Instructables

Computer fan wiring issue?

I just bought 3..

SONY
MODEL SFF22C
10 VDC 0.51 A
DC BRUSHLESS FANs

..from Princess Auto in the surplus section. It was just labled "Sony Blowfan", so I assumed that they were computer fans, so I could use them with my server I'm setting up. It turns out my server's motherboard doesn't have the correct outlet for the fans plugs. In fact, I haven't ever seen a fan with a plug as small as this is! I'm assuming that the red wire is positive+, the black is ground or negative-, and the white lets the motherboard control the speed. I will only need the + and -, I want the fan to go full blast all the time. It is only rated for 10 VDC, but could I hook up all three of the fans to one of the extra hard drive 12 VDC power cables (yellow and black wires)? Or do I need a resistor, with how much resistance? Also, so do I make the fan run full blast off of only power, when it needs the white wire to have a signal?

This question has been answered! See if you can help me with the next step of my project.
http://www.instructables.com/answers/Server-Airflow-Help/

-Shadow Ops


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gmxx4 years ago
you would be safe to wire all three of the fans to the same molex connector. the extra 2 volts shouldn't hurt the fans. the red and black lines should be tied to positive and ground.... try wiring them to the psu, and see if they need to be set with a speed control setting. i imagine that they are using pwm to do speed control, so if doesnt work by themselves, you might need to pick up one of those fan speed controller things that mount into the front of the case. Those fans should connect to the mobo though.
Arbitror (author)  gmxx4 years ago
The cpu already has a fan connected to the motherboard. The 3 fans I picked up are just extra fans, to get the airflow going. I don't want the speed for them to change depending on the cpu's temp, I want them to go full blast all the time. I haven't tried it on my fans, but computer fans will not run without a current going through the white wire too.. I think I read somewhere that if you hook up the white wire to power (or was it ground?) the fan will go as fast as it can, all the time. I'm also making my own plastic case, so I wont have to worry about space..
Arbitror (author)  Arbitror4 years ago
??? Glitch! I replied to ZEROGX comment (Aug 26, 2009. 1:52 PM) That's weird..
gmxx Arbitror4 years ago
im guessing that you would connect the white wire to power... makes the most sense to me...

i know ive said the fan controller... but theres ones like this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811992002
that will show the temperature of the server... which almost always is an issue with servers. And because you are building your own case, i would be careful not to overheat anything.
Arbitror (author)  gmxx4 years ago
I'll try the white connected to power. Here is my setup...
frollard4 years ago
I've got one of those blower fans at home...works on 12 volts dc. Third wire is rpm signal.