[Closed] Qu for the electronerds

I would imagine that motor is waaaaaayyyy overspecced!

I would see what power you can get out of the thermacouple first.

probably a good idea. will try and set up a test rig with a hot plate and a cold blowing hairdryer to get a c.60deg differential and see what I get out of it...

What should I look for in the motor spec then?

No idea, but I would expect the ones they use are 1-2W at most.
You will probably need a fairly low RPM too.

how are motors controlled? voltage?

I see I can get one of the ecofan replacement motors for £10 so might just use one of theirs?

The one in your picture is controlled mostly by magic. You'll need a special controller for it to generate AC signals rather than just plugging a DC voltage in.
One of these
[url]

Then you'll need some more magic to make that bit of magic work 🙂
Lipo batteries look fun though.
[url]

magic you say?

now Im really confused 🙁

Yeah I'd be inclined to get a conventional 2 wire DC motor.
However if you've got basic programming skills you could buy something like this [url]

that could be made to talk to the motor controller above by emulating RC servo signals.

Or buy one of these and a lathe for your shed:)
[url]

aha - I see, brushless, AC etc.

Right.

However if you've got basic programming skills you could by something like this

COOLCOMPONENTS.CO.UK "http://www.coolcomponents.co.uk/catalog/product_info.php?cPath=50_74&products_id=583"

that could be made to talk to the motor controller above by emulating RC servo signals.

ahhaahahha, ahahhahhaa.
Only if you can program it in Excel 🙂

right cheapo DC motor it is then.

He means it's a clever motor that needs a computer to control it! You can't just feed it DC straight off a battery. Looks like someting for a RC car really.

Anyway I would say buy the motor & fan blade from ecofan, it will probably be about right and save you from the R&D 🙂

That'd be good for cooling my toast in the morning.

http://shop.ebay.co.uk/?_from=R40&_trksid=p5197.m570.l1313&_nkw=dc+motor&_sacat=See-All-Categories

what RPM do you reckon? 200? 2000?

haha! How about this, hovercraft model fan 🙂

[img]

Type - GW/EDF64x6

Motor - EM150

Volts - 7.2 - 9.6v (11.1v can be used but will shorten motor life)

Amps - 4.4 - 8.3A

Thrust - 117 - 169g (201g @ 11.1v)

Weight - 69g

For testing i'd start with one of the very low power ones like this
[url]

The ratings of
Umax (V): 15.2V
I max (A): 9A

For the heat pump will be the maximum you can put into it, rather than what you get out.
If you're using it to generate electricity the figures will be a lot smaller - though I don't know what magnitude, but I'd guess around 50-100
There's some links off here to follow -
[url]

SPARKFUN.COM "http://www.sparkfun.com/products/10080[/url]"

If you are using a motor for a RC car/plane thing, then you will need a ESC (Electronic Speed Controller).

RC motors are rated in Turns, an 11 turn motor is more powerful than a 27 turn motor.

I would think you need to find out what voltage and current you are going to get first. Need to do this with a load on.

Once you know that and know how fast you need to turn the fan deciding on the motor RPM/V is the last thing needed.

You don't need to shy away from brushless motors. The motor and controller for the power you are talking may well be cheaper than a DC one.

good point.

Which is more likely to be fixed/steady in output from the thermocouple A or V?

What does it do actually??

I always thought the Voltage was dependant on the temperature differential between the hot and cold sides. bigger differential bigger Voltage.

Its been a long time since I had to think about anything like this but I am also thinking the Current is going to vary with the amount of heat applied to the hot side.

Best just have a play around and see what you get out of them i think. Once you got some figures choosing a motor ought to be simple.

Is that a stove fan ?

They are only £80 to buy, probably spend that on messing about, unless thats what the desire is of course ?

Oh, and it's geeks not nerds 🙂

They are only £80 to buy, probably spend that on messing about, unless thats what the desire is of course

well duuurrr 😉

cheers for the help guys.

I think my old mans got an old brass billet somewhere I can use as the conductive stand onto which I can attach the TEC. I can then thermopaste a modded heatsink on top of that with the fan in it/on it once Ive found out the output from the heat rig.

fun fun fun....

Did you ever get anywhere with this?

blimey.. retro thread!
But yeah, this is mine:

It works and it was fun to make, but its probably about 20% as effective as a bought model.

Cool. I quite fancy a go at making one - can you remember where you got the parts, and what motor you went for in the end?

Cheers

Tom

this motor from this supplier, but without the gear box

2mm shaft prop like this (but mine was differnt ebay seller, no longer listing them)

and I bought a pair of CPU heatsinks to sandwich the thermocouple between. Since the video Ive wrapped the bottom sink with foil.

Great stuff - thanks.

no worries. post the results here when youre done!

Will do. You said you'd bought a couple of the Peltier doofers - did you use them both in the fan, or just the one? I ordered one off ebay last night, then re-read this thread!

Only used one, but I wrecked the other I think when I tried to remove it from the sink having arctic glued it.

Oooh thats nice. Not seen the thread before. I've used a few on my old PC's when going for Sub Zero CPU cooling.