Method and apparatus for online condition monitoring of variable speed motor applications

Abstract

The subject matter disclosed herein describes a method and system to monitor and identify vibrations in a rotational mechanical system. Various fault conditions in a rotating machine operating at variable speeds may be identified, at least in part, by identifying the multiple of the fundamental frequency, or order, at which the vibration occurs. The orders of vibration present in a measured vibration signal may be determined by finding an order spectrum of a measured vibration signal in the position domain. A fault vector is generated from the order spectrum that identifies the magnitude of each order of vibration present in the measured vibration signal. The fault vector may be plotted on a radar chart to provide a visual indication of the type of fault present in the mechanical system. Evaluation models for each fault determines a probability and magnitude for each fault condition being present in the sampled vibration signal.