Sunon Magnetic Levitation System - any good?

Kreesto · Post by **Kreesto** » Thu Feb 27, 2003 4:37 am

I've been searching for a quiet 40mm fan to replace the power supply fan in my SN41G2 and I ran across these "magnetically levitated" fans from Sunon that they claim to be really quiet. Here's the manufacturer's link:

http://www.sunonusa.com/ms.htm

Does anyone have any experience with these fans? I know most of the noisy fans I own are Sunons, but these are different from what I have. Also, if you know of a really quiet 40mm x 10mm fan, please let me know!

Thanks,
Kreesto

Fastman · Post by **Fastman** » Fri Feb 28, 2003 2:39 pm

According to the specs on that page
for 40 x40 x 10 fans,
the noise is

36 dB for 8.6cfm at 8800 rpm for fastest in series
or 25 db, 5.9cfm, 5500 rpm for the slowest in the series.

They don't seem very quiet.

No room for a larger, quieter fan? Could you mount a fan on the outside?

BriceB · Post by **BriceB** » Fri Feb 28, 2003 9:02 pm

I agree with Kreesto.. it'll be really hard to get a 40MM quiet & still have it move air.. I just hacked the hell out of my PSU & Case.. and now have a 92MM exhausting out of the top!

Cheetos for skil saws..

Brice

Justin_R · Post by **Justin_R** » Fri Feb 28, 2003 10:00 pm

I might be mangling the model number a bit, but the Sunon KD1204PFS3 is very quiet for a 40x10mm fan. I think you can get them from digikey.com in the US; electronics suppliers in other countries might have them, too.

Basically, what you want to look for is a fan with the right kind of ending on it's model number. For Sunon, all their slower fans end in "3" (I think there might be a "4" somewhere). Slow Delta fans I believe are "L", as are Panaflos.

jinu117 · Post by **jinu117** » Sat Mar 01, 2003 2:28 am

Fastman wrote:According to the specs on that page
for 40 x40 x 10 fans,
the noise is 36 dB for 8.6cfm at 8800 rpm for fastest in series
or 25 db, 5.9cfm, 5500 rpm for the slowest in the series.

They don't seem very quiet.

No room for a larger, quieter fan? Could you mount a fan on the outside?

25db 40x40x10 fan with that much airflow is darned quiet. If there is less "bearing noise" the quality of noise might be better than panaflo as it has much less friction surface, etc.
One thing might be worth looking at 40x40x20 option which will lower the noise a little more for same output (and rotates perhaps a little slower).

Kreesto · Post by **Kreesto** » Sat Mar 01, 2003 5:22 am

Thanks you all for your replies. I haven't yet torn apart my power supply to see if there's room for a bigger fan, but it's pretty darned small in there!

I don't believe anything larger than 40mm diameter will fit, but I might be able to get away with a 20mm depth for increased air flow and then slow the fan speed down to reduce noise.

I was thinking I could wire a resistor inline with the 12v power lead to reduce the voltage. Does anyone have any experience with this?

Thanks!

Kreesto

BriceB · Post by **BriceB** » Sat Mar 01, 2003 10:42 am

Kreesto wrote: I was thinking I could wire a resistor inline with the 12v power lead to reduce the voltage. Does anyone have any experience with this?
Kreesto

One way I went about this was soldering a few (6) 1N4001 Diodes together (each giving a 0.7v forward voltage drop), then insultating the thing and attatching it in front of my 12 volt connection.

Brice

Justin_R · Post by **Justin_R** » Sat Mar 01, 2003 10:03 pm

Kreesto wrote:I was thinking I could wire a resistor inline with the 12v power lead to reduce the voltage. Does anyone have any experience with this?

I did exactly that to the 40x20mm fan (a Fonsan ???LL) that I used to replace the stock fan in one of my small PSUs. Just buy some resistors in the appropriate range for the current your fan draws and see which one provides a good balance between noise and airflow. Don't cut it close with the resistor power rating, though; try to get ones that are at least 0.5 W.

Edit: Addendum

Also be sure to remove the fan grill on the back of the PSU. It just adds turbulence (and noise) to the air coming out of the fan. Also, it allows you to mount a 40x20mm fan on the outside of the PSU if one won't fit inside the PSU.