Blade detection sensor having an active cooling system

Abstract

A passive blade detection sensor exploits the electrically conductive trait of typical turbo machinery components such as fan, compressor and turbine blades. A permanent magnet is placed strategically adjacent to a wire coil to generate a single pulse/antipulse signal when a blade passes in front of the sensor. The electrically conductive blade allows eddy currents to flow briefly as it passes through the magnetic field, the local reluctance is momentarily increased, and the magnetic field is momentarily changed. The coil is sensitive only to the portion of change through its cross section, so that a simple voltage pulse, useful for precise timing of blade passage, is produced. The present disclosure also describes an open-loop and closed-loop active cooling system. The cooling system includes a casing, having internal sensing components and an inlet, coupled to one end of the casing. A cooling medium is transferred from the inlet into the casing, where the inlet is arranged to cause the cooling medium to travel around the components. An outlet is coupled to another end of the casing, where the outlet is arranged to direct cooling medium out of the casing. The cooling medium may flow freely or through a predetermined path within the casing.