I want to slow down a Prescott stock HSink fan via a variable resistor with cct board, you have a guide on that?

i think "Variable fan speed controller" was same as volume controler like the normal radio used one... ur modded just like Cooler Master HSF connection...

Nope, i don't have it...
I'm not an electronic engineer...

However, you could ask some forumer here on how to do it...

Im not saying you...Im asking 'dj.eRicZzz' for pics coz maybe we can help him..

This is to make it faster or slower?

Faster laaa...

That method is used for those people who's using Fans that comes with 4 PIN PWM but using it on 3 pins motherboard header...

i have done do it.wah so noisy.it get to full speed.but have massive air flow.

hey can i put the fan controller on my fan for slow down the rpm.

Good for you...
And, yes...
The airflow is massive...
Just like my Hyper 6+ fan with setting on the maximum speed...

My hyper 6+ 100MM fan is 46.6DBa when on maximum speed...

About your question on the fan controller, i don't know about that...
Why don't u go ask "allngap" maybe he has the right answer for you...

Oh..was confused...thanks..

No problem...

Bro "Sniper On The Roof"
Help me please...

Ehh?
No one interested in this topic aa?

You can use a variable resistor from the hardware shop (abt RM1), though you'll have to solder the wires to it. Just connect the wires to the centre and one of the side pins-which pin you connect to will affect which direction you have to turn to adjust the fan. Will try out first which resistance is suitable, if you want to try (and not blow your system) I suggest the steps below

1. Before you try this on your proc main fan, try it on one of your spare fans connected to a 3pin/4pin connector on the motherboard (chassis or power fan connector).
2. Cut the +12V wire on the fan connector, connect one end to the centre pin of the var. resistor. Using the black one might also work, but could potentially mess up the fan speed signal (yellow) & speed control (4th wire in 4-pin connector).
3. Connect the other end of the cut wire to one of the side pins of the var. resistor, set the resistor to the centre.
4. Start up the PC & adjust the fan controller from min to max. If the direction is wrong, then shut down & reconnect the wire to the other side.

What will most probably happen (haven't tried on a fan, but tried on a lamp)
-if resistance is too high, fan won't spin at all except when set to almost max.
-if the resistance is too low, you won't be able to noticably control the fan (not much difference in speed even when you adjust the resistor.
-worst case, the variable resistor will overheat and blow (for high power fans). 1 out of 2 things could happen, neither is very serious-short through the resistor & fan spins at max speed only (less common) OR resistor contact blows & fan stops (more common)

Anything I miss, pls correct me

Planning to build a suite of fan controllers for my rig, will experiment with variable resistors, then try transistors & PWM.

this is sumthin like what happened when i tried it with a Delta FFB1212EHE (3.0A Fan). the VR started smoking man!!!

im guessing doing this without a proper board with other stuff (dunno exactly what) on them is not ideal unless its a low powered fan (im guessing sumthin below 1.0A??)

high powered ur definitely gonna be needing those circuit boards. although 1 thing to check is to make sure ur fan can run (AND start) at low voltages.... mebbe a minimum of 5v. coz if ur building a fan controller with the VRs ull be adjusting the voltage being fed to the fan...and too low ur fan will just end up stopping if it cant run at low voltages. but if ur building a PWM controller than no need to worry about the low voltage thingy as a PWM will be sending out 12v on pulses.. and ur just controlling the frequency of the pulses.

EDIT: forgot to mention that i made a switch instead of using VRs to control my fan speed...but all ull get is hi-low speed....

12v-5v SWITCH <- i did this for the fans (ALL fans including my Deltas) in my case

12v-7v SWITCH


This post has been edited by mADmAN: Sep 24 2006, 02:04 AM

3A is crazy for a VR..even 1A is tough for cheap transistor circuits, even then they need heatsinks Look in your PSU if you don't believe me-those are costly, EFFICIENT transistors-power MOSFETs to be precise, and they still need heatsinks (though they handle like 20x more current than the cheap transistors we get at the electronics shop).

Most resistors can handle 1W output across the resistor, VRs are notably lower. Quick estimate calulation-5V on fan means 7V taken over on resistor..whole circuit probably pulls 0.5A when fan is spinning slowly at 5V..comes to about 3-4W on the VR-sizzle .... VRs probably only suitable for fans drawing well below 1A when at full speed, at 5V probably only 0.1W so VR can probably take it. No way to know till try it out..guess have to redouble efforts to design & build transistor (<1A) or PWM switching (1-3A) controllers..sigh..thought it would work..didn't have time to do the calulations earlier..forgot that most of the noisy fans needing fan controllers pull 1A++..

edit:
Oh btw, I've heard that fans can still not spin if PWM is set to too low a speed. Fan just vibrates in place...pulse not long enough to give power to turn..

This post has been edited by lohwenli: Sep 25 2006, 06:07 PM

Damn you're pro in this...

***Can help me build a PWM voltage controller for my Nidec Beta 5 fan?

No le...just happen to be studying electronics as part of my physics course..also like to mess around. Anyway I'll try building it first, then I'll get back and give my results..dunno where to find time to do it also..exams coming soon . Basically need an adjustable timing circuit (can rig a 555 circuit 4 a few ringgit) to give pulses to switching MOSFET or JFET which will act as an electrially controlled power switch turing on and off hundreds/thousands of times per second (FET-field effect transistors, sounds cool, but they're still just basic transistors, not some fancy energy thingy). The longer the switch is closed compared to when its open, the faster the fan will spin. Have parts for the timing circuit already, will try these few days when free, but need to do research on FETs (gotta dig up them datasheets-sigh, easy to find low Amp mosfet, but tough to pick good ones) before I rig one to the timing circuit.

I don't even understand even a word you're saying here...
But, what the heck, i'll just wait for the results of the incoming PWM fan controller then...

agreed...

too technical already.... halfway thru ur paragraph i got so blur i could barely see the words

anyway...concentrate on ur exams first... then later screw around with the controller. all the best with exams dude

Yerp, what lelaki gila says is right...
Concentrate on you're studies first, then build a PWM fan controller for me later...

Joking only...