ROTATIONAL SPEED LIMIT OF ACTIVELY CONTROLLED JOURNAL BEARINGS AT STABLE LUBRICATION

: The paper deals with the stability of the journal motion in hydrodynamic journal bearings while actively controlling their vibrations by the position of the bearing bushing. The bearing journal motion can only be stable when lubrication is stable. The first chapter of the paper contains a description of the conditions for forming a stable oil film. The paper deals with the mathematical model of the journal bearing with a fixed and movable bushing. The analysis uses verified mathematical models in the form of motion equations describing the motion of the journal axis in the plane which is perpendicular to the rotor axis in contrast to the magnetic bearing; the equations are coupled. The stability analysis aims to determine the critical rotational speed of the rotor at which vibrations of the whirl type are generated. The stability analysis tool is the Nyquist Criterion.