Max Muller wrote:
On Wed, 04 May 2016 04:02:46 -0400, Paul wrote:

Have you verified the fan is a maglev ? The documentation
here, says it doesn't use oil.

http://www.sunon.com/tw/products/pdf/maglev.pdf

Thank you for finding that nice 74-page Sunon Maglev fan reference.
It's interesting reading, But I need to find a cross reference
to figure out which fan it is that is the equivalent of the
fan in the Lenovo W510 Thinkpad FRUNO: 60Y5493 P/N: 60Y4981


It's as likely to be an issue with excessive friction
causes by dust and hair getting into the bearing
area, as being a need for the addition of oil.
And the device might not be designed for
easy maintenance.

This youtube video shows how a guy fixed the brushless fan.
https://www.youtube.com/watch?v=ewbMYAB0qwM

The guy took the fan apart, and merely cleaned and lubed
the shaft.

You need some realistic mechanical drawings of the
fan, to understand how easy it will be to disassemble
and clean/repair. It may be easier to track down that
information, if an actual Sunon part number is on it.
If it is custom designed as an OEM item by Sunon,
then there might not be any documentation available
for it.

It looks like a bunch of people have disassembled Sunon Maglev
fans, cleaned, lubricated, and put back together.

This guy literally drops the entire fan into motor oil:
https://youtu.be/vkLgqMPmmZg
https://www.youtube.com/watch?v=vkLgqMPmmZg

The first thing you notice in the video, is
the fan spindle moves easily, when he applied a
finger to it. The bearing is not locked. This
looks more like an electrical failure, like the
two transistor circuit that commutates the field
on the brushless DC motor isn't working. There are
also small ICs for driving the two windings, ICs
with four pins or so, and a similar comment would
apply to them. Being brushless, and using things
like a Hall probe for position sensing, there really
isn't a lot to go wrong electrically. The motor
drive uses saturated transistors for low heat
dissipation, so the chip driving the motor doesn't
need to get hot while it operates.

The brass item in the video, does appear to be
a bearing. At least to me it does. And not a
needle bearing either (as the Sunon PDF might
lead you to believe). It looks like a relatively
conventional bearing. Similar to the bearing design
I see on the cheapest hard drives I own here. (The
bearing has the same shape and appearance.)

On hard drives, the motor is FDB, the bearing is sealed,
two drops of oil circulate continuously inside the hub.
The motor can be constrained just on one end, or on
both ends. (Some WDC drives lock down the spindle on
both ends, even though the oil film is supposed to
be providing all the support when it is running.) By
floating on an oil film, and by having oil pumped continuously
over the bearing surface, the FDB motor is frictionless
and would run forever. Except when the oil evaporates
over time, or otherwise leaves the sealed area. And with
no significant oil reservoir, once it leaks, there is
no spare oil to be had. When Seagate evaluates the
operating status of the motors in the lab, they use
a gram balance, and note the difference in weight,
to figure out how much oil is left.

I think the Panaflo computer fan uses a similar idea.
Conventional bearings, but sealed to keep the oil in.
There are other kinds of computer fans, where the bearing
is not sealed. My favorite story, is the 40mm fan in a
disk enclosure - when the enclosure was acquired as
a brand new product, there was a "pool of oil" below
the fan. And within only one day of operation, the
fan was toast. That's what happens when the mechanical
tolerances are poor, and nobody gives a rats ass about
keeping the lubricant in place. There would be no point
immersing a fan like that in 5W30, because three weeks from
now, not a bit of the oil would still be in the bearing.
It would be sitting in a pool below the fan.

Paul