Control of the rotary equipment disbalance by the spectrum of envelope vibroacoustic signal

Abstract

© 2018, Institute of Advanced Scientific Research, Inc.. All rights reserved. Rotor equipment (electric motors, pumps, fans, compressors, etc.) is widely used in almost all industries. One of the most common defects of such equipment is the rotor imbalance. The imbalance arises as the result of the action on the centrifugal force and is manifested by the rotor vibration increase in the radial and axial direction. There can be the following imbalance causes: rotor material heterogeneity, manufacturing and assembly errors, the wear of assemblies, the settling of polluting particles, etc. The article considers the method of rotor equipment imbalance control along the spectrum of the vibro-acoustic signal envelope. The method is the following one. Using a bandpass filter, a signal is extracted in a narrow frequency range. Then the received signal is detected (its envelope is allocated) and spectral analysis is carried out. In this paper, we propose the technique to analyze the envelope spectrum of a vibro-acoustic signal. The package of applied programs and an information and measuring complex was developed. Experimental studies were carried out on an axial fan. The imbalance of the fan was created by its attachment of loads to its blade. It was determined that at the absence of fan imbalance only background components with similar levels are present in the envelope spectra. In this case, there is the symmetry of the amplitude distribution in the envelope spectrum relative to their mean value. With the appearance of an imbalance, this symmetry is broken, discrete components appear in the envelope spectrum. The comparison of the central moments of the third order of the envelope spectra makes it possible to determine the degree of the imbalance development.