D13 - Vibration analysis

Abstract

Vibration analysis uses vibration measurements taken at an accessible position on a machine and analyzes these measurements to infer the condition of moving components inside the machine. Overall level monitoring is the simplest method for vibration monitoring of complete machines. It uses the cheapest and most compact equipment. It has a disadvantage, however, that it is relatively insensitive, compared with other methods, which focus more closely on the individual components of a machine. The various components of a machine generate vibration at characteristic frequencies. If a vibration signal is analyzed in terms of its frequency content, it can give guidance on its source and therefore, on the cause of any related problem. This spectral analysis is a useful technique for problem diagnosis and is often applied when the overall level of vibration of a machine exceeds normal values. If monitoring a particular critical component is required, the measuring system can be turned to signals at its characteristic frequency to achieve the maximum sensitivity. This discrete frequency monitoring is, particularly appropriate for use with portable data collectors, particularly if these can be preset to measure the critical frequencies at each measuring point.