"Les Hemmings" wrote in news: snipped-for-privacy@mid.individual.net:
That 127 in the first number is almost certainly the number of couples, so it's likely to work well on 12V DC. Vmax will actually be higher, around 14 or 15 volts but the best compromise for efficiency is to run at a tad lower than maximum volts/amps. Imax (max current) for a 40mm square TEC could be anywhere from 4 to 8 amps, with Qmax (pumping power maximum when both sides are at same temperature) can be anywhere from 32 to 72 watts. If you can see the elements between the ceramic slices (easy if it's not sealed with something to keep water out), look at the ratio of element width to air gap width. If it's about even (1:1) assume low power and current, if the elements are thicker than twice the air gap, assume high.
If you want to do general experiments, make sure it's not going to get water vapour in it for more that very short periods, as that degrades them. Also, hot spots and strong thermal cycling can degrade them, so first thing is to get a big chunky bit of heatsink with a FLAT surface, and use the thinnest smear of heatsink compound you can manage, between the TEC and the metal.
You might get a precise part identification from someone here, which I can't do, but what I said here will always help with working out specs for unknown TEC's. if you go to the Marlow and Melcor sites, you can find data books that will let you do this too, and maybe narrow it down further. The geometry and construction of a TEC will usually tell you more than the numbers written on it, unlike with transistors and IC's.
One thing that is worth trying to discover is whether it was built for cooling, or power generation. Most are for cooling, but if you have a power generating Peltier, you have something more interesting than usual. They are meant to run hot, wheres most TEC's will fall apart if they get to more than
136°C, and even running them at over 80°C is bad because the metal atoms migrate in the soldered junctions and degrade performance a lot within a few tens of hours.
"Les Hemmings" wrote in news: snipped-for-privacy@mid.individual.net:
Almost certainly. Remember you can program for volts OR amps, if you're setting Vmax you'll find it drawing Imax, near enough. I think there is some complex stuff like seebeck voltage that appears as a kind of back-emf-like effect but it's still a DC two-node network so basic rules apply. So set
12VDC as upper limit, give it all the amps it wants, and use a damn good heatsink. FLAT means milled, if possible.
Sounds like it could be from a small portable fridge.
Good call. Water-cooling blocks are often milled flat, and water cooling is the best way, for short experiments you can just use hose and vent the waste water to a vessel so you can use it for other stuff.
Ha! Score one. :) If you can see the sticker on it to tell you power consumption you can refine the estimates for device specs.
The fan will likely suck, best replace with a decent brushless ball-bearing type, but the rest should be ok. I repaired a fridge once, was just a open- circuit diode failure.
No problem. Helps keep sci.electronics.components alive as well. I still think if had been called 'applied' it would be a lot more active than it is now.
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