thermal controled fans HELP!

[HDCHOPPER]

got 2 of these fans spec's say thay will do 5000+ rpm and put out 121 cfm want to put them on my new COOLIT unit

but thier a green thermal do daaa that controls the speed acording to temps ... want to by pass that and run them at full speed ! could you just wire across the leads for the thermal control (green thing ) and remove it (green thing) ???

dont care about the noise played with jets & hoggs all my life & half def anyways

any help would be greatfull .. here's a link to the fans


http://www.directron.com/ds923812hbtl.html

again thanks in advance

[littleowl]

I could be wroing but your fans are not what is dealing with the heat it would be your mobo. if you take the black wire (ground) and the red wire (12v) and plug them into the psu then you should be running at 100%. you can try this by using a small wire and plugging into the 3 pin clip and the psu molex connector. red to yellow and black to black.

[HDCHOPPER]

ya thought about doing that
thay came off of a pair of dell's with plain alum sink with a 90* duct to the rear of the box with this fan mounted at the back
that green thing (in the middle of the hub) is a thermal sensor

[littleowl]

yeah I have seen several fans with the thermal sensors! I remember reading that you can cut them out and jump it but I don't know if that is true or not.

[HDCHOPPER]

thanks you littleowl thought eye read that somewhere also so thats 2 feel better now !!

hopeing uncle jimbo will show up the man seems to know his biz

[Uncle Jimbo]

yeah I have seen several fans with the thermal sensors! I remember reading that you can cut them out and jump it but I don't know if that is true or not.

To make the fan run full speed, take the thermistor out and replace it with a resistor which has a larger value. You can just measure the resistance of the thermistor with a voltmeter. It is probably a 10K at 25C unit, so a 15K resistor should give full speed.

[ZOMGVTEK]

I thought some thermally controlled fans would just run at 100% if the two probe leads were shorted?

[HDCHOPPER]

thank you uncle jimbo !
figgered a resistor might be required just didnt have a clue which ones
will mesure it and get the required value resistor

thanks again all for your replys!!

[littleowl]

To make the fan run full speed, take the thermistor out and replace it with a resistor which has a larger value. You can just measure the resistance of the thermistor with a voltmeter. It is probably a 10K at 25C unit, so a 15K resistor should give full speed.

hum I learn something new everyday on this forum!!!

[Uncle Jimbo]

I thought some thermally controlled fans would just run at 100% if the two probe leads were shorted?

No that will turn the fan off - see above. You need a resistor between the leads.

[leuler]

Sanyo Denki fans seem to work differently. Adding resistance raises the
temperature set points. To run an external thermistor controlled fan at
low speed all the time, you replace the thermistor with a 10k resistor.
To run the fan at high speed all the time, connect the control lead to the
negative lead.


http://www.sanyo-denki.com/CurrentCo...alog/Index.pdf
(thermal speed controlled fans)

[Uncle Jimbo]

Sanyo Denki fans seem to work differently. Adding resistance raises the
temperature set points. To run an external thermistor controlled fan at
low speed all the time, you replace the thermistor with a 10k resistor.
To run the fan at high speed all the time, connect the control lead to the
negative lead.


http://www.sanyo-denki.com/CurrentCo...alog/Index.pdf
(thermal speed controlled fans)

Thanks - good info!
Replacing the thermistor with a 15K variable pot (or 1.5 times whatever resistance the thermistor measures at 25C) allows you to adjust speed in either type of fan

[leuler]

Thanks - good info!
Replacing the thermistor with a 15K variable pot (or 1.5 times whatever resistance the thermistor measures at 25C) allows you to adjust speed in either type of fan

Even better info!

[HDCHOPPER]

thank you thank you exellent info !

yup learn something new every day