During a thermographic inspection it’s not always easy to detected problems cause by electromagnetic induction. In general, during an inspection we focus our attention on the electrical flow to found hot spot on electrical connections. A poor connection, has a bigger resistance and will generate heat.
The electromagnetic induction occurs on metallic pieces, that are affected by a magnetic field created by an electric current. It is important to note, that the infrared camera read the heat emitted by an material base on the emissivity of that material. The metallic pieces, usually has a low emissivity, that make hard to read the temperature of this pieces. Moreover, that, a piece with a low emissivity and a shinny finish, usually reflected as a mirror and they could reflect the infrared wave of another piece.
On the following thermogram, we could hardly read directly the temperature of the metallic structure. The temperature of the structure could be measured on the tie-wrap that maintain the cable (reference 1). It’s also possible to see the reflect of the infrared wave emitted by the surface of the cable near by the structure. (reference 2).
The phenomenon of reflection could also be observed at left of the picture, this part of equipment is the door cabinet. It’s the infrared wave reflect of the tie-wrap that maintain the cable.
In this case we recommended to distance the cables from the metallic structure, that will reduce the induction phenomenon and will avoid creating problem on the cable insulation.