Rotor Balancing: Theory and Application

This textbook was written for engineers and technicians who work or are planning to work on balancing rigid or flexible rotors, either in a production line or in the field (in-situ balancing). Chapter I reviews necessary mathematical concepts, such as vectors, moments, complex numbers and Fourier transform. The concepts of vectors and complex numbers must be very clear in order to understand some of the topics in subsequent chapters. Chapters II, III and IV describe balancing in detail. Chapter V presents the different mathematical methods and graphical methods for the solution of balancing on one plane. Chapter VI describes a graphical and a mathematical procedure for solving balancing in two planes. It is very important to understand the graphical method, otherwise we cannot really say we are able to balance. Even though now a days all the balancing calculations are done by electronic equipment, these calculations are based on a lineal response of the entire system, which is not always the case. So, when the weights suggested by the equipment do not solve the unbalance, we need to resort to using the graphical method manually. Chapter VII presents practical aspects of balancing that I have learned during over 40 years of field work. Chapter VIII describes balancing equipment. Chapter IX deals with balancing of flexible rotors. It described two different methods: modal balancing, and balancing with influence coefficient. Finally, the Appendices include tables and charts that are useful in the process of balancing, and Appendix G includes the User Guide for a computer program that performs balancing calculations for rigid and flexible rotors.