Gatortailale March 17, 2004 Share March 17, 2004 is is possible & SAFE to take a power supply from a computer and connect a computer fan to it and have it run the fan? Why I ask is in the past I took a 3.5 inch fan and wired it directly to wall outlet. However, the thing had so much power it operated at max speed and was too noisy. Would the regulated power supply slow the fan enough so it would be a dull roar similar to the speed it runs on a PC case? I just assembled a new pc at home. I have the old 350w power supply. Was thinking of taking it out of case and hooking fan up to try it. Was hoping some of you electrical wizards can chime in on safety of this idea. I sure don't want to burn the house down. [tr] Many thanks in advance Craig [beer2] Link to comment Share on other sites More sharing options...
Sph2sail March 17, 2004 Share March 17, 2004 It depends. Assuming you are powering a 12V DC fan. You certainly should have the power supply in some kind of safe enclosure. A ventilated plastic box would be fine. Then you need to wire to the correct outputs, which should not be too hard. Personally, I'd look for a radio shack (or equiv) 12V DC plug in transformer and wire the fan to that. Tell me you didn't hook up a 12V DC fan directly into 120V AC... [pcwin s Link to comment Share on other sites More sharing options...
traveller7 March 17, 2004 Share March 17, 2004 Best to avoid the insides of pc power supplies. Quite dangerous, even when they are not plugged into the wall. Capaciters might hold a charge for and extended period of time. As Sph2sail advised, better to get cheap DC fans and AC to DC power adapters at Radio Shack. AC fans can be purchased at RS as well, but tend to cost more AND it is more difficult to regulate the speed with simple electronic mods. Cheers. Link to comment Share on other sites More sharing options...
xeon March 17, 2004 Share March 17, 2004 It can be done, I'm assuming this is an ATX PSU right? To enable the PSU to run externally, all you have to do is short Pin 14, which is one with the green wire to any of the ground pins... the black ones. You could run all sorts of DC stuff off of a 350W supply. The aforementioned safety tip is a good one. If you are concerned about fan speed... you can do two things. Get a lower rpm fan with a better dB (sound) rating. Or you can buy a fan bus off of e-bay and be able to control the fans speed. Essentially it moves the voltage from ~7 to 12V. There are fancier models that will work with different temp alarms and so forth, but a simple knob fan bus will set you back a cool $15 on E-bay. Fan Bus Search on E-bay Here's a pretty beefy 12V DC supply that is rated for 3.1A, but it sounds like you've already gone the wall adpater route... i think? Here Link to comment Share on other sites More sharing options...
Grav March 17, 2004 Share March 17, 2004 If you are like me you have a lot of power converters left over from old cell phones and things like that. If you have one that matches (if it is a 12v... that is common) it could save you a few bucks. Link to comment Share on other sites More sharing options...
ReefMon March 17, 2004 Share March 17, 2004 Here's a affordable 3 to 12 volt adapter so you can switch the voltage to your desired RPM/noise level. 3-12VDC/800mA Regulated AC-to-DC Adapter ild ild ild Glenn Link to comment Share on other sites More sharing options...
Gatortailale March 18, 2004 Author Share March 18, 2004 fan 1 which fan? Fan 2 Fan 3 Link to comment Share on other sites More sharing options...
Gatortailale March 18, 2004 Author Share March 18, 2004 2nd review shows fan 1 is 2.5 inches - guess not that one. Link to comment Share on other sites More sharing options...
xeon March 18, 2004 Share March 18, 2004 Fan 1 is small and moves very little air. It also has sleeve bearings. Fan 2 lists a spec of 85cfm, without a dB spec listed my guess is it would fall in the "loud" range like ~50dB... only a guess though. Fan 3 is probably the best of the bunch, but personally I wouldn't pay that much for a 12V fan. I've posted this before, but I buy all my fans for various projects from Nexfan.com because of their great prices and selections. If you want quiet, you probably want to shoot for around 30dB. Link to comment Share on other sites More sharing options...
