"Karl Townsend" wrote in message
anews.com...
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.

Karl


Get a couple of load cells and a digital storage scope, trigger from a
signal once per revolution. Perhaps a vibration sensor at each pillow block
would do the same thing? This probably isn't practical unless you already
have the DSO.

RogerN