Diagnostics procedure for identification of rubs in rotor bearings

It is well known that old design high-power generating machines were on duty for more than 35-40 years and will successfully continue operation after proper renovations and overhauls. this paper considers vibrational characteristics of the old continuously operated 110 mw turbounit with steam turbines and electric generator rotating system running at nominal speed of 3000 rpm. vibration and technological parameters were systematically monitored in the course of 5 years after installation of condition monitoring and diagnostics system, which is based on measurements of rotor relative vibration displacement. it is demonstrated that application of optimized vibration monitoring and diagnostic system and several vibration data formats is effective in evaluation of overhaul quality through vibration severity of rotor system and identification of causes of these vibrations. the research focus in the reported research work is placed on inspection of mechanical effect of horizontal rotor-to-stator rubbing in upper part of journal bearing. the validity of the results is verified during overhauls and renovations, and can reduce the possibility of bearing failures