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More than you cared to know about PC fans

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Re: More than you cared to know about PC fans

#11

Post by owenversteeg »

Does anyone know if there are high-heat-resistant PC fans (and at what temperatures normal PC fans will melt)? The only fans I can find that claim to be heat-resistant are the Noctua Industrial PPC series which, aside from not being cheap at $33/piece are "only" heat-resistant up to 140C and the airflow isn't crazy high - subjectively the ones I've got feel like they move substantially less air than a standard diesel heater blower fan.

Ideally I'd be interested in something that's >180C resistant but if there are any other options around say 140C max then I'd also be interested.

Re: More than you cared to know about PC fans

#12

Post by tinco »

owenversteeg wrote: post #11

Does anyone know if there are high-heat-resistant PC fans (and at what temperatures normal PC fans will melt)? The only fans I can find that claim to be heat-resistant are the Noctua Industrial PPC series which, aside from not being cheap at $33/piece are "only" heat-resistant up to 140C and the airflow isn't crazy high - subjectively the ones I've got feel like they move substantially less air than a standard diesel…

If $33 is not cheap then maybe not. But I buy my delta fans at mouser or digikey, and they have a wider range of specs than typical consumer websites. They come without connectors though so there's some crimping/soldering required.

For our little rendering cluster I bought a bunch of 12.000 rpm fans to cool the rack mounted threadrippers. Worked fine, no watercooling in the rack needed and 4ghz on all cores under load.

Re: More than you cared to know about PC fans

#13

Post by ilyt »

I'm surprised it doesn't mention hysteresis some fans have at low speed.

Cheap fans often don't have actual proper speed controller on them which means they might start spinning at say 30% PWM but only stop spinning at 15% PWM. That was probably the thing that surprised me most when I upgraded to nice Noctua, at certain PWM it just started, always, and below that it stopped, always.

Re: More than you cared to know about PC fans

#14

Post by magicalhippo »

hoseja wrote: post #6
magicalhippo wrote: post #4

What I want to know is how a ballbearing-less fan suddenly decides to go brrrrrrr. So far I've been lazy and just replacing them, but I'd be nice to know as they seem fine when I spin them manually.

Are you sure it's not a resonance elsewhere?

Yes, if I run the fan stand-alone it will start to brrrr after a short while.

Re: More than you cared to know about PC fans

#15

Post by jenscow »

owenversteeg wrote: post #11

Does anyone know if there are high-heat-resistant PC fans (and at what temperatures normal PC fans will melt)? The only fans I can find that claim to be heat-resistant are the Noctua Industrial PPC series which, aside from not being cheap at $33/piece are "only" heat-resistant up to 140C and the airflow isn't crazy high - subjectively the ones I've got feel like they move substantially less air than a standard diesel…

I prefer fans that are not heat-resistant. That way, it has more motivation to do its job properly.

Re: More than you cared to know about PC fans

#16

Post by lazide »

owenversteeg wrote: post #11

Does anyone know if there are high-heat-resistant PC fans (and at what temperatures normal PC fans will melt)? The only fans I can find that claim to be heat-resistant are the Noctua Industrial PPC series which, aside from not being cheap at $33/piece are "only" heat-resistant up to 140C and the airflow isn't crazy high - subjectively the ones I've got feel like they move substantially less air than a standard diesel…

Why?

Re: More than you cared to know about PC fans

#17

Post by Eisenstein »

rietta wrote: post #10
azalemeth wrote: post #3

Honestly this isn't more than I cared to know about PC fans. I've worked extensively with industrial appliances and fans are bloody important and underlooked: fan failure is often the step that precedes component failure. The one part of the spec I wasn't aware of was just how insanely high the maximum current draw is; I'm glad that we've made more efficient, longer-lasting, effectively silent air-movers that can fit…

Adding fans to consumer devices that don't have them but should, such as a cable modem, certainly improves its reliability in my experience!

The problem with that is when the fan would block the natural venting if it stops working. These devices are engineered to have the heat move the air through and out of the device, and though a fan will usually do a better job of that, it will ultimately fail. When it does, if the fan body is in the way then the intended convection is blocked and the entire unit shuts down or is damaged.

Re: More than you cared to know about PC fans

#18

Post by michaelt »

owenversteeg wrote: post #11

Does anyone know if there are high-heat-resistant PC fans (and at what temperatures normal PC fans will melt)? The only fans I can find that claim to be heat-resistant are the Noctua Industrial PPC series which, aside from not being cheap at $33/piece are "only" heat-resistant up to 140C and the airflow isn't crazy high - subjectively the ones I've got feel like they move substantially less air than a standard diesel…

Unfortunately many plastics, and the most common types of solder, start softening before you get to 180C. You can get smoke extraction fans and chimney flue fans that will tolerate higher temperatures, but they're generally an all-metal affair costing more than $33.

Assuming the 180C is at your system's ventilation output, could you move your fan to the air inlet so it only has do deal with ambient temperature air? That's what's done for blacksmith's forges etc

Re: More than you cared to know about PC fans

#19

Post by Retric »

Eisenstein wrote: post #17
rietta wrote: post #10

Earlier quoted context omitted.

Adding fans to consumer devices that don't have them but should, such as a cable modem, certainly improves its reliability in my experience!

The problem with that is when the fan would block the natural venting if it stops working. These devices are engineered to have the heat move the air through and out of the device, and though a fan will usually do a better job of that, it will ultimately fail. When it does, if the fan body is in the way then the intended convection is blocked and the entire unit shuts down or is damaged.

Cable modems are often placed in poorly ventilated spaces that overheat. So you can get the best of both worlds by including generally unneeded fans which enable the device to function in sub optimal conditions, but can also extend lifespan in better ventilated spaces.

The alternative of passive cooling in such spaces is unreasonably expense because only a subset of devices are subjected to such conditions.

Re: More than you cared to know about PC fans

#20

Post by antifa »

I wish noctua would sell aftermarket replacement CPU fans for laptops. I thought there was something wrong with the loudness of my Dell laptop's fan (with low confidence), but I couldn't gauge that any replacement product wound actually be quieter or cared about noise levels.
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