SU1631447A1 - Compensator for measurement of mutual impedance between two windings - Google Patents

Abstract

The invention relates to a technique for measuring electrical and magnetic quantities, in particular, devices for measuring mutual inductance, and can be used in monitoring windings of electric motors, transformers, as well as for measuring non-electrical quantities, such as weight, displacement, temperature, etc., using mutual sensors. inductance. A compensation device for measuring the mutual impedance between the two windings contains a power source 1, an equilibrium detector 2, terminals 3, 4, 5, 10 for connecting the measurement object. Introduction to the current-voltage converter 6 device, the first 7 and second 8 control voltage dividers and the adder-phase shifter 9 allowed to increase the measurement accuracy due to the exclusion of unstable measure, mutual inductance, low accuracy class from the signal processing path, as well as due to the change in several orders of the transmission coefficient of the nodes that provide the necessary signal conversion 1 Il. cl

Description

The invention relates to techniques for measuring electrical and magnetic quantities, in particular to devices for measuring the mutual impedance of magnetically coupled four-terminal devices, and can be used in the development of metrological equipment for checking stores of mutual inductance, as well as for measuring non-electrical quantities, such as weight, displacement, temperature, etc. using appropriate mutual inductance sensors.

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

The drawing shows a functional diagram of a compensation device for measuring the mutual impedance between two windings.

The device contains a power source 1, an equilibrium detector 2, the first 3, second 4 and third 5 terminals for connecting the measurement object, a current-voltage converter 6, the first 7 and second 8 controlled voltage dividers, the adder-phase shifter 9 and the fourth 10 terminal for connecting the measurement object .

Compensation device for measuring the mutual impedance between the two windings operates as follows.

Under the action of the supply voltage 1, a current h flows in the primary winding circuit of the measurement object, which is converted to the voltage at the output of the converter 6. This voltage is scaled by dividers 7 and 8 to form two independently varying voltages, which are quadrature summed by the adder-phase shifter 9. At the output of which the voltage acts where Κι and Кг are the transmission coefficients by controlled dividers 7 and 8;

R, Ri, R2 - resistance values of the current-voltage converter, adder-phase shifter and Ci - capacitance of the adder-phase shifter.

This voltage is compared with the voltage on the secondary side of the measurement object.

U ₂ = hZb3 (jwM + R _n ).

where u is the frequency of the generator.

By changing the transfer coefficient of the dividers 7 and 8, achieve equal voltages U and U ₂ . From the equilibrium equation, dividing the real and imaginary parts, get

M = KiRR ₂ Ci - mutual inductance;

Thus, the transfer coefficient of the divider 7 determines the mutual inductance, and the transfer coefficient of the divider 8 determines the loss resistance, while a tenfold change in such parameters as R, Ri, R2, Ci allows you to easily change the measurement limits. Thus, this device has a higher accuracy, since it lacks an exemplary measure of mutual inductance. The measuring range of the device is quite wide and can exceed 5-6 orders of magnitude, since there are a sufficient number of elements that allow multi-stage (multiple of ten) scaling of the measurement result.

Claims (1)

Claim Compensation device for measuring the mutual impedance between two windings, containing a power source connected between the first terminal for connecting the measurement object and a common bus, an equilibrium detector connected between the second terminal for connecting the measurement object and a common bus, and the third and fourth terminals for connecting the measurement object characterized in that, in order to increase accuracy and expand the measuring range, a current-to-voltage converter, the first and second voltage dividers, and the adder A rotator whose output is connected to the fourth terminal for connecting the measurement object, the third terminal of which is connected to the input of the current-voltage converter, the output of which is connected to the information inputs of the first and second voltage dividers. the control inputs of which are connected to the first and second control outputs of the equilibrium detector, the outputs of the first and second voltage dividers are connected respectively to the first and second inputs of the adder-phase shifter.