On Wed, 12 May 2010 16:32:59 -0500, "Karl Townsend"
wrote:


What happens when you change the tension on the fan drive belts? If they
are
implicated at all, that'll change the resonant frequency. It's a bit far
to
drