Evaluation of the performance of infrared thermography for on-line condition monitoring of rotating machines

This study evaluated the possibility of infrared thermography to measure accurately the temperature
of elements of a rotating device, within the scope of condition monitoring. The tested machine was
a blower coupled to a 500 kW electric motor, that operated in multiples regimes. The thermograms
were acquired by a fixed thermographic camera and were processed and recorded every 15 minutes.
Because the normal temperature variations could easily mask a drift caused by a failure, a corrected
temperature was computed using autorecursive models. It was shown that an efficient temperature
correction should compensate for the variations of the process, and for the ambient temperatures
variations, either daily or seasonal. The standard deviation of the corrected temperature was of a
few tenth of degree, making possible the detection of a drift of less than one degree and the
prediction of potential failure.