Rotating machinery diagnostics based on fusion of infrared and vibration measurements

Systems for on-line vibration diagnostics of rotary machines requires the installation of vibration sensors on practically each bearing. For a typical machine there are at least a couple of bearings to be monitored and for many machines to be monitored it generates considerable costs arising from the price of sensors, diagnostic modules, software and wiring. In this paper we discuss the possibility of reduction in the number of vibration measurement points, with occasional inspection with IR (Infra-Red) camera, which globally could reduce the system costs without compromising the quality of the machine diagnostic. A measurement stand modeling operation of a simple machine driven by an electric motor and a typical industrial vibration diagnostics system together with a thermal imaging camera were used for this purpose. It allows controlled induction of various defects that result in vibrations. Vibrations was measured with properly parameterized system for on-line vibration diagnostic, separately for each bearing. The research involved performing a few experiments, which modeled a typical defect in rotating machines: quasi static unbalance of the shaft, outer race defect of the bearing and cage defect of the bearing. The fusion of obtained IR and vibration information was discussed.