cpu fan motors with 3 wires

[aljsk8]

not really a flashlight question but i want to use a cpu heatsink and fan in a project

all the fans i see (the old used ebay ones im looking at) have 3 wires which tells me they are brushless (although im not sure if they are)

can i run these motors off 2 of the wires from a 12v battery?

thanks

Alex

 

[Marko]

I think the 3rd wire is usually for rpm sensing, so yes You can run it with only 2 wires.

 

[rizky_p]

Yes the third wire (yellow but cant quite remember) is for rpm signal. Just connect the other two. There other newer cpu fans with 4 cables, this one for PWM signal.