Mr. Microscope Posted February 19, 2011 Share Posted February 19, 2011 Hello All, I'm trying to hook up a 12 volt DC fan to a 12 volt DC power supply. The fan came from a computer heat sink and is brushless. The wires coming out of it are red, black, and blue. I'm assuming the red is positive, black negative, and blue for tachometer on a motherboard. I've hooked up the + to + and - to - from fan to power supply, but nothing happened. Do I need to do something with the blue wire? I'm going to get some batteries tomorrow to determine if perhaps either the PS or fan is shot. Before I get a bunch of double A's however, does anyone have a simpler solution. No, I don't have a multimeter. Thanks in advance! Mr. M Quote Link to comment
LPS-Crazy Posted February 19, 2011 Share Posted February 19, 2011 Hello All, I'm trying to hook up a 12 volt DC fan to a 12 volt DC power supply. The fan came from a computer heat sink and is brushless. The wires coming out of it are red, black, and blue. I'm assuming the red is positive, black negative, and blue for tachometer on a motherboard. I've hooked up the + to + and - to - from fan to power supply, but nothing happened. Do I need to do something with the blue wire? I'm going to get some batteries tomorrow to determine if perhaps either the PS or fan is shot. Before I get a bunch of double A's however, does anyone have a simpler solution. No, I don't have a multimeter. Thanks in advance! Mr. M The blue is going to be the 12v contant...red on PC is +5v Hook the blue and the black up and it should work. Blue is a generic color in PC wiring. Quote Link to comment
Mr. Microscope Posted February 19, 2011 Author Share Posted February 19, 2011 So, just leave out the red? Quote Link to comment
Mr. Microscope Posted February 19, 2011 Author Share Posted February 19, 2011 Thanks! I'll give it a try tomorrow. Quote Link to comment
cptbjorn Posted February 19, 2011 Share Posted February 19, 2011 I disagree, the majority of fans have black ground and red +vin. The third wire is the tach, usually yellow but sometimes blue (delta fans have blue.) If black and blue make it spin then its some weird non-standard and/or OEM thing. Quote Link to comment
LPS-Crazy Posted February 19, 2011 Share Posted February 19, 2011 (edited) I disagree, the majority of fans have black ground and red +vin. The third wire is the tach, usually yellow but sometimes blue (delta fans have blue.) If black and blue make it spin then its some weird non-standard and/or OEM thing. Yeah wow, now that I think about it, that is correct...I work on computers daily to...wow.... Yeah ON THE FAN the red is +12v Black is Return (Ground) Blue or white is the speed sensor. When your looking at a 4 pin molex power connector the yellow is the +12v the red is the +5v and the black is the two black are the return. Thats what I had the blonde momment on here That shows me to be up for 22 hours and try to help someone. You got a multi-meter ? Edited February 19, 2011 by LPS-Crazy Quote Link to comment
glazer Posted February 19, 2011 Share Posted February 19, 2011 The blue is going to be the 12v contant...red on PC is +5v Hook the blue and the black up and it should work. Blue is a generic color in PC wiring. Yeah, but he's not talking about a PSU, he's asking about the fan. Your fan, red/black/blue... the red is going to be the + and the black the -. Now on some older fans the blue, if a two wire fan would be the ground. The blue wire on the fan is is a speed sensor or controller. On a happy note, it's pretty hard to fug up a DC fan, just use whatever wires work....lol Steve Quote Link to comment
Deano Posted February 19, 2011 Share Posted February 19, 2011 (edited) Yeah, but he's not talking about a PSU, he's asking about the fan. Your fan, red/black/blue... the red is going to be the + and the black the -. Now on some older fans the blue, if a two wire fan would be the ground. The blue wire on the fan is is a speed sensor or controller. On a happy note, it's pretty hard to fug up a DC fan, just use whatever wires work....lol Steve Agreed, Just connect the power to the red and black if it doesn't work reverse your connection. It's a polarity deal. Also I don't no of any PC fan that will run backwards this is why when you connect the pols wrong you get nothing. Edited February 19, 2011 by Deano Quote Link to comment
Mr. Microscope Posted February 19, 2011 Author Share Posted February 19, 2011 (edited) Okay, Tried the fan with eight 1.5v batteries. I think it might be dead. It was a heatsink-fan combo that I found laying around the lab. Perhaps that was why it was not in use. 'Gonna stop messing around and just get a new fan. Thanks for the advice. Edited February 19, 2011 by Mr. Microscope Quote Link to comment
Mr. Microscope Posted February 19, 2011 Author Share Posted February 19, 2011 Problem solved. It turns out I wasn't doing anything wrong. Both the powersupply (also salvaged) and the fan were dead. Oh well. I've got new ones now that work fine. Thanks again. This thread was not useless as I couldn't find any threads asking specifically about what to do with the tacho wire. Now its in here for some future DIY'er to find. Quote Link to comment
Stephensx04 Posted February 21, 2011 Share Posted February 21, 2011 I got 5 of them sititng around with the heat sinks still. I know Ill build something with them one day. Quote Link to comment
Jim Wester Posted August 31, 2020 Share Posted August 31, 2020 As dumb as it sounds brushless DC motors actually run off of an AC wave Quote Link to comment
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