Wiring Fan...Can someone help me??

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awarner322

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Alright I need some help. I bought the wrong fan for a stir plate on accident at Best Buy today. I attached pictures below. It is a 4 wire DC12V fan. I have a charger that works good with a little laptop fan that I tore apart (also picture attached below). I have the potentiometer as well to wire into it. Is there anyway I can wire this fan up and use it???

2012-10-31_16-18-01_65.jpg


2012-10-31_16-18-09_56.jpg
 
Not all are standard color codes but I hope this helps:
The computer muffin fans with four wires are usually: black for ground, red for positive DC, yellow for the output tach from the fan and the blue is for a pulse width modulated signal to control its speed.

So... most likely red to red black to black.

Good luck!
 
I connect the reds and the blacks and I get just the smallest 'budge' from the fan. Like it is sensing some sort of signal...but not going to fly.... Anything else :/
 
You need a power adapter with a bit more juice; the one you have is just a bit below the rating for the fan.
If you can find another that's 250mA or more, it'll run full speed just fine.
The 4 wire fan motors have internal circuitry that doesn't like a potentiometer on the black wire - it'll work for a while but it's hard on the motor.
You can go nuts and put a pwm circuit on the blue wire just like smooth said, if you want to speed control on it properly, but it needs to be high frequency - 25kHz is the standard. Wikipedia has lots of good, nerdy reading on the subject.
 
If you can find a computer on the curb, the power supply from it will power your fan (as that's what it's normally connected to).
You might be able to get away with a phone chager since they're 5v @ 1 amp. If it works it will be slower and depending on how 'smart' the fan it it might not like being run at a lower voltage.
https://www.homebrewtalk.com/f170/b...nual-control-pwm-gravity-fed-no-pumps-347581/
Has everything you need to know to get a Pulse Width Modulation(PWM) circuit set up.
 
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