Influence of Bearing Alignment on Vibration of Multi-Span Rotor
Abstract This paper describes the influence of bearing alignment (vertical position) on vibration of multi-rotor-bearing system. The rotor-bearing system used in this study consists of three rotors and six bearings. It is designed to have the equivalent dynamic characteristics to the turbo-generator-systems for utility power generation plant. And it is equipped with alignment setting devices which can set the bearing alignment in vertical direction precisely without disassembling the test rig. It was confirmed that bearing alignment affects the rotor vibration. Some critical speeds and their peak amplitudes change. When the bearing alignment changes, the load of the bearing changes and it affects oil film characteristics. The calculated results considering this agree with the test results. The effect of the bearing alignment on the rotor vibration becomes large when the bearing load is about zero.