SU1449940A1 - Device for monitoring phase sequence - Google Patents

Abstract

The invention relates to a measuring technical assembly and can be used in devices for controlling the phase alternation of a three-phase AC network. The purpose of the invention, the expansion of the field of application of the device, is achieved by ensuring that it can be used to control the alternation of the phases of a three-phase network both with and without zero conductor. The device contains voltage dividers at the co-capacitors 1,2 and 5,6, inputs 3,4 and 7, load elements 8 and 9, a series circuit of active 10 and reactive 11 and 12 elements. The operation of the device is explained in timing diagrams given in the description of the invention, where possible uses of various circuit elements are also indicated. 2 Il. F

Description

1

The invention relates to a measurement technique and to be used to control the alternation of the phases of a three-phase AC network.

The purpose of the invention is to expand the field of application of the device by allowing it to be used to control the phase rotation of any three-phase network: a kick without and without a neutral wire.

Fig. 1 is a schematic diagram of a device for controlling phase rotation; 2 is a voltage chart.

The device contains the first voltage divider from capacitors 1 and 2 connected between the first 3 and second 4 inputs of the device, the second voltage divider from capacitors 5 and 6 connected between the second 4 and third 7 inputs, load elements 8 and 9 connected in series between the middle points of the first and second voltage dividers, as well as a series circuit of active 10 and reactive 11 elements, the first output of which is connected to the second input of the device, and the total connection point of the active 10 and reactive 11 elements - to the common ton chke compound elements 8 and 9 of the load. The second output of the serial circuit from the active 10 and reactive 11 elements is connected to the first input 3 of the device, and the middle point of the subsequent circuit from the elements 10 and 1 1 to the third input 7 of the device through the I2 element, the same type with the 11 element of the serial circuit, connected to the first input 3 of the device.

 The device works in the following way.

With the order of phase alternation ABC indicated in FIG. 1, the voltage between points n and O is close to zero, and between points m and O is maximum, therefore load element 9 is de-energized and current passes through load element 8. If the element 8 of the bottom is a light-emitting element, then it is illuminated, and if the winding of the electromagnetic relay, the contact groups are jammed.

The slave device is illustrated by a voltage diagram (Fig. 2), from which it is known that the voltage and, pa element 10 and voltage, реакт and the reactance of elements 1 1 and

12 are 90 relative to each other, and the voltage at their common point O coincides with the voltage at the midpoint n of the voltage divider on the capacitors 5 and 6, therefore the voltage on the load element 9 is close to zero. At the same time, on the load element 8, the voltage Ug between the points O

and m, excluding the load current, is 0.75 line mains voltage. When the device operates through the elements 8 and 9 of the load is limited by the internal resistance of the dividers

from capacitors 1,2 and 5,6.

The resistances of elements 10 and capacitors 1.2 and 5.6, elements 11 and 12 are selected from the ratios

20 X 3Xg; X SX,; X ,, - X - 2Rio

g

Where

ten

- active resistance of the element O;

X 5- Xg,) With ,, Xj X ,,

and X, - capacitance of capacitors

5,6 and 1,2 and elements 11 and 12.

When the phase order changes, for example, if phase A is connected to input 7, and phase C to the input

3, between the phases A and B is turned on a divider from capacitors 5 and 6, and between phases B and C - a divider from capacitors 1 and 2. In this case, in the diagram of FIG. 2, the voltage U, and U

change places with voltages Uj. and Ug, point m - with point p, and the voltage Ug changes to U. As a result, load element 8 is de-energized, and load element 9

under maximum voltage and a current passes through it causing it to glow or fire.

As load elements, both light-emitting elements (incandescent lamps, gas discharge barks, n1, LEDs, sign indicators, etc.) and input circuits of different actuators (electromagnetic windings) can be used.

relays, input control circuits, and others.). Primary windings can be used as the first and second voltage dividers with transformer taps already existing in the equipment. At low load currents or low voltages of a three-phase network, losses in the elements of voltage dividers can be neglected and elements 1,2 and 5,6 can be made in the form of resistors. If element 10 is made in the form of a capacitor, and elements 11 and 12 are in the form of resistors, the device operates in a similar way, but in the direct order of phase alternation, element 8 is de-energized.

Claims (1)

Invention Formula A device for controlling alternating PIA phases containing the first voltage divider connected between the first and second inputs of the device, the second voltage divider connected between the second and third inputs, two load elements connected in series between the middle points of the first and second dividers voltage, as well as a series circuit of active and reactive elements, the first output of which is connected to the second input of the device, and the general output of the active and reactive elements - to the general output of load elements, is different In order to expand the field of application, an additional element is introduced into it, which is of the same type as a serial circuit element connected to the first input of the device, with the second output of the serial circuit from the active and reactive elements being connected to the first input of the device, and their common output is to the third input of the device through an additional element.