Can AC fans be used inside cases?

[Phisherman]

I have several Panaflow AC fans, powerful and quiet. Is there any
reason these could not be used inside a case? I realize the power
supply could not be used, so I'd have to tap in the power supply or
run a separate power line into the case. Has anyone tried this?

 

[w_tom]

Obviously 120 VAC wire outside of power supply violates
human safety principles. It can also result in hardware
damage. Furthermore you have not mentioned other important
facts such a wire size meaning potential building fire
problems. The AC fan does nothing that conventional DC fans
already accomplish. Furthermore, why do you need more air
flow. Too much airflow can even create hardware failures.
One 80 mm DC fan is more than sufficient for most every PC.
Do the numbers. Even a second fan provides insignificant
improvement. Just more reasons to question your AC fan
solution.

 

[ric]

I have several Panaflow AC fans, powerful and quiet. Is there any
reason these could not be used inside a case?

Safety concerns aside, no reason whatsoever. +12v is just handier
(and safer) in computers. PSUs for idustrial mainframes have used
AC fans for decades.

 

[Guest]

I have several Panaflow AC fans, powerful and quiet. Is there any
reason these could not be used inside a case? I realize the power
supply could not be used, so I'd have to tap in the power supply or
run a separate power line into the case. Has anyone tried this?

High voltage is reason enough to avoid trying this, but not
understanding high voltage construction practices should completely
rule it out. The ARRL Handbook, available at any library, has
chapters about electrical safety and proper construction practices

You need wire with insulation rated for 600 volts (zip cord is fine),
and you have to keep this insulation from being pierced by sharp
objects, such as the rough edges found in almost every computer case.
Smooth these off if they pass near the wiring, taking care not to let
metal filings get into the electronic circuitry and create shorts. If
you can't smooth them, cover the wires with split looming. Rough
edges can instead be covered with plastic or rubber edging, provided
it can't possibly come off.

Connections must be secure and cover any exposed high voltage. Nylon
connectors are good for this, but cover them with heatshrink tubing
after crimpling them because the crimpling tool often pierces the
nylon.

The AC power cord for the fans has to pass through a hole in the
computer case, and that hole must have a nylon strain relief in it to
prevent the wiring from being pierced or pulled out. Do not
substitute a rubber grommet for a good strain relief. I'd prefer a
chassis-mount fuse holder inline with the fans, even if they're
inherently protected from shorts (may be labelled "impedance
protected"), but its connections must be covered with 2 layers of
heatshrink. It's possible an improperly installed fuse holder could
create more hazards than it's meant to protect.

I hope you're not thinking of getting the high voltage from inside the
power supply.

Because of the hazard and possible need of a second AC power cord, I'd
rather use low voltage DC fans, especially since no home computer
needs more than 2 case fans anyway.

 

[SteveH]

High voltage is reason enough to avoid trying this, but not
understanding high voltage construction practices should completely
rule it out. The ARRL Handbook, available at any library, has
chapters about electrical safety and proper construction practices

You need wire with insulation rated for 600 volts (zip cord is fine),
and you have to keep this insulation from being pierced by sharp
objects, such as the rough edges found in almost every computer case.
Smooth these off if they pass near the wiring, taking care not to let
metal filings get into the electronic circuitry and create shorts. If
you can't smooth them, cover the wires with split looming. Rough
edges can instead be covered with plastic or rubber edging, provided
it can't possibly come off.

Connections must be secure and cover any exposed high voltage. Nylon
connectors are good for this, but cover them with heatshrink tubing
after crimpling them because the crimpling tool often pierces the
nylon.

The AC power cord for the fans has to pass through a hole in the
computer case, and that hole must have a nylon strain relief in it to
prevent the wiring from being pierced or pulled out. Do not
substitute a rubber grommet for a good strain relief. I'd prefer a
chassis-mount fuse holder inline with the fans, even if they're
inherently protected from shorts (may be labelled "impedance
protected"), but its connections must be covered with 2 layers of
heatshrink. It's possible an improperly installed fuse holder could
create more hazards than it's meant to protect.

I hope you're not thinking of getting the high voltage from inside the
power supply.

Because of the hazard and possible need of a second AC power cord, I'd
rather use low voltage DC fans, especially since no home computer
needs more than 2 case fans anyway.

So my home PC with 4 HDD's, 2 Opticals, high end graphics card, Athlon
XP3200, 1024Mb ram etc only needs 2 case fans eh?

SteveH

 

[Zotin Khuma]

I have several Panaflow AC fans, powerful and quiet. Is there any
reason these could not be used inside a case? I realize the power
supply could not be used, so I'd have to tap in the power supply or
run a separate power line into the case. Has anyone tried this?

In theory, you'll introduce some 60Hz electromagnetic field inside the
case. I don't think this will be strong enough to interfere with your
computer's operation as the innards of a PC are mostly low-impedance
circuits which are lees susceptible to EMI than high-impedance
circuits. Just try it out and see. It may be a good idea to keep the
wires as far away as practicable from the video and audio sections.

