• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Metal Heatsinking for SMPS transformers suffers eddy current losses?

Not open for further replies.


Well-Known Member
We have a 3kw offline battery charger which we bought and they keep stopping working.
We therefore took it apart, and we noticed a 3kW LLC converter using a transformer of Epcos PQ35/35 dimensions and shape. (yes, it was really THAT small!)
Anyway, this transformer is thermally coupled to a 5mm thick aluminium plate heatsink as in the attached diagram.
Surely having a metal plate close to the open side of a high frequency transformer (the PQ35/35 core is not shielded) is going to result in too much eddy current heating in the aluminium heatsink?

Epcos Ferrite databook shows PQ35/35 core on page 281:



Well-Known Member
Most Helpful Member
It would only be the leakage flux that would cause eddy currents, and I would think that would be fairly small.
Not open for further replies.

Latest threads

EE World Online Articles