engleski

Rotor-stator partial rub diagnosis using Hilbert Huang transform

Rotor–stator rubbing is occasional problem faced by rotating machines especially during startups and shut downs when passing through their critical speeds. The rubbing often occurs in rotating machinery at position with small clearances and can sometimes cause catastrophic breakdown of machine. So it is important to develop reliable tools for rub diagnosis. This paper investigates partial rub occur-rence during constant and slightly variable speed operation and try to define vi-bration diagnosis patterns for its detection with Hilbert Huang Transform (HHT). The HHT is relatively new method which includes Empirical Mode Decomposi-tion (EMD) and the Hilbert Transform. Diagnostic tool is tested on laboratory test rig for rotor to stator contact dynamics research at two different rotor operat-ing conditions i.e. without rotor–stator contact and with partial rotor–stator rub. Measurements were performed with non-contact eddy current displacement sen-sors. Results are presented in the shape of HHT spectra of Intrinsic Mode Func-tions (IMF) and are compared to classical FFT spectra and spectrograms based on Short Time Fourier Transform (STFT). Rotor orbits are also presented to ad-ditionally verify rubbing condition.

Rotor-stator partial rub; fault diagnosis; Hilbert Huang transform; Empirical Mode Decomposition

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