Rheostat questions

[Deathknight]

I am looking using a vantec tornado as my CPU fan with a rheostat to dial down the rpms. I do have a few questions though.

I have looked at a couple of rheostats that advertized that they are for fans under a certain wattage (like 5 watts). Most of the bigger fans I have been looking at (like the tornado) are above this watt range. Will this be an issue for me?

I was actually looking at the FAN SPEED H.M.L RPM. Setting Cable from thermaltake specifically but I couldn't find any hard stats on what wattage it supported etc. Also I could not find specifically what voltage it dialed down to at the medium and low settings. Would anybody happen to know what voltage these settings would put a fan at and possibly what rpm/cfm/and dba it would put this fan at?

Thanks much

PS: If you have any fan suggestions other than the tornado with a rheostat please feel free to offer them. I am looking for something that can really chill a cpu but that I could also quite down if I wanted to. Perhaps the thermaltake smart fan II would be good?

 

[mjones73]

I have looked at a couple of rheostats that advertized that they are for fans under a certain wattage (like 5 watts). Most of the bigger fans I have been looking at (like the tornado) are above this watt range. Will this be an issue for me?

Yes, you could burn up your rheostat if you pull more wattage through it then what it's rated for.

 

[JimmyG]

You can use a 25 ohm rheostat with a 25 ohm 10 watt fixed wirewound resistor connected in parallel with the rheostat. This will reduce the amount of current through the rheostat and thus reduce the power dissipated by the rheostat. You will still have good control over the fan and increased safety, because if the rheostat burns out, the fan will still be connected via the parallel resistor. I have been using that setup on a Delta EHE for a long time with no problems.

 

[hellrazrblade]

or get a bigger rheo
http://www.allelectronics.com/cgi-bin/category.cgi?category=100&item=RHE-15&type=store