Detection of Rotor-Stator Contacts Using Continuous Wavelet Transform

Large rotors used in power plants, turbo-compressors, and transmissions are susceptible to rotor-stator contacts, leading to undesirable consequences such as shaft heat bending and redistribution of rotating unbalance. To address these issues, this study aims to detect the contacts (rubs) to understand better the non-linear behaviour of these complex systems and, most importantly, to make an early warning for these states that can cause undesirable rotor behaviour. When the rotor impacts the stator at the contact point, waves propagate through the structure. This study employs an experimental approach to detect the contact within these structures utilizing an array of sensors placed along the shaft to measure the relative velocity between the stator and rotor. Simultaneous measurements of vibration waveforms at stationary sensors enable the recognition of the impact waves. This work introduces an enhanced method for detecting rotorstator contact by combining the continuous wavelet transform with the denoising procedure using the 3σ rule and soft thresholding.