In most of my power converter applications, I end up with a choke of some description, somewhere in a steel chassis. I have seen and heard tell of situations where the choke couples to the steel of the chassis. In some cases, the windings heat up more than desired, as does some part of the box. In other cases, the box itself has the powder coat baked off the metal. The general solution has been to keep the windings away from the steel, as well as any core gap.
However, "away" is a vague term. Is there any rule I can follow to determine the safe distances required to prevent coupling? Example situations include:
- Distance between winding and steel box
- Distance between choke gap and steel box
- Distance between air core choke and steel box
I imagine that an exact solution is dependent on a detailed geometry of the system, so general rules are preferred.