Is it worth being super concerned over the risk of fire hazard using fan speed reducers?

frogtech

Well-Known Member
Jan 4, 2016
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Got some Noctua fan speed reducers which I'm sure everyone here knows are just in-line resistors however I'd never actually used them before in any scenario so just learned that by nature they're 'supposed' to be hot. I just wonder how much of an actual risk there is there of them being a fire hazard.

I may not end up using them, it depends on how anal I am about sound/airflow, but if they're not worth using if you're paranoid about a fire hazard I have Noctua 20mm fans I'll just use that should be fine. But I would rather be able to force more air into the chassis while still being quiet, if I can, if it's considered relatively safe.

Also, can you create more airflow by putting two fans of the same type behind one another?

Thoughts/comments?
 

Evan

Well-Known Member
Jan 6, 2016
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You absolutely can do a fan in front of another, it’s how lots of servers are for redundancy.
Now other than that I don’t know the effect, I assume it would increase static pressure (a good thing from a cooling point of view, less so sound)
 

Dawg10

Associate
Dec 24, 2016
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Two identical fans in series will move the same volume as one fan. Static pressure across the two will be twice that of one fan minus some efficiency loss.

Power resistors are designed to dissipate heat; some applications require heat sinks.
 
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Spartacus

Active Member
May 27, 2019
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I would be concerned with off brand or random ones, Noctua products are pretty solid though and they wrap them so you at least avoid any direct contact with the hottest part of the resistor/wires.
As long as you don't put it touching anything, they should be fine IMO.
 
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laserpaddy

Active Member
Jul 17, 2017
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out there
They would have to get damn hot to cause a fire- if you wanted you could use 3m heat-shrink on them- that stuff takes direct flame- I have an ink-bird cheap temp/ac outlet switch in key points to separately monitor temps at various locations in rack- they are cheap and effective
Amazon.com: inkbird