Electrical and Mechanical Inspection Applications
Electrical inspection
Electrical thermography looks for resistance heating at connections, overloads, imbalance, harmonics and insulation defects. Findings depend on current: with no load there is no heating, so always record load and, where possible, express results as a rise above ambient and a delta between similar components on the same phase set. Compare like with like: same component type, same load, same emissivity, same wind exposure. Safety governs everything: arc-flash boundaries, appropriate PPE and permits apply before any enclosure is opened.
Mechanical inspection
Mechanical work covers bearings, couplings, misalignment, belt drives, gearboxes, lubrication, motors, insulation, refractory, tanks, piping and steam traps. Patterns matter more than single values: a bearing running hot shows a local footprint at the housing; a failed steam trap shows a continuous temperature profile where cycling is expected; missing insulation shows a sharp-edged hot or cold band following the cladding.
Traps
- Reporting a hot spot on a de-energised or lightly loaded circuit as a fault.
- Comparing components at different loads or with different surface finishes.
- Quoting absolute temperature instead of rise over ambient.
- Ignoring solar gain, wind cooling, or reflections from adjacent hot equipment.
- Assuming any warm bearing is failing, without a baseline or trend.
- Missing that loose-connection heating is concentrated at the joint while overload heating runs along the whole conductor.
Worked example
Three identical feeder connections under the same load read 42, 44 and 68 C at 25 C ambient. The third shows a rise of 43 K against 17 to 19 K for its peers, a delta of about 24 K. Typical qualitative guidance treats a delta above roughly 15 K between similar components as a deficiency requiring prompt repair, so this is flagged and re-inspected after corrective work.