Gatortailale March 18, 2004 Author Share March 18, 2004 stealth fan High output fans are nice but they also produce tons of noise. This is the fan of choice if you are looking for a fan that does not sound like a jet airplane but still pushes a decent amount of air. These fans push more air and produce less noise than the competition. Specifications Dimensions: 92x92x25 mm Air flow: 28 CFM Fan speed: 1750 RPM Sound level: 20 dBA Bearing: Dual Ball Bearing It doesnt say if it's DC. Will it work. I would like to get 3.5 inch sice. I think 3 inche = 80 mm and 4 inch is 120. Could do 4 inch, but would have to drill bigger. Link to comment Share on other sites More sharing options...
ErikS March 18, 2004 Share March 18, 2004 These fans push more air and produce less noise than the competition. No...no...NO! Do not buy this fan, it's a piece of junk. The 8cm & 12cm aren't so bad but this particlular model is terrible. It emits a low frequency noise that's bothersome AND it doesn't move much air at all. There are two kings in the fan game Panaflo & Papst. Papst is expensive and IMHO the best value is Panaflo. Move good amounts of air & are very quiet. They are also durable, I have a couple that are WAY past 3yrs of 24/7 use (one is actually over 6 years, it was recently retired but may go back into service in my canopy) Panaflo @ Directron For Panaflo's the last three char's tell you the speed/noise. L1A = low speed/noise, M1A = medium, & H1A = high (regardless of the size). As fans get bigger they move more air/noise produced. The larger fans need to spin @ lower rpm's to produce the same airflow - this means less noise. You don't need a holesaw to cut a 12cm hole, a jigsaw will work fine. A template is easy, use a CD it's the same size. Also, as Xeon mentions you can use an ATX PS, just be advised that some of them don't like being run w/o a load (jumped grn/black). They make PS testers for this, about $11 - $12. I think I might have a spare 9cm Vantec laying around if you REALLY want one of those (I might just have tossed it out also - ). If you have any Q's about PC fans give tag me w/ a PM. I've spent more time in the last 8 years d*cking around w/ fans than any sane person should. EDIT: To give you an idea how much of a rip RS fans are - the Panaflow 9cm is $7.99 @ Directron. sph: fixed link Link to comment Share on other sites More sharing options...
Gatortailale March 18, 2004 Author Share March 18, 2004 Thanks, I was leaning toward Reefmon's suggestion of getting the adjustable ac to dc converter. Now I just need to pick a fan with will work with it. I'll look at your site to see if I can find anything. I do have a atx power supply. Not so hip on hot-wiring it if I can get the adjustable ac/dc thingy. I already have the holes drilled for I guess a 92 mm / 31/2 inch fan. Thus, choice a would be to get some fan that size. Maybe ones I have would work if I get the power converter. As mentioned above, hotwired to wall outlet, they spun fast and made LOUD hight pitch roar - drive a fella nuts. I now use 4 inch clip on fan, but not sure that is sufficient once spring hits. Did last year, but last fall, I added 400w to middle of my 125 in place of a 250, so I have more heat this year gr Link to comment Share on other sites More sharing options...
ErikS March 18, 2004 Share March 18, 2004 I was leaning toward Reefmon's suggestion of getting the adjustable ac to dc converter. That would be my choice. It's should be no problem to match them up, all PC fans are 12v & most can run on anywhere from 5 - 12v. The only thing you'll need to check is the draw of the fan(s). The one reefmon linked to has a max current of 800ma which is .8 amps. Just check the fans, most will have the amps &/or the watts listed. Example: Panaflo 92mm L1A draws 1.32w @ 12v this equates to .11amps (w/v). Using the linked adapter you could run 7 of them I know lots of places to get fans but Directron probably has the largest variety & best price (they're huge). They usually get stuff to me in a couple of days (in Houston I believe). Local CompUsa carries the EverCool brand & they're pretty good but I'm not sure how the Aluminum will hold up in our environment. Link to comment Share on other sites More sharing options...
