VARIABLE RELUCTANCE SENSOR WITH NOISE ELIMINATION

摘要

A system and method for sensing the periodic proximity of one or more objects, such as the relating blades of a gas turbine. The system includes a passive eddy current sensing unit (variable reluctance sensor) having first and second magnets and first and second coilwound cores coupled to generate and detect first and second magnetic fields The sensing unit is positioned relative to the object such that the first and second coilwound cores produce outputs in response to the object periodically passing through the first and second magnetic fields, respectively. Circuitry electronically combines the outputs of the first and second coil-wound cores to produce output signals corresponding to the proximity and timing of the object as it periodically passes through the first and second magnetic fields Electromagnetic interference noise (common mode signals) present in the outputs of the first aid second coil-wound cores is eliminated from the output signals of the circuitry.