Thread: Balancing a fan
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Tim Wescott[_3_] Tim Wescott[_3_] is offline
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Default Balancing a fan

Karl Townsend wrote:
I got so much help on my sprayer, I'm trying again...

Full time investigation and part replacement has me working on this theory
of the problem cause: The squirrel cage fan is out of balance. It is barely
detectable because the fan has a 2" solid steel shaft and some serious
pillow block bearings mounted solid to a beefy frame. At the resonate RPM,
this imbalance feeds on the slack in the drive line. Any system upset causes
the fan to become unstable and it lurches back and forth.

I've called around and not found a place to dynamic balance something like
this. Are there any home brew methods? Or other suggestions? Its built so
solid I don't think I'm looking for a minor imbalance.


Something like this, only bigger?

http://www3.towerhobbies.com/cgi-bin...&I=LXHY61&P=ML

Before you dynamic balance, can you check the static balance? If the
static balance is perfect then I'd doubt that the thing is out of
dynamic balance.

If those bearings aren't as free as free can be then you've got a
problem. How much of a pain is it to take the fan out? Could you use
the "knife edge" with the fan shaft on a couple of angle irons, corner up?

Or: can you take the shaft out, and make an adapter so the thing will go
on a truck tire balancer?

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com