Mag Lev fans any good?

Rokugo · Post by **Rokugo** » Thu Sep 08, 2005 7:50 pm

Just wondering.. no bearing=low noise?

I was just in my local PC shop asking about Northbridge cooling saying my fan was loud and i might run it undervolted.. and The guy tosses me a 40mm Sunon Mag lev fan and said thats what they use for replacment fans... should i bother bolting this bad boy up to give it a try or just undervolt my stock unit?

Thanks

EvilNick · Post by **EvilNick** » Fri Sep 09, 2005 9:24 am

I used to have a Sunon MagLev 40mm fan too and let me tell you, even though it spun at 6000 odd rpms, it was excellent from an acoustic standpoint. Practically silent even when you held your ear up to it.

vine-au · Post by **vine-au** » Fri Sep 09, 2005 10:13 pm

never even knew there were maglev fans

(I used to use a Vantec TMD TipMagneticDriven CPU cooler but that doesnt really qualify)
great concept... <me goes googling>

nici · Post by **nici** » Sat Sep 10, 2005 1:42 pm

The chipset fan on DFI nF4 boards are MagLev fans..

ronrem · Post by **ronrem** » Sun Sep 11, 2005 5:55 pm

Mag Lev is fine-its the brutal fact that to get airlow small fans run at 3000-6000 rpm. The typical stock NB sink on an NF4 is pretty minimal and rather than do a better sink a high rev mini fan is the cheap answer...which won't be silent. A 6000 rpm maglev only takes a lousy basic concept and improves it a bit.. Glue a chunk of wood in place and bolt on an undervolted 120 at about 600 rpm-you get silent operation and cooling. A 700 rpm mag-lev 140 mm fan may someday be the favorite here amongst the cult of quietness but for now its as unavailable as good lookin' chicks hot for fat guys with no money and bad breath.

pangit · Post by **pangit** » Sun Sep 11, 2005 6:04 pm

^^^^^^^^^^^

Nice one ronrem! Must be where I've been going wrong all this time with the chicks!

As has been alluded to already, most fan noise is turbulence, not bearing noise, it's only when you really slow them down to <1000rpm that quiet bearings have much benefit.

So yes, in theory maglev fans would be great if slow 120mm ones existed, but decent sleeve bearings such as in the Nexus contributes very little to the overall noise anyway.

ryboto · Post by **ryboto** » Mon Sep 12, 2005 12:29 pm

these fans could potentially be "immortal"...without a bearing, they could last much much longer than typical bearing fans. My only curiosity is about how they act when given a lower than rated voltage...would it even work? if the mag lev bearing requires a certain amount of power to generate the magnetic field and "float", what happens if you run it at a lower voltage??? There's a 92mm mag lev fan available at a very few number of online retailers, but I don't want to spend the money if it's not going to run on 7v or lower.

BrianE · Post by **BrianE** » Tue Sep 13, 2005 12:19 pm

ryboto wrote:these fans could potentially be "immortal"...without a bearing, they could last much much longer than typical bearing fans. My only curiosity is about how they act when given a lower than rated voltage...would it even work? if the mag lev bearing requires a certain amount of power to generate the magnetic field and "float", what happens if you run it at a lower voltage??? There's a 92mm mag lev fan available at a very few number of online retailers, but I don't want to spend the money if it's not going to run on 7v or lower.

From what I've seen, it looks like MagLev uses permanent magnets on the bottom plate of the fan (where it's mounted). They pull down on the regular magnets surrounding the shaft/stator and even out the forces on the shaft.... it doesn't sound like it's really totally contact-free and completely levitating, it just prevents vibrations and uneven wear between the bearing and shaft.

www.sunon.com.tw/english/wealth/tech/tech-05.htm

I think it would be foolish to produce a technology that can't operate at lower voltage, since fans are routinely undervolted all the time in applications like PSU and CPU fans.

johnjv · Post by **johnjv** » Thu Sep 22, 2005 5:45 pm

They can still be had if you know where to look.
http://www.gruntville.com/reviews/heats ... /index.php
**they say it runs at 5v.

The price has gone way up now at frozencpu. Comes with mosfet heatsinks too. I put this on my AN7 and the noise is higher pitched at 12v. It runs MUCH more quiet at 8v but I could still hear it (not quiet).
Glued the copper hs with artic alumina and retired the mag-lev.