Anyone experimented with 120V fans?

Bartender · Post by **Bartender** » Fri Dec 02, 2005 7:01 am

Good day to everyone -
Strange voices in my head are sending me messages - something about trying to build a wood case with 120V fans instead of 12V. I can't find much information about that, although there are a LOT of 120V fans available. Papst makes hundreds of 'em.
If a guy's thinking about building an entirely non-traditional case anyway, it's not entirely nutty to re-examine everything as part of the process. For instance, why do we ask our PSU's, whose real job is to provide clean low-voltage power to those sensitive computer parts, to do grunt work like spinning fans? Because that's the way we've always done it.

Has anyone got any thoughts on this? Are there very quiet 120V fans? If I'm going to build some sort of weird science wood case, I'm not limited to traditional fan sizes, either. Betcha a couple of fans in the 150mm to 170mm range would move some air...

Aris · Post by **Aris** » Fri Dec 02, 2005 7:44 am

spinning a fan, for a psu, is barely any work at all. take the nexus 120mm fan thats so popular around here, its slated max input power is only 1.8watts. a typical 3.5" hard drive pulls around 10-20watts of power.

i would guess the reason no one has ever put an AC motor in a computer before is because every other device runs on DC power. also theres already an AC-DC powersupply inside the case, so why not just go ahead and use it since it already has to be there.

theres no doubt that you can get some hefty ac fans that push some major air, but i highly doubt their acoustic properties are going to beat somthing like a 120mm nexus fan. thats going to be your major obsticle if you decide to go this route, finding large AC fans that are quiet.

StarfishChris · Post by **StarfishChris** » Fri Dec 02, 2005 8:22 am

Have you looked here and the threads linked from it?

Post by **Rusty075** » Fri Dec 02, 2005 8:23 am

Actually, there's been quite a bit of discussion, and use, of 120v fans. See this sticky atop the Fans forum: The Top SPCR Quiet 120mm Axial Fans Compared + 120mmAC Fans.

Bartender · Post by **Bartender** » Fri Dec 02, 2005 11:18 am

Hi, everyone -
Sorry about that. Typical mistake, posting dumb questions before looking around a little. I'll try to educate myself with the info already available here. Thanks for writing back, though...

Post by **Rusty075** » Fri Dec 02, 2005 11:50 am

No biggie, we were all new at some point.

From a personal opinion standpoint, with regards to the AC fans I would have trouble justifying the cost, trouble, and potential hazards of using 120v fans for what sounds like noise gains that are marginal at best. Just something about adding 120v AC inside an already tight case, where I always seem to end up tinkering with bare hands, strikes me a a bad idea.

Qwertyiopisme · Post by **Qwertyiopisme** » Fri Dec 02, 2005 12:15 pm

This a just an idea off the top of my head, but shouldn't you be able to make an AC fan extremly quiet (assuming the bearings are any good) by running them off a variac? (variable transformer).