Vibration Analysis

Simply stated, Vibration Analysis is a technology that correlates the health of a machine with it’s vibration signature. 

Shaft movement is monitored using displacement probes if pre-fitted to the machine. Alternatively, (or additionally if probes are fitted) an accelerometer (typically), fitted to the bearing housings of a machine is used to acquire the vibration signals. These signals are then processed and the data is viewed, generally using an FFT spectral plot. 

Much useful information on the health of the machine is derived from this data. Through extensive knowledge of what should and should not be present in a machine’s spectra, (as well as by contrasting the data to previous readings taken on the machine or on identical machines) a qualified analyst determines if there is a problem developing in the machine. What frequencies are noted in the vibration spectra, the amplitude (how much vibration) of these frequencies, and the extent that the reading has changed (if previous data is available) are all criteria for what kind of problem (if any) is developing in the machine and how severe the problem might be. 

Changes in vibration levels measured on the surface of a machine are the result of changes, either in internal forces within the machine, or external forces acting on the machine. These forces, and therefore vibration levels, increase when the condition of the machine deteriorates – due to unbalance, misalignment, bearing & gear tooth wear. High vibration can also arise from resonances or structural modifications such as corrosion, structure and foundation cracks, coupling resonances, etc.