Fan differences?

  • Thread starter Thread starter Tai Tze Hou \(Alvin\)
  • Start date Start date
kony said:
It's not hard to have 40C exhaust. High-end P4 with similar high-end
video card, a few drives, etc, will create over 160W of heat at full
load. If the user has a giant case they can fit all the fans they
want and easily achieve ~22CFM needed to keep temp rise at 10C, but
they'll need minimum of two fans to do it since fan's free-air rating
doesn't correspond to realized airflow, and beyond a certain point the
additional openings in the chassis are counter-productive, will allow
more noise to escape. That 10C rise isn't always in a perfect
air-conditioned environment, some systems are in sunlight or near a
heater/vent or clustered together.. for a variety of reasons there
needs be a margin enough to tolerate moderately elevated temps.
Click to expand...

Again check the temp yourself even at full load. Note that Papst rates their
BB and sleeves with the same temps and Mtbf.
But you are only adding sound energy, the "noise" is what we hear. If
the difference isn't audible outside of the chassis...



Nope, every time mention is made of mounting position and how it
affects lifespan, the mention is that it does reduce MTBF. If you
know of a manufacturer that claims otherwise please disclose this.
Click to expand...

There is not a manufacture that makes that claim. Its up to you to support
your position.

Lane


snip
 
There is not a manufacture that makes that claim. Its up to you to support
your position.
Click to expand...

I vaguely remember reading it on multiple manufacturer's tech sheets,
but unfortunately I had no clue at the time that I'd need to collect
links, and feeling it's not worth the hours of time it might take to
prove my point I'll just provide the links from a couple pages of a
Google search and leave it at that.

"However, when sleeve-bearing fans are mounted in any position
other than vertical, the fan's life span decreases."
http://www.currentsolutions.com/knowledge/ballbearingvssleevefans.htm


"Despite the slightly higher noise factor and shock sensitivity of
ball bearings, this bearing technology should be given preference when
exposed to extreme thermal load and adverse application conditions
(e.g. extreme environmental conditions, critical
installation position, etc.)." - Papst fan catalog (~11MB)
http://www.papst.de/pdf_dat_e/KAT_01GB.PDF


"If you will be mounting the fan in such a way that the shaft that the
blade spins on is horizontal, then the weight of the blade will be
resting on the side of he shaft. In that case, a sleeve bearing fan
should work fine, and be a little cheaper. If the shaft points up,
the weight of the blade will attempt to make the blade slide down the
shaft. In this case, a ball bearing fan should be used..."
http://www.partshelf.com/sleevbearhea.html


"However, when sleeve bearing fans are mounted
in any position other than vertical the fan’s life span decreases."
http://synergy.sager.com/ProductPDFs/Fans_Ball_vs_Sleeve.pdf


"The information most important when selecting a fan, are as follows:
size, voltage, airflow, bearing type, mounting (horizontal or vertical
air flow) and ..."
http://www.crouzet-usa.com/faq/Fans_FAQ.doc


"What orientation of the bearing shaft does your design permit,
horizontal or vertical?"
http://www.indek.com/services/services.html


"The ball bearing system is superior to the sleeve bearing with good
performance for a long period of time running at high speeds and at
elevated temperatures. Also it can run horizontally or vertically due
to the fact that it is spring-loaded."
http://216.239.41.104/search?q=cach...ve+bearing+vertical&hl=en&lr=lang_en&ie=UTF-8
http://www.pelkomotors.net/engpqnm.asp


"In comparison, sleeve-bearing fans can maintain life spans comparable
to their ball-bearing counterparts when the sleeve-bearing fans are
mounted in vertical positions. However, when sleeve-bearing fans are
mounted in any position other than vertical, the fan's life span
decreases. "
http://www.powerpulse.net/cgi-bin/pp_techpaper.pl?id=aa_092401a&page=2
 
kony said:
I vaguely remember reading it on multiple manufacturer's tech sheets,
but unfortunately I had no clue at the time that I'd need to collect
links, and feeling it's not worth the hours of time it might take to
prove my point I'll just provide the links from a couple pages of a
Google search and leave it at that.

