SU1753249A1 - Biparametric linear displacement transducer - Google Patents

Abstract

The invention relates to a measurement technique and is aimed at improving the accuracy of a biparametric linear displacement transducer by increasing linearity over the entire measurement range. The displacement transducer comprises a U-shaped magnetic core 1 with primary excitation winding 2 placed on its base. A variable capacitor with a liquid-crystal dielectric, located between the parallel rods 4 and 5 of the magnetic conductor 1, is connected in parallel to the secondary winding 3 of the converter, which is concentrated on the base of the fixed magnetic conductor. The gap between the plates of the variable-capacitance liquid-crystal capacitor is made varying according to a quadratic law. By maintaining the resonant mode in the secondary circuit of the converter over the entire measurement range, the sensitivity of the converter and the linearity of its output characteristic are ensured. 1 il. Yo

Description

This invention relates to a measurement technique and can be used to measure linear displacements.

Known Converter, which consists of a magnetic U-shaped, having a primary and secondary windings. The secondary winding is evenly distributed along the parallel rods of the magnetic circuit, and the movable non-winding measles is placed between them. One of the capacitor plates is kinematically connected to the core, and both plates are connected respectively to the ends of the secondary winding 1.

Also known converter, in which at the base of the magnetic circuit U-shaped form is placed primary

an excitation winding, and a distributed secondary winding is wound on one of the parallel rods. In the space between the parallel rods, there is a variable capacitor with a liquid-crystal dielectric and a movable measles screen, which encloses the core part of the magnetic circuit. The capacitor is shunted by the secondary winding of the converter 2.

However, lime biparametric converters have a high nonlinearity of the conversion characteristic, the inductance of the output winding varies non-linearly due to the simultaneous change of the magnetic resistance in the path of the worker (screened)

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flow F and the number of turns of the secondary winding. Therefore, the resonance condition is violated, i.e. the product L-C varies over the entire range of movement of the movable part of the converter, which significantly increases the degree of non-linearity of the conversion characteristic, which results in lower measurement accuracy.

The purpose of the invention is to improve the accuracy by increasing the linearity of the hara, conversion conversion rate over the entire measurement range.

This goal is achieved by the fact that in a biparametric linear displacement transducer, which contains a U-shaped magnetic conductor, a primary winding located on its base, a capacitor of variable capacitance with a liquid-crystalline dielectric, having a negative anisotropy, is connected between parallel magnetic rods a capacitor and a secondary winding placed on the magnetic core and mounted with a measurable shield that can be moved along parallel rods the winding is made concentrated and placed on the basis of a U-shaped magnetic circuit, and the gap in the capacitor is made varying according to a quadratic law.

Due to the concentrated placement of the secondary winding on the basis of the fixed magnetic circuit and the change in the gap between the plates of a variable capacitor, the linearity of the conversion characteristic is ensured, which is achieved by maintaining the resonance condition over the entire measurement range, resulting in improved measurement accuracy.

The drawing shows a diagram of a biparametric transducer of linear displacements,

The converter consists of a U-shaped fixed magnetic core 1, on the basis of which the primary excitation winding 2 and measuring secondary winding 3 are placed. In the space between the parallel rods 4 and 5 there is a variable capacitor with a liquid-crystalline dielectric having a negative anisotropy made in the form of along the rods of the magnetic circuit of the electrodes 6 and 7. The gap between the plates of the variable capacitor is made varying according to quadratic law:

P

(52 w2 0 TS0 Јo - Ј1 (Hm - X) + 82 X X

M

where w is the number of turns of the secondary winding;

b, di is the width of the magnetic circuit and the gap between them;

X m - the maximum value of the X coordinate of the movable part of the converter;

Ј1 is the dielectric constant of a liquid crystal substance whose molecules are non-oriented in the magnetic field;

Ј2 - dielectric constant

liquid crystal substances whose molecules are oriented along a magnetic field

Movable Measles Screen 8 Covers

the core part of the magnetic circuit with a liquid-crystal capacitor 9 of variable capacitance, shunted by the secondary winding of the converter. When moving the mobile bar-screen 8

along a fixed magnetic core, the inductance L and the capacitance C vary inversely with each other, as recorded by the secondary apparatus.

The biparametric linear displacement transducer works as follows.

When powering the primary winding 2 from the alternating current source 1E1 in the secondary winding 3 of the converter is induced by EMF, the inductance L.2 of the secondary winding 3 of the converter and the capacitance C of the variable capacitor

liquid crystal dielectric so that the parallel circuit is in resonance at any position of the crust of the screen 8 along the length of the rods 4 and 5 of the magnetic cores 1. As the X coordinate of the crust of the screen 8 increases, the inductance La of the secondary winding 3 increases linearly and the capacitor capacitance decreases due to the reorientation of the liquid crystal molecules substances that under the action of a magnetic field are arranged in parallel along magnetic lines of force.

A positive effect is achieved by maintaining the resonant mode over the entire measurement range.

Claims (1)

Invention Formula A biparametric linear displacement transducer containing a U-shaped magnetic circuit, a primary winding placed on its base, a variable capacitor with a liquid-crystalline dielectric having a negative anisotropy, connected between parallel magnetic cores, connected in parallel to a capacitor and placed on the magnetic conductor secondary winding and installed the ability to move along the parallel rods a measles-shield, characterized in that, in order to increase the accuracy and by increasing the linearity of the conversion characteristics throughout the measuring range, the secondary winding is concentrated and placed on the basis of the U-shaped yoke, and a gap is formed in the condenser varying quadratically. U would