Vibration Study for a Subassembly – Part of Hydraulic Turbines

A common problem with hydraulic turbines is the rupture of turbine horizontal shaft in the area between the rotor and its bearing, caused by different stresses [1], as well as problems caused by excessive bearing wear, vibration caused by instability of lubricant film from bearings, lubrication supply interruption of hydrodynamic bearings, gripping, decrease of bearing stiffness due to fatigue of supporting structures. In addition, during operation, vibration appear depending on exciter forces or bearing type. In present paper we present an analysis of vibrations measured on a subassembly found at hydraulic turbines. For the experimental subassembly was used a straight-lined shaft, having variable cross-section, and a sliding type bearing. The tests were made for bearings of different dimensions and materials. Vibrations were measured on two axes for established case studies and results were compared.