Speed controlling computer fans

SCVJeff wrote:

It sounds like you haven't tried the Noctra on a PWM control.

I have not. The Noctuas I currently have are mounted on my fridge compressor, 120mm, and my Meanwell power supply 60 and 80mm, and I will not be experimenting on them.

The intended location for the 3000 rpm nf-f12 is extremely close to where my head resides when sleeping. There are 3 fans side by side in a tight fitting shroud used as intake fans for positive air displacement. One of them is 180mm, and used to be a silverstone 2000 rpm ap182, but this fan failed due to corrosion on the circuitboard, and it required holding voltage to no more than 11 volts when on highest speed or the hub got stinky hot. It has been now been replaced with a 1300 rpm max 180mm silverstone which is basically silent on slowest speed. but I miss the near 2000 rpms of the ap182 on the scorching days when all three fans in this shroud are on high.

Next to the 180Mm cut out are 2 120mm cutouts In one of these is a silverstone fm121, and the other is a single speed sleeve bearing 72cfm fan which came on my compressor fridge and is not impressive in noise, airflow, or amp consumption.

This time of year I always have one of these fans running all night long, and it has been the 180mm as it is so quiet and moves ~60 cfm at this speed. But hotter nights I'd like to have two fans on slowest speed rather than bump up speed on the 180mm. The silverstone fm121 is now too loud on any speed to use this close to my head. It sounds like the bearings are shot, but they are not. it sounds like playing cards in bike spokes, but there is no obstructions to the blades. the Hub had previously broken its glue joint, and some hot glue restored function, for a few weeks, but now is loud again, and i have not removed shroud to inspect further. Next time I remove it is to replace a fan. I suspect something driving the fan has failed causing the noise, but perhaps the hot glue let go.

Buying the 3K rpm Noctua or a replacement silverstone fm121 is the decision i now face. It appeared the fm121 quality control was lessened on each one I purchased in the last decade, and I am dang impressed with Noctuas now employed on fridge and Meanwell, and the IP67 or even IP52 ratings of the industrial versions would be a big step up over the silverstone. I've basically had to resolder the wires to circuit board on almost every fan in this location, until I spooged dielectric grease over them, but even that has not prevented their failure. The latest 180Mm fan got sprayed liberally with Deoxit shield on windings and circuit board and a spooge of dielectric grease over where wires meet circuit board.

I am sensitive to high pitched noises, often hearing high pitched whining/noises others cannot. So the Noctua on a regular PWM motor speed controller/dimmer on the red black wires, would be an experiment, where the silverstone's unknown entity would mostly be a quality control factor. Has it dropped even further since I last purchased one many years ago?

In my humble workshop on the tilted concrete slab, the screwy31 still powers fans and LEDS, and I have many of the LED dimmers, but since having smoked my 25khz motor speed controllers, I cannot tolerate the fans on these ~13khz led dimmers. Far too annoying, the Whine. The Screaming banshee fan is too loud to notice any whining, but how I'd love to be able to tame this fan to whisper quiet through to full screaming banshee rpms.

The 25khz motor speed controllers certainly did not cause instant failure on the fans employed in my workshop, but these are not PWM 4 wire fans. The 4 wire screaming banshee has likely less than 2 hours total on the 25KHZ controller, and I can detect no loss of function from feeding pwm through the power feed lines.

I have some Vantec tornado fans, 80 and 92mm that I use a voltage controller similar to the one linked below, ciggy plug style, for a speed controller. this works well, No whine. These fans whined even on the 25KHZ controller IIRC.

https://www.amazon.com/CyberPower-CPUDC1U2000-2000mAh-Universal-Charging/dp/B00ELGA23E/ref=pd_sim_sbs_107_1?ie=UTF8&dpID=31j17YxAl6L&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&psc=1&refRID=BBX31KS0MD3B9TRCZ9SQ

Note to readers, The above product is loose in ciggy receptacles and can be kinked sideways and short out blowing the circuit's fuse, not the one in the device. Some heatshrink over most of the tip but for the spring loaded nipple, prevents this. Dumb Ciggy plug design but the electronics have proven durable in my usage. But only 5 set voltages/speeds, and at 14.5 battery volts, it will only deliver 12.09 volts max. There are times I would appreciate higher airflow at 14.x volts.

So I am gambling that the Noctua 3000rpm version can be tamed on a regular pwm controller without the whine, or I go for the Silverstone fm121 replacement and its possible declining quality control issues, or I make or buy the PWM controller linked to at overclockers.com, to PWM control the PWM fan the way it was originally intended to be controlled.



Least risk and time consumption would be the silverstone fm121 replacement. But I learn nothing doing that.

I think I need to order more 25KHZ motor speed controllers just for the fans in workshop and take steps to prevent their smoking. I use these as air filters and do notice the increased dust without them.