Uster Technologies Ag

Reto Gehrig

Philipp Ott

Rolf Joss

Phillipp Ott

Karl Bleisch

Beat Koller

A measuring circuit used for the capacitive examination of a moving elongated textile test material such as card sliver, roving, yarn or woven fabric, having a measuring capacitor for accommodating the test material, and a component with a capacitance which can be changed by an electric control signal. The measuring circuit can thus be balanced in a simple, rapid, cost-effective and especially automatic way.

Capacitive measuring circuit

The capacitive measuring circuit for a moved elongated test material contains at least two measuring capacitors, each of which is configured for receiving the test material. It further contains electrically actuatable selection means, by means of which one of the measuring capacitors can be selected in such a way that only the selected measuring capacitor contributes to the measurement, whereas the other measuring capacitors do not. As a result, the total capacitance of the measuring circuit is reduced and its sensitivity is increased.

Capacitive analysis of a moving test material

An apparatus for determining a dielectric property of a capacitor arrangement, having an alternating signal generator for applying an electric alternating signal to the capacitor arrangement. It further contains an evaluation circuit for evaluating at least one electric measuring quantity of an electric signal tapped from the capacitor arrangement. It further comprises balancing means which are arranged in an electric path between the alternating signal generator and the capacitor arrangement and by means of which a parameter of the electric alternating signal can be changed in such a way that an output signal of the evaluation circuit assumes a specific value, preferably zero, under defined constant conditions. Control means are provided for emitting an electric control signal to the balancing means, by means of which the change of the at least one parameter can be controlled. The apparatus can thus be balanced in a simple, rapid, cost-effective and especially automatic way.

Determining a dielectric property of a capacitor

An apparatus for determining at least one dielectric property of a capacitor arrangement, and especially for capacitive examination of a moving elongated test subject such as yarn. It contains an alternating signal generator for applying an electric alternating signal to the capacitor arrangement. The capacitor arrangement is uncoupled from the alternating signal generator by means of an amplifier in such a way that it does not relevantly influence the basic frequency and the signal shape of the applied alternating signal. Detection means detect an electric measuring variable of an electric signal tapped from the capacitor arrangement. The alternating signal generator is set up in such a way that at least one of the basic frequency and the signal shape of the applied alternating signal can be changed.

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Winterhur, Switzerland

Reto Gehrig