I have a 80mm 10.2V-13.8V .13A 1.56W 31.7CFM 2700RPM 28db fan...

simms

Diamond Member
Sep 21, 2001
8,211
0
0
If so, what's the equation I would use? V=IR? What resistor should I wire in series?


Simon
 

Calin

Diamond Member
Apr 9, 2001
3,112
0
0
Use a rheostat. It would be easy to reduce the sound, but you might remain with unsufficient air flow.
Also, think at the fact that decreasing the voltage will decrease the rotational speed, but not so much the amperage in the motor, so the heat generated by the motor will remain mostly the same. You don't want to reduce very much the rotational speed.
Use a rheostat with max resistance up to twice the fan motor "perceived" resistance (V/I) - something like 200 ohm, and a minimum of 0 or at least half of the motor's "perceived" (50 ohm). You could use a step rheostat (not continuu variations). The power rating for the rheostat should be like 2W.

Calin
 

Viper96720

Diamond Member
Jul 15, 2002
4,390
0
0
Or mod one of the ps molex connectors. Use a +12v and -5v. Then have the fan running on 7v.
 

0roo0roo

No Lifer
Sep 21, 2002
64,862
84
91
remember the rating is free air situation. mounting to case + fan grill turbulence will increase noise level
 

simms

Diamond Member
Sep 21, 2001
8,211
0
0
I really don't have a use for a fanbus, all my fans run at 20db except for this one. Anyone else have suggestions aside from a 7v mod? Will that keep temps the same? And, aside from googling anyone have links?
 

simms

Diamond Member
Sep 21, 2001
8,211
0
0
I just read SPCR forums that a 7V mod won't actually be that beneficial.. it cald fry the PSU and even worse set your system on fire.. hahah :)

What resistance would I have to use? I'll go home and try resistors ragning from 100ohm-a few kiloohms and see what works.