RU23687U1 - INDUSTRIAL FREQUENCY ELECTRIC FIELD MEASUREMENT DEVICE GRADING DEVICE - Google Patents

Abstract

A device for calibrating industrial frequency electric field strength meters, containing an air capacitor with flat electrodes, an adjustable high voltage source in the form of a high voltage transformer, a voltage meter, a calibrated meter, characterized in that not a flat, but a spherical capacitor having a closed system is used as a field forming system electrodes, and the voltage meter on the electrodes of the spherical capacitor is pre-calibrated in units of maskers electric field based on the distortion correction coefficient field a graded meter.

Description

ELECTRIC ZERO NOMINAL FREQUENCY VOLTAGE METERS GRADING DEVICE

The utility model relates to measuring equipment, in particular to measuring the magnitude of the electric field of industrial frequency, and can be used for calibration of instruments for measuring electric field strength.

A device is known for calibrating electric field strength meters 1, containing a spherical electrode connected to a source and a voltage regulator, in the field of which a voltage meter is placed, after which the device reads and compares them with the calculated value of the intensity.

However, this device provides low accuracy in the calibration of electric field strength meters due to the influence of the calibrated meter and the surrounding conductive bodies on the model field.

There is also known a device for calibrating electric field strength meters of industrial frequency 2, comprising an air capacitor with flat electrodes, an adjustable high voltage source in the form of a high voltage transformer, a voltage meter, a measuring plate with central and peripheral sections, resistors, a graduated meter and a shielded cable.

This device also provides low calibration accuracy, as due to the openness of the field forming system, the exemplary electric field of this device is affected by the surrounding conductive bodies. In addition, calibration is carried out without introducing the meter into

MKIO 01 R 29/12 R 35/00

electric field, and therefore not the meter itself is graduated, but only its measuring circuit, i.e. excluding sensor. The known device is also large, and the calibration process itself is complex and requires additional calculations.

The objective of the utility model is to provide the possibility of calibrating tension meters with increased accuracy, eliminating the influence of surrounding conductive bodies, reducing the size of the calibration device and simplifying the calibration process itself by eliminating additional calculations during the calibration process.

This problem is achieved by the fact that in the known device for calibrating electric field strength meters of industrial frequency, containing an air capacitor with flat electrodes, an adjustable high voltage source in the form of a high voltage transformer, a voltage meter, a calibrated meter, a spherical capacitor is used as a field forming system having a closed system of electrodes, and a voltage meter that measures the voltage at the electrodes of a spherical condensate and pre-calibrated in terms of the electric field, taking into account the correction factor for a graded field distortion meter.

The utility model is illustrated in FIG. 1 and FIG. 2, where FIG. 1 shows a diagram of a utility model device, and FIG. 2 shows the dependence of the correction coefficient k on field distortion by a calibrated meter on a and the ratio of the radii of the spherical body r of the calibrated meter and electrodes of the spherical capacitor R.

The calibration device for measuring electric field strengths of industrial frequency contains an air spherical capacitor.

field-forming electrodes (hereinafter referred to as electrodes) 1 and 2, made in the form of hemispheres of metal or other conductive material and coated inside and out with a thin layer of dielectric; the electrode 1 is fixedly mounted on the stand 3, and the electrode 2 is connected to the electrode 1 by means of a dielectric joint 4; a dielectric insert 5, consisting of two parts mounted in a spherical capacitor, the outer surface of which coincides with the inner surface of the spherical capacitor, and the inner surface with the outer surface of the graduated meter 8, serves to fix the graduated meter in the spherical capacitor; an adjustable high voltage source 6 in the form of a high voltage transformer, the terminals of which are connected to the electrodes 1 and 2; the voltage meter 7 supplied to the air spherical capacitor is connected between the electrodes 1 and 2 of the air spherical capacitor and calibrated in units of electric field strength taking into account the correction factor for field distortion by a graduated meter and a graduated meter 8.

The calibration device of the electric field strength meters works as follows.

A graduated meter 8 of electric field strength is placed between the electrodes 1 and 2 of a spherical capacitor and close the latter. They apply voltage to an adjustable high voltage source. At the same time, a high voltage appears at the output of the high-voltage transformer 6, forming a uniform electric field EQ in the center of the electrodes 1 and 2. The magnitude of this field before placing the graduated meter between the electrodes of a spherical capacitor is determined by the expression

where and is the voltage between the electrodes 1 and 2; R is the radius of the electrodes of the spherical capacitor, and after the room - the expression

where k is the correction factor for field distortion by a graduated meter. With the known configuration of the fado meter, the coefficient k is determined by calculation or experimentally. For example, with the spherical shape of the body of the graduated meter and its sensitive elements made in the form of spherical segments, the coefficient k can be determined, for example, by the formula

G a M, Y (IV-, 4 + 3 a 9l-a,, 2n-ll-a - 2n + ll-a y

where 00 is the angular size of the sensitive element of the meter; a is the ratio of the radii of the spherical body r of the graduated meter and the electrodes of the spherical capacitor R, n is the number of members of the series. This coefficient can also be found from the graphs presented in figure 2.

A voltage meter 8 measuring high voltage at the electrodes 1 and 2 of a spherical capacitor is calibrated according to formula 1 in units of electric field strength. By adjusting the voltage using a high voltage source 6, various voltage values are controlled by the voltage meter 8 and the meter is calibrated.

The described device allows you to achieve all your goals. The spherical capacitor used in this device may have dimensions only slightly larger than the dimensions of the graduated meter, and

E

E k.k.E ,, (1)

allows you to get the necessary field strength at much lower voltages than for a flat capacitor. Because the correction factor for field distortion by a calibrated meter can be calculated with any required accuracy and much simpler than for a flat capacitor, and taken into account when calibrating a voltage meter, this allows to increase the accuracy of calibration of electric field strength meters. In addition, the description shows that this device simplifies and speeds up the calibration process and increases the safety of working with it.

1.A.S. 154939 USSR, MKI G 01 R 29/12. A method for calibrating a device with unknown characteristics for measuring the parameters of an electrostatic field / Verevkin V.N. Publ. in bull. No 11 for 1963.

2.A.s. 1366971 USSR, MKI G 01 R 29/12, G 01 R 35/00. Graduation device for measuring electric field strengths of industrial frequency. / Jerusalem A.P., Meilakh D.I., Portnov F.G. and other publ. in bull. No 2 for 1988.

Literature

Claims (1)

A device for calibrating industrial frequency electric field strength meters, containing an air capacitor with flat electrodes, an adjustable high voltage source in the form of a high voltage transformer, a voltage meter, a calibrated meter, characterized in that not a flat, but a spherical capacitor having a closed system is used as a field forming system electrodes, and the voltage meter on the electrodes of the spherical capacitor is pre-calibrated in units of maskers electric field based on the distortion correction coefficient field a graded meter.