[hpsdr] Cooling.

[Ben Hall]

Good afternoon all!

+12 volts at 200 ma = 2.4 watts
-12 volts at 60 ma = 0.72 watts
+5 volts at 140 ma = 0.7 watts

Sum = 4 watts.  Let's up that to 5 watts, just for fun.  (Note that I'm 
neglecting the heat of the little power supply, for now.)

At 5 watts, all the cases I described in my last e-mail can be covered 
with a 20 CFM computer fan, easily!

Probably the 95 deg F (35 deg C) case can even be cooled by natural 
convection - at 1 CFM, the outlet T is 110.8 deg F (43.8 deg C).

Even the 110 deg F (43.3 deg C) case can easily be cooled with just 5 
CFM, for an outlet T of 113.2 deg F (45.1 deg C).

I also put in a 120 deg F (48.9 deg C) case.  With 10 CFM, the outlet T 
is just 121.6 deg F (49.8 deg C).  That's not bad at all.

If you go up to 10 watts, say to account for the little pico ITX power 
supply, a 5 CFM flow is all that's needed except for the 120 deg F inlet 
case.

I'm going to start a spreadsheet tracking power/heat.  Can the future 
board team leaders project power consumption?

thanks and 73,
ben


Bill Tracey wrote:
>  From memory, so don't take it as gospel truth:
> 
> For a Janus+Ozy playing SDR 1000 sound card
> 
> +12v draw: 200 ma or so
> -12v draw: 60 ma or so
> +5v draw: 140 ma or so
> 
> Don't believe anything is generating much heat -- warmest part is one of 
> the voltage regs on Janus that I'd classify as warm but not hot.
> 
> Bill

-- 
Thanks and 73,
Ben, KD5BYB


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