Computer fan cooling
- Thread starter theappe
- Start date
threed240
Member
Originally Posted by theappe
I have some computer fans set up for cooling my tank. The thing is that I need something to regulate the speed of the fans. What can I do to achieve this?
Question! I am doing the same thing. I just bought 4 120mm computer fans. Each one produces 105cfm. I was thinking about using a computer powersupply to run these. Or would it be better to purchase some kind of adapter? I have all kinds of room in my stand to mount the powersupply.
I have some computer fans set up for cooling my tank. The thing is that I need something to regulate the speed of the fans. What can I do to achieve this?
Question! I am doing the same thing. I just bought 4 120mm computer fans. Each one produces 105cfm. I was thinking about using a computer powersupply to run these. Or would it be better to purchase some kind of adapter? I have all kinds of room in my stand to mount the powersupply.
scsinet
Active Member
Originally Posted by Goblin
You could also wire in a potentiometer, around 4 dollars at radio shack.
Do this and you'll smoke the potentiometer. It's not that simple. You need a transistor to handle the current, a potentiometer alone isn't rated to handle the amount of current that fans draw.
A computer power supply will usually work, but it depends on what you get. Old style AT power supplies use a manual 120 volt switch. These are the easiest to adapt. These supplies are no longer used in computers so you'd need to go to a big dealer to still find one.
The newer style is ATX.. To get an ATX supply to start you need to short the +5vsb and the PS_ON wire (usually gray and green if I remember) on the motherboard connector.
Some computer supplies, both AT and ATX need to see a minimum load to work properly, and that minimum load has to be across a couple different outputs, so fans alone might not work. It depends largely on the supply.
Once you get your supply going, you can run your fans on either the +12 volt or the +5 volt. You can also modify they way you connect them.
For example, to run all your fans at full speed, you connect all in parallel across 12 volt.
To run your fans at half speed, connect pairs of fans in series across the +12 volt legs.
To run your fans at slightly less than half speed, connect them all in parallel across the +5 volt line.
You'll need to experiment to see what suits you best. On almost all computer power supplies (except Compaq), the ground is black, the +5 is red, and the +12 is yellow. On Compaq supplies, it's the same except the +12 is orange. You can usually read the label on the supply and tell.
All this is moot though as it's a waste to do it this way, since computer supplies waste a lot of energy over a couple dinky fans. The best thing to do is get a +9 volt power supply adapter from Jameco (.com). 9 volts is a good voltage because the fans are a little slower and hence quieter.
A 9 volt 1500ma supply will run at least 5 fans. PN 237067CM $9.95
For full speed, use 12 volt. A 1350ma supply is PN 235096CM $13.49
They have cheap fans too, even a grab bag of 5 fans for $8.75, 149649CM
You could also wire in a potentiometer, around 4 dollars at radio shack.
Do this and you'll smoke the potentiometer. It's not that simple. You need a transistor to handle the current, a potentiometer alone isn't rated to handle the amount of current that fans draw.
A computer power supply will usually work, but it depends on what you get. Old style AT power supplies use a manual 120 volt switch. These are the easiest to adapt. These supplies are no longer used in computers so you'd need to go to a big dealer to still find one.
The newer style is ATX.. To get an ATX supply to start you need to short the +5vsb and the PS_ON wire (usually gray and green if I remember) on the motherboard connector.
Some computer supplies, both AT and ATX need to see a minimum load to work properly, and that minimum load has to be across a couple different outputs, so fans alone might not work. It depends largely on the supply.
Once you get your supply going, you can run your fans on either the +12 volt or the +5 volt. You can also modify they way you connect them.
For example, to run all your fans at full speed, you connect all in parallel across 12 volt.
To run your fans at half speed, connect pairs of fans in series across the +12 volt legs.
To run your fans at slightly less than half speed, connect them all in parallel across the +5 volt line.
You'll need to experiment to see what suits you best. On almost all computer power supplies (except Compaq), the ground is black, the +5 is red, and the +12 is yellow. On Compaq supplies, it's the same except the +12 is orange. You can usually read the label on the supply and tell.
All this is moot though as it's a waste to do it this way, since computer supplies waste a lot of energy over a couple dinky fans. The best thing to do is get a +9 volt power supply adapter from Jameco (.com). 9 volts is a good voltage because the fans are a little slower and hence quieter.
