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[filmscanners] Re: keeping the 16bit scans; now=HD longevity OT
I just did a very quick Google search. These are called both liquid and
fluid bearings, fluid being more accurate, since sometimes air can be
used (not in hard drives (yet), but in other applications.)
Anyway, without providing proper attribution (please forgive me)...
Here are two explanations of the concept. The second actually comes
from a magazine, I believe it is EETimes, the first part is a small
except from an article from I believe Extreme Technology, on quieting
Liquid, or fluid, "bearings" aren't bearings at all, in the
traditional sense. The term refers to a micro thin layer of liquid
lubricant which is sealed between the rotor and the shaft of the drive
motor. The lack of actual ball bearings creates less vibration, the
liquid absorbs shock better, and, of course, it transmits less sound.
In fluid bearings, oil replaces steel ball bearings, which have become
a headache for drive designers as track density and rotational rates
increase. When metal bearings rub on a metal motor shaft, vibration is a
key issue. Moreover, bearings are sensitive to shock and their friction
causes wear that affects long-term reliability. Analysts predict that
other drive makers will also switch from bearing motors.
"This has to happen between now and the turn of the century," said
Dennis Waid, president of Peripheral Research (Santa Barbara, Calif.).
"Everyone is pushing for higher spindle speeds, like the 14,400-rpm
programs some people have started. You can't do 14,400 rpm with bearing
motors. I think we'll see a lot more of this to decrease noise, improve
shock resistance and avoid non-repetitive runout."
That last problem describes the tendency of a disk's outer edges to
vibrate when the platters spin. As tracks move closer together to
increase capacity, this vibration makes it tougher to position the head
on the desired track. Fluid motors can reduce vibration to about 0.5
microinch, against a 5-microinch movement for most bearing motors, Waid
Seagate technicians called non-repetitive runout a key problem that
drove them to fluid bearings. But they noted that fluid bearings also
bring other, sometimes-subtle benefits, including decreased vibration,
quieter operation and improved shock resistance.
"Fluid-bearing motors have three to five times better shock absorption
than any bearing motor," said Hans Leuthold, senior director of the
motor group. "They will also let us increase our factory yields. Drives
are very delicate, and this technology is much less sensitive than
The rise in rotational speed is another obvious benefit. The motors draw
no more power than ball-bearing ones, Seagate said, so they won't add
heat. And the fluid can be used at much higher speeds.
"Every fluid-bearing motor performs better as spindle speed rises,"
Heine said. "Going to 10,000, 12,000 or 14,000 rpm is easier if you use
fluid bearings. Before the end of the year, we expect to have prototypes
of faster [than 7,200-rpm] motors running."
> Hi Art et al,
> My experience with my current IBM-DTLA 307045 hard drive (45GB ) which is an
> EIDE 7200rpm drive is a 50/50 split. The first one installed in my computer
> three years ago burned out in 3 months, as I turned the computer off every
> day. It was replaced under warranty and at the suggestion of the technician,
> I have left the computer on 24/7 for the past 30 months. The only time I
> shut down is for a reboot after a software upgrade or when I lose the
> connection on my internet cable.
> ( infrequently ) Not one hiccough from this drive.
> Secondly, I work in an industry wherein bearings are an extremely important
> part of our products. Our bearings turn at 130,000 rpm! These are high
> temperature 'ceramic' bearings because there is no way to generate these
> speeds on metal bearings ( even bathed in refrigerated oil, constantly )
> since they will break down and fail miserably in very short order. Our air
> cooled bearings are warranted for ten years!
> High speed usage (7,000 rpm isn't getting up there at all ). has been a
> common application for over 25 years in my industry. In fact all of my
> products which spin under 30,000 rpm still use captured metal bearings.These
> bearings are machined very precisely and need no additional lubrication once
> enclosed. Surely a hard drive manufacturer could put a decent set of
> bearings into a hard drive!!
> I have never heard of "liquid bearings"! Would you please elaborate on these
> "liquid bearings"; I am always prepared to learn something new!
> ART ENTLICH WROTE:
> ----- Original Message -----
>>From: "Arthur Entlich" <email@example.com>
>>Sent: Saturday, March 29, 2003 7:36 AM
>>Subject: [filmscanners] Re: keeping the 16bit scans
>>A MAjOR (j=XT) hard drive company indirectly >admitted to me that there
>>was a large failure rate on their 7200 rpm drives with >standard bearings.
> They have since switched to "liquid >bearings" which "may" resolve this
> problem. I guess >time will tell.
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