Fan (and other cooling-related) basics

[LongRunner]

I thought Sunon was the one with noisy motors (not bearings or impellers). AFAIK that's because of the unusual stator design. Both their sleeve and ball bearing fans produce that vibration, which you can hear if you place a running Sunon on top of a PSU case (or presumably any other similar steel construction). Other fans produce the same noise but to a lesser extent. How the motor itself would degrade to worsen it, I really don't know. I'm familiar with the sound in question, and it's nothing like that from the impeller, which in most fans is the dominant noise source.

[Wester547]

Sunon fans move ample air even for their rattling noises and vibration. I have a Newton Power 250W whose Sunon sleeve bearing fan still works. Within the first 15-20 minutes of use, the rattling noises start. But I noticed that before that, when I press my hand against the fan grille, it starts making rattling noises and stops when I remove my hand from it. ADDA fans while not very reliable are incredibly quiet for the amount of air they move at least. I can't even hear their stators when they're temperature controlled.

[c_hegge]

I find that Sunon fans definitely vibrate and rattle much more than most other fans. It's as if the impellers aren't very well balanced.

[LongRunner]

Added bearings (long overdue, I bet) and sizes. Also, if you can figure out a new use (in-PC) for small (≤50mm) fans, post it here.

By the way: What's the loudest fan you've ever used???

[LongRunner]

Not all "fluid-dynamic bearing" fans actually have true fluid-dynamic bearings.

[c_hegge]

I saw that. That logisys bearing design was a little disturbing. I too would class that as just a regular sleeve bearing.

EDIT: The loudest fans I've ever used would have to be the Deltas on the old load tester

EDIT 2: I occasionally see 40 and 50mm fans being used as chipset fans and as case fans in small form factor PCs. In standard ATX computers, though there no reason why they need to be used these days.

[LongRunner]

Added: How to tell the difference between one ball + sleeve bearing and dual ball bearing fans.

[LongRunner]

There's a non-obvious problem with one ball + sleeve bearing fans. (Read my edited first post.)

[c_hegge]

Other than the marketing hype, I've never seen the advantage in 1B 1S bearing fans. They are more expensive for no gain, as they are generally no more reliable than plain old sleeve bearing fans.

[LongRunner]

Updated: Much of the post.