Using operating data to locate and quantify unbalance in rotating machinery

Abstract

In a previous paper entitled Using Operating Deflection Shapes to Detect Unbalance in Rotating Equipment [Ganeriwala, S.N.,Schwarz, B.,Richardson, M.: Using operating deflection shapes to detect unbalance in rotating equipment. In: IMAC XXVII, Orlando, February 2009], we introduced the idea of numerically comparing currently acquired operating data with archived data to identify unbalances in rotating machinery. In a follow-up paper [Richardson, S.,Tyler, J.,McHargue, P.,Richardson, M.: A new measure of shape difference. In: IMAC XXXII, 3–6 February 2014], we introduced a new metric for comparing two deflection shapes called the Shape Difference Indicator or SDI. In this paper, we introduce a refined version of the SDI algorithm, and present new results to verify its utility for locating and quantifying unbalance in rotating machinery. We make two underlying assumptions about rotating machines; (1) all rotating machines are excited by inherent unbalance forces which cannot be directly measured, and (2) order-related vibration levels acquired from multiple locations on a machine can be directly correlated with specific unbalance conditions. We show that by comparing current with archived ODS data, specific unbalance conditions can be pinpointed.