black or red??

[lightning]

i want to put a reostat on my Y S tech 120mm fan. hope can decrease the loudness!! i saw 3 wire on it and i know the white wire are use for speed sensor. now the problem is should i put the reostat on red color wire or white color wire?? i'm not familiar with those electrical stuff, so anyone please help!! oh by the way, what kind of reostat should i get, how many ohm??

 

[Hoot]

If the fan did not have a tachometer output, you could put it on either, but since it does, put it on the red, to make sure it does not interfere with the tachometer signal.

Hoot

 

[lightning]

thanks hoot!! now i know what i should do!!!

err....just now went to radioshack.com and do some research on rheostat, most of them are rate on 5W but Y S tech fan are rate on 7.92W!! would it be a bit low to use 5W?? and they also hv 10ohm, 100ohm, 1kohm.....and so on!! what ohm should i use???

 

[pqt]

Found this somewhere:

A rheostat is basically a variable resistor - used with a fan, you can adjust the fan's speed. I found the Radio Shack 25 Ohm Rheostat, catalog #271-2658, to be an effective solution with 120 mm 5-6 watt fans. All you do is clip the black wire on the fan, attach one end to the center pole and one end to either of the side poles; insulate with shrink wrap and you're all set to go. Buy a knob or use it as is.