Abstract

The article presents results of the vibration analysis of the rundown process of a large-power turbine set at the presence of the bearing lateral dislocation defect. Numerical calculations were carried-out, with the aid of a package of MESWIR codes, on a model turbine set in which the bearings had been dislocated by the maximum permissible range with respect to the kinetostatic catenary of rotors. The results are presented in the form of cascade diagrams of the relative and absolute vibrations of an examined bearing set vs. rotational speed during the machine rundown. The research makes it possible to formulate a system of diagnostic relations connected with the bearing lateral dislocation defect, which can make the knowledge basis for a diagnostic system. It has been found that the dislocations of certain bearings in certain directions may make vibrations go beyond permissible regimes during machine rundown, even in cases when the vibrations have been within the limits at nominal operating conditions. Determined were most vulnerable location points and dislocation directions of the bearings, along with accompanying symptoms.