Does a 250 watt PS really need a Fan?

  • Thread starter Thread starter Herbert Snow
  • Start date Start date
It's not recommended that you do that. They do make devices in which you
can use to slow down the fan speed if it's the noise you are concerned with
though...

Jason
 
Herbert said:
It never really gets hot any way. Do I really need it?
Click to expand...
The fan on power supplies often removes heat from not only the PS, but
the computer case as well. Even if the PS did not need the fan for its
purpose, it would not be a good idea to remove it.

Ken
 
Nobody can answer that question. For example, how large are
heatsinks on power supply semiconductors (large as defined by
thermal equations)? How much heat is generated by that
semiconductor? Since you did not provide those specifications
unique for that power supply, then no one can tell you if that
fan is necessary or how many CFMs really need be pulled
through that power supply.

Is the power supply hot? Does not matter what air
temperature is. How hot are semiconductor junctions inside
that power supply? Without even than simple number, then no
one can possibly answer your question.
 
Crack open the PSU and slide in a Vantec stealth case fan if you're
trying to quiet it down.
 
It never really gets hot any way. Do I really need it?
Click to expand...

It WOULD get hot without the fan.

The wattage of the power supply is not necessarily the issue though,
the issue is the amount of power the system is using, as that (and a
fairly standard power supply efficiency) determine how much heat is
dissipated inside the power supply.

Without question you will drasticaly reduce the lifespan of the power
supply by using it without a fan (except for one specifically designed
to operate without one). If the system power usage is relatively low
you might change the fan in the power supply to something very low-RPM
and therefore quiet.... a tiny bit of quiet, fan-forced airflow is
MUCH better than none. This is assuming you aren't dependant on the
power supply to move air though the system chassis, that it either is
VERY low-heat or has an additional exhaust fan.


Dave
 
Herbert Snow said:
It never really gets hot any way. Do I really need it?
Click to expand...

A 250W will put out less heat only if it powers a smaller load than a
more powerful PSU. But with equal loads and no fans, I ASSume that
the 250W would become hotter because its heatsinks will probably be
smaller. OTOH even the bigger heatsinks found in most higher power
PSUs probably won't keep the PSU's components that cool at low load
because www.silentpcreview.com ran tests and found that the heatsinks
got toasty. And when I ran a 300W Antec Smartpower outside a computer
case with a 466 MHz Celeron, its low voltage heatsink (other heatsink
had 170 volts on it -- too dangerous to measure) reached 70C in a few
minutes with the cover removed and the fan running, not much hotter
with the fan stopped, compared to about 45C with the fan running and
the cover in place (actually a clear plastic test cover with a hole in
it for the temperature probe). I think that www.silentpcreview.com
mentioned a similar "tunnel effect" helping the cooling a lot. But
while the highest heatsink temp. was still far lower than the 90-125C
max. temp. allowed for the big transistors and diodes, I still
wouldn't feel comfortable running without a fan because I was told to
keep those components at least 30C below maximum, and in a crowded PSU
they touch other parts that aren't rated for such temperatures (or
that aren't known to last that long at them).
 
Herbert Snow said:
It never really gets hot any way. Do I really need it?
Click to expand...

Yep!
It is actually not only the Semiconductors which over heat the Transformer
may also overheat with catastrophic Results as the electromagnetic
properties of Ferrite change as it becomes hot......

Regards
Richard Freeman
 
You are the master

Richard Freeman said:
Yep!
It is actually not only the Semiconductors which over heat the Transformer
may also overheat with catastrophic Results as the electromagnetic
properties of Ferrite change as it becomes hot......

Regards
Richard Freeman
Click to expand...
 
FuzionMan said:
You are the master
Click to expand...

No not really .....
I just know more about Lightning than w_tom (not a difficult ask) and have
seen many Switchmode Power supplies used in Audio Amplifiers that failed due
to inadequate cooling across the Power supply components Particularly the
Transformer .

Regards
Richard Freeman
 
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