fan controller noiser when lower voltage?

[tony4704]

I just bought a fan controller for my fans hoping to make them quieter. For some reason when I turn down the speed at anything less than full speed, the fans make a whining noise. I have 3 different fans, a chipset fan, and 2 120mm fans. all of them do this its awfully loud. Its quieter to have the fans at full speed then to reduce their speed and listen to this whining s@#t. Anyone know what the heck this is? thanks

 

[suszterpatt]

How much (in RPM) do you need to turn down the fans before they start making noise? Or is it literally anything less than full speed?


What kinds of fans are these, and how old are they?

 

[tony4704]

yes, anything less than full speed does it. They are brand new fans. The 120mm ones are from performance pcs they are ac ryan fans and the small one for the chipset is for an asus a8n32 board. All of them whine like little bishes.

btw what is the little yellow wire for that is on some fan connectors and not on others?

 

[GalvanizedYankee]

Link the 120 fans plz.
what brand and type of controller?
Black=ground, Red=12V, Yellow or blue=sensor wire but it may not monitor rpm.


...Galvanized

 

[tony4704]

here is the baybus http://www.frozencpu.com/bus-34.html
and here are the fans http://www.performance-pcs.com/catalog/...product_info&cPath=69&products_id=2939

thanks

 

[mindwreck]

the PVM controller is probably screwing with the fan's motor and causing it to make the noise

 

[GalvanizedYankee]

The ball bearings should not be a loose running clearance like 3500 rpm fans would need because the fans you linked are 2500 rpm. Generally high speed fans will click and growl when undervolted. Your fans are NOT high speed fans.

Since all the fans are acting up when slowed down, I suspect the PWM controller that is in use. I have bench tested atleast 12 differant types of fans using a Sunbeam Rheobus and a NeXus PWM controller. Most fans in my testing run in undervolted sweetness when on a rheostat because there is no pulse of voltage hitting the motor. On a rheostat the LEDs my dim. If you can live with that get this controller.

http://www.jab-tech.com/Sunbeam-5-1-4-Rheobus-Kit-BLACK-pr-2530.html

Note that this same unit is $30 at frozencpu. If your not sure what PWM is, Google it as it is a bit much to explain here.
The LEDs on the Sunbeam are quite bright but two coats of dark nail polish will dim them to your liking. www.silentpcreview.com has a good tutorial on this controller. You will find it in the fans and controls section. The only danger with this controller is that the fans can be turned off. If you are the only user of this rig it won't be a problem.


...Galvanized

 

[GalvanizedYankee]

Originally posted by: mindwreck
the PVM controller is probably screwing with the fan's motor and causing it to make the noise

Great post and detailed explaination.

BTW, what's PVM?? Google shows it as a Parallel Virtual Machine

What does running Unix and/or Windows have to do with the OP's question. Oh! I get it!
Your working on post count


...Galvanized

 

[mindwreck]

get the sunbeam from svc. its only 10 bucks there. i've had mine for 3 years and it is still the best fan controller i have ever tried

 

[tony4704]

Thank you much for the details, I happen to know what PWM (pulse width modulation) is because I'm an electronic engineer. Are you suggestion that I need a baybus that does not use PWM or is the one you listed better at doing PWM? thank you again!

 

[mindwreck]

the sunbeam doesn't use pwm, a non pwm fan should fix your problem

 

[GalvanizedYankee]

The one I linked uses four rheostats, they are not the old fashioned kind that use windings around a round core but some type of electronic set-up that uses small pots to direct the current through a resistance. Read the review on it at SilentPCreview.com.
Since your the EE come back and explain to us how it operates, once you get it.

I bought three of them when they were on sale at Xxoide(?) awhile back.


...Galvanized

 

[Zepper]

Some fans work well with a PWM fan controller but fans can buzz (usually sleeve bearing like Panaflo) or whine (usually ball bearing). I've been wondering for a while if putting nice sized caps on the fan outputs of PWM controllers would reduce this problem, but it would also reduce the effectiveness of the PWM controller as it would reduce or eliminate the "off periods" between the pulses. So I've gone to a linear controller (Sunbeam Rheobus - http://www.jab-tech.com has been selling them for $9. lately) myself. I think the newer Sunbeams are also PWM as they are less expensive to make than the linear designs.
. It's a sad trade-off as the PWM controllers are more efficient (less wasted power).

.bh.

 

[tony4704]

So why exactly then does the fan controller I have not work. I still dont understand why, because the ones you listed seem to be PWM as well.

 

[Zepper]

The original Sunbeam Rheobus is a linear controller. It does not cause either whine or buzz. The output of a PWM controller is like a square wave, basically like turning the fan on and off a number of times a second. The type of motors and bearings of the fans as well as the shape of the output wave determines how those on/off pulses are translated into sound.

A 120mm Nidec SmartFan I have seems to handle PWM better than most, but I don't really know why. It does have precision dual ball bearings, but I don't know how the design of the motor might be significantly different from others. The 92mm Nidec I have doesn't handle PWM as well.

Perhaps a smaller cap on the output of PWMs just to smoothe the edges of the output wave might reduce the tendency to create noise a bit. I'll have to experiment with that one day.

.bh.