Tales from a Ventilation Lunatic

[Snikwahjm]

^^^ Mini hamburger grills???

[Motrukdriver]

Yep... cook em over a butane lighter.

[sternwake]

Those are 92MM fan guards.

With these delta fans front stator blades which concentrate the flow into a column, one would have to try and get their finger in via the front and if they did the blade would push the finger out, but the rear is open exposed and dangerous and would chop off fingertip and perhaps break off a fan blade rendering fan too imbalanced to use.

The fan grilles do restrict air flow. I do have one 92Mm grille, and basically only need one as the other fan I put a filter sock on the intake side with a couple of longer screws which keep it from getting sucked into the blades. The front fan is on my engine cover and the filter sock would be annoyingly cumbersome, so that one gets the grille.

Rather amazing how quickly the filter gets loaded with dust/lint.

Anyway I am rather happy just how well these new 7K rpm 92mm fans respond to the newer 5 amp voltage bucker. The range of air velocity I can choose is awesome, and maximum velocity is rather insane.

[sternwake]

Despite not being sure of the dielectric status of Amazing Goop's Marine version, I picked up a tube, and found out it is.


I wound up cutting up the packaging it came in, to make a precise  applicator tool, and covered all my solder joints and also act as a stress relief on the wires, and tacked down the wire wound toroid to the circuit board.  I also tacked the 2 potentiometer wires and 2 power wires to the one hub support blade, and then the circuit board to fan body, and the potentiometer to the hub's sticker.  Amazing goop can be removed.  It tends to stretch a lot in the removal process, and is not quick and easy, but it is by no means impossible and does not leave a big mess.

The AG marine version seems to tack off a bit quicker, but the smell sticks around a bit longer than the non marine version. not a pleasant smell.  The marine version is said to be UV resistant, not really required in this use, but they were out of the regular version unless I bought a 1/3rd the amount for 1$ less.

The 10 turn potentiometer is slightly less convenient, in that to go from fully OFF, to maximum speed is a bit more than 6 full turns, and once fully off one needs to turn at least 4 full turns clockwise for it to start spinning the fan, then adjust backwards unless one wants that amount of airflow.  When turning the fan off, it requires 2 full turns CCW after the fan has stopped spinning before the POt bottoms out.  I cannot measure any amp flow in that 2 turn range, and the blue LED turns off with 1 turn to go, but I will try to always turn it fully CCW every time I want it off rather than installing a switch or unplugging the Anderson powerpole.

If oe were to feed this fan 12.8 v by a switch, it takes a half second befor ethe impeller starts spinning, and then about 2.5 more seconds before it ramps upto full speed.  It has some soft start circuitry built in, which leads to a delay when spining the potentiometer.  it will ramp up to a much higher speed than one intended due to this delay, so for meduim quiet arflow I basically turn clockwise 4 turns, wait for it to ramp up and stop increasingrpm, then dial it back to tolerable noise and airflow levels.  it responds nearly instantly when slowing down, except in the super slow/  near silent rpm ranges.

What is nice about the 10 turn potentiometer is the ability to fine tune the speed so precisely. My previous 3/4 turn potentiometer on the 3 amp speed controller made it difficult to dial in the slower speeds precisely, but it took one flip of the wrist to go from fully off to max speed, instead of 6.

When turning it up, the last two turns from 4 oto 6 are like' surely it cant go any faster, this is ridiculous!" but it responds and screams even louder and blasts even more air.  The final 4 turns CW do nothing, and if they sold an~ 650 OHM potentiometer the full speed range could be dialed in in those 10 turns but I can't see needing that level of speed control. A 5 turn 6.5K Ohm potentiometer would be the sweet spot me thinks for precise control.

The volume of air these fans move at higher rpms, inside the van once mounted is a bit ridiculous.  I have one mounted on my engine cover's ash tray, and aimed at an open  door window blowing outward would  easily blow out the bic  lighter of someone standing lighting a cig outside the door.

The circuit boards have a single bright blue LED which gets brighter with increased voltage output.  I covered these with a few coats of liquid E tape, as I dislike blue light and the fan itself is an indicator it is getting power.

I did spray the circuit board with Deoxit Shield s5 spray and covered over where the wires enter and are soldered to the circuit board with Amazing goop, so hopefully these are much more resistant to my salt air environment and last a lot longer than the 6K version did.

Even with my filter sock on the rear fan intake, the air moved at max rpm is ridiculous.  When making the bed with sunlight coming in the side window highlighting the airborn dust/lint, it is impressive just how fast it removes it all from the air, and rather disturbing how quickly the filter sock gets loaded when the fan is running all the time and one is folding laundry/ making the bed.  Makesone wonder how much of that lint would otherwise wind up in ones lungs and what all those synthetic fibers are doing in there.

Very impressed with these fans, and having full speed control from  near dead silent barely detectable breeze to screaming banshee wind tunnel is pretty much the pinnacle of my desire in the airflow department.  Max speed's noise level is intolerable for long but hard to imagine it being required for long either.  Its not a cool pleasant breeze, but more akin to a passing storm, which i can dial down to cool breeze twisting a dial.

