RU2238573C1 - Device for calibrating high-voltage separators for constant voltage - Google Patents

Abstract

FIELD: electric engineering.

SUBSTANCE: device has adjustable source of constant voltage, auxiliary separator of constant voltage and two-row comparator. Auxiliary separator is made in form of serially connected stabilitrons with possible disabling of portion of stabilitrons and changing division coefficient. Output shoulder of auxiliary separator is connected to clamps of first row of two-row comparator of voltages, and output shoulder of calibrated high-voltage separator is connected to clamps of second row of two-row comparator of voltages.

EFFECT: simplified process and simplified construction.

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Description

The present invention relates to electrical engineering and is intended for calibration of high voltage DC dividers in a wide range of measured values.

A device for calibrating high-voltage dividers of constant voltage, containing a calibrated high-voltage divider of constant voltage with the ability to close part of its resistive elements, an auxiliary divider of constant voltage in the form of a multi-decade low-voltage divider of constant voltage and an additional resistor to the operating voltage connected in parallel with the calibrated divider, and a zero indicator [ 1].

The disadvantage of this device is the difficulty of manufacturing a multi-decade high-precision low-voltage constant-voltage divider, as well as the need to close part of the resistive elements of a calibrated high-voltage constant-voltage divider, which is not always ensured by its design.

A device (prototype) is known for calibrating high-voltage DC voltage dividers, which contains an adjustable DC voltage source, an auxiliary DC voltage divider consisting of zener diodes connected in series, and a current stabilizer, in parallel with which a voltmeter is connected [2].

A disadvantage of the known device (prototype) is the complexity of its calibration, as well as the need for careful selection of zener diodes of the high voltage unit in order to minimize the error of the device.

The problem to which the invention is directed is to develop a technical solution that simplifies the process of calibrating high voltage DC dividers and the device as a whole.

This problem is solved as a result of the fact that in the device for calibrating high-voltage DC voltage dividers containing an adjustable DC voltage source, an auxiliary DC voltage divider consisting of zener diodes connected in series, and a current stabilizer, in parallel with which a voltmeter is connected, the auxiliary DC voltage divider is made in the form series-connected zener diodes with the ability to disable part of the zener diodes and change the division ratio auxiliary voltage divider. The division coefficient of the calibrated high voltage DC voltage divider is determined using a two-row voltage comparator, the output arm (output zener diode) of the auxiliary DC voltage divider is connected to the terminals of the first row, and the output arm of the calibrated high voltage DC voltage divider is connected to the terminals of the second row.

The simplification of the calibration process of the high voltage DC voltage divider is ensured by the fact that during the operation of the device it is not necessary to calibrate the auxiliary DC voltage divider, consisting of a large number of zener diodes connected in series.

The drawing shows a diagram of a device for calibrating high voltage DC dividers.

A device for calibrating high-voltage DC voltage dividers contains an adjustable DC voltage source 1, an additional resistor 2, an auxiliary DC voltage divider 3 in the form of series-connected zener diodes, made up of a high-voltage arm 4, a closable arm 5 and an output (low-voltage) arm 6, a calibrated high-voltage DC divider voltage 7, composed of a high-voltage arm 8 and an output (low-voltage) arm 9, and a two-row voltage comparator 10. Output p lecho 6 of the auxiliary DC voltage divider 3 is connected to the terminals 11 of the first row of the double-row voltage comparator 10, and the output arm 9 of the calibrated high-voltage DC voltage divider 7 is connected to the terminals 12 of the second row of the two-row voltage comparator 10. The elements of the auxiliary DC voltage divider are switched using the switch 13 (the diagram shows conditionally).

The operation of the device for calibrating high voltage DC dividers is as follows.

At the first measurement stage, the circuit is assembled in accordance with the drawing, with the switch 13 being set to position 2. A voltage equal to the nominal input voltage of the calibrated high-voltage DC divider 7 is supplied to the circuit from an adjustable DC voltage source 1. Using an additional resistor 2 in the auxiliary circuit DC divider 3 sets the operating current. In this case, at the zener diodes constituting the auxiliary divider of the constant voltage 3, a voltage drop is set equal to the stabilization voltage of the zener diodes. The voltage drop at the output arms 6, 9 of the auxiliary 3 and calibrated 7 DC dividers is measured using a two-row voltage comparator 10.

The equality is fulfilled:

where U ₄ , U ₅ , U ₆ - voltage drops, respectively, at high voltage 4, closable 5 and output 6 shoulders of the auxiliary voltage divider 3;

R ₈ , R ₉ - resistance, respectively, of high-voltage 8 and output 9 shoulders of a calibrated high-voltage DC voltage divider 7;

U ₁₁ , U ₁₂ - readings of the first 11 and second 12 rows of a two-row voltage comparator 10, respectively.

Equation (1) can be represented as:

where K ₇ is the division coefficient of the calibrated high voltage DC voltage divider 7;

ρ ₁ = U _11-1 / U _12-1 - the ratio of the readings of the rows of a two-row voltage comparator 9.

At the second measurement stage, part of the Zener diodes 5 of the auxiliary DC voltage divider 3 is closed (switch 13 is set to position 1). From a regulated constant voltage source 1, a voltage is applied to the circuit at which the voltage drop at the high voltage 4 and output 6 arms of the auxiliary DC voltage divider 3 would remain unchanged. The voltage drop at the output arm 8 of the calibrated constant voltage divider 6 is measured using a two-row voltage comparator 10. A new equality is fulfilled:

Equation (3) can be represented as:

where ρ ₂ = U _11-2 / U _12-2 is the ratio of the readings of the rows of a two-row voltage comparator 10.

At the third measurement stage, the conversion coefficient of the auxiliary DC voltage divider 3, composed of the closable arm 5 and the output arm 6, is determined by the method of autonomous (independent) verification:

where ρ ₃ is the conversion coefficient of the auxiliary DC voltage divider 3, composed of a lockable arm 5 and the output arm 6;

U _5i is the stabilization voltage of the zener diodes of the closing arm 5 of the auxiliary DC voltage divider 3;

U ₆ - stabilization voltage of the zener diode of the output arm 6 of the auxiliary divider DC voltage 3.

Equation (5) can be represented as:

Solving equations (2), (4), (6) together, we find the division coefficient K _{7 of the} calibrated constant voltage divider 7 from the obtained values of ρ ₁ , ρ ₂ , ρ ₃ :

The division coefficient of the auxiliary DC voltage divider, based on the expressions (1), (7), is equal to:

A feature of the developed device for calibrating high-voltage dc voltage dividers is that during the measurement process, the long-term stability of the auxiliary dc voltage divider 3 is not required due to the stability of the current-voltage characteristics of the zener diodes used in the divider, and the division ratio of the auxiliary dc voltage divider is determined directly during calibration high voltage constant voltage divider.

Thus, the proposed technical solution provides the ability to calibrate high voltage DC dividers in a wide range of measured values.

Sources of information

1. Zhuravlev E.N. Methods and means of measuring high DC voltages and their metrological support. - M.: Mechanical Engineering, 1982. - S.45-52.

2. Zhuravlev E.N. High voltage meter / E.N. Zhuravlev, Yu.M. Tverdov, V.S. Shtillerman. A.S. No. 661335 (USSR). Published in B.I., 1979, No. 17.

Claims (1)

A device for calibrating high-voltage DC voltage dividers containing an adjustable DC voltage source, an auxiliary DC voltage divider consisting of zener diodes connected in series, and a current stabilizer, in parallel with which a voltmeter is connected, characterized in that the auxiliary DC voltage divider is made in the form of zener diodes connected in series with the ability to disable part of the zener diodes and change the division ratio of the auxiliary a DC voltage divider, and the output arm of the auxiliary DC divider is connected to the terminals of the first row of a two-row voltage comparator, and the output arm of a calibrated high-voltage DC divider is connected to the terminals of the second row of a two-row voltage comparator.