A 9 volt 1500ma supply will run at least 5 fans. PN 237067CM $9.95
For full speed, use 12 volt. A 1350ma supply is PN 235096CM $13.49
They have cheap fans too, even a grab bag of 5 fans for $8.75, 149649CM
gsd
Member
The controller was not rated for the current draw.......Like SCSI stated, there is more to just wiring in a pot to control the speed..Least worse case scenerio, it smokes the pot and does not work. Worse case pot gets hot and catches something on fire. Much cheaper and easier to buy the variable power supplies which change voltage outputs by a simple sliding of the switch to various voltages.....can't get any simplier....or cheaper
scsinet
Active Member
Another solution might be to either home brew or use a commercial lighting dimmer. Obviously this isn't an electronics forum, so I'll briefly state that light dimmers don't exactly control magnetic loads (transformers for example) correctly, but it *might* work.
Frankly though, I'd use two very high capacity fans like those vantec deal... and connect them in series.... this way each fan runs at half speed. Frankly, you don't need very much air to keep a canopy cool... a canopy doesn't hold more than about 10 cubic feet or so, so even if you run two 105cfm fans together at half speed, you are changing the air 10 times per minute... many times what's necessary.
I attached a professional looking graphic to illustrate. Sorry, I don't have my sim software on this machine so that's the best schematic I can do.
You might also try what I did. Check out my web site (www.davestanks.com) and click on DIY, then "Metal Halide Smart-Canopy." I built a temperature adaptive speed controller. What it does is actually varies the speed of the fans based on the temperature in the canopy, so the fans never spin faster than they have to. I'm not exactly willing to share the schematic, but you can find circuits like this online by hunting around.
Frankly though, I'd use two very high capacity fans like those vantec deal... and connect them in series.... this way each fan runs at half speed. Frankly, you don't need very much air to keep a canopy cool... a canopy doesn't hold more than about 10 cubic feet or so, so even if you run two 105cfm fans together at half speed, you are changing the air 10 times per minute... many times what's necessary.
I attached a professional looking graphic to illustrate. Sorry, I don't have my sim software on this machine so that's the best schematic I can do.
You might also try what I did. Check out my web site (www.davestanks.com) and click on DIY, then "Metal Halide Smart-Canopy." I built a temperature adaptive speed controller. What it does is actually varies the speed of the fans based on the temperature in the canopy, so the fans never spin faster than they have to. I'm not exactly willing to share the schematic, but you can find circuits like this online by hunting around.
cgrant
Active Member
you could always get a variable speed cpu cooling fan, like a thermaltake and dial it in, then run it off a power supply, would be alot easier to setup for someone that isnt a computer geek...I can say this cause i am one
Now if you understand the lingo then I say go for it!
Now if you understand the lingo then I say go for it!
threed240
Member
Originally Posted by SCSInet
Do this and you'll smoke the potentiometer. It's not that simple. You need a transistor to handle the current, a potentiometer alone isn't rated to handle the amount of current that fans draw.
A computer power supply will usually work, but it depends on what you get. Old style AT power supplies use a manual 120 volt switch. These are the easiest to adapt. These supplies are no longer used in computers so you'd need to go to a big dealer to still find one.
The newer style is ATX.. To get an ATX supply to start you need to short the +5vsb and the PS_ON wire (usually gray and green if I remember) on the motherboard connector.
Some computer supplies, both AT and ATX need to see a minimum load to work properly, and that minimum load has to be across a couple different outputs, so fans alone might not work. It depends largely on the supply.
Once you get your supply going, you can run your fans on either the +12 volt or the +5 volt. You can also modify they way you connect them.
For example, to run all your fans at full speed, you connect all in parallel across 12 volt.
To run your fans at half speed, connect pairs of fans in series across the +12 volt legs.
To run your fans at slightly less than half speed, connect them all in parallel across the +5 volt line.
You'll need to experiment to see what suits you best. On almost all computer power supplies (except Compaq), the ground is black, the +5 is red, and the +12 is yellow. On Compaq supplies, it's the same except the +12 is orange. You can usually read the label on the supply and tell.
All this is moot though as it's a waste to do it this way, since computer supplies waste a lot of energy over a couple dinky fans. The best thing to do is get a +9 volt power supply adapter from Jameco (.com). 9 volts is a good voltage because the fans are a little slower and hence quieter.
A 9 volt 1500ma supply will run at least 5 fans. PN 237067CM $9.95
For full speed, use 12 volt. A 1350ma supply is PN 235096CM $13.49
They have cheap fans too, even a grab bag of 5 fans for $8.75, 149649CM
Thanks. I ended up doing this. I tried the power supply and quickly realized I didn't know which wire was for the switch. But I already have a 12v power supply that I use to use for a PA system at work. So, I just hooked them all up parallel to the 12v supply. I will probably use some type of thermal controller or just a potentiometer. I actually went to school for electronics/pc repair. It's just been so long since I actually got that deep into the wiring part of it. All 4 fans run great off the power supply. It moves alot of air!
