The Effect of Shafting Oscillations in the Turbo Unit on the Accuracy of Rotation Frequency Measurement

An analysis of the influence produced by torsional and bending oscillations of a shaft assembly on the accuracy of measuring rotation frequency is presented. Based on the obtained data about the level of fluctuations in the frequency measurement cross-section, an assessment was made concerning possible changes in the values of the measured frequency in various operational modes of a turbine unit. The dependences of frequency change on the damping and phase shift of oscillations are obtained. A reduction in the effect of torsional oscillations on the accuracy of frequency measurement can be achieved by selecting the location of frequency measurement in the nodal point zone of natural modes—in particular, in the span between the generator and turbine bearings. © 2022, Springer Science+Business Media, LLC, part of Springer Nature.