My new fan controller.

emo · Post by **emo** » Tue Aug 31, 2004 7:22 pm

Well i just finished installing a Noise Isolator RH-35 fan controller into my machine. But the problem is that when i turn the fans down (i'm using pana lows) this damn thing starts squeeling like a stuck pig. So needless to say i am a little P.O.ed with this thing. It's 40 bucks out the window near as i can figure.

I did a search on these forums, (this fourm has been a god send to me) and now i am finding out this is a common noise with pwm fan controllers. DOH So what i am asking is there anyone out there who knows of some sort of solution to this problem? Thanks in advance for your input.

silvervarg · Post by **silvervarg** » Tue Aug 31, 2004 11:23 pm

The panaflos made in Japan usually works a bit better with PWM than the ones made in china. Still panaflo fans might not be the best choise to drive with PWM.
If you are up to DIY you can reduce the problem by soldering a capacitor on 1uF in parallell with each fan. The idea is that the capacitor smooths out the PWM pulses, so it becomes closer to voltage regultation. So you will loose some torque.

Another way is to connect a Zalman fanmate before the fan. This way the fanmate will reduce voltage quite a bit, so you can run with higher PWM duty cycle. This will help you noise-wise, but will reduce the speed range you can set with the controller.

Or you might just want to change to a controller that uses voltage regulation.

MadModder · Post by **MadModder** » Thu Sep 02, 2004 2:16 pm

It is possible to build a sort of low-pass filter with a diode, an inductor and a capacitor. This will smooth the edges of the pulse to make it look more like DC that is proportional to the duty cycle. However, this will generate an extra cost of about $6 or so per channel.

emo · Post by **emo** » Thu Sep 02, 2004 5:14 pm

Thanks for the input everyone. I tried putting a fan mate inline but that did not seem to help. I wll pick up some 1uF caps and try putting them in and see what happens.

MadModder: you said it i can build a low pass filter, the 6 bucks is no problem if it stops the whine from this thing. Can you elaborate on this? Thanks again.

Project · Post by **Project** » Thu Sep 02, 2004 5:40 pm

can doing that fix the ticking noise from my artic silver vga cooler?

MadModder · Post by **MadModder** » Wed Oct 13, 2004 10:53 am

Sorry for not answering in quite a while... :/
Anyway, I totally forgot one thing about this LC filter. It's designed for PWM pulses at the range 20kHz and up, to make a smooth DC level output of it, because the inductance in the fan motor coils becomes huge at these frequencies.
I have not had the chance to test something out for such low frequencies as from an ordinary PWM fan controller. I have to make one myself first, and I have no plans on doing that. Yet.

[edit]
I decided to show you the schematic anyway. Maybe it helps.
The 100µF inductor should be enough powerful to handle the maximum current the fan controller can put out.

Edward Ng · Post by **Edward Ng** » Wed Oct 13, 2004 6:33 pm

silvervarg wrote:The panaflos made in Japan usually works a bit better with PWM than the ones made in china...

WHOA--not that I don't believe you, but where did you learn this?

Bat · Post by **Bat** » Fri Oct 15, 2004 7:42 am

More details on that type of circuit.

MadModder · Post by **MadModder** » Fri Oct 15, 2004 7:58 am

Oooh... I never saw that one

silvervarg · Post by **silvervarg** » Tue Oct 19, 2004 2:53 am

silvervarg wrote:
The panaflos made in Japan usually works a bit better with PWM than the ones made in china...
Edward Ng wrote:
WHOA--not that I don't believe you, but where did you learn this?

From personal experience with a few 80mm L1A both China and Japan made. It has also been confirmed by others on this forum after my posting about differences between Japan and China made Panaflo fans.
I am not sure if it has been confirmed to be true for all sizes.

Edward Ng · Post by **Edward Ng** » Tue Oct 19, 2004 6:03 am

Gotcha'. Somebody feel like posting that up to my original thread where I invented the terms, "Japanaflo," and, "Chinaflo?"

I haven't tested this for myself, so I don't think I should be the one posting it in there.