Blind sensing [eddy current sensor]

Describes a precise and accurate noncontact measuring device based on eddy currents. It is based on the principle that when an oscillator induces an eddy current in an electrically conductive target, the circuit loses energy. It works at high speeds, is nonoptical and is impervious to variations in temperature and other ambient conditions (oil, dirt, water, electromagnetic fields etc.). Electrical runout (inhomogeneity) disturbs the propagation of the eddy currents and affects the transducer output, which in turn results in noise and degraded resolution, but this effect can be reduced by an appropriate design. The sensors are used for various measurements, including distance, thickness, deflection, position, eccentricity, shaft run-out, imbalance, lubrication gap, vibration, deformation, valve stroke, compression gap, wear, shaft oscillation, shaft elongation and centring. The sensor has frequency output distance measurement; thickness measurement; deflection measurement; position measurement; eccentricity measurement; shaft run-out measurement; imbalance measurement; lubrication gap measurement; vibration measurement; deformation measurement; valve stroke measurement; compression gap measurement; wear measurement; shaft oscillation measurement; shaft elongation measurement; centring measurement;