Cooling an external controler

[Hastings]

I have not modified my controller in any way but as I wanted to weatherproof all the wiring. I noticed that the poor cooling was made even worse by me encasing it in a stainless steel battery box so.....
I sanded down the rudimentary cooling fins, attached the controller to a 4 mm alu plate and then added 2 old CPU coolers to the outer surface. Now it is never more than lukewarm.
From what I read in the discussions there is no cooling paste for the Mosfets on the inside so it might still be warm in there .... But for you who wants to modify the shunt this is the way to go with the heat sink problem

[Leslie]

http://amasci.com/freenrg/iontest.html#six

Stuff we are working on now.  Just interesting how science is going to change engineering.

"HIGH WIND-CHILL FACTOR: Charged air should attract itself to any grounded metal object (and be discharged as the ions touch its surface.) But objects normally have a "boundary layer" of unmoving air which adheres to their surfaces. This air acts as a thermal insulator. It is stripped away by high winds (above 50MPH generally), and this is the origin of the "wind-chill factor". Even when flowing slowly, ionized air has maximum wind-chill factor, since it dives right down to a conductive surface and penetrates the boundary layer. If a gentle stream of charged air is directed at a red-hot metal object, the stream of air will cool the object as if its velocity were around 50MPH! Charged air causes anomalous cooling of hot objects and anomalous heating of cold objects (but only for conductive objects. Insulators would quickly gain a surface charge and thenceforth REPEL the charged air.)"

 

[Morgen 3Eman]

Hi Les,

Bill Beaty?  "It is advantageous not to be too skeptical"  is the quote I remember from him.  When I suggested he should believe he can fly, and give it a try, he never got back to me.
 
As an easy start, wind chill is caused by evaporative cooling, not some magical ionic flow.  With all the crap he has put out, some of it is probably right, but certainly not this .

TTFN.
Dennis

[Leslie]

http://img200.imageshack.us/img200/8351/2dsc02323.jpg

Yer sorry, wrong link, I know of those who fall upon old discoveries and or misconceptions and brandish them as some new weird thing. But some times we understand these things personally.

We reinvented wheel too often, its pointless inventing these days.  But this one is real.  You like a more technical explanation.

Link excerpt>

"In the presence of a pre-existing bulk flow, an ionic wind can modulate the boundary layer, and, when aligned with the flow, it will accelerate the flow, thinning the boundary layer and enhancing convection. This area has received significant attention for drag reduction in aeronautics, often using dielectric barrier discharge plasma actuators [9]. Figure 3 shows infrared thermographic images of a heated glass plate when cooled by only natural convection, a low-speed pre-existing bulk flow (0.3 m/s), and a corona discharge ionic wind enhancing the bulk flow. For a constant heat flux of 4 W, when the bulk flow was superimposed with the ionic wind, an additional ~20 K of convective cooling was obtained"

Cheers.

[Morgen 3Eman]

Hi Les,

I'm sorry to be a thorn in your side again.  I really don't mean to be, but what does all that mumbo-jumbo have to do with the fact that Hastings was clever enough to make a huge increase in the surface area of the heat sink for his controller, with a concomitant drop in controller temperature?  He probably added several square meters of heat transfer area to his controller.

TTFN,
Dennis

[Morgen 3Eman]

Hi Hastings,

What got lost while Les and I were whining, was :
How did you physically attach the extra bits so you could get good thermal contact and thermal transfer? 

I already said I was sorry for disagreeing with you, Les.  I know you don't like it very much, but we just see the world in dramatically different ways. I have personally conceived, designed, built and put into daily usage plasma systems for manufacturing semiconductors, and I don't remember measuring much ion flow in the wind going by the heatsink I call my head.  But I do remember my skin freezing as I walked to school in the windy North Dakota winter and being warmer when most of my body was covered up, reducing the surface area available for heat transfer.  I remember my skin and body feeling cooler when I took my shirt off in the  warm summer breeze, increasing the surface area available for heat transfer.    If your results are different from mine, I have to guess that things are different in Oz.  I didn't notice the difference when I visited , though. 

How about we each agree that we are both taller, smarter, and better looking on the internet, and call it good.  And please feel free to disagree with anything I put up here.

I'll shut up now.

TTFN
Dennis

[Morgen 3Eman]

I forgot to say Thanks for the link to the plasma actuators.

Thanks, Les.  I found the article interesting, and thought provoking.

TTFN,
Dennis

[Hastings]

Sweden where I live, have had a hot summer without much Ion wind, but my coooler worked anyway....

The heatsinks come from pentium processors. They probably are larger than they had to be. I used processor heat transfer paste ( zink or titanium oxide)  in three layers : between the alu profiles and the stainless steel box, between the steel and 4 mm alu plate and finally between  the  plate and controler.  I drilled and treaded  the alu plate from two sides  for M4 screws. expoxy in the treads keep them from vibrating loose

[Morgen 3Eman]

That sounds like a good heat transfer plan.

TTFN,
Dennis