I have come across much discussion online about Delta T and their importance. Some people consider low Delta’s to be irrelevant. I even came across the following statement “some people call for a repair with temperature differences of 5 Deg C. I say no need”.
From a personal point of view I consider it unprofessional to ignore low delta T’s like this. Our job as thermographers is to find potential problems, and highlight them. It is our customers job to decide if they want to carry out repairs and in which order. Not highlighting a problem eliminates the possibility that they might consider it a very important piece of kit, and critical to operations, it therefore limits their ability to carry out repairs according to their own criticality study. If an anomaly is detected and there is a thermal gradient, then this is a problem regardless as to how much the Delta is. The delta only serves to help classify the seriousness of the problem found while doing electrical thermography.
Below are a few images of a low Delta T electrical anomaly. As you can see the Delta is only 3.6 degC. The photos reveal how loose the connection is. To simply ignore this because the Delta T is low displays a huge lack of intelligence. Anomalies with even a very small Delta that clearly show a gradient are problems that do need to be repaired, or at least investigated. Choosing to do nothing whatsoever with problems is not up to me, my job, is to highlight them for my customers. It is up to them to decide what to do after that.