SU901922A1

SU901922A1 - Single four-arm dc bridge

Info

Publication number: SU901922A1
Application number: SU792795842A
Authority: SU
Inventors: Леонид Иосифович Клибанов; Сергей Павлович Цисун; Ихиль Шулимович Юдкович
Original assignee: Кишиневский Научно-Исследовательский Институт Электроприборостроения; Научно-Производственное Объединение "Микропровод"
Priority date: 1979-07-11
Filing date: 1979-07-11
Publication date: 1982-01-30

Description

Изобретение относится к электроизмерительной технике, а именно к устройствам для измерения высокоомных сопротивлений (свыше Ю^Ом).The invention relates to electrical engineering, and in particular to devices for measuring high-resistance resistances (over 10 ^ Ohm).

Известны мосты постоянного тока, содержащие измерительную цепь, источ- ⁵ник питания, индикатор, ключ для коммутаций индикатора и защитную ветвь [1 ].Known DC bridges containing a measuring circuit, a power source ⁵ , an indicator, a switch key for an indicator and a protective branch [1].

Недостатком их является наличие паразитных токов утечки через сопротивления изоляции опорных элементов конструкции, которые влияют на точность измерения.Their disadvantage is the presence of stray leakage currents through the insulation resistance of the supporting structural members, which affect the measurement accuracy.

Наиболее близким к предлагаемому является мост постоянного тока.^содержащий измерительную цепь с измеряемым резистором, источник питания и индикатор ^2 ].Closest to the proposed is a DC bridge. ^ Containing a measuring circuit with a measured resistor, power source and indicator ^ 2].

Недостаток его состоит в невысокой точности за счет влияния паразитных токов утечки.Its disadvantage is its low accuracy due to the influence of spurious leakage currents.

Цель изобретения - повышение точности за счет устранения шунтирующего влияния сопротивления изоляции вершины диагонали питания моста на одно из сопротивлений моста.The purpose of the invention is to improve accuracy by eliminating the shunt effect of the insulation resistance of the top of the bridge power diagonal on one of the bridge resistances.

Поставленной цели добиваются за счет того, что в одинарном четырехплечем мосте постоянного тока, содержащем источник питания, включенный в диагональ питания одинарного четырехплечего моста, плечи которого образованы измеряемым и постоянными резисторами, нуль-индикатор, включенный в измерительную диагональ одинарного четырехплечего моста, вершина измерительной диагонали противолежащей⁹ветви измеряемого резистора соединена с общей шиной, с которой соединены подключенные к вершинам одинарного четырехплечего моста постоянного тока первое, второе и третье сопротив·¹ления· изоляции опорных изоляторов, расположенных на изолированной проводящей панели, четвертое сопротивление изоляции опорного изолятора включенного в диагональ питания оди3 90192 парного четырехплечего моста, а сам изолятор расположен на изолированной проводящей панели, электрически соединенной с одним из полюсов источника питания. 5This goal is achieved due to the fact that in a single four-arm DC bridge containing a power source included in the power diagonal of a single four-armed bridge, the shoulders of which are formed by measured and constant resistors, a zero indicator included in the measuring diagonal of a single four-armed bridge, the top of the measuring diagonal ⁹ opposite branches measuring resistor is connected to the common bus to which are connected the vertices connected to a single DC bridge chetyrehplechego he first, second and third soprotiv · ¹ Lenia · insulation support insulators, arranged on an insulated conductor bar, the fourth insulation resistance of the support insulator included in diagonal supply odi3 90192 pair chetyrehplechego bridge, and the insulator is located on an insulated conducting panel electrically connected to one of the poles power source. 5

На фиг. 1 представлена схема четырехплечего моста постоянного тока; на фиг. 2 - конструкция предлагаемого моста.In FIG. 1 is a diagram of a four arm DC bridge; in FIG. 2 - design of the proposed bridge.

Мост содержит измеряемый резне- ю тор .1, резисторы 2-4, вершины (точки) 5-8 моста сопротивления 9“11 изоляции вершин, нуль-индикатор 12·, источник 13 питания.The bridge contains the measured torus .1, resistors 2-4, peaks (points) 5-8 of the resistance bridge 9 “11 of the vertex isolation, null indicator 12 ·, power supply 13.

Резисторы Т-4 плеч моста установ- 15 лены на металлической панели 14 в опорных точках 5~8 (узловые точки вершин моста, фиг. 1). Опорные точки 5-7 (точка 8 соединена с панелью 14, которая является корпусом прибора) 20 изолированы от металлической панели. Точки 7 и 6 изолированы с помощью проходного изолятора 15, изготовленного из изоляционного материала (полистирол, фторопласт, янтарь); кото- 25 рый собран с помощью контакта 16, шайбы 17 и винта 18.The resistors T-4 of the bridge arms are mounted on a metal panel 14 at reference points 5 ~ 8 (nodal points of the bridge peaks, Fig. 1). The reference points 5-7 (point 8 is connected to the panel 14, which is the body of the device) 20 are isolated from the metal panel. Points 7 and 6 are isolated using a bushing 15 made of an insulating material (polystyrene, fluoroplast, amber); which is assembled using pin 16, washer 17 and screw 18.

Опорная точка 5 (вершина моста 5, фиг. 1) имеет двойную изоляцию: изолирована от металлической панели 19» зо которая, в свою очередь, изолирована от общей панели 14 с помощью изоляционной прокладки 20; металлическая панель 19 имеет электрическую связь через крепежный винт и лепесток 21.The reference point 5 (the top of the bridge 5, Fig. 1) has double insulation: it is isolated from the metal panel 19 ’which, in turn, is isolated from the common panel 14 using an insulating strip 20; the metal panel 19 is in electrical communication via a fixing screw and a tab 21.

На фиг. 2 изображены все электри-In FIG. 2 shows all electric

4 с панелью 14 через сопротивление 22 (изоляционная прокладка 20).4 with panel 14 through resistance 22 (insulation strip 20).

Параллельное соединение сопротивлений 10 и 22 может быть представлено результирующим резистором 23·A parallel connection of resistances 10 and 22 can be represented by the resulting resistor 23

Предел случайной погрешности схемы прототипа составлял 0,00015%, а по предлагаемой схеме 0,00003%.The limit of random error of the prototype scheme was 0.00015%, and according to the proposed scheme, 0.00003%.

Действительно, сопротивление изоляции вершины 5 R₅ 10^Ом по схеме шунтирует резистор 4 с R4 10⁷ Ом; погрешность от шунтирующего влияния Rg. на R4 составляет · Ю ^Z= 10'VIndeed, the insulation resistance of the top 5 R ₅ 10 ^ Ohm according to the scheme shunts the resistor 4 with R4 10 ⁷ Ohm; error from the shunt effect of Rg. to R4 is xlO ^Z = 10'V

По схеме эта погрешность отсутствует.According to the scheme, this error is absent.

Ожидаемый технико-экономический эффект предлагаемого изобретения заключается в повышении точности измерения сопротивлений более 10⁶ Ом.The expected technical and economic effect of the invention is to improve the accuracy of measuring resistances of more than 10 ⁶ Ohms.

Claims

The invention relates to electrical measuring equipment, namely, devices for measuring high resistance withstanding (above). DC bridges are known, comprising a measuring circuit, a power supply, an indicator, a key for indicator mutations, and a protection branch 1. Their disadvantage is the presence of parasitic leakage currents through the insulation resistances of the supporting structural elements, which affect the measurement accuracy. Closest to the present invention is a DC bridge containing a measuring circuit with a measured resistor, a power source and an indicator 2. Its disadvantage is low accuracy due to the influence of parasitic leakage currents. The purpose of the invention is to improve the accuracy by eliminating the shunting effect of the insulation resistance of the top of the diagonal of the bridge supply to one of the resistances of the bridge. This goal is achieved due to the fact that in a single four-shoulder DC bridge containing a power source included in the power diagonal of a single four-shoulder bridge, whose shoulders are formed of measurable and fixed resistors, the null indicator included in the measuring diagonal of a single four-shoulder bridge, the top of the measuring diagonal of the opposite branch of the measured resistor is connected to a common bus with which the single four-shoulder constant bridge connected to the vertices is connected and the first, second, and third resistances are insulators of supporting insulators located on an insulated conductive panel, the fourth insulating resistance of a supporting 413poltor included in the diagonal of a single four-shoulder bridge, and the insulator itself is located on an insulated conductive panel electrically connected to one of the poles of the power source. FIG. Figure 1 shows a diagram of a four-shoulder DC bridge; in fig. 2 - the construction of the proposed bridge. The bridge contains the measured resistor .1, the resistors 2-, the tops (points) of the bridge of the insulation from the peaks, the zero-indicator 12-, the source 13 of the power supply. Resistors T-shoulders of the bridge are installed on the metal panel I at the reference points (nodal points. Tops of the bridge, Fig. 1). The reference points 5-7 (point 8 is connected to the panel 14, which is the instrument housing) are insulated from the metal panel. Points 7 and 6 are insulated using a bushing insulator 15 made of insulating material (polystyrene, fluoroplastic, ntar), which is assembled using contact 1b, step 17 and screw 18. Reference point 5 (top of bridge 5, fig. 1 ) has double insulation: isolated from the metal panel 19, which, in turn, is isolated from the common panel AND with the help of the insulation strip 20; the metal panel 19 is electrically coupled via a fastening screw and a tab 21. In FIG. 2 shows all the electrical connections of the bridge with respect to leakage protection according to FIG. 1 It should be noted that each insulator 15 and insulating gasket 20 can be represented by its physical essence as a resistor with a resistance value depending on the insulating material and the geometric dimensions. From this it follows that the top 7 of the bridge is connected to the body (metal panel I) through a resistor 11 (Fig. T), by analogy the top 6 is connected to the body through a resistor 10 .. The top 5 is connected to the top 6 through a resistor 9 (panel 19 has electrical connection to the top 6). Panel 19, in turn, is connected 4 to panel 1A via a resistance 22 (insulating gasket 20). A parallel connection of the resistances 10 and 22 can be represented by the resulting resistor 23. The limit of the random error of the prototype circuit was 0.00015. and according to the proposed scheme 0,00003. Indeed, the insulation resistance of the tip 5 RC Yu Ohm bypasses the resistor with R Yu Ohm; the error due to the shunting effect of R on R, 4 is j. | f. According to the scheme, this error is absent. The expected technical and economic effect of the present invention is to improve the accuracy of resistance measurements of more than 10 ohms. Claims of the invention A single four-shouldered DC bridge containing a power source included in the power diagonal of a single four-shoulder bridge, whose arms are formed by measurable and fixed resistors, a zero indicator included in the measuring diagonal of a single four-shoulder bridge, the top of the measuring diagonal of the opposite branch of the measured one the resistor is connected to a common bus, to which the first, second and third cones connected to the vertices of a single four-arm DC bridge are connected insulating the supporting insulators located on an insulated conductive panel is one that, in order to increase accuracy, the fourth insulation resistance of the supporting insulator is included in the supply diagonal of the single four-shoulder bridge constant The insulator itself is located on an insulated conductive panel electrically connected to one of the poles of the power source. Sources of information taken into account during the examination 1. A. Teplinsky. Bridges for measuring high-resistance and low DC currents. L. Energie, 1970, p. thirty.

2. In the same place 26 (prototype).

FIG. one