 

[Zotin Khuma]

I have several Panaflow AC fans, powerful and quiet. Is there any
reason these could not be used inside a case? I realize the power
supply could not be used, so I'd have to tap in the power supply or
run a separate power line into the case. Has anyone tried this?

In theory, you'll introduce some 60Hz electromagnetic field inside the
case. I don't think this will be strong enough to interfere with your
computer's operation as the innards of a PC are mostly low-impedance
circuits which are less susceptible to EMI than high-impedance
circuits. Just try it out and see. It may be a good idea to keep the
wires as far away as practicable from the video and audio sections.

 

[w_tom]

If you have any doubts, then put up the numbers yourself.
One 80 mm fan of about 25 or 30 CFM is sufficient. Two fans
operating in series maintains airflow should any one fan
fail. do_not_spam_me posted accurately - and in
contradiction to popular myth. What myth purveyors must do to
promote their myths? Fear and avoid numbers. Do the numbers
if in doubt.

Another point that do_not_spam_me could have included.
The zip cord to fan must be large enough to trip a breaker box
20 amp breaker during a short circuit - without creating
fire. Fan's power cord must be 18 AWG or heavier. So much
easier to install a DC fan - to avoid these engineering
complications.

Also not mentioned is how to control those AC fans from
power switch. Even more complex.

AC fan proposal has one positive attribute. It exposes so
many technical facts we never learned when assembling
computers with DC fans. Readers here probably learned
engineering reasons for using DC fans.

 

[SteveH]

If you have any doubts, then put up the numbers yourself.
One 80 mm fan of about 25 or 30 CFM is sufficient. Two fans
operating in series maintains airflow should any one fan
fail. do_not_spam_me posted accurately - and in
contradiction to popular myth. What myth purveyors must do to
promote their myths? Fear and avoid numbers. Do the numbers
if in doubt.

How is it you know how many fans are sufficient for my PC? You don't know
how warm the room I hve the PC in is, the CPU temperatures and the heat all
the other components in my PC generate.
What I do know is that if I slow the fans in my PC down to their minimum
settings (or indeed disconnect them) the CPU overheats and I get lockups
etc.
And yes, I do have a more than adequate, correctly fitted heatsink on my
CPU.

SteveH

 

[w_tom]

Put up some numbers. It is not rocket science.

 

[Odie Ferrous]

especially since no home computer
needs more than 2 case fans anyway.

Bullshit. You and w_tom are propagating garbage here.

How can you so arrogantly imply that all computers are alike, and that
none needs more than two fans?

I have had to install a 120mm fan at the front of my case, blowing over
3 x 10K rpm SCSI drives.

Another cools the Maxtor 160GB drive, CD recorder and DVD recorder.
Hard drives tend to fail if they get hot. Running this drive in this
case with 2 fans and the sides closed - it would probably have failed
long ago. Fairly crappy drives at the best of times.

Another 80mm fan blows onto the area around the memory/chipset area.

On top of that, my case is permanently open - both sides.

You can always get the cooling wrong, but for you two to state that no
computer needs more than 2 case fans - well, you're talking out that
dark space behind you.

Heat is a computer's worst enemy. Aside from the blinkered approach
adopted by you and your ilk, that is.


Odie

 

[SteveH]

Put up some numbers. It is not rocket science.

I don't need to do theoretical calculations to tell me how many fans I need
running. The heat sensors in my CPU and case can tell me that.
You'll be telling me I need a 3.5 digit multimeter next.

And please don't top post.

SteveH

 

[SteveH]

Bullshit. You and w_tom are propagating garbage here.

How can you so arrogantly imply that all computers are alike, and that
none needs more than two fans?

I have had to install a 120mm fan at the front of my case, blowing over
3 x 10K rpm SCSI drives.

Another cools the Maxtor 160GB drive, CD recorder and DVD recorder.
Hard drives tend to fail if they get hot. Running this drive in this
case with 2 fans and the sides closed - it would probably have failed
long ago. Fairly crappy drives at the best of times.

Another 80mm fan blows onto the area around the memory/chipset area.

On top of that, my case is permanently open - both sides.

You can always get the cooling wrong, but for you two to state that no
computer needs more than 2 case fans - well, you're talking out that
dark space behind you.

Heat is a computer's worst enemy. Aside from the blinkered approach
adopted by you and your ilk, that is.


Odie

Indeed. I've got 4 hdd's, 2 opticals, Gig of ram, high end Nvidia card etc
in a Xaser III case.
And as I said to w_tom, I don't need to do sums to see the effects of heat!
I admit. I could do without all the fans, coz I could do without the noise,
but as I'm not interested in watercooling, this is the price you pay.
As you say, to generalise on how much cooling people need (especially
without knowing individual circumstances) is arrogant in the extreme.

SteveH

 

[Guest]

"do_not_spam_me" <[email protected]> wrote in message

no home computer needs more than 2 case fans anyway.

