Model i badania czujnika wiroprądowego

Praca przedstawia eksperymentalny model czujnika wiroprądowego oraz wskazuje częstotliwości pracy pozwalającej uzyskać maksymalną jego czułość. Badany czujnik przeznaczony jest do pracy w systemach obrazowania 2-D obiektów metalowych, a przeprowadzone badania mają na celu wskazanie warunków pracy pozwalających osiągnąć maksymalną strefę detekcji zależną od jego czułości.

The paper presents the principle of operation and experimental model of an eddy current sensor. The investigated sensor will work in systems of 2D visualization of metal objects. The aim of measurement experiments was to reach operation frequencies at which the sensor sensitivity is maximum, and to determine such conditions of work which allow getting the maximal detection zone of the sensor dependent on its sensitivity. In the preliminary research a circuit model of the sensor was formulated. It was pointed out that such a model has to be nonlinear in order to obtain consistence with verification measurements. The investigation results show that there are four resonances on the frequency characteristics. These points of characteristics are also points of the maximum sensor sensitivity. The maximum value of the amplitude-frequency characteristic resonance was at about 147 kHz which was the lowest resonance frequency and was chosen as a work frequency for scanning process. The final investigations deal with observation of the influence of the type of object on the sensor sensitivity. They show that the sensor sensitivity is higher under influence of nonferromagnetic materials.