Can you mod a thermal control fan?

S

SelRahc

Limp Gawd
Joined
Aug 12, 2004
Messages
389
I have 2 fans I sleeved for a project im working on. They are just a noname brand from compusa, but are hella quiet. I think better than my stealths at same speeds.

Anyways, I egerly sleeved them for installation and I realized I made an oppsey. The fans are thermal controled. Thermal controled fans on a water cooled setup are not exactly what I was looking for....

Heres a closeup of the fan in question.
work_20.jpg


Power lines (3 wires) run up into the fan. Then 2 wires run out of the fan to a thermal temp sensor.

My question is, can I mod this fan to remove the thermal sensor so it will run at full 12v speed? This way I can use the controller I have to adjust the fan speed.

Or do you think Id just be better off picking up another stealth 120mm fan. (I have 1 spare already)

Or will it matter? Will the thermal sensor interfear?

Im thinking it would keep the rpm low no matter what voltage you push through, since the hot temps are in the water, not the air. This fan would ignore the fan controller wouldnt it?
 
well if you are not afraid of losing the fan, Im not very sure if this will work, you can get rid of the temp. sensor and try connecting the two wires. This will work if it controls the fan by using switch type circuit, using the temp. sensor as a sort of resistor.
 
Most thermistors have a resistance that increases with temperature. So you can put a smaller resistor across the two wires to make the fan think it's cooler than it is (and consequently slow itself down). I don't know exactly how thermally sensitive fans work, but shorting out the wires may not be the wisest choice. Then again, it could be harmless. You'll have to find out for yourself.
 
meh.... I'll just pick up another stealth tonight. Perhaps ill just play with it later.
 
I have replaced thermisters on fans with 10k pots in the past. It is a easy way to get a speed controllable fan.
 
Teancum said:
Most thermistors have a resistance that increases with temperature. So you can put a smaller resistor across the two wires to make the fan think it's cooler than it is (and consequently slow itself down). I don't know exactly how thermally sensitive fans work, but shorting out the wires may not be the wisest choice. Then again, it could be harmless. You'll have to find out for yourself.
Click to expand...


You have this backwards.
Most Thermistors have a negative temperature coefficient, meaning a rise in tempature will result in a decrease in resistance .

If you remove the thermistor, and short the wires(0 ohms of resistance) that will turn it into a normal fan.
 
Spazilton said:
You have this backwards.
Most Thermistors have a negative temperature coefficient, meaning a rise in tempature will result in a decrease in resistance .

If you remove the thermistor, and short the wires(0 ohms of resistance) that will turn it into a normal fan.
Click to expand...

agreed.
 
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