How would i go about running a couple/few 12v 12cm fans from mains electricity?
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How would i go about running a couple/few 12v 12cm fans from mains electricity?
Get a couple of those voltage/wattage changeable power plugs and wire them up to it. make sure you check the impedece etc. of the fans.
Never heard of such a thing, where do I find them? And also, impedence?
Maplin
something like this should work:
http://www.maplin.co.uk/Module.aspx?...brick&doy=22m8
...Or pare the wires...plug 'em in directly, and feelsome serious air flow as they spin at 20times their norm...*
*Don't actually try this at Home...or Work....or near anything flammable...
...and wear safety glasses and gloves...crash helmet might be an idea...and padding
In fact, just don't try what FatalSurvivor said, it's not very safe.
Especially when you think the fans like DC and your mains feed is AC:shocked2:
you could rig a car radiator to your computer, hehe.
These fans...are they the usual 4-pin molex type?
I haven't tried it myself, but you may want to think about buying an uber-cheap HD caddy, with a 4-pin power connection and using that?
They'll prob be 4 pin, standard. I'm not using them in a PC, which is why i'm wanting to power them from mains. I'll prob be using 2, and yeah, maybe a cheap HDD cooler would be a good idea. Just need to keep air circulating on some seedlings
you could use a cb psu to power them thats what im using for my block of 4 :)
http://www.maplin.co.uk/Module.aspx?...upply&doy=23m8
mine is 13amp one :) since i used to use some high power sideband rigs
A diode in series should convert that to DC, then just need to run 14 of them in series so the volts across each one is under 12V :-)Quote:
Originally Posted by BigFatCat
Seriously, you can buy cheap variable voltage battery replacement supplies from places like Asda for a few quid. Fans can run down to as low as 5 volts, so variable output means you can play with the fan speed by selecting an output lower than 12V.
Or you could wire it to a big 9V battery.
dont think thats possible, as i dont know of a diode that takes 240V through it! certainly not on an economicly acceptable level. you'd need to do a step down before converting, and a diode will just rip out the positive bits of the sine wave so all ud get is n_n_n_n you'd then need to add smoothing caps to pull the zero line up to the peak, but even then you'd lose voltage off the peak. its hard:D
Yeah, so after all that, just buy a DC power pack that'll give you 12 volts, and wire your fans up to it.
Fans don't usually consume more than 6W unless they're particularly beefy models (and I picked 6W as the near-upper limit in Panasonic's Panflo 12cm range). So that's 0.5 amps per fan; bear that in mind when you check the rated output current of the power adapter.
Quote:
Originally Posted by Steve B
It's called half wave rectification. Never said it was a good idea, just felt like joining in with the silliness :)
The diode would be cheap & easy to get: 300V reverse voltage isn't exotic, and nothing compared to the cost of all those fans!
Ever seen inside a cheap car battery charger? A 30V transformer, one diode and a big resistor that doesn't mind getting hot to limit the current.
Anyway, to get back on topic...
Sounds like you need a 12V >=2A power source. Maplins or even Halfords will sell you something around the 20 quid mark, or for less money you could rig up a PC power supply.
more expensive than a 12v mains transformer anyway, and less risk of getting electrocuted!