Some kind questions about silent fans

[ginetto61]

The easiest solution, if not the cheapest, would be to replace the power supply with a different, lower current Meanwell with an open, mesh type top surface. These have no fans ... If you need the 350, the only workable solution would be to open the case and disable or remove the existing very loud fan, ...

Yes you are right There is no more silent solution that a no fan solution
I really like to have some power available But i will keep that in mind
It could be that my next amp will need even 48VDC and 10A to sound right.
I am using some class D boards at Voltages below the ones recommended and i am really thinking that i am limiting their potential
I was wrongly thinking that amperes are more important than Volts
Instead of using let's say 36V/10A i am using more 24V/20A ... but this limits the max power delivery from the amps. I made a mistake.
And moreover i have to face now the fan issue.
Anyway it will cost some efforts but i really like the idea to gut one of this very good smps and put in in a completely new and bigger case where i can also place a proper and bigger pc silent fan. I have already seen some nice cabinets ... more expensive that the psu
But i see this as an investment for the future
From what i understand psu has a very big impact on these chips performance.

 

[ginetto61]

Another idea, that I used a few years back is to remove the fan and use a single larger fan for the case + power supply cooling. This pic is for a Meanwell 36VDC 350W PS ... My current project uses a similar strategy (one intake, one exhaust) now but I'm using an open mesh PS design described by ^@tubesguy.

Thank you for the very interesting advice. The more i think about it the more i see the need of a new enclosure taken maybe from an old broken mid size pc
There is also another issue with these smps ... the connections are exposed and so very dangerous.
I could take out as you say the upper lid and mount the psu inside the pc box and put a very good fan above the psu inside the box
I have to look around
It will cost money and time ... but maybe it will be worth the effort
These chips performance is very dependent on the power supply quality
Very much

 

[stratus46]

Small fans are noisier than large ones.
Running a fan at a lower speed makes either ones much quieter.
There is no need for a hurricane flow, I gentle breeze is effective right away.

On a PC case with two case fans, I rewired their 12V normal supply to 5V, an easy mod at their Molex connector. All, I need is enough air movement to break eventual hot spots.
Now this PC is perfectly quiet.

You might also try running the fan BETWEEN the +12 and +5 to get 7 Volts on the fan. Some 12V fans won't run
on 5 but I've never seen a 12V that won't run on 7V. The fan will be very quiet on 7V. Yes, your 12V is now "helping"
the 5 V supply.

G²

 

[Mattes]

Ciao Gino,


for my fieldcoil PSUs, I wanted some cooling airflow inside the box, containing switching supplies for heating and auxiliaries and LiIon batteries and chargers for the fieldcoils. I decided to use Noctua fans on each end of the enclosure, running in opposite direction at reduced voltage. They are very quite, ALMOST not detectable in a very silent room (if you don´t know they´re running, you´ll most probably not notice them at all). The airflow seems to be sufficient for 4 Meanwell supplies, 2 large batteries and 2 chargers, no issues since some time.


All the best


Mattes

 

[ginetto61]

I think that also another thing to consider is that a bigger fan can move more air running at lower speed. Speaking of server psu for instance they have a very small fans making a lot of noise because running at very high speeds.
In order to reduce the voltage to the fan i have also found this

A red LED typically drops around 1.7 to 2.0 volts, but since both voltage drop and light frequency increase with band gap, a blue LED may drop around 3 to 3.3 volts

maybe one small 12V led (or more) in series with the fan can be enough ?

 

[mchambin]

The most terrible fans are the very small ones spinning like crazy, fitted on mother board chipsets, graphic cards and removable hard drive docks.

 

[wiseoldtech]

Hi thanks but sorry i am ignorant. You say that if i put a 6V zener on the positive wire in series with the fan it gets only 6V ? just that ?
Speaking of zeners i know that they are used very commonly as voltage regulator is a slightly more complex schema

This is what I was referring to.... I've used it many times to tame fan noise.

 

[banana]

There is another no fan cooling technology from 3M. The Novec engineering fluid.

Introduction to Two-phase Immersion Cooling - YouTube

 

[lcsaszar]

The easiest solution is to remove that tiny 60 mm fan, and install a 120 mm fan, like this:

SILENT WINGS 3 | 120mm silent high-end Fans from be quiet!

Then it can be run from lower voltage. A series resistor of suitable wattage could do.

 

[ginetto61]

The most terrible fans are the very small ones spinning like crazy, fitted on mother board chipsets, graphic cards and removable hard drive docks

Hi ! thanks a lot for the valuable advice. I guess that to accomodate a bigger fan a bigger enclosure is needed. This smps is quite long in size.

 

[ginetto61]

This is what I was referring to.... I've used it many times to tame fan noise

Hi thanks a lot. I would prefer to have some kind of control on the fan speed with a pot maybe ? i should do some tests with different voltages.

 

[ginetto61]

There is another no fan cooling technology from 3M. The Novec engineering fluid ...

Thanks ! very nice

 

[ginetto61]

The easiest solution is to remove that tiny 60 mm fan, and install a 120 mm fan, like this:...

Hi ! thanks and yes ! but i have to change the enclosure
Actually now that i think better i could drill some big holes in the upper lid and mount a bigger fan externally on the lid. I will be a little exposed to dust and bumps but it should work quite ok.