Rotor Orbits at Operation Speed and Model-Based Diagnosis of Multiple Errors

Measured and simulated orbits of the rotor deflection and bearing forces are applied to understand and separate the effects of multiple, simultaneous errors. Hereto, the paper firstly defines a clear terminology which is mandatory when dealing with multiple errors. The physics and mathematical descriptions of several errors are summarized and illustrated for the Jeffcott rotor model. Furthermore, a short introduction to orbit dynamics is given including force orbits. Based on these fundamentals, the authors present the theoretics of an online roundness error identification method. This method uses a Fourier decomposition for reconstruction the different components. One example recorded at an academic rotor test rig proves these methods.