Synthetic Amplitude Spectrum and Its Extensions for Analyzing the Two Perpendicular Directional Vibration Displacement Signals of a Rotating Rotor

Abstract

Classical Amplitude Spectrum analysis and Full Amplitude Spectrum analysis exhibit deficiencies in analyzing the two perpendicular directional vibration displacement signals of a rotating rotor. The shape of Classical Amplitude Spectrum is influenced by the installing position of its sensor. Neither Classical Amplitude Spectrum nor Full Amplitude Spectrum can indicate the actual radial rotor vibration amplitude on every frequency. Therefore, the previous two methods are not convenient to be used in rotating machine diagnoses. To solve these problems, this paper proposes a new rotor vibration analyzing tool here called Synthetic Amplitude Spectrum (SAS). The paper discusses the principle of SAS analysis, provides the specific making process of SAS, and applies it to two other current important analyzing methods in rotating machine diagnoses, resulting in two SAS extensions. The two extensions include a short-time SAS array tool for rotor vibration time-frequency analysis and a SAS waterfall plot tool for analyzing rotor vibration during machine startup or shutdown. The experiments and theoretical analysis showed that SAS and its two extension methods are not influenced by the installation position of the two sensors, and each amplitude of the spectrums can represent the actual radial rotor vibration amplitude on the frequency.