AN AUTOMATED METHODOLOGY FOR PERFORMING TIME SYNCHRONOUS AVERAGING OF A GEAR SIGNAL WITHOUT SPEED SENSOR

摘要

Time Synchronous Averaging (TSA) is a widely adopted pre-processing technique which offers noise reduction and removal of interference from other rotating components in a gearbox. However it requires a device for the measurement of the shaft speed. In this paper we propose an algorithm for performing TSA without the need of a speed sensor for a gearbox submitted to limited speed fluctuation. The method is based on narrow-band demodulation of one harmonic of the mesh frequency in the measured acceleration signal. We propose a solution to select automatically the best harmonic to use for the shaft angular position estimation. The TSA result is compared with that obtained when using a tachometer on an industrial gearbox used for wastewater treatment. The proposed methodology requires only the knowledge of an approximate value of the average shaft speed and the number of teeth of the gears. It forms an automated scheme which can prove useful for real time diagnostic applications based on TSA where speed measurement is not possible or not advisable due to difficult environmental conditions.