computer fan to ac adapter

this one seems to be a no-go.  hopefully someone else has better luck than i did.

cashcomp

They are either 5 volts or 12 volts DC.
About any wall transformer adapter that puts out that and has enough amps for the fans will do.
The amps for fans isn't much but the more fans, the more amps.
The amps and volts are usually printed on the fan somewhere.

A fan is just a fan, just like those nifty 12 volt DC ones that stick to the dashboard of your car and plug into the cigarette lighter for those "stuck in traffic in summer" days, or like those stupid baseball caps with a battery-powered fan that flamboyant tourists wear when waddling around Disney World.

I have to ask this question, just out of curiosity.  Why would you want to have the case fans running when the computer wasn't powered up?  Are you worried that your computer's power supply unit isn't a high enough wattage and is being overused by the fans to the detriment of other hardware?  Perhaps you just intend to use them strategically positioned around your room the same way as the car dashboard ones?

One thing you must be aware of is that if the BIOS has features to monitor the fans, and sets off an alarm if fans fail, or if you have a software temperature and fan utility running, then these functions will not work because the fans need to be plugged into the proper motherboard sockets.

WOW! ok, I thought I had a decent answer.  some people here are just a LOT smarter than the rest of us when it comes to finding an answer to a problem.  I would never have thought of making my own, no matter the simplicity of the electrical theory involved.

i guess that is why we post our questions here :-)  Hats off to the creativity, and brains, here!

cashcomp

poko2121

What you are looking for is a cheap transformer (power adapter) that has a slider switch you can move to different voltages (3v, 4.5 v, 6v, 7.5v, 9v, 12v).  Some come with different sized jack plugs and fittings that connect to standard-sized sockets on things like portable radios, dictaphones, etc.
http://www.maplin.co.uk/images/full/-9870i0.jpg
http://www.maplin.co.uk/images/full/43448i0.jpg
http://www.maplin.co.uk/images/full/43094i0.jpg

As PCBONEZ said, check that it supplies enough Amps to match that needed by the fans.
All you have to do then is cut the connector off the end of the output cable and the connector off the fan wires, strip the plastic sheathing back to reveal the wires, and wind them together making sure that the joins are insulated from each other.  You can stagger the joins, solder the wires for a permanent connection, and use heat-shrink tubing to cover the joins.

To join more than one fan to a single mains transformer, you would have to use some kind of multi-connector.
Ask in your local electronic shop and see what they have.

In case you wondered, here's what is inside your cheap mains adapter:
http://www.ecmweb.com/ops/electric_basics_transformers_2/

thanks everyone, the actual reason why i wanted to do this is for cooling off a stereo system inside of a cabinet.  Computer fans would be an optimal way for me to do this so i am going to have to run the fans from a wall power outlet.  Splicing the wires would work and i did think of that, but a simple adapter would be best.  I am assuming that there are none that exist unless someone can find me some :-)

I'd just pick your fans so you know the voltage and amps you need then head on down to a thrift-shop (Goodwill or whatever) and find a wall transformer with the right volts and enough amps. (More amps is okay.)
Then stop by a RadioShack, a hardware store, or an automotive store for some electrical connectors that tickle your fancy.
Attach the connectors and off you go.........

I also like this place for this sort of project:
http://www.allelectronics.com/cgi-bin/category/220100/D.C._Fans.html
http://www.allelectronics.com/cgi-bin/category/189/Connectors_(Multi_Pin).html
http://www.allelectronics.com/cgi-bin/category/480/Power_Supplies.html
http://www.allelectronics.com/matrix/DC_Wall_Transformers.html
.

For that you could use a small AC fan designed for electronics gear.
http://www.allelectronics.com/cgi-bin/category/220200/A.C._Fans.html

ok, if i get 5 volt fans and have 6 of them i would have them all connected to eachother just like in a pc and have one of them spliced with the transformer.  Should i set the transformer to 5 volts even if it is power 6 5volt fans?

thank you

#1 you want to wire them in parallel.
All is 5 volts, the fans and the adapter.
The amps is additive.