"However, when sleeve-bearing fans are mounted in any position
other than vertical, the fan's life span decreases."
http://www.currentsolutions.com/knowledge/ballbearingvssleevefans.htm


"Despite the slightly higher noise factor and shock sensitivity of
ball bearings, this bearing technology should be given preference when
exposed to extreme thermal load and adverse application conditions
(e.g. extreme environmental conditions, critical
installation position, etc.)." - Papst fan catalog (~11MB)
http://www.papst.de/pdf_dat_e/KAT_01GB.PDF

"If you will be mounting the fan in such a way that the shaft that the
blade spins on is horizontal, then the weight of the blade will be
resting on the side of he shaft. In that case, a sleeve bearing fan
should work fine, and be a little cheaper. If the shaft points up,
the weight of the blade will attempt to make the blade slide down the
shaft. In this case, a ball bearing fan should be used..."
http://www.partshelf.com/sleevbearhea.html
Click to expand...
"However, when sleeve bearing fans are mounted
in any position other than vertical the fan's life span decreases."
http://synergy.sager.com/ProductPDFs/Fans_Ball_vs_Sleeve.pdf

"The information most important when selecting a fan, are as follows:
size, voltage, airflow, bearing type, mounting (horizontal or vertical
air flow) and ..."
http://www.crouzet-usa.com/faq/Fans_FAQ.doc

"What orientation of the bearing shaft does your design permit,
horizontal or vertical?"
http://www.indek.com/services/services.html

"The ball bearing system is superior to the sleeve bearing with good
performance for a long period of time running at high speeds and at
elevated temperatures. Also it can run horizontally or vertically due
to the fact that it is spring-loaded."
Click to expand...
http://216.239.41.104/search?q=cach...ve+bearing+vertical&hl=en&lr=lang_en&ie=UTF-8

Spring loaded ?????
"In comparison, sleeve-bearing fans can maintain life spans comparable
to their ball-bearing counterparts when the sleeve-bearing fans are
mounted in vertical positions. However, when sleeve-bearing fans are
mounted in any position other than vertical, the fan's life span
decreases. "
http://www.powerpulse.net/cgi-bin/pp_techpaper.pl?id=aa_092401a&page=2
Click to expand...

How about an engineering paper. What surprising is that there is no mention
of this on either Papst or Panaflos website and these people should know.
The one reference to the Papst paper mentions "critical" which could mean a
lot of things such as hard to access. I loved the paper about the spring
loaded BB fan, just goes to show that a lot of people have no clue what
their talking about.
Lane
 
Lane Lewis said:
news:[email protected]...
Click to expand...

Found an engineering paper.
[qt]
For normal computer type environments we recommend our sleeve bearing units
since they will meet the life requirements, are quieter, are less expensive,
and can be used in any mounting attitude. For high ambient temperatures, or
other operating conditions which result in the bearing system seeing very
high total temperatures, or hostile environments, ball bearings should be
considered. If a sleeve bearing model will do the job, we suggest it be used
instead of a more expensive, less quiet ball bearing model.

http://www.comairrotron.com/Engineering/LifeReliability.htm

Note this might not apply to the poorly designed cheap fans but there is
nothing inherent in the design of a sleeve bearing fan that would prevent it
from being mounted horizontally.

Lane
 
Lane said:
The heat from a hard drive is several times that of a PC there just is no
relevance at all.

Lane
Click to expand...

Apparently, ball bearings are more solid, the only downside would be the
noise. If you don't care about noise, then a ball bearing fan is always
best.

BTW, it's true that in my experience ball bearings are more noisy. I've
tried several fans to shut up my system. I now use a papst 12 db in my PSU
(I know, it gets too hot, I still have to figure something out). All the
ball bearing fans I've tried make a high pitched noise, the sleeves don't.
But, the titan 12x12cm ball bearing aluminium fan I also have in my
computer doesn't make this high pitched tone. In fact, I think it's one of
the most quite fans I've heard turning at that speed in terms of mechanical
noise (not turbulence noise, but which is OK as well).

Halfgaar
 
Lane Lewis said:
news:[email protected]...
Click to expand...

Found an engineering paper.
[qt]
For normal computer type environments we recommend our sleeve bearing units
since they will meet the life requirements, are quieter, are less expensive,
and can be used in any mounting attitude. For high ambient temperatures, or
other operating conditions which result in the bearing system seeing very
high total temperatures, or hostile environments, ball bearings should be
considered. If a sleeve bearing model will do the job, we suggest it be used
instead of a more expensive, less quiet ball bearing model.

http://www.comairrotron.com/Engineering/LifeReliability.htm

Note this might not apply to the poorly designed cheap fans but there is
nothing inherent in the design of a sleeve bearing fan that would prevent it
from being mounted horizontally.

Lane
Click to expand...


What's amusing about spring-loaded fans?

