On 2010-11-19, David Billington wrote:
Ignoramus5827 wrote:
I have a couple of devices with very noisy and annoying fans. One is
an old laptop and another is a car inverter. In both, fans make a very
annoying, inconsistent, and rattling sound. Before taking those things
apart etc, I wanted to double check what is the typical cause of this
and how to deal with them.

i

Sounds like a sleeve bearing fan and the bearings have gone dry. Quite
often they can be rejuvenated by re-lubricating the bearing. I have a
couple in my PCs and they require treatment every couple of years.
Normally you can left the label off the centre and you'll find the end
of the shaft with a small circlip, so far all the circlips have been
plastic, so remove the circlip and the fan and shaft can be removed.
Clean the shaft and bearing with some tissue , add a drop of oil, I use
airline oil, and re-assemble and all should be well again. BTW one fan
has a rubber bung sealing the end of the shaft which needs to be removed.

If that is a Rotron muffin fan (now Comair Rotron), they used to
offer a lubrication kit which included a hypodermic to puncture the
rubber seal and an oil with lots of toxic hazard warnings affixed to the
container.

The old ones had the rubber seal under the label. Some newer
ones have an aluminum washer staked into place over the rubber -- the
hole in the center allowing the hypodermic access to the rubber without
removing a label or having to guess where to poke in. :-)

BTW I got an interesting fan at the local metalworking club meeting
last Tuesday. It is a 1" cube, powered by your choice of 26 V
or 115 V -- but 400 Hz in either case. You adapt to 115 V 400
Hz by hooking a second capacitor in series with the whole
thing. :-)

I haven't bothered to hook it up yet, but I expect an impressive
amount of airflow through it (for its size) when I do.

Enjoy,
DoN.

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