If you have 6 fans that pull .3 amps (300 milliamps) each then the adapter needs to be at least
6 x .3 amps = 1.8 amps

Hey, that's actually a great idea.

You know what I use an old case fan for?  Making jerky!!
I grew up in Africa where they call it "Biltong", but it's much the same idea.  You just can't get the stuff here in the UK, and I longed for it when I moved to the UK.
You smother strips of good meat in spices and stuff like corriander after soaking in vinegar, and then put it somewhere away from flies in a constantly moving airflow.
My rig is a cardboard box with coat-hangers and a drip-tray to catch excess juices until the surface starts to dry out.
A case fan moves just enough fresh air constantly through the box to do the job perfectly.

Yeah, so in your case you could use an old "radiogram" cabinet, or a state-of-the-art cabinet, but they will still trap heat.
There are a lot of different types of connectors you could use because it is such a low voltage.  It's enough to burn the wire and cause a fire if they short out, but anything around the 9 to 12 volt mark doesn't need particularly thick wires.

You'll be able to improvise some kind of multi-connector block that hides discretely in at the back of the cabinet and allows you to connect two or more fans.

Chop the old wiring loom off a busted pc power supply and you have a bunch of connectors that you can piece together, or use some old extensions, Y-splitters, etc.

http://www.pctoys.com/misccables.html
http://www.pctoys.com/840556016359.html
http://www.pctoys.com/840556000037.html

Molex plugs and sockets are ideal for a good secure connection that keeps the wires well insulated.
http://www.pctoys.com/840556000662.html

To keep it neat, you should ask in your local electrocics shop for some kind of patch-bay like this, but perhaps with smaller connectors:
http://www.pctoys.com/840556056836.html
Apart from the garish colour, you'll see that you could use something like the above patch-bay along with these Molex to Fan connector adapters:
http://www.pctoys.com/3mato4fancaa.html

Have fun :-)

More amps is okay but not more volts.

Using the molex connectors off a y-splitter is a great idea.
It gives you both the male and female connector without too much hassle.
And they don't cost much....... (-:
.

What about something like this

http://shop.store.yahoo.com/cablesonline/mo4inpotoacp.html

would that work?
will it regulate the power correctly, because i can't tell if its for 5v or 12v considering one of the pins in the diagram is 5v and the other is 12v.

thanks

It all depends which pins are occupied by the wires on the connector that pushes into (or over) it.
You can have 5 volts by only using the ground and the +5v position (right), or +12v by using the ground and the 12 volt connector (left).  You just have to make sure that your patch cables all correspond with each other.

so this will be able to power both 5v and 12v fans.  It doesn't say how many amps though

See how the molex connector in this image only has the ground (black) and only one of the wires connected.  In fact, the pins aren't in the connector either.
http://shop.store.yahoo.com/cablesonline/123pinfancon.html

I HAVE one of those.
It's used to power drives.
The 5 volt and 12 volt are regulated seperatly.
It's a bit of overkill but it would work and if you ever need 12 volts for something you'd aready have it.
Just so far as the 5 volts this gives you the same amps.
http://www.allelectronics.com/cgi-bin/item/DCTX-5200/search/5_VDC,_2000_MA_WALL_TRANSFORMER_.html

Have you checked the current requirements (amps) on your fans?
The numbers I gave were for example only. I dunno what your fans are.

the fans are each 12v 0.4amps.  All I have to find out is if this item will take the amps and i'll be set

http://shop.store.yahoo.com/cablesonline/mo4inpotoacp.html

No, that's something you would have to check out.
Remember that it only outputs to a cable terminated by just ONE Molex connector.  It's hard to see whether it is a male (plug) or female (socket) on the end.  You would still then need to connect a corresponding set of wires that would split off to supply all your fans.

I'm not sure if you are aware of the difference between a parallel and a series connection.
http://shop.store.yahoo.com/cablesonline/6in35ypowspl.html
You see how the larger (molex) socket in the middle two yellow wires joining into one pin, and two red wires joining to another pin.  That's what you call a parallel connection.
The same voltage will be supplied to each of the smaller connectors feeding off from it, but if you had a fan joined to each of the two smaller connectors, the source leading into the large molex connector would have to be able to supply enough current for BOTH fans, ie. the TOTAL number of Amps if you add up both the fans' ratings.
The fans are DRAWING the current they need. Both fans in this example will be drawing current, so the requirement is cumulative.