Take a decent fan apart... there's a spring on the shaft right after
the hub. Of course I mean ball-bearing fans. A sleeve-bearing fan
WOULD benefit from a spring too, except that the spring would put too
much pressure against the thrust washer, increase wear.

There are are least two reasons any sleeve-bearing fan must be mounted
vertically to have a "normal" lifespan. The first is gravity, the
shape of the bearingway... the oil will not be evenly distributed as
it diminishes, so the accelerated-wear portion of the life-cycle
starts earlier. Second there is always a slight bit of imbalance,
even in Papst's method of balancing. This imbalance will cause more
slapping around in the bearing in a non-vertical position... not much
more, but a tiny bit is all it takes to decrease lifespan.

Note also that while the Comair paper mentioned that the fans could be
mounted in different attitudes, it did NOT state that this has no
effect on lifespan.. good marketing is all about mentioning a
product's positive benefits but omitting the negative.

Sooner or later I'll come across those spec sheet mentioning the
lifespan differences... they're probably on one of my HDDs... but
somehow what was once a few MB HDD, is now more reading than a person
could do in a lifetime... that's progress I suppose.


Dave
 
kony said:
On Thu, 09 Oct 2003 17:20:58 GMT, "Lane Lewis"

Take a decent fan apart... there's a spring on the shaft right after
the hub. Of course I mean ball-bearing fans. A sleeve-bearing fan
WOULD benefit from a spring too, except that the spring would put too
much pressure against the thrust washer, increase wear.

There are are least two reasons any sleeve-bearing fan must be mounted
vertically to have a "normal" lifespan. The first is gravity, the
shape of the bearingway... the oil will not be evenly distributed as
it diminishes, so the accelerated-wear portion of the life-cycle
starts earlier. Second there is always a slight bit of imbalance,
even in Papst's method of balancing. This imbalance will cause more
slapping around in the bearing in a non-vertical position... not much
more, but a tiny bit is all it takes to decrease lifespan.

Note also that while the Comair paper mentioned that the fans could be
mounted in different attitudes, it did NOT state that this has no
effect on lifespan.. good marketing is all about mentioning a
product's positive benefits but omitting the negative.

Sooner or later I'll come across those spec sheet mentioning the
lifespan differences... they're probably on one of my HDDs... but
somehow what was once a few MB HDD, is now more reading than a person
could do in a lifetime... that's progress I suppose.
Click to expand...

Be glad to read it, in the meantime I'm looking at the 60 mm panaflows as a
fan for video cards as I might be upgrading soon. They have a thin design
(15mm) and either 24 or 32 decibels at 12 and 16.6 CFM respectively. Might
take some doing to actually mount the fan on the card and the heatsink might
have to be upgraded but it should be interesting. Space is always a factor
and it might not clear the card next to it but I have an extra slot anyway.
Will keep you informed.

http://www.panasonic.com/industrial/appliance/pdf/fba06t.pdf

As far as springs go it sounds like a cost cutting factor rather then an
optimum design. I'll check into that as well.

Lane

There are two roads in life, Take the twisty one
 
Be glad to read it, in the meantime I'm looking at the 60 mm panaflows as a
fan for video cards as I might be upgrading soon. They have a thin design
(15mm) and either 24 or 32 decibels at 12 and 16.6 CFM respectively. Might
take some doing to actually mount the fan on the card and the heatsink might
have to be upgraded but it should be interesting. Space is always a factor
and it might not clear the card next to it but I have an extra slot anyway.
Will keep you informed.

http://www.panasonic.com/industrial/appliance/pdf/fba06t.pdf
Click to expand...

Sounds like a plan.... of course I have some of those (I am fan god).
I even have some of the OLD ones, back when they had a larger exposed
metal center hub.

The 60x15mm fans I've used more recently on video cards are these NMB
2406KL (in the thermally-controlled
version):http://www.eminebea.com/content/pdf/TMP00123/I/2406kl.pdf


As far as springs go it sounds like a cost cutting factor rather then an
optimum design. I'll check into that as well.
Click to expand...


Not at all, even a $100 giant Papst fan has 'em, as do the PC-sized
versions, the Comair-Rotrons, the Panaflo Ball-bearing versions... for
a mid-to-good quality dual ball-bearing fan, it is more likely than
not that it'll have such a spring. You can often tell by pushing in
on the center of the hub, it will move a mm or two and spring back.
Even on the 60x15 fans I mentioned above, where the space/thickness is
at a premium and with two ball-bearings, they still put a spring in
'em.


Dave
 
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