collector current of transistor 2 will drive transistor 1 out of saturation state, which will lead to an avalanche-like process of closing transistors 1 and 2. The time delay for disconnecting the load is determined by the capacitance of the capacitor 8 and the input resistance of transistor 2.

IIIWorking the device in timer mode with time delay to keep the load under voltage.

In this mode, the switch is set to the Timer position, i.e. the same as in previous mode II.

At the same time, contacts 15. and 16 are closed, thus connecting a starting circuit consisting of button 12, starting capacitor 11 and discharge resistor W. When you press button 12, a starting pulse through capacitors 11 and 8 creates a timer start circuit. Transistors 1 and 2 turn on. On

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the load is set to a voltage that will be maintained until the charging current of the capacitor 8 becomes less critical and an avalanche-like process of locking transistors 1 and 2 occurs, as has already been described in previous modes. The diode 9 serves to discharge the capacitor 8 after disconnecting the voltage on the load 7.

IV Operation of the device in the electronic fuse mode with manual start.

In this mode, contacts 1 and 15 are broken, and contacts 15 and 16 are closed, while contacts 17 and 18 are also closed. The electronic fuse is started by pressing button 12. In this case, the operation

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Claims (1)

Invention Formula Device to protect the power source from overcurrent by aut. St. No. 1367005, characterized in that, in order to extend the functionality by providing timer functions, parallel to the KS circuit, a closing button, a switch with two opening and closing contacts, and a series-connected capacitor and diode, the junction point of which is connected to the control base, are introduced into it transistor, the diode anode is connected to the common bus, the free capacitor lead is connected to the collector of the blocking transistor and to one of the pins of the RC circuit, the other pin of which is through the closing button and the closing -contact switch is connected to the emitter of the latch transistor with a first normally closed contact of the switch is connected between the emitter of the latch transistor and the resistor start pulse generator, and the second break contact connected between the base of the control transistor and the collector of the latch transistor.