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need opinion about changing PSU fans

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fezder

Well-Known Member
Hey all!
again, i decided to ask before i do anything stupid and burn anything (yet, but you get the idea)
i have this programmable psu 36v/30A if i remember it correctly that has too noisy fans to my liking....
it has total of six fans:
front:40*40*10mm
ADDA AD4512HB-G70
12v/0.08A
8.67cfm/14.73 m3/hr
27.4db


back 60*60*25mm
delta AFB0612VH
12v/0.3A
30.5cfm/51.8 m3/hr
42.5db

so, basicly the noise is coming from those back fans, but the question is, is it wise to change them to less-noisier? i have only experience about noctua and corsair brand, as they mostly are what they spec for, but noctua's ones are about half as powerful airflow vise

Advice is greatly appreciated! surely you understand it's hard to concecntrate in noisy environment....
 
thanks for input, that thought did cross my mind.
 
Hey Fez

The problem is rpm, the faster it has to spin to provide the required cfm, the noiser it gets. Smaller fan=Higher rpm required. If you had the space in the casing, and open vents of course, you could go up a size in fan frame and slow them down a smidge. This would quieten them down a fair bit whilst still providing about the same cfm as the smaller fans, but as Nigel mentioned, these supplies run very warm and need serious cooling, so you would need to make sure that you don't drop the cfm levels below what the smaller fans provide at the moment. One other possible alternative might be an active fan control where the fan speed then becomes directly related to internal temperature. If you load the supply and it begins to heat, the fans run full on, but at idle with minimum heat the fans run at say 65% or something along those lines :)
 
well its indeed those back fans that cause most of the noise, they run at 5500rpm according tot their datasheet. i'll keep that controller in mind. i don't think it's possible to add bigger fans, i'll take photos from inside in a moment
ps: had to repair my computer mouse just minute ago, switch came to end of its life, luckily i had those salvaged from old mises :)
 
sorry it took long to post these photos, as you see, it's pretty crowded, so biger fans are not an option (except if i mount them on top, drilling mounts....)

edit: lol, forgot to insert photos....

IMG_0784.jpg IMG_0785.jpg IMG_0786.jpg
 
Hey Atte, Merry Christmas!

Yup, looks pretty crowded in there already. I think I would look at thermal fan controls for that :)
 
Hey Atte, Merry Christmas!
haha thanks wolf, you too, Alistair was it? quite confusing when people refer to real names in forums :D
 
Haha, always. Alastair now was it? i give up if it now is wrong :D. trouble with thermal controller is where do i mount sensor, and what kind sensor?
 
I assume that this power supply is used a piece of test equipment, and so it is not running at full load all the time.

So why not let the front (quiet) fans run all the time, and fit a temperature controlled switch for the rear (noisy) fans.
That way it will be reasonably quiet when lightly loaded, which is probably most of the time that it is used.

JimB
 
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I assume that this power supply is used a piece of test equipment, and so it is not running at full load all the time.
well i don't think i need such power levels frequently. i just don't have many current-limiting psu's, and due other features this would be jewel to use.
 
trouble with thermal controller is where do i mount sensor
A very good question.
My first thoughts are, run the psu and see what gets hot, and mount a sensor on that.
Second thoughts, one set of fans must be blowing into the cabinet, the other set must be sucking out. Mount the sensor on the input to the exhaust fans. That way, hot air taken out by the quiet fans will give an indication of general internal temperature.

JimB
 
Yeah, smaller fans (40mm) at front are intake, back fans (60mm) are exhaust. only temperature sensors i currently have are non-linear NTC/PTC's and lm335's
 
OK, sounds like time for a bit of experimentation.
Set up two of your LM335s, one to measure the amient air temperature outside the PSU, and one to measure the air temperature on the inlet side of the exhaust fan(s).
Disable the exhaust fans.
Run the PSU for an hour or so with no load and see what the temperature rise is inside the cabinet. (make sure that all the covers are in place for this test.
Repeat the test with the PSU supplying say 10% of its rated load.

If the temperature rise is significant, set the temperature switching circuit to start the exhaust fans when the temperature is greater that what you measured with 10% load.

There is a lot of guesswork here, the important thing is to run a test and see what happens, then you can make a decision on how to control the fans.

JimB
 
ok, i'll do those tests once i have enought time :) thanks!
 
^^^
Whats up Doc :)

Hiya Fez in cold Finland :eek:
Christmas OK ?

Cheers Buddy,
tvtech
 
mostly good, managed to make that first ''idle'' test for that psu, temperature rose about 2c. so, for 10% rated load, load should be around 108ohms right? at least maxinum load is 1080....
well it's cold enought, had small drama just yesterday when dad tried, or at least was thinking committing suicide (he has alcoholic problems & deep depression, bad combination) He's currently at medcical treatment, rehab and stuff, all is pretty well now.
 
for 10% rated load, load should be around 108ohms right? at least maxinum load is 1080....
Ugh?
Full load current = 30A
10% of 30A = 3A
R = V/I = 36/3 = how many Ohms?
And how many watts will be dissipated by this resistor?

Sorry to hear about your "old man", short days and not much sun at this time of year can really mess with your head - it does with me!

JimB
 
mostly good, managed to make that first ''idle'' test for that psu, temperature rose about 2c. so, for 10% rated load, load should be around 108ohms right? at least maxinum load is 1080....
well it's cold enought, had small drama just yesterday when dad tried, or at least was thinking committing suicide (he has alcoholic problems & deep depression, bad combination) He's currently at medcical treatment, rehab and stuff, all is pretty well now.

You know Fez...
Christmas is a crap time for many..me included. It's all about kids and happiness and all that.

Three Years ago I had a break from here and a proper holiday on the farm with fun and stuff. My beloved Brother (in law) decided to give up last December just before Christmas..his heart was too hammered to have yet another bypass.

A REALLY good person. Always helped all and Sundry. Had time for everyone. Fun and a good person.

Now that he is dead...things are not the same anymore. Just not the same. Nobody can replace him. People can act all they want..does not work. False.

And I am sitting here moaning about stuff Fez and you also have lots to deal with :eek: and you are only 22...

When I am in a mood like this I tend to feel sorry for myself. Meanwhile I have genuine friends here that don't know me. But are prepared to listen.

All I can say is Fez...you made it through Christmas. Your Dad made it too.

No other advise to give Buddy...still trying to work my own stuff out :wideyed:

In the meantime and through the Year...I try my very best to keep things light and humorous on the Forums.

Somebody has to do it :)

Regards,
tvtech
 
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