Heatsink Position, Temp, and Vgs - Page 3 - diyAudio
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Old 14th November 2006, 02:23 PM   #21
sajti is online now sajti  Hungary
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And the 3rd is about the different mounting of the heatsinks:
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Old 17th November 2006, 04:14 AM   #22
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Quote:
Originally posted by MattM
Thanks for the replies!

Yes, I am using these.

I plan to mount 3 devices per heatsink (two heatsinks per monoblock). The heatsinks will be mounted with the fins running vertically. In that orientation, they are 12" tall, 5.8" front to back, and the fins are 3" wide. Each heatsink weighs 5-1/2 pounds and has 16 fins. They are Wakefield Engineering part number MD387A, but I can't find them on their web site so they may have been a custom item. They are closest to extrusion profile 8415 - here is a link with some specs.

They will have air space under them, so I am expecting natural convection to create quite a healthy air flow across the 12" height.

Maybe the answer is simply to mount the devices at the same level. I had originally planned to spread them out across the heatsink (as depicted in the "wrong" half of the diagram below). While mounting them close together may or may not make them run a little hotter, at least they will all be at the same temp.
Hi,

Looking at the heatink profile it hardly matters but I would tend to distribute the devices 2 inches apart vertically. The thickness of the heatsink to provide conservative temperature gradients across the heatsink. In terms of thermal performance Convection is proportional to width and to the square root of length.

If provided in the specification attempt to provided temperature correction factor K(T) ie The hotter a heatink becomes the efficient at higher temperatures it becomes .
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