Hydro-quebec

Jean Marc Bourgeois

Marius Cloutier

Francedillaois Lalonde

Sylvain Savard

Francois Lalonde

A method for dynamic and non-contact measurement of the displacement of a conductive substance with respect to a capacitive sensor formed by two parallel conductive plates, superimposed, electrically insulated from one another, and fed by a high frequency signal having a predetermined voltage, the capacitive sensor being connected to a device for detecting a current value. Also disclosed is a method for dynamic and non-contact measurement of the permittivity of a dielectric substance between a conductive part and a capacitive sensor of the above-mentioned type.

Dynamic and non-contact measurement of displacement or of permittivity

A method and an apparatus for the dynamic and non-contact measurement of the distance separating the surface of a first part that may be conductive or not, from the surface of at least one second conductive part closely spaced from the first conductive part. The method resides in positioning, on the surface of the first part, at least one sensor including two conductive plates that are parallel, superimposed and electrically insulated from one another. The two plates of this at least one sensor are then fed with a same high frequency signal under the same voltage and the current generated by this high frequency signal, between the plate of the sensor which is closest to the surface of the second conductive part and this second conductive part, is measured. This measured current varying as an inverse function of the distance separating the surface of the second conductive part from the surface of the sensor which is closest to this second conductive part, it is then easy to determine the value of the distance separating the first and second conductive parts as a function of the value of the measured current. This method as well as the apparatus for carrying it out are particularly well adapted for measuring the air gap in any type of rotating machine such as an electric generator.

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Longueuil, Canada

Jean Marc Bourgeois