A new condition monitoring technique is under development which is based<br/>on electrostatic charge. This was originally employed for the detection of debris in the<br/>gas path of jet engines and gas turbines, and is now being developed for lubricated<br/>systems. Previous investigations have demonstrated the viability of this technique in<br/>dry and lubricated tribo-contacts using laboratory-based equipment. This paper<br/>reports on the evolution of wear during a tapered roller bearing test, using a suite of<br/>condition monitoring techniques, that incorporated electrostatic wear-site sensors to<br/>identify charge during surface wear and oil-line sensors to detect debris in oil<br/>scavenge lines. The multi-sensor arrangement also included a vibration accelerometer,<br/>thermocouples, inductive and ferromagnetic particle counters. Additionally, oil<br/>samples were taken during various stages of the test and were analysed for sub-100<br/>?m debris content. Off-line debris analysis included optical particle counting,<br/>ferrography, spectrometric oil analysis and electron microscopy. Further tribological<br/>assessments included mass loss calculations and photographic evidence of damage.<br/>During the initial 7 hours, running-in wear was identified by dynamic wear site<br/>charge, acceleration and temperature. Also at this time, increases in oil-line charge<br/>correlated with debris detection by the inductive sensor, optical particle counter and<br/>ferrographic analysis. Following running in, benign wear was indicated by a reduction<br/>in wear site charge, acceleration and temperature, as well as reductions in oil-line<br/>charge, inductive and optical particle counts. Around 42 hours, increases in inductive<br/>and optical particle count were considered to be an early indicator (or precursor) of<br/>the impending wear out phase. At 53.5 hours, wear out was identified by increases in<br/>wear site charge, acceleration and temperature. Evidence of wear debris was shown<br/>by increases in oil-line charge, inductive and ferromagnetic particle count. The debris<br/>was further corroborated by optical particle count, ferrography and spectrometry. The<br/>test was then stopped after 63 hours and post-test analysis confirmed outer race and<br/>roller spallation
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.