[Roadtripp]

Gods in the details. Something like that. It’s a breath of fresh air. Boy howdy, I’ve got a lot of messing around with fans to do so enjoyed the great focus. Especially regarding efficiency, speed control, and longevity. As it’s cool here and I’m heating. I’m thinking of using a air to air heat exchanger I picked up at the junk store cheap. It’s new but missing the fans for some unknown reason so I’ve been wondering what might fans work best. It’s designed for a 2000 sq ft house so I’m reducing the ducts from 6” to 4” and low power fans for my 250 sq ft space. I don’t want to cut 6” holes if unnecessary. I’m hoping this will also be a good moisture trap that can used to drain water condensate to the outside.

[sternwake]

The 120Mm fan size has so many options, but 4.75"=120mm and would present issues for your 4 inch vet diameter desire.

92mm is 3.62 inches.

I Do not know if the slightly lower rpm 120 MM delta fans respond to voltage control like my newest 92mm delta fans do, but the 252 cfm 120mm delta fan does not, nor could i get it to respond to a PWM signal sent on the 4th blue PWM wire.

The Silverstone fm121 do come with potentiometers and built in speed controllers. exteding the wires for a distant potentiometer is simple wire splicing. I have not used one potentiometer to control a pair of ss fm121 fans but it should not be an issue to do. They are a good dual ball bearing fan with good airflow and speed range.

The Noctua industrial 3000 rpm 120mm fans are impressive, but I have suffered two fan failures, and although they were quickly warrantied, if I were out on the road during failure getting a new one would be a PITA.

If 92Mm fans are what you decide to use, well my latest 7k rpm have the power and speed control abilities on the 5a voltage bucker, but there could be more efficient options in a narrower or lesser speed range. The brute force of these 7k rpm 92mm fans is impressive, but it is like a loud stereo turned up all the way, when the best part of the song is over, turning down the volume becomes necessary, quickly, but it was nice to have that volume available to tickle ones bones and the inner surface of one's skull.

I'll blast these 92mm fans aimed at me at high rpms briefly when I am a sweaty mess, but thats about it. The rest of the time they will likely be in the 700 to 2000 rpm range, and there are likely many fans which can move the same air for much less wattage consumed to do so in this range. But I want that 7k rpm on tap, so I accept that compromise.

[Roadtripp]

https://www.surpluscenter.com/Electrical...6-1553.axd
Here is a link to a German made fan that looks heavy duty and only $9.95. It’s 5.65” inches and 285 cfm
I may buy a couple of these for the 6” heat recovery ventilator that might go in the RV.

[Roadtripp]

There’s 6” holes in the ventilator. The Silverstone fm180 or fm181 might be good. I’d like to have reserve capacity to push air through the heat exchanger and to be able to turn it down in rpm. I have 12 volt and 24 volt battery power available and could rig one of the quiet fan series by silverstone on a voltage switch? But the PWM control sounds better.

[sternwake]

Nice fan find! if it can blow 282 cfm at 28v, then I would try and use a buck/boost converter for full speed range from silent slow to turbofan.
The 1.1 amp maximum seems a bit sispiciously low though for that much air movement, even at 30v. The 120Mm delta fan I have draws 3.3 amps at 12.8v and is rated at 252 cfm.

I tried to control the 120mm fan on a buck booster converter rated at 5 amps, but it did not have control that 120mm fan well, and the converter was not very efficient.

I bought this buck boost converter:
https://www.amazon.com/DROK-180050-Stabi...+converter

and it sits unused since the failed experiment.

Removing the voltae adjustment potentiometer and soldering wires to te circuit board is not difficult, but a very small drill bit to drill through the solder left behind after removal makes it easier.

The product above uses a 50K ohm potentiometer.

If you look in the related products you will see many buck/boost converters to use as a speed control.

You can also use a PWM motor speed controller, but if you do, make sure it is rated at 21Khz or higher, or it will whine audibly when slowed, and that whine is annoying all all F***. 21KHZ is likely only irritating to Fido or fluffy, but apparently some humans range approaches being able to heat that as well.

Do note many computer fans are listed as PWM fans, these fans have 4 wires and the 4th wire is for a PWM signal to control the speed. The noctua NA-fc1 speed controller will likely work on most every 4 wire PWM fan. I fed a 5v PWM signal generator with the 3 amp buck converter to feed that 4th wire, but it was ineffient, and clunky in comparison to the Noctua controller.

If you have 24v available to feed the fan you linked, then a PWM motor speed controller can be much simper than the buck boost converter for speed control.

Nice fan find though, That one is bookmarked, but I am going to hold off on getting one, eveb though my wind tunnel tendencies are imagining placing them everywhere

[sternwake]

If the Fan you linked does indeed only draw 1.1 amps, then this product would likely be about the simplest way to control its speed. Built in voltmeter and finger twist potentiometer, just join 4 wires, input and output easy peazy.

https://www.amazon.com/dp/B071CZ5P1Z/ref...B071CZ5P1Z



It is rated at 2 amps.

Others shoud note if they hook a 12v fan to this, it would be easy to crank it well up above 15 volts. and a 1 amp fan at 12 v might pull 2 amps at 19 volts, and thus excees the rating of this buck/boost device, releasing its magic smoke.

I've made some small, not very powerful 12v computer fans levitate at around 28 volts through a 150 watt voltage booster, but I would not trust them to last very long at 2x+ their rated voltage.

Next summer I might be replacing those Noctua 120mm intake fans with the fans linked above. They are smaller than the FM181 net to them, and move 2x the air, almost, if their specs an be believed.