Thermal-controlled fans

[slowpogo]

I've been wondering about "thermal-controlled" case fans such as this Vantec:

http://www.newegg.com/Product/Product.asp?Item=N82E16835110014

Do fans like this require a separate fan controller to operate thermally, or do they do it all on their own? What is the advantage of using a separate fan controller to make fans operate thermally?

thanks...someday soon I can hopefully contribute knowledge, appreciate the help.

 

[RallyMaster]

No, they do it on their own. However, they aren't always what you want for a temperature level, which is where the fan controller comes in.

 

[cyberkost]

Not sure what is meant by "operate thermally"... anyways, this fan appears to have a temperature sensor, which will make it spin faster if the temperature gets higher. You don't have to have a separate fan controller ... however, you may not like what the sensor does, e.g., if it makes the fan spin too quickly and make a lot of noise even if the temperature is Ok, in which case you might be better off getting a regular fan and a fan controller (which would allow you to control other fans, typically 4 total). If you decide to go with this one and face a problem as one described above you might want to experiment with the placement of the sensor (that's of course if it's embedded in the fan itself).

 

[Operandi]

The best way to control fans is either at the BIOS or software (SpeedFan) level.

Most boards now offer control for at least the CPU fan, most are also able to control one or more system fans.

 

[Zepper]

Thermally controlled fans have a device called an NTC (Negative Thermal Coefficient) (resistance drops with increasing temperature) thermistor (a device that responds to temperature in a known way) in series with the + lead of the fan. This is usually mounted in the exhaust flow of the fan (or can be on a pair of wires so you can put it where it can sense some specific temperature for control - called a remote sensor).

The 80mm Vantec TFs I have here have the thermistor built into the fan - it sticks up from the hub of the fan into the air stream. So they really are designed as exhaust fans. For an intake fan, you will want a separate fan controller or a remote sensor type. The thermistors can usually be easily bypassed (or cut off and attached to wires for remote sensing) on most fans so they can also be used as intake fans with a bit of easy modding. I can't hear my 80mm TF over my SCSI drives most of the time, but that's not saying much.

The vantecs have a nice chart on the box that shows you what the thermistor's response curve is so you can tell if it would be suited to your application quite easily. The 80mm TF units aren't the quietest in the world. I haven't had a 120mm TF here yet. I do have an NMB SmartFan here and it is great. CFM range is 50 to 118, while the TF is from 54 - 92 and is relatively low power vs the SmartFan ~ 0.3A vs 0.74A max (3.4 vs 9 Watts).

.bh.