Single and Multi-Plane Balancing of Rotor in Static and Dynamic Condition - A Review

Abstract

Static and dynamic balancing of a rotor plays an important role in deciding the life of any turbo-machinery. Vibrations generated due to unbalance rotor is considered as one of the major factors that can lead to accelerating degradation of machine components or even catastrophic failure especially at high speed where reliability is important consideration. Rotor unbalance may result due to error in manufacturing process, wear and tear of rotating component, thermal deformations, deposition of material on rotor surface etc. There are various static and dynamic balancing methods depending upon type of rotor. Different methods of rotor balancing requires different trial runs (number of times the machine has to stop) so as to place trial weights and measure vibration amplitude. This paper studies the number of trial runs required in various rotor balancing methods in static and dynamic condition. Any method which balances the rotor in less number of trials is considered to be the efficient one because stopping machine results in more energy consumption and reduction in machine life. It is normal human psychology to find and search for a method that solves the problem in least possible time and the work can be started again. The paper also includes the derivation of two balancing methods that has reduced the number of trial runs to a considerable number and also reviews the literature concerning the origin of various balancing techniques including the ones that use influence coefficient method, cradle balancing method, modal balancing method.