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Another simple fan for the Adapteva case

PostPosted: Sun May 04, 2014 7:15 pm
by Dr.BeauWebber
I like the tiny 5V fans that some people are using, but could not find one in my Canterbury Maplin.
However they did have a couple of different 40mm x 40mm fans, and I went for the (cheaper) slimline brushless one -see picture 1.
12V slimline brushless fan from Maplin.
P1180726_fan-on-card_cr_en_lo.jpg (66.9 KiB) Viewed 7590 times

I have simply mounted it outside the case using super-glue (my home tool-box was over in my lab for the long-weekend), and so-far just covered the appertures each side with clear tape.
The 12V fan mounted on the case.
P1180733_Case_with_fan_lo.jpg (98.38 KiB) Viewed 7605 times

This is a 12V fan, and I am currently powering it from an old external USB drive supply. However it seems to run fine on 5V, almost silently, and after the weekend I will borrow a digital temperature monitor from my lab, and check the heatsink temperature running off 5V. If that is OK I will wire it into the case as per the 5V designs.

[Edited] :
Ah, of course, the FPGA has an on-chip temperature sensor. And in the Parallella example program directory there is an already compiled temperature grapher program : xtemp.

I ran this, first with 12V applied to the fan : ~59C
then with the fan stopped : the temperature rows rapidly to over 70C and was still going up rapidly,
then with 5V applied to the fan : the temperature stabilised around 69C,
and then with 12V applied again, when the temperature again dropped.
This is when basically idelling - a few windows open and xtemp running.

Temperature graph : xtemp.
P1180736_xtermp_en_cr_lo.jpg (71.41 KiB) Viewed 7590 times

So the question is, is about 70C OK, running from 5V ?
Or should I go back to 12V ? I might see if a bigger heatsink helps.

Re: Another simple fan for the Adapteva case

PostPosted: Mon May 05, 2014 1:29 pm
by Dr.BeauWebber
Well I have added a second slimline 12V fan, running them push-pull (both facing the same way).
As before, the appertures both sides of the fans have been blanked with clear tape.

Running them both off 12V gives a temperature of about 55C.
Running them both off 5V gives a temperature of about 65C. which is I think fine.
See the temperature graph using xtemp :

Graph of temperature, initially 12V, then 5V.
P1180740_2-fan_rot_cr_en_lo.jpg (75.22 KiB) Viewed 7578 times

So connecting the fan leads to the 5V jumper and an earthed mounting hole, the system looks like as follows
- and runs whisper quite off the 5V :

Standard Adapteva case with 2x 12V fans running off 5V.
P1180742_cr_br_lo.jpg (92.92 KiB) Viewed 7578 times

A final thing one could so is use Arctic silver heatsink compound on the heasink which can reduce the temperature a few degrees further, see thread