SU1553912A1

SU1553912A1 - Electric measuring tongs for a.c.

Info

Publication number: SU1553912A1
Application number: SU884454795A
Authority: SU
Inventors: Мартирос Григорьевич Тер-Мартиросян; Лева Шаваршевич Мелконян; Морис Нерсесович Мовсесян
Original assignee: Предприятие П/Я А-7445
Priority date: 1988-07-01
Filing date: 1988-07-01
Publication date: 1990-03-30

Abstract

Изобретение относитс к приборам дл бесконтактного измерени величины переменного тока. Цель изобретени - повышение точности измерени за счет введени компенсации нелинейности преобразовани , вносимой магнитопроводом и схемой выпр млени информационного сигнала. Цель изобретени достигаетс введением делител напр жени 5 и сумматора 9. Кроме того, электроизмерительные клещи содержат разъемный магнитопровод 1 с намотанной на нем вторичной обмоткой 2, схему выпр млени 3, шунтированную резистором 4, аналого-цифровой преобразователь 6 (АЦП), работающий по принципу двойного интегрировани , источник опорного напр жени 8, цифровой индикатор 7. На первый и второй входы АЦП 6 поступает информационный сигнал от схемы выпр млени 3. На третий вход (опорного напр жени ) АЦП сигнал поступает с выхода сумматора 9 сигналов источника опорного напр жени 8 и информационного, снимаемого с делител напр жени 5, включенного параллельно шунтирующему резистору 4 и состо щего из последовательно соединенных переменного резистора 5.1 и параллельно включенных резистора 5.2 и диода 5.3. 1 ил.This invention relates to instruments for non-contact measurement of alternating current. The purpose of the invention is to improve the measurement accuracy by introducing compensation for the nonlinearity of the conversion introduced by the magnetic core and the rectifier circuit of the information signal. The purpose of the invention is achieved by the introduction of a voltage divider 5 and an adder 9. In addition, the electrical clamp includes a detachable magnetic circuit 1 with a secondary winding 2 wound on it, a rectifier circuit 3, shunted by a resistor 4, an analog-to-digital converter 6 (ADC), operating according to the principle dual integration, reference voltage source 8, digital indicator 7. The first and second inputs of the ADC 6 receive an information signal from the rectifier circuit 3. The third input (reference voltage) of the ADC signal comes from the output of the adder 9 signals of the source of the reference voltage 8 and the information taken from the voltage divider 5 connected in parallel with the shunt resistor 4 and consisting of a series-connected variable resistor 5.1 and in parallel with the connected resistor 5.2 and diode 5.3. 1 il.

Description

5 напр жени . Второй вывод делител 5 соединен с первым входом сумматора 9, второй вход которого соединен с первым выводом источника 8S второй вы вод которого соединен с общей шиной, а выход сумматора 9 - с третьим входом (вход опорного напр жени ) АЦП 6, Делитель 5 напр жени содержит послеВыбором коэффициента К (посредс вом переменного резистора 10 делит л 5) достигаетс требуема степен линеаризации характеристики блока пр млени 3 и нелинейности, вносим магнитопроводом 1. Это обеспечивае благодар тому, что на третий вход опорного напр жени АЦП 6 поступает5 voltages The second output of the divider 5 is connected to the first input of the adder 9, the second input of which is connected to the first output of the source 8S, the second output of which is connected to the common bus, and the output of the adder 9 to the third input (input of the reference voltage) of the ADC 6, voltage divider 5 contains after the selection of the coefficient K (through the variable resistor 10 divides l 5) the required degree of linearization of the characteristics of the block 3 and nonlinearity is achieved, we bring in the magnetic conductor 1. This is ensured by the fact that the third input of the reference voltage of the ADC 6 has aet

довательно соединенные переменный ре- 10 сУмма ное напр жение источника 8 иalternately connected alternating voltage of 10 is the sensible voltage of source 8 and

зистор 10 и параллельно включенные ре зистор 11 и диод 12.resistor 10 and parallel-connected resistor 11 and diode 12.

Устройство работает следующим образом .The device works as follows.