Hmm, a bit late with my comment which is now out of context.  Just ignore it :-)

pcbonez, where does it say that the power supply takes 2 amps?

why don't you simply buy 130 V AC fans? they exist too...and 220 V AC also

i already have the fans

As I said before I HAVE ONE OF THOSE. .. I read the label... hehehehe

o got it :-)

ill keep looking for one that can handle more and if anyone finds one i'd appreciate it...worse comes to worst i buy 2.  3 fans on each

buying fans or buying AC adaptors will cost about the same.

Exactly, about the same cost.
Wiring and mounting one fan would be much easier.

http://www.allelectronics.com/cgi-bin/item/PS-1226/480/12_VDC_2.6_AMP_SWITCHING_POWER_SUPPLY_.html
12 volts x 2.6 amps.
Change the connector.
In there.........

That's just the beast :-)
OK, now you'll need some tools to drill some nice big holes through the sides of your Hi-Fi cabinet to mount the fans!!
Are you sure this is what you really want to do?

By the way, I suggest that you make gaskets from rubber or silicone-type plastic for each fan, and mount them with rubber "screws".  Depending on the size of the cabinet, the thickness of the sides, etc, you could end up with amplified vibrations from the fans creating harmonic resonance that can sound like a booming to a loud hum..
http://www.acoustiproducts.com/en/antivibration.asp
http://www.coolerguys.com/840556020431.html
Case fans are usually very quiet and well balanced, so perhaps just wait and cross that bridge IF it happens, but you are as well knowing this possibility in advance.

I like that adapter at the Yahoo store, but it's a bit expensive there. For just more, you can get the same type of adapter and a USB to IDE cable (http://www.mwave.com/mwave/Skusearch.hmx?scriteria=AA42580). I have that adapter, and love it. Then, if you decide you no longer want to use the fans, you'll have a nice way of quickly getting data off a drive.

--
Troy

thats a nice one...you know how many amps it can take?

It's at work. I can check tomorrow.

nevermind its 2 amps i found it

may i ask why you don't simply buy an AC fan, instead of buying an AC adaptor, and installing fan + adaptor?

because we already had these fans, and i like the amount of power they give out.  Didn't want to just throw them out they're pretty good fans :-)

i can understand that; however i would try to use them in a pc, where the 12 V is available.
Outside, it is much easier to use AC fans.
Thanks for your kind explanation

that 2amp power supply takes 12v

do you have an old pc power supply? then you have alll voltages, and amps.

poko2121
You are taking a simple thing and making it hard.

If you insist on using ALL the fans then all you need to do is get this adapter and change the plug to one you like.
http://www.allelectronics.com/cgi-bin/item/PS-1226/480/12_VDC_2.6_AMP_SWITCHING_POWER_SUPPLY_.html
If you can't handle changing the plug you probably shouldn't be doing a project like this...

Nobus is correct, and old AT power supply would work if you have a place to mount it.
They aren't small and they'll put out much more heat than a wall adapter.

Have you considered:
The more fans running the greater the NOISE will be.
If you use all of them then you have no spares if a fan fails.
How much airflow do you really need?
-- If these are 40 CFM (cubic feet per minute) fans then 6 would be 240 CFM. (Noisy and over-kill)
-- A typical bathroom fan is 50 only CFM and how big is a bathroom compared to your cabinet?
-- Lets say you cabinet is fairly big, that would be about 6 cubic feet.
-- 240 CFM through 6 cubic feet means you'd be changing 100% of the air in 1.5 seconds.
-- You'll need a pry bar to get the door open, and it will tend to slam shut.......
.

k guys thanks a lot for all the help, i really appreciate it

he, he.  I like that PCBONEZ.  It could end up sucking like the extraction rate of aeroplane toilets when you flush them :-)