CONDITION MONITORING OF GEARS UNDER CYCLIC STATIONARY AND NON-CYCLIC STATIONARY LOADING CONDITIONS

摘要

In recent years the online monitoring of large capital equipment has received greater interest. A continuous flow of diagnostic information can be used to improve the maintenance, production utilisation and the life expectancy of capital equipment. The majority of capital equipment in the mineral mining industry operates under fluctuating load conditions that modulate the measured vibration signals and instantaneous shaft speed signals. Load modulation will deteriorate the repeatability of measurements and may conceal diagnostic information when using conventional vibration monitoring methodologies. The combination of rotation domain averaging and load demodulation normalisation has been shown to improve the repeatability and diagnostic capability of vibration monitoring under fluctuating load conditions. A further in-depth study on the cyclic stationary nature of the loading is presented. Three regions are defined namely cyclic stationary load modulation, non-cyclic stationary load modulation and an intermediate region where economic feasibility determines the methodology used to reduce the negative effects of load modulation. A mathematical model of a gear system was developed to illustrate the principals and a non-cyclic stationary load modulation experimental case study is presented.