I just got some fans in for the mix 'n match 630's builds, and was trying to come up with a way to evaluate them for how effective they might be and how much work they might be expected to do.
Absolute quantification isn't needed, just how they compare to each other, and to other 120 and 140 fans I've used before and have at hand.
I got to thinking that the tach circuit in a fan is independent of the fan running under its own power, and that if I let the fan to be evaluated spin up a slave fan, how fast the slave fan spins would be a good indicator of how much energy the powered up fan was supplying.
To that end, I cobbled up a little adapter to measure the pulses from the slave fan's tach circuit and display the number on my Bench DMM and on the scope. The scope trace doesn't show up so well, but the DMM photos well and is easy to read the pulse per second count.
To convert that reading to RPM, multiply it by 30.
Since I had several 120 fans to test, and some 140's, I used a 120 as a slave fan, and a120 to 140 adapter to couple the 140's and a 120 phobia acrylic shroud to couple the 120's.
That gave a similar difference between the slave and test fans for both sizes, and eliminated errors that may have been the result of the larger blade hubs on the more powerful fans.
First I tried some 120 fans:
The test fan is the one on the right, and the slave is on the left.
For a baseline, I tried with a stock NZXT 120 case fan, it was unimpressive as expected, and the slave had to be nudged a bit to start spinning when I powered on the test fan: ~720 rpm
I've used the Aerocool shark fans in several builds, and having one handy, wanted to see how it compared: ~1140 rpm
Then I tried an old Thermaltake LED fan that used to be available at Radio Shack stores: ~1230 rpm
I've used the Silverstone FM121's before and consider them good air movers, so I put one to the test: ~1815 rpm
Now the bigger guns I was planning for the 630's builds, first up the Silverstone FM122 . . This puppy delivered: ~2130 rpm
The Koolance medium speed, 2600rpm, compared to their 4000 rpm monster was up next, and while I was expecting similar, if not better performance to the FM122, it was measurably less. It's definitely over spec'd, where the Silverstone is likely much closer to reality. ~1860 rpm
With most of the 120's at hand tested, I wanted to take a look at how the Prolimatech Vortex Aluminum compared. I have a lot of them in several builds and I've been happy with the performance, but something less subjective would be nice too. ~1230 rpm
I also tried the stock NZXT 140 case fans, a plain one and a LED one: both ~840 rpm
I should have tested an Aerocool shark 140, but didn't think of it until now, so I'll do it later.
Anyway, hope you find this bit of info worthwhile.
DarleneEdited by IT Diva - 4/19/13 at 12:51pm