При прохождении тока по проводки- 75 ку, охваченному магнитопроводом 1, во вторичной обмотке 2 индуктируетс напр жение, которое выпр мл етс посредством выпр мительного блока 3. Падение напр жени на резисторе 4 по- 20 даетс на информационные входы АЦП 6, работающего по принципу двойного интегрировани . В первом такте производитс интегрирование информационного сигнала, во втором такте обеспечи- 25 ваетс деинтегрирование напр жением (U0ft+K.UK), поступающим с выхода сумматора 9 .When current passes through the wiring 75 enclosed by the magnetic core 1, a secondary voltage is induced in the secondary winding 2, which is rectified by the rectifier unit 3. The voltage drop across the resistor 4 is applied to the information inputs of the ADC 6, which operates according to the principle dual integration. In the first cycle, the information signal is integrated, in the second cycle, voltage is deintegrated (U0ft + K.UK) from the output of adder 9.

Аналитическое выражение временного интервала, получаемого в АЦП 6 в JQ результате преобразовани информационного сигнала, имеет видThe analytical expression of the time interval obtained in the A / D converters 6 in JQ as a result of converting the information signal is

части информационного сигнала (сним емого с резистора 11 делител 5), держащее информацию о фактической нелинейности преобразовани . Диод усиливает вли ние информационного сигнала на результат измерени при лых значени х измер емого тока, ко да напр жени на выходе вторичной мотки малы.parts of the information signal (removed from resistor 11 of divider 5), holding information about the actual nonlinearity of the conversion. The diode amplifies the effect of the information signal on the measurement result at the measured current measured values when the voltage at the output of the secondary skein is small.

Claims

Invention Formula

An AC current clamp containing a detachable magnetic core with a secondary winding wound on it, a straightening unit shunted by a resistor, a voltage source, an analog-to-digital converter, the first and second of which are connected to the plugs of the connecting resistor, and the outputs are with a dictator , characterized in that, in order to improve the accuracy in them, an adder and a voltage divider are inserted, connected in parallel with the connecting resistor and consisting of consequently connected variable resistors and parallel connected th resistor and a diode, the average output voltage divisor d and the first terminal and a source of reference voltage us connected respectively to the first and second adder inputs, the output of the connections to the third input of the analog-Dig

t ah

YYY + k-yh

where ux u

on

an information signal, a reference voltage at the output of source 8; the constant time interval during which the information signal is integrated into the ADC in the first integration cycle;

AC current clamp, which contains a detachable magnetic core with a secondary winding wound on it, a rectifier, shunted by a resistor, a voltage source, an analog-to-digital converter, the first and second inputs of which are connected to the leads of a shunt resistor, and the outputs with an indicator that are different By the fact that, in order to increase the accuracy, they have introduced an adder and a voltage divider connected in parallel to the shunt resistor and consisting of consequently connected variable resistors ora and a parallel resistor and diode, the average output of the voltage divider and the first output of the source of the reference voltage are connected respectively to the first and second inputs of the adder, the output of which is connected to the third input of the analog-digital

The second transducer, and the second output, the division ratio of the divisor-source of the reference voltage, is connected to the common bus.

3912L

By choosing the coefficient K (using a variable resistor 10 divider 5), the required degree of linearization of the characteristic of rectifier unit 3 and the nonlinearity introduced by the magnetic circuit 1 is achieved. This is ensured by the fact that the third input of the reference voltage of the ADC 6 enters

reasonable voltage source 8 and

part of the information signal (taken from the resistor 11 of the divider 5), containing information about the actual nonlinearity of the conversion. Diode 12 amplifies the effect of the information signal on the measurement result at small values of the measured current, when the voltage at the output of the secondary winding is small.

Invention Formula

AC current clamp, which contains a detachable magnetic core with a secondary winding wound on it, a rectifier, shunted by a resistor, a voltage source, an analog-to-digital converter, the first and second inputs of which are connected to the leads of a shunt resistor, and the outputs with an indicator that are different By the fact that, in order to increase the accuracy, they have introduced an adder and a voltage divider connected in parallel to the shunt resistor and consisting of a series-connected variable resistor ora and a parallel resistor and diode, the average output of the voltage divider and the first output of the source of the reference voltage are connected respectively to the first and second inputs of the adder, the output of which is connected to the third input of the analog-digital