certain temperatures, some guidelines can provide consistency and help plant personnel make better decisions.
The first step should be to determine the actual temperature of the bearings being monitored. Keep in mind that the temperatures measured are only the skin temperatures of the bearing housings. The actual bearing temperatures will be 15-25 degrees hotter. Observe the surface condition and type when measuring temperature. Also, ensure the measuring device’s emissivity is correct for the surface being measured. Most dark carbon-steel surfaces will have an emissivity setting around 0.95, while shiny stainless steel or aluminum will have a much lower setting. A typical infrared camera shot is shown below.
Process buildup on bearing housings can result in lower measured temperatures when the actual bearing temperatures are much hotter. Buildup will insulate the bearing and not allow it to dissipate heat, which will in turn make the bearing run even hotter. Temperature checks should be performed in the same locations on the equipment and the bearings. Variations in bearing temperatures can be expected when different locations are measured due to load zones, ambient temperatures, lube levels, etc. Consistency is also important when different individuals are taking the measurements.