So my home PC with 4 HDD's, 2 Opticals, high end graphics card,
Athlon XP3200, 1024Mb ram etc only needs 2 case fans eh?

Right, unless the case fans are set up wrong (blowing in the wrong
direction) or are too small (5" may be needed) or the system is
overclocked. The only additional need may be a duct to bring outside
air to CPU fan.

 

[Guest]

do_not_spam_me wrote:

Bullshit. You and w_tom are propagating garbage here.

How can you so arrogantly imply that all computers are alike, and that
none needs more than two fans?

Because of the large number we've had running for years in 105F
environments.

I have had to install a 120mm fan at the front of my case, blowing over
3 x 10K rpm SCSI drives.

That's the best way to cool them and interior, and vertical mounting
will protect the drives better in case of fan failure.

Another cools the Maxtor 160GB drive, CD recorder and DVD recorder.
Hard drives tend to fail if they get hot. Running this drive in this
case with 2 fans and the sides closed - it would probably have failed
long ago. Fairly crappy drives at the best of times.

Most Maxtors have 6 hot chips driving the motor and head coil and can
use heatsinks or air flow.

Another 80mm fan blows onto the area around the memory/chipset area.

Unnnecessary, except when overclocking. Otherwise the only RAM that
may need a fan or heatsink is on the video card.

Heat is a computer's worst enemy. Aside from the blinkered approach
adopted by you and your ilk, that is.

Unless you've equipped your computer with thermal shutdown protection
that works even if the system locks, then you haven't protected your
computer well enough from heat.

 

[w_tom]

Your numbers then say only one chassis fan is required. But
then a simple calculation demonstrates what most every system
requires.

Don't insult others by bottom posting to make posts
difficult to read. Wading through old and now irrelevant
information is both intentionally and obviously wasteful. Or
learn what top poster do - be tolerant of the intolerant - and
ignore their misguided bottom posting.

You asked how I know what your system needs. No problem. I
kindly asked for the appropriate information. Provide the
numbers. Instead you will attack me with your intolerant
bottom posting rhetoric? Shame on you. No wonder you will
never learn from your question. It requires you to provide
numbers. Apparently that is a little too difficult? Please
learn respect, provide numbers so your original question can
be answered, and top post to make your posts readable.

 

[w_tom]

Rather than make wild speculation, why not instead put up
the numbers that show us how wrong we are? If you know so
much, then you can provide those numbers instead of
accusations and arrogant responses.

Others are cautioned. Odie Ferrous has proclaimed by his
attitude that only he knows better. IOW he too will refuse to
provide numbers. If he did, we would learn he never really
knew what he was posting.

Heat is a computer's worst enemy when the naive promote
urban myths. Any computer that does not work properly in 100
degree F room is defective by design. How many chassis fans
are required? One in most cases.

What happens to an Intel processor that overheats? Nothing
destructive. How hot can other IC become before complications
set in? We will let Odie Ferrous answer that since he
apparently knows so much more than hardware designers.

 

[Norm De Plume]

Heat is a computer's worst enemy.

I thought it was Gog the Luddite Giant on one of his computer-stomping
rampages. Fun fact: His fallen arches allow him to crush far more
computers per stomp than can other giants with similar size feet.

 

[w_tom]

Sometimes memory is defective. Those with engineering
backgrounds will heat memory chips to be uncomfortable to
touch. Defective memory suddenly demonstrates its defects.
But some like SteveH install more fans to 'fix' the defect.
That proves that more fans are necessary? Of course not. It
proves that people like SteveH never learned basic electronic
principles. They just know some hardware works better with
more fans.

Best way to find defective memory - memory that will fail
even more often prematurely? Heat it with a hairdryer on
high. If memory fails, is failure due to heat? Of course not
(but don't tell SteveH). Failure is due to defective and
'slowly getting worse' memory. Heat is how we find defective
ICs. More fans are how 'those who know better - damn the
engineers' fix defective hardware.

 

[SteveH]

Your numbers then say only one chassis fan is required. But
then a simple calculation demonstrates what most every system
requires.

Don't insult others by bottom posting to make posts
difficult to read. Wading through old and now irrelevant
information is both intentionally and obviously wasteful.

As far as I and plenty of others are concerned, bottom posting make it easy
to skim through the previous post (hopefully snipped where necessary) and
then follow on and read the current reply.

Funny that yours are the only top postings in this thread (and plenty of
others).

You asked how I know what your system needs. No problem. I
kindly asked for the appropriate information. Provide the
numbers.

After you originally generalised that any PC only needs one fan, without
knowing 'the numbers' of peoples PC's. You keep going on about 'the
numbers', which numbers are you talking about?

Besides, as you presumably know, it's not just about numbers and how much
airflow a fan kicks out. It's also about what happens to that airflow, as in
obstructions (cables, drives, cards etc), the shape of the case etc. As well
as the ambient room temperature. And sometimes all the science in the world
doesn't make any difference, you just have to 'suck it and see'.

SteveH