As the sun works its way across the skies, the shadows it casts can become long and influential. This is especially true on walls where a soffit or overhang can shade the upper part of a wall but not the lower. This is obvious to anyone looking at the exterior (above image), although even there you may see, thermally, the time lag of the moving shadow (see the shades of blue (image right) at the red line).
Refractory is the type of insulation used in high heat applications such as boilers and furnaces. It is usually installed in brick form and this material is subject to degradation during normal use. Infrared thermography is a very efficient method of inspecting refractory insulation while it’s in use, and therefore not disrupting operations. At what point do we determine that refractory insulation is missing or damaged and in need of repair? The simple answer to that question is, whenever there is a difference in temperature across the outer surface of the vessel.
We have all grown dependent on power being delivered reliably and continuously whenever we need or want it. Many utility system assets are both aging and being loaded past anything previously imagined. Replacement equipment, especially transformers, may be months or years in construction and delivery. The cost of a failure in the grid can, as a result, have costly, even devastating, consequences.
Understanding the differing insulation classes, and limitations for each is an essential part of an effective reliability program. The operation of motors within the designed parameters of their insulation class can yield significantly increased reliability and motor longevity.
Los efectos térmicos de la acumulación de polvo y suciedad en las superficies de los equipos no solo podrían afectar el patrón térmico al momento de inspeccionar equipos mecánicos, también podrían afectar el funcionamiento de los mismos. En la imagen de la parte superior se puede observar un motor eléctrico sobrecalentado (300°F/149°C), esto debido a que el sistema de refrigeración de dicho equipo estaba bloqueado.
In the last part of our three-part series, we will discuss insulation materials and summarize what we have learned about destructive elements that can cause deterioration of materials and failure of building assemblies. There are four different physical mechanisms that can cause moisture to affect surface temperature. We will address the fourth of them in this tip.
4. Moisture detection through increased conductivity
Electric motor testing has developed into a preeminent technology. Utilizing test instruments for analyzing de-energized and energized motor data can avert catastrophic failures of critical motor assets. A motor testing programs success is going to be determined by how much of the motors operational parameters can be monitored. Motor test equipment’s provide considerable data, however, one area that is not or is under utilized is monitoring motor starts or in-rush.
The visual image above is a duct of a transformer showing no visual indication of heat-related failure.
Using thermal imaging to determine both the source, cause, and severity of a hot spot isn’t always easy. Just because you see a thermal anomaly doesn’t necessarily mean you have located the source of the abnormal heating. In almost all cases, thermographers are only detecting heating that has by some method of heat transfer, conduction, convection, or radiation, migrated to an area where they have a direct line of sight.