Use of composite higher order spectra for faults diagnosis of rotating machines with different foundation flexibilities

It is commonly observed in practise that rotating machines installed at different plant locations often exhibit different dynamic behaviours, due to variations in the flexibilities of their supports, which often affects faults diagnosis. In the current study, a similar scenario has been experimentally simulated on a rotating rig with different foundation flexibilities. Also, different faults were experimentally simulated at different machine speeds so as to develop a reliable diagnosis technique that will be suitable for different machine foundations. Recently developed data fusion methods for constructing composite spectrum (CS) and composite bispectrum (CB) for a machine are again applied for faults diagnosis here. In addition, the present study introduces the composite trispectrum (CT) as a new feature for diagnosis. The paper hereby presents the computational concepts of all composite spectra, rig details, data analysis and diagnosis.