Do this and you'll smoke the potentiometer. It's not that simple. You need a transistor to handle the current, a potentiometer alone isn't rated to handle the amount of current that fans draw.
A computer power supply will usually work, but it depends on what you get. Old style AT power supplies use a manual 120 volt switch. These are the easiest to adapt. These supplies are no longer used in computers so you'd need to go to a big dealer to still find one.
The newer style is ATX.. To get an ATX supply to start you need to short the +5vsb and the PS_ON wire (usually gray and green if I remember) on the motherboard connector.
Some computer supplies, both AT and ATX need to see a minimum load to work properly, and that minimum load has to be across a couple different outputs, so fans alone might not work. It depends largely on the supply.
Once you get your supply going, you can run your fans on either the +12 volt or the +5 volt. You can also modify they way you connect them.
For example, to run all your fans at full speed, you connect all in parallel across 12 volt.
To run your fans at half speed, connect pairs of fans in series across the +12 volt legs.
To run your fans at slightly less than half speed, connect them all in parallel across the +5 volt line.
You'll need to experiment to see what suits you best. On almost all computer power supplies (except Compaq), the ground is black, the +5 is red, and the +12 is yellow. On Compaq supplies, it's the same except the +12 is orange. You can usually read the label on the supply and tell.
All this is moot though as it's a waste to do it this way, since computer supplies waste a lot of energy over a couple dinky fans. The best thing to do is get a +9 volt power supply adapter from Jameco (.com). 9 volts is a good voltage because the fans are a little slower and hence quieter.
A 9 volt 1500ma supply will run at least 5 fans. PN 237067CM $9.95
For full speed, use 12 volt. A 1350ma supply is PN 235096CM $13.49
They have cheap fans too, even a grab bag of 5 fans for $8.75, 149649CM
Thanks. I ended up doing this. I tried the power supply and quickly realized I didn't know which wire was for the switch. But I already have a 12v power supply that I use to use for a PA system at work. So, I just hooked them all up parallel to the 12v supply. I will probably use some type of thermal controller or just a potentiometer. I actually went to school for electronics/pc repair. It's just been so long since I actually got that deep into the wiring part of it. All 4 fans run great off the power supply. It moves alot of air!
fishy7
Active Member
Just a suggestion. This is what I use and it is GREAT. VERY little noice and I run 4 of these babies in my canopy. They are a little pricy $40 but well worth the investment.
IceCap 4 inch Fan - Variable Output
Thermal speed control with thermal sensor. 112–50 CFM. Includes: 4" Fan, AC Adapter, Fan Cover, Heat sensing Probe.Our NEW super quiet, high performance 4" canopy FAN is engineered...
IceCap 4 inch Fan - Variable Output
Thermal speed control with thermal sensor. 112–50 CFM. Includes: 4" Fan, AC Adapter, Fan Cover, Heat sensing Probe.Our NEW super quiet, high performance 4" canopy FAN is engineered...
goblin
Member
WOW....
If I knew I was going to get flamed for answer a simple question, I wouldn't have said anything.
The question was "I have some computer fans set up for cooling my tank. The thing is that I need something to regulate the speed of the fans. What can I do to achieve this?"
If I would have said a rheostat, which is essentially a potentiometer, would that have been better. If you choose the correct pot or rheostat for your application you wont smoke it. And also a typical domestic light dimmer uses a potentiometer.
If I knew I was going to get flamed for answer a simple question, I wouldn't have said anything.
The question was "I have some computer fans set up for cooling my tank. The thing is that I need something to regulate the speed of the fans. What can I do to achieve this?"
If I would have said a rheostat, which is essentially a potentiometer, would that have been better. If you choose the correct pot or rheostat for your application you wont smoke it. And also a typical domestic light dimmer uses a potentiometer.
scsinet
Active Member
Nobody flamed you... at least if you are saying I did, I can tell you I didn't. Flaming is saying that somebody put you down, yelled at you, took personal attacks, etc. All we did was disagree with you. If you consider getting disagreed with a flame, then you're going to be very unhappy on this board. Half the stuff I post people disagree with.
Also, a light dimmer uses a potentiometer, but it also uses a triac to handle the current, in the same respect that I said you'd need a transistor to handle the current in a DC application.
Also, a light dimmer uses a potentiometer, but it also uses a triac to handle the current, in the same respect that I said you'd need a transistor to handle the current in a DC application.