Rectifier heat sink

[oregon wind]

How would you heat sink this rectifier in a rain tight box like this?

The rectifier is 150 amp 6 or 600 volt.

[TomW]

If it is the box in this photo, what I did was cut a hole thru the back big enough to let the bridge mate with the heat sink, mount the heat sink to the back and the bridge to the heatsink. I "glued" the box to the heat sink with silicone caulk for weather seal.Mine is a PVC box.

Tom

[SparWeb]

I didn't try too hard to put the heat sink directly on the rectifier.  Instead, I mounted both through the steel panel.  I cleaned the paint off both sides of the panel, applied heat sink compound to both sides, and tightened them up together.  A bead of silicone caulk around the base of the heatsink keeps the moisture out.  The longevity of this arrangement is still a good question.  I have not taken it apart to inspect for corrosion since doing this 6 months ago.

[hamitduk]

I would be worried about the Al and the Copper not a good mix, in an environment with a lot of thermal change, they corrode, build resistance, get hot, burst into flames. That kinda stuff!

Hami

[Ungrounded Lightning Rod]

If the box is big enough I wouldn't bother with the aluminum fin assembly, but would just use the box itself as the heat sink.  I'd clean the paint off the inside and use heatsink compound against the inside of the box.

Sure the surface area in contact with the air is somewhat insulated by the paint and a steel box has lower thermal conductivity than aluminum.  But at 100A you're only dissipating about 120 watts.  So a moderate sized box exposed to the outdoor air should be adequate.

[TomW]

ULR;

Good point. Not useful with PVC as in my case tho.

I am paranoid about thermal issues.

Tom

[imsmooth]

I don't know if you have gotten your question answered, but I just build something similar.  It is in a water-tight Hammond box.  I used a carbide blade on my Dremmel to cut out a rectangle just slightly larger than my rectifier block.  The block is attached to an aluminum heat sink fin.  I put silicon II sealant around the heat sink where it attached to the outside of my box.  The rectifier's metal back has silicon contact paste to facilitate heat transfer to the heat sink and it is screwed to the sink.  The heat sink is screwed onto the side of my box.  If you want I can send pictures.

[oregon wind]

Thanks for your info.  Please send me pics

[Roger Stafford]

Sounds like you have alot of good answers, but I have a question where did you get the rectifier and heat sinks? I'm still tring to get my system together.