SU977927A1 - Inductive measuring converter - Google Patents

Description

one

The invention relates to a measurement technique and can be used in devices for measuring and controlling various quantities, based on converting the measured value to a change in the inductance of a coil.

Known .inductive measuring transducer containing the magnetic core and winding located on the magnetic circuit. Cl., Q

The disadvantage of the converter consists in the measurement error caused by the change in the magnetic state of the sections of the magnetic conductor under the influence of various factors., J

The closest in technical essence to the present invention is an inductive measuring transducer comprising a magnetic core with windings and a generator G 2 .20

The disadvantage of this converter lies in the low accuracy of measurements due to the random magnitude of the residual magnetization of the sections of the magnetic circuit at the moment when the current in the windings is turned off and the calibration characteristic is shifted upon re-activation.

The purpose of the invention is to increase the accuracy of measurements.

This goal is achieved by the fact that an inductive measuring transducer containing a magnetic core, windings located on the magnetic core, and a generator, is provided with a capacitance, a direct current source and a switch, the capacitance is connected to the input of the switch, the first output of which is connected to the windings, and the second to source of direct current.

The drawing shows a diagram of the Converter.

Claims (2)

The converter contains magnetic core 1, windings 2 located on it, which through the switch 3 can be connected either to the input of the switching circuit 4 or to the capacitor 5, the power supply generator 6 of the switching circuit 4, the threshold device 7, the input of which is connected in parallel to the Output of the generator 6, and a source 8 pos3 07 of this current, connected to the switch 3 and the capacitance 5. The switch 3 can be ejected both on the contact and on the contactless elements.,. The device works as follows. When measured, the full voltage of the power supply generator 6 is supplied to the input of the switching circuit 4 and the threshold device 7. In this case, the output of the threshold device 7 generates a signal that switches the switch 3 to the position shown in the drawing. In this case, the windings 2 are connected to the switching circuit 4 and the measurement signal is converted, and the capacitor 5 is connected to the DC source 8 and charged — from this source to its voltage. "" When the generator 6 is turned on, the threshold device 7 comes to the off state and switches the switch 3 in such a way that the connection between the windings 2 and the turn-on circuit 4 is broken and the windings 2 are connected to the capacitor 5, which, in turn, turns off source 8 direct current. When this occurs, the self-oscillating damped process of discharge of the capacitance 5 through the windings 2 of the converter, which causes demagnetization of the magnetic circuit 1 of the converter. As a result, each time the ispereater is switched on, the magnetic core 1 has the same small residual inductor value. When the inverter is turned off, the switching off time is a random value, and at the moment of shutdown, the voltage applied to the windings can vary from. zero to the maximum. Since at the moment of current cessation in the inductance an emf of self-induction arises, this value, exceeding the instantaneous value, the voltage at the moment of switching off the converter, causes residual magnetization of the cores. The magnitude of this magnetization is random and the repeated switching on of the transducer will result in a shift of its calibration characteristic and the occurrence of measurement error. Since, due to the emf of self-induction, the amplitude of the magnetizing pulse at the moment of switching off the converter exceeds the amplitude of the magnetizing current during the operation of the transducer, when it is switched on again, the magnetic state of the core does not return to its initial state and the offset of the characteristic must be compensated for by tuning the converter. The use of the converter will eliminate the error caused by the shift of the calibration characteristic due to the unstable residual magnetization of the magnetic circuit at the time of shutdown, and improve the accuracy of the converter operation and re-switching, after turning off the converter, the magnetic circuit is automatically demagnetized and with repeated switching off the working point on the magnetization curve the material of the magnetic circuit remains unchanged. Inductive measuring transducer containing a magnetic circuit with windings and a generator, characterized by the fact that, in order to measure accuracy, it is equipped with a capacitor, a DC source and a switch, the capacitance is connected to the input of the switch, the first output of which is connected to the windings, and the second is to the source of direct current. Sources of information taken into account in the examination I. Ageykin D. ... And. Sensors of control and regulation. M., Mechanical Engineering, 1965. 2. Patent of Germany M 1807207, cl. G OlD 5/244, 1979 (prototype).