A Novel Speed Measurement System for Turbomachinery

A novel speed measurement system for turbomachinery has been proposed. The electro-mechanical system is comprised of variable reluctance sensor(s) and a ferrous cylindrical drum that rotates around the magnetic sensors. The cylindrical drum incorporates axially extending fingers that are circumferentially located around the drum. These fingers deflect radially outwards away from the magnetic sensor as a function of increased rotational speed. The deflection and return of the fingers provides a voltage regulation function that dynamically limits the voltage output from the magnetic sensor within a desired output range for improved signal processing. These design changes have resulted in a speed measurement system that is optimized for low speed and high-speed operation. As a further benefit, the system has more engagement with the shaft while exposed to the axial displacement resulting from rapid acceleration or deceleration of the turbomachinery.