RU1826100C - Phase-failure detector - Google Patents

Abstract

Usage: for reliable and reliable indication of the presence of an n-phase alternating voltage. SUMMARY OF THE INVENTION: when the voltage of phase A disappears or decreases to a value at which the voltage at the output of the divider is less than the unlock threshold of the common support element, the controlled key is locked, the current and glow of the light-emitting element are stopped. Due to the decrease in the current through the elements, the voltage drop across the resistor decreases and the voltage across the elements increases, which leads to the unlocking of the threshold element and the passage of current through the light-emitting element, which is lit in red, indicating the absence of phase A voltage at the input of the device. The device works similarly in the absence of voltages of phases B and C at the inputs. 1 ill.

Description

The device relates to electrical engineering and can be used to control the presence of alternating voltages.

The purpose of the invention is to increase the reliability and reliability of the indication.

The device diagram is shown in the drawing.

The device contains input terminals.

1,2 and 3 for connecting the monitored voltages, a common terminal 4 for connecting the neutral wire, indication cells 5, 6 and 7, each of which contains a serial circuit of a controlled key 8 and a light-emitting element 9, a constant voltage source 10, AC / DC converters 11,12,13, each of which is connected between one of the input terminals 1,

2,3 and a common terminal 4 of the device, the output of each converter 11, 12. 13 is connected to the input of the controlled key 8 of one of the cells 5, 6. 7 indications, in each of

of which, in parallel with the serial circuit, the second light-emitting element 14 is connected through the threshold element 15, the first output of the serial circuit of each indication cell 5,6,7 is connected through a common reference element 16 with a common terminal 4 of the device, the second output of each cell is connected through a separate resistor 17, 18, 19 with the first a terminal of a constant voltage source 10, the second terminal of which is connected to a common terminal 4 of the device. Each converter 11, 12, 13 contains a series circuit of a diode and a capacitor 21, in parallel with which a divider of resistors 22 and 23 is connected, the common point of which is the output of the converter.

The device operates as follows. If there are phase voltages A, B, and C at the inputs 1, 2, and 3 in each converter 11.1, 2.13, the capacitor 21 is charged through the diode 20 to a certain level of

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sp. A part of this voltage from the output of the resistor voltage divider from the elements 22, 23 is fed to the input of a controlled switch 8 of the indication cells 5, 6, 7. The controlled key 8 is unlocked and a current flows through the light-emitting element 9, the value of which is determined by the voltage of the voltage source 10 and the resistance of the resistor, respectively 17, 18 and 19. At the same time, the element 9 is lit in green, indicating the presence of a phase voltage, and the light emitting element 14 is not lit, since the voltage drop on the element 9 and the open key 8 is less than the threshold for unlocking the circuit from the elements 14 and 15.

When the voltage of phase A disappears or decreases to a value at which the voltage at the output of the converter 11 is less than the unlock threshold of the support element 16, the controlled key 8 is locked, the current and glow of the element 9 are stopped. Due to the decrease in current through the elements 8 and 9, the voltage drop across the resistor 17 decreases and the voltage applied to the circuit of the elements 14 and 15 increases. This leads to the unlocking of the threshold element 15 and the passage of current through the element 14, which is lit in red, indicating lack of phase A voltage at input 1 of the device. In the absence of voltages of phases B and C at inputs 2 and 3, the device operates similarly.

Thus, when the voltage of any phase of the network disappears, the color of the glow changes from green to red of the corresponding display element, and the rest continue to glow green.

The introduction of a common reference element 16 is not necessary, since its functions can be performed in each indication cell by a series circuit from the base-emitter junction of the transistor 8 and LED 9, or a low-current reference element is switched on between the output of the converter and the input of the corresponding indication cell.

The converters 11, 12, 13 can be made as with sequential rectification and the inclusion of a capacitor 21 parallel to the voltage divider from resistors 22, 23 or only resistor 23, or with parallel rectification of the alternating voltage.

As light-emitting elements 9 and 14, two light-emitting diodes placed in a common housing and radiating to a common light guide, two rectangular-shaped light-emitting diodes placed side by side, microminiature incandescent lamps and other elements can be used. Light emitting

elements 9 and 14 may vary with elements 8 and 15, respectively, without disrupting the operation of the device.

The device is operable with one or more controlled alternating voltages. The switching polarity of the elements 9, 10, 14, 15, 20 can be reversed by changing the polarity of the operating voltage of the controlled key 8, which can be, for example,

pnp transistor or integrated logic element.

The device provides a significant increase in the reliability and reliability of the indication of alternating voltage of the network and

reduction of active power losses, usually occurring at high values of controlled voltages, since the power of the display elements is carried out from a low-voltage constant source

for example

Claims (1)

SUMMARY OF THE INVENTION A device for monitoring the presence of a p-phase alternating voltage, comprising n input terminals for connecting monitored voltages, a common terminal for connecting a neutral wire, indication points, each of which contains a serial circuit of a controllable key and a light emitting element, and a voltage source, characterized in that. that, in order to increase the reliability and reliability of the indication, n AC converters are introduced into a constant, each of which is connected between one of the n input terminals and the common terminal of the device, the output of each converter is connected to the input of the controlled key of one of the indication points, at of each of which a second light-emitting element is connected in parallel with the serial circuit through a threshold element, the first output of the serial circuit of each display cell is connected directly or through a common reference element to the common terminal of the device, the second output of the serial circuit is connected through the input resistor to the first output of the voltage source made in the form a constant voltage source, the second terminal of which is connected to a common terminal of the device.