Wiring Computer fans.....

[parkinsn]

we sell fans that are 120vac, for around $30 and you would just need a chunck of cord and a male plug end...... thay are a 4"

[spreerider]

dimmers are SCR's not Potentiometers just so you know, they dimm by flickering the power on and off, thats why you cant use them on arc lamps.
Most computer fans will be fine to run at 15-20V but it will shorten their lifespan.

[untamed]

Well...maybe you can't get really tiny computer fans in 115V...but you can certainly get them in about 4" diametre.

Check out RP Electronics....Look at the fans they have available and you can choose from a good variety of air movements and they all connect to 115V directly. (just plug them in!)

You can even choose the 230V ones. If you plug those directly into 110V, they run at 1/2 speed and are especially quiet. If you are going to do this, you have to purchase the ball bearing type otherwise they may fail to restart when stopped. (Mine never have, but that is what I understand)

http://www.rpelectronics.com/

[midgetwaiter]

Originally Posted by Tarolisol

its super easy, all you need is a coverter thingy(one of those larger things that plug into the wall), to covert the PC power to a wall plug. Ill take some pics of mine and post them tomorrow for ya.

You need to be picky with this. There are two types of plug in transformers, regulated and unregulated.

If you use a regulated power supply like the Circuit City adjustable one it's easy but they are more expensive. No matter what the current draw is you will get 12v out of it.

With a cheap unregulated one like most of the ones everyone has sitting in a drawer you need to be a bit more careful. First figure out how much current you need for all your fans by adding up the mA rating on them. (eg. 4*150=600) and then go looking for a power supply that is rated at 12v and 600 or more mA. If you get one that does 600mA you're done, wire it up and go, however you are more likely to find one that provides more current like 1000mA. This is a problem because what that means is that the power supply will give you 12v only when you draw 1000mA, because we are only drawing 600mA the voltage will be higher like 15v. This probably won't set anything on fire but it will make them noisy and probably shorten their life.

The easiest way to fix this is to add a variable resistor or potentiometer (think dimmer) to the circuit to adjust the current draw and adjust the fan speed.