Peltier Plate ID please...

[Les Hemmings]

Hi Chaps )

I've found a peltier plate ... white ceramic plate 4cm x 4cm x .5cm with +
& - leads.

Markings are LN/127068 (last digit may be a 'B')
and HL 03/02/17

Extensive googling hasn't given me a match anywhere except for some visually
similar.

Does anyone know how I could find out what voltage / amps this thing needs?

Any specs at all would be very handy! )

Cheers!

Les (thinking CPU cooler, car drinks cooler, night light for a hot bath
widget and generally playing around with it! First one I've ever come
across!)

 

[Lostgallifreyan]

"Les Hemmings" <l.c@v.n> wrote in news:7h7fa3F2schkiU1@mid.individual.net:

Hi Chaps )

I've found a peltier plate ... white ceramic plate 4cm x 4cm x .5cm
with + & - leads.

Markings are LN/127068 (last digit may be a 'B')
and HL 03/02/17

Extensive googling hasn't given me a match anywhere except for some
visually similar.

Does anyone know how I could find out what voltage / amps this thing
needs?

Any specs at all would be very handy! )

Cheers!

Les (thinking CPU cooler, car drinks cooler, night light for a hot bath
widget and generally playing around with it! First one I've ever come
across!)

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]

Lostgallifreyan wrote:

"Les Hemmings" <l.c@v.n> wrote in


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.

Have a 14v 3 amp (5 amp surge) supply handy... might need something beefier
perhaps?

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.

Nope... sealed.

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.

Time to raid the old pc bits box for a heatsink then i think!

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.

Designed for cooling. Taken from the broken casing of a mini fridge that was
put out for the rubbish.

Might go back and see what else is salvageable now i know what i'm looking
for.. ie; power supply, heatsink, fan etc.

Thanks for the help ) Much appreciated!

Les

--
http://armsofmorpheus.blogspot.com/

Rev. Les Hemmings (First Church of Atheism) aa #2251

http://firstchurchofatheism.com/

 

[Lostgallifreyan]

"Les Hemmings" <l.c@v.n> wrote in news:7h7purF2sjs20U1@mid.individual.net:

Lostgallifreyan wrote:
"Les Hemmings" <l.c@v.n> wrote in


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.

Have a 14v 3 amp (5 amp surge) supply handy... might need something
beefier perhaps?

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.

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.

Nope... sealed.

Sounds like it could be from a small portable fridge.

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.

Time to raid the old pc bits box for a heatsink then i think!

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.

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.

Designed for cooling. Taken from the broken casing of a mini fridge that
was put out for the rubbish.

Ha! Score one. If you can see the sticker on it to tell you power
consumption you can refine the estimates for device specs.

Might go back and see what else is salvageable now i know what i'm
looking for.. ie; power supply, heatsink, fan etc.

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.

Thanks for the help ) Much appreciated!

Les

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.