New approach in machine shaft centering: Potential and prospects for future development

Lots of failures on rotating machines such as defects and faults on the bearings, bearings vibrations increase and others are, directly or indirectly, caused by an inadequate centering of a shaft. Mechanical imperfections like out of roundness and non-concentricity of the shaft in large hydro machines cause great stress on the bearings as well as on the shaft itself. The result from these imperfections, usually known as runout, must be reduced if it exceeds the recommended value. This paper describes methods for shaft runout measurement that are still in use today ; a plumb wire method and mechanical comparators method which are largely dependent on a vast human experience. And a new innovative method of measuring runout with a Slow Roll Instrument (SRI) which on the other hand measures these imperfections with no influence of a human mistake. It has proven to be a valuable and reliable instrument for quick and easy shaft alignment.