RadioLocman.com Electronics ru
Advanced Search +
  
Go Back   RadioLocman Forum > Electronics and ... > Projects and Advices

Projects and Advices Schematics and projects for elrctronic engineers.

Reply
 
Thread Tools Search this Thread
Old 08-10-2011, 06:47 PM   #1
Radiolocman Robot
Member
 
Join Date: Jan 2011
Posts: 223
Radiolocman Robot is on a distinguished road
Default Discussion: Build Yourself a Fan Temperature Control

Quote:
Tillmann Steinbrecher CPU coolers have been getting more and more efficient over the last years. However, this higher performance usually has a price: More noise.
More: Build Yourself a Fan Temperature Control
Radiolocman Robot is offline   Reply With Quote
Old 08-10-2011, 06:47 PM   #2
philipsbe
Junior Member
 
Join Date: Aug 2011
Posts: 1
philipsbe is on a distinguished road
Default

I am a total noob with electronics - can anyone explain to me why do we need a MOSFET in this circuit. Can we not use only the potentiometer in this circuit with same effect.
philipsbe is offline   Reply With Quote
Old 12-03-2012, 11:12 PM   #3
sonda
Junior Member
 
Join Date: Dec 2012
Posts: 3
sonda is on a distinguished road
Default

Quote:
Originally Posted by philipsbe View Post
I am a total noob with electronics - can anyone explain to me why do we need a MOSFET in this circuit. Can we not use only the potentiometer in this circuit with same effect.
Hi, this mosfet is acting here as a controlling gate. once it reaches the set point from potentio meter & from NTC simply the gate allows the current flow..
sonda is offline   Reply With Quote
Old 12-03-2012, 11:15 PM   #4
sonda
Junior Member
 
Join Date: Dec 2012
Posts: 3
sonda is on a distinguished road
Default

Quote:
Originally Posted by Radiolocman Robot View Post
Hi i did this circuit.... its awesome thanks for the circuit..... i want to add another function for this. can u pls tell me how to add an over ride signal to drive the fan directly at any time without damaging the circuit??
sonda is offline   Reply With Quote
Old 12-05-2012, 11:10 PM   #5
sonda
Junior Member
 
Join Date: Dec 2012
Posts: 3
sonda is on a distinguished road
Default

Hi can you please tell me how to add an + positive signal to override the circuit and run the fans directly when i needed.. thanks in advance..
sonda is offline   Reply With Quote
Old 01-28-2013, 05:20 PM   #6
kato
Junior Member
 
Join Date: Jan 2013
Posts: 5
kato is on a distinguished road
Default how to add a manual override switch

Quote:
Originally Posted by sonda View Post
Hi can you please tell me how to add an + positive signal to override the circuit and run the fans directly when i needed.. thanks in advance..
Sonda, yes, I can tell you how. I had the thought to do the same thing, then saw your question.

A fan override function is as simple as adding a switch.
You need only a SPST toggle switch to connect the "ground" of the fan. See how the positive 12v is always connected to the fan? Connecting the ground completes the circuit and turns the fan on. The MOSFET does this when temperature is reached. You will add a 2nd switch that will allow the fan to turn on either way, either by Mosfet/Thermistor automation, or human hand flipping a switch.

Simple instructions:

• Connect one lug of the SPST toggle switch to where Tillmann has has designated "To ground wire from power supply."

• Connect the other toggle lug to "To fan's black (-) wire."

Voila!

Let me know if you have any troubles.
kato is offline   Reply With Quote
Old 03-12-2013, 12:26 AM   #7
calmeida
Junior Member
 
Join Date: Mar 2013
Posts: 2
calmeida is on a distinguished road
Default

Hi there! I really appreciate this document. Very useful and exactly what I was looking for. I am a rc helicopter enthusiast and I recently adapter a dell server power supply to power a new charger I purchased.

The problem I was having was that the fan had no temp control and just ran full blast. I did build the circuit as you specified and it was perfect, until the PSU stopped working because the built in speed tac noticed the fan wasn't spinning.

What would be the best way to build this circuit to allow for a low end adjustment of the fan speed independent of the thermister? IE....an additional pot somewhere in the circuit. See attached.

Thanks!
Attached Images
File Type: png Speed controller.png (82.5 KB, 13 views)
calmeida is offline   Reply With Quote
Old 03-12-2013, 03:38 PM   #8
kato
Junior Member
 
Join Date: Jan 2013
Posts: 5
kato is on a distinguished road
Default

Calmeida, As I adjusted the 10k trimpot, the fan slowed and slowed as I continued to adjust until I moved past that sweet spot where the fan stopped altogether - presumably to reactivate at high temperatures.

You could try adjusting your trimpot for just before this spot and let your fan slowly spin at all times perhaps. Then it would ramp up at higher temperatures. (I'm using a 25-turn trimpot btw. A single turn trim would be hard to dial in just right.)

Dunno if that's enough of a draw to keep the PSU sensor happy. You may have to trick it with a dummy load so it thinks the fan is always spinning.
kato is offline   Reply With Quote
Old 03-13-2013, 01:05 PM   #9
calmeida
Junior Member
 
Join Date: Mar 2013
Posts: 2
calmeida is on a distinguished road
Default

Kato,

Thanks for the response. I've tried a number of way to adjust the pot but if it's too cold than the fan wont come on at all and the PSU will not work. If I adjust the fan at the coldest point in the day then by later in the afternoon the fan is almost going full blast, which is unnecessary and loud. I am using a 25 turn POT as well. I think the best bet would be to somehow set a baseline speed where the fan cannot go any slower. Believe me, I have adjusted this thing quite a bit to find a happy medium and either the next time I turn it on the fan doesn't come on or it comes on full blast.

Thanks,
Chris
calmeida is offline   Reply With Quote
Old 05-05-2013, 09:24 PM   #10
Scooby
Junior Member
 
Join Date: May 2013
Posts: 2
Scooby is on a distinguished road
Default How to adapt for 5v fan?

This controller is exactly what I need to run a fan in my cctv dvr. However, space is limited and I can only accommodate a 5V laptop fan.
How do I adapt this circuit to run from 5V supply instead of 12V? (HDD supply has 12v and 5v, but I don't want the fan to run continuously.)
Guidance appreciated.
Scooby is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 04:05 AM.




Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Slices ↓
Radiolocman facebook Radiolocman twitter Radiolocman google plus