Gatortailale April 14, 2004 Author Share April 14, 2004 I went to the R. shack saturday & got the AC to Dc converter and some 4 inch fans. Well one of the fans appeared to be open box but I got it thinking what could be the harm, fan looks new. Sucker did't work - that is the harm. Good think I still have 25+ days to return it. Other one worked so I could at least try it to the ac/dc to see how much change of power on switch changed rate of fan. I like it a lot. At least I will keep my sanity this summer. In the past I tried the AC fans wired to outlet. Moved lots of air, but the made high pitched hummmmmmmmmmmmmmm. variable will help keep noise down and still move some air - I hope. However, I'm going to return all the fans (keep dc converter) and I ordered the panaflo fans & that website also had some noise gaskets I'm going to try. :D Erik & others, thanks again for help! Now just have to find time to install them. o- Link to comment Share on other sites More sharing options...
michaelg April 14, 2004 Share April 14, 2004 I will be brining about 6 DC fans to the meeting ( if that is the type that don't need any convertor). I have one wired so you can see the pull and noise. These were "donated (AKA given to me by a member who moved out of the area)" to the club- so a small donation to the group would be appreciated (and this can come in forms other than $). Link to comment Share on other sites More sharing options...
ErikS April 14, 2004 Share April 14, 2004 Glad to hear the convertor worked for you. It could be worse, I got one & it crapped out 5 minutes after I cut the wires to rig my fans = no return. Another option is to just use a 10ohm/1watt resistor inline with the fan, this gives you about 9volts & much quieter. Link to comment Share on other sites More sharing options...
michaelg April 14, 2004 Share April 14, 2004 I always get confused on ac vs dc ( I made a descision that chemistry and physics were not my fortee years ago- though I majored in chemistry)..... the kind I have do not need any convertor- a lamp cord is all that is required. Link to comment Share on other sites More sharing options...
Lee Stearns April 14, 2004 Share April 14, 2004 Michael, I'll take one this Sat. and be happy to contribute $. Thanks, Lee Link to comment Share on other sites More sharing options...
Gatortailale April 14, 2004 Author Share April 14, 2004 I will be brining about 6 DC fans to the meeting ( if that is the type that don't need any convertor). ones wired with no convertes = AC I had some of them, but they were loud!!!! in my canopy. Looking forward to dc with adjustable rate via converter. Link to comment Share on other sites More sharing options...
michaelg April 14, 2004 Share April 14, 2004 Gee- thanks gaitortail- that really helps me "REMEMBER" what the difference is..... Lee, as I said, I have one wired up that you can plug in to see if it is acceptable. :p Link to comment Share on other sites More sharing options...
tree April 19, 2004 Share April 19, 2004 michaelg, the difference is not too difficult to remember. AC = Alternating current = outlets in the wall DC = Direct Current = Batteries The way I remember it is that for DC I have the batteries so I control the current, for AC I just think of the air conditioner & it is wired into the house circuits. Link to comment Share on other sites More sharing options...
Gatortailale April 23, 2004 Author Share April 23, 2004 Had time last night to connect the 3 1/2 inch (92mm). Moved fair amount of air with little if any noise. [big noise improvement over the ac fans that cranked at max rpn and sounded like jet engine gearing up for takeoff] Can't hear it over the hum of my gen-x mak4 Would prefer to move a bit more air than the 3.5" moves; will see how the 4" sounds what air it moves when I get it wired up on the 120g tank. Using panaflo fans found via link by eriks ? in earlier post in this thread & the radio shack 3-12v AC/DC converter. HTH Link to comment Share on other sites More sharing options...
tree April 23, 2004 Share April 23, 2004 Let us know how the 4" fans go. I have the AC versions in my light hood and they are definitely a noise maker. I would love to replace them with something much quiter. Link to comment Share on other sites More sharing options...
Gatortailale May 5, 2004 Author Share May 5, 2004 Installed the 4" Sat. night. Slight hummmm to them at max speed / power with the AC to DC converter at 12v. Tank temp was getting to 83 in my basement with just 7" clip on fan blowing in 4 inch fan hole. I put a 4" fan on each end of canopy and now at max speed the temp gets to 81 and last night with temp cooler, it was only at 80.3 after MH on for 5+ hours and the fan power cut back to 10v. :D Little less noise and temp still down. Real test will be when it heats up, but for now I love it - temp down and little noise vs. the AC fans that just made a loud high pitched hummmmm. Hopefully I can get the house in shape to do tank tour in the near future. :D Link to comment Share on other sites More sharing options...
ErikS May 5, 2004 Share May 5, 2004 Glad to "hear" it's working :D At 10v the fan is moving almost as much air as at 12v (it's a progressive curve) & as you noticed it's considerably quieter. Link to comment Share on other sites More sharing options...
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