Back in the old days (when I didn't know better), I used to build PC with $20 cases wthat comes with a silver box "200W" PSU. Those fans gives out much faster than the cheap PSU and usually start to rattle in about a month's time. I found a quick fix back that allowed an additional 2-3 years of rattle free life before another maintenance.
Recently I had to fix a sleeve bearing fan on my Antec 380W PSU that had been running 24/7 for 5-6 years. I figure out that I should share what I have learnt.
Here is my theory:
These fans use a bronze bushing which is a soft material and allows for low friction. The permanent magnet in the fan's rotor aligns itself with the iron core of the stator with the coils. It normally just floats there by the magnetic attraction and have a springy feel when you push or pull against the rotor. There is a retainer clip at the end to prevent the fan rotor from being pulled out.
As the bear wears out, the axial can now tilts slightly and chaotic motions would generate the rattling noise. Most people would just add oil at this point and hope the problem would go away or simply replace the fan.
What I have found out that a thick washer between the retainer clip and the bearing can temporarily fix the rattle fan. The washer has to be slightly thicker than the space between the retainer and the bushing. This puts a bit of tension of the magnetic pull so that the retainer is now riding on the washer. This tension eliminates the off axis movements and bring temporarily fix to the problem.
This adds a bit of friction and more metal bits to the oil in the long run. The fan now requires some oil change and maintenance every 2-3 years. That's price to pay to put off replacing the fan. I hate to throw things out before its time. :P
This is not something new as I have seen springs inside ball bearing fans for tensioning when I modded them previously.
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.