SU731387A1 - High-voltage measuring bridge - Google Patents

Description

The invention relates to electrical engineering and can be used as a device for checking precision high-voltage voltage dividers.

The closest in technical essence to the proposed one is a high-voltage measuring bridge, containing two voltage dividers connected in parallel, each of which consists of a high-voltage arm and a low-voltage arm, an exemplary low-voltage divider, switch, power supply and null indicator [11 The disadvantages of this measuring bridge are low measurement accuracy and narrow measurement range.

The purpose of the invention is improving the accuracy of measurement and expanding the measuring range.

This is achieved by the fact that an additional resistor, switches, amplifiers, rectifiers, actuators are introduced into the measuring bridge, formed by two parallel-connected voltage dividers, consisting of high-voltage and low-voltage arms, and containing a power source, the output of which is connected to one of the terminals of the voltage dividers and a control generator, the outputs of which are connected to the control inputs of the keys and rectifiers, an additional resistor, shunted by the first key, is included in the low-voltage arm 5 of one of voltage dividers, the outputs of voltage dividers are connected to the signal inputs of the second and third switches, the outputs of which are connected respectively to 10 first amplifiers, first rectifiers, first actuators and second amplifiers, second rectifiers, second actuators, and actuators are mechanically connected to the motors 15 high voltage and low voltage shoulders of another voltage divider.

The drawing shows a functional diagram of the proposed measuring bridge.

The measuring bridge contains voltage dividers 1, 2, respectively, consisting of pz of high-voltage arms 3, 4 p of low-voltage arms 5, 6, a power supply 7, an additional resistor 8, switches 9, 10, I, amplifier 25, 12, 13, rectifiers 14, 15, executive bodies 16, 17 and a control generator 18.

The measuring bridge operates as follows.

In the corresponding two clock cycles controlling the operation of the measuring bridge by the control generator 18, in which: in the first cycle, the key 9 is open, the keys 10, 11 are in the right position; in the second step, the key 9 is closed, the keys 10, And are in the left position, in the measuring bridge, the output voltages of the voltage dividers 1, 2 are compared.

The output voltages of the switches 10, 11 are a modulated voltage, the modulation depth of which is determined by the values of the compared voltages from the outputs of the voltage dividers 1, 2. The modulated signals from the outputs of the switches 10, 11 are amplified by amplifiers 12, 13, and rectified by the corresponding rectifiers 14, 15. Signals with the outputs of the rectifiers 14, 15 go to the inputs of the executive bodies 16, 17, which act respectively on the high-voltage arm 4 and low-voltage arm 6 of the voltage divider 2 according to the law, which contains some function of the modulated signal.

In the absence of a modulated signal at the outputs of the switches 10, 11 (equality of the compared voltages from the outputs of the voltage dividers 1, 2) in the measuring bridge, the following relationships are established:

(1) _ and (¾ l ₆ ) Az + T? _8th up ·. BR _S Az + Az ’ Up with _ UR _B. 'Rs + Rt ’ IR ₌ <' ^e) A _e ^ Ri'

(1) (2) (3) (4) where U is the voltage of the power source; ί / ί ^υ , m ²⁾ - output voltage of voltage divider 1 with open and closed key 9, respectively;

Up, Up - output voltages, respectively, from the outputs a and b of voltage divider 2;

Rs, Rt, R &, Rs, Rs - respectively, the resistance of the high-voltage arms 3, 4, low-voltage arms 5, 6 and an additional resistor 8;

Rp ^c) is the resistance of the part of the low voltage arm 6 between the terminals b and c. Wherein

UP = Up; (5)

Up = UP, (6) and the measurement result is read from the graduated low-voltage arm

(7) where is the resistance of the low-voltage arm 6 between the terminals a and b.

Because

- [= - = В = const, (8) then from (5) and (6), taking into account (7) and (8), it follows that ¹⁵ = (9) where 02 ⁰⁾ is the division ratio of voltage divider 2 relative to the output and bottom 20 of the voltage arm 6.

Based on the above ratios, the coefficient of the voltage divider 1 and the resistance of the high voltage arm 3 can be determined.

Claims (3)

neither the operation of the measuring bridge by the control generator 18, in which: in the first cycle, the key 9 is open, the keys 10, 11 are in the right position; in the second cycle, the key 9 is closed, the keys 10, And are in the left position; in the measuring bridge, the output voltages of voltage dividers 1, 2 are compared. The output voltages of the keys 10, 11 are modulated voltages, the modulation depth of which determined by the values of the compared voltages from the outputs of voltage divider 1, 2. The modulated signals from the outputs of the keys 10, 11 are amplified by amplifiers 12, 13, respectively, and rectified by the corresponding rectifiers 14, 15. Signals from the outputs of the rectifiers 14, 15 are fed to the inputs of the actuators 16, 17, which act accordingly the high voltage leg 4 and the low voltage leg 6 of the voltage divider 2 according to the law, representing a certain function of the modulated signal. In the absence of a modulated signal at the outputs of the keys 10, 11 (the area of the compared voltages from the outputs of the voltage dividers 1, 2), the following ratios are established in the measuring bridge: (1) and (R, -r-R,). -L G Rz + Rb IjW URs Re + Ri T-R-i where and is the voltage of the power source; M, Ui are the output voltages of the voltage divider 1 with the open and closed key 9, respectively; f / a / - output voltages, respectively, from outputs a to b, voltage divider 2; 3, 4,,, -, respectively, the resistance of the high-voltage arms 3, 4, low-voltage arms 5, 6 and the additional resistor 8; - resistance of the low-voltage arm 6 between the terminals b and c. At the same time i - (5) U U. (6) a, the measured result is read from the graduated low-voltage arm 6. Д «- О- А Я1 where is the resistance of the low-voltage arm 6 between the terminals a and b. Since 1-8 const, then from (5) and (6), taking into account (7) and (8), it follows that where is the division ratio of voltage divider 2 relative to the output a of the low voltage arm 6. iia the basis of the above relations can be determined The coefficient of the voltage divider 1 and the resistance of the high voltage voltage 3. The invention of the High-voltage measuring bridge, formed by two parallel-connected voltage dividers, consisting of high-voltage and low-voltage arms, and containing a power source, the output of which is connected to one of the terminals of voltage dividers, different from that, 410, to improve accuracy measuring and extending the measuring range; a further resistor, keys, amplifiers, rectifiers, operating units and a control generator, whose outputs are connected to the control inputs of the key It and the rectifier, an additional resistor, which is clamped by the first key, is connected to the low voltage arm of one of the voltage dividers, the outputs of the dividers are connected to the signal inputs of the second and third keys, the outputs of which are connected to the successively connected nerve amplifier, the first rectifier, the first the executive body and the second amplifier, the second rectifier, the second insulator, the executive bodies are mechanically connected to the engines of the high-voltage and low-voltage arms another divider voltage. Sources of information taken into account during the examination 1. USSR author's certificate N ° 451957, cl. G 01R 17/02, 25.05.70.