SU1468208A1 - Device for simulating tangent of loss angle - Google Patents

Abstract

The invention relates to electrical measuring technology and can be used as a measure of the loss angle tg of the calibration and adjustment of three-clamping alternating current bridges. The purpose of the invention is to improve the accuracy of simulated tg values. The device contains a shielding case, outputs 7, a resistor 6 8 74 and a differential capacitor, consisting of a rotor electrode (RE) 4, a stator electrode (EF) I connected to the output, and an EF 2 connected to, EF 1 through a resistor 6, the differential capacitor 3 is inserted into the differential capacitor, and the reel 5 placed in it 180 ° with respect to one other, and the ER 4 is electrically isolated from the axis and connected to another output of the device. The loss tangent at the terminals of the device is proportional to the angle of rotation of the axis of the differential capacitor. Capacitating is achieved by adding plates to the ESS and EH packages. 2 pe. (L

Description

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This invention relates to electrical measuring technology and can be used as; loss tangent measures (tgS).

The aim of the invention is to increase the accuracy of the simulated tgS values.

Fig, 1 shows the proposed device; Fig. 2 is an electrical replacement circuit of the device.

The device for simulating the loss-angle tangent contains electrodigs made in the form of plate packs and placed in the shield housing three stator - first, second 2 and third 3 and two rotor - and 5, Second stator electrode 2 is installed coaxially with third stator electrode 3, strengthened together with. on common racks electrically isolated from the housing, and connected through a resistor 6 to the current 7, nepBbrti, and the stator electrode 1 is connected to this current well directly. The rotor electrode U is installed through an insulating sleeve on the rotor axis with the ability to overlap the plates of the sturdy electrodes I and 2 and is connected through a current collection to another current 8. The second rotor electrode 5 is mounted on the same axis with the ability to overlap the plates of the third stator electrode 3, is rotated by 180 relative to the rotor electrode 4 and electrically connected via an axis to the housing. Between the first stator electrode 1 and the rotor electrode 4 is a plate 9, also connected to the housing. 40 The device works as follows. at once.

Rotating the rotor core, and inserting the plates of the rotor electrode 4 into the space me: (two plates of the second stator electrode 2, which leads to an increase in capacitance C between them. Accordingly, the loss tangent of the series RC circuit containing a resistor 6 and the capacitor formed by the stator electrodes 2 and 3 (Fig. 2), With .ggom, due to the reduced 1-capacitance C between the first stator electrode 1 and the rotor electrode 4, the total capacitance at outputs 7 and 8 remains unchanged. At the same time, the capacitance Cj between tr the rotor electrode 3 and the second rotor elec

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40 tgS

Kcf,

(I)

82082

with electrode 5, which, influencing only the active conductivity on the current leads of device j, allows to obtain a linear dependence of the loss tangent on capacitance C, and the angle of rotation, proportional to it, cf of the rotor axis:

WRCjiC.

 SG + s;

where K, (C, -i-Ci) and (C ,,) are constant values.

The plate 9 serves to ensure that the capacitance of the first stator electrode 1 is constant on the housing when the second rotor electrode 5 is rotated.

The accuracy of the proposed device in comparison with the known one is no less than 2 times higher, due to the linearity of the tg5 scale, and at the same time the possibility of checking bridges by tgS appears at a capacitance value in the middle part of the bridge measurement range. Due to this, the capacitances at the outputs of the device are increased to 1000 pF by adding plates to the packages of electrodes. This capacitance exceeds the known capacitance no less than 10 times, and corresponds to the middle part of the capacitance measurement range in modern bridges (the usual U pF range — SOO μF).

0

j

0

five

The accuracy of the device, along with the linearity of the tgS scale, is promoted by the constancy of its secondary capacities, i.e. the constancy of the capacity from each output to the housing. The side capacitance from the current lead 7 is determined by the capacitance on the body of the first stator electrode 1. This capacitance is lost permanently due to the presence of a plate 9 playing the role of a cutting screen. The side capacitance from the current output 8 is determined by the capacitance on the body of the rotor electrode 4. This capacitance remains constant due to the fact that the plates of the rotor electrode 4 are immersed in packages of stator electrodes 1 and 2. When the device is connected to the bridge, the constancy of the side capacitances provides a constant load on bridge shoulders and facilitates bbe / eri ie amendments.

Formula (1) is valid for,. At values, l be- C in the denominator should be multiplied by the sample (1 + tg o).

invention formula

A device for simulating a loss angle tangent, comprising a shielding case, current-voltage modules, a resistor and a differential capacitor consisting of a first stator electrode connected to the current core and an second stator electrode connected to the first stator electrode through a resistor, characterized in that that, with the aim of turning

8208.

No accuracy, it is provided with the third rotor electrodes made in the form of plate packs and the second rotor electrodes located in it, while the second and third s. electrodes are coaxially and electrically insulated from the shield body.

to

The second rotor electrode is mounted on an axis with a turn of 180 ° relative to the rotor electrode, the rotor electrode being electrically isolated from the axis and connected to the current output of the device.

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Claims (1)

Claim A device for simulating a loss tangent, comprising a shielding body, current leads, a resistor and a differential capacitor, consisting of a first stator electrode located on the axis of the rotor electrode connected to the current lead and a second stator electrode connected to the first stator electrode through a resistor, characterized in that , in order to improve accuracy, it is equipped with a third stator made in the form of packets of plates and a second 5 rotor electrodes placed in it, while the second and third stator electrodes ktrody coaxially arranged and electrically insulated from the shield frame, the second rotary electrode eakrep10 flax on axis with 180 ° relative to the rotary electrode, the rotary electrode is electrically insulated from the axis and soedinen.s cold end of the device.