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Old July 30th 04, 05:26 AM
kony
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On Thu, 29 Jul 2004 15:51:11 -0600, "Chris Stolworthy"
wrote:


"kony" wrote in message
.. .
On Thu, 29 Jul 2004 04:26:03 -0600, "Chris Stolworthy"
wrote:

Hey guys I was just wondering if there is a better forum for asking

peltier
questions? I have another problem. I hooked up and tried both peltiers
independantly, the power supply I used was an Antec True Power 480.

Which
should have enough power to run 1 peltier. What I did was clipped a

spare
molex power add on cable I had and spliced the peltier in. I hooked the
yellow wire (12V) to the positive side, and one of the black (ground)

wires
to the negative side I jumpered the ATX connector to turn on the PSU.

Well
both my peltiers did the same thing, they get EXTREMELY hot on the hot

side,
but the side that is supposed to cool got about 5 degrees F, less than

room
tempature. So I let one run for 6 hours thinking maybe it just needed

time
to warm up? Oh and yes I did have a heatsink on them, it is one made
specifically for this peltier. Any ideas?

-TIA
Chris


First, measure voltage going to peltier. Some PSU need a load on
5V to stabilize output. That's not necessarily related to your
issue but I may not have mentioned it previously.

Peltiers cause a temp differential... you must keep the hot side
cooler for the cold side to be cooler. Ensure that heatsink is
very good, and making good interface to peltier. I presume you
had a fairly strong fan on it too, right? It shouldn't have been
extremely hot if you had it properly 'sinked and fan moving
enough air. Reducing hot side temp will reduce cold side temp.

Peltiers do not need break-in, warm up time beyond a few dozen
seconds to move the heat and have uniform temp.

Well I pulled a different heatsink out, this one came with my 2500+ barton.
I put the paste on the peltier, and hooked up the fan. Now the heatsink is
warm, but not hot, however the peltier is still not getting cold on the
opposite side...like I said before about 5-6 degree temp difference. Also
how can I put a load on the 5v line? I have read that it needs a 1 ohm load
for the 12v side to put out 12v.

-Chris


Don't know what to tell you about the temp "issue". If you have
a multimeter you might check the input voltage, input current,
and compare to the peltier's spec sheet. If it's probably 'sunk,
cooled on hot side it should be far lower than 5 below ambient
without any load. If on the other hand you meant it gets 5 under
ambient while cooling the CPU, that could simply be because the
single pelter isnt' sufficient for CPU it's cooling.

Load on 5V rail can be whatever you want... typically a power
resistor is used. It'll create 5W so you'd need load that can
dissipate that much heat... with power resistor it is wise to use
one rated much higher than actual wattage, perhaps a 10W or even
higher if it's mounting will be difficult to isolate it from
anything else (since it will get fairly hot).

Here's 10 of 'em for a buck, though they may have a minimal $
order requirement so could end up being more expensive that
elsewhere... don't think radio shack has any 1 Ohm that big but
you could put a few in a network (parallel and series for needed
values).
http://sales.goldmine-elec.com/prodinfo.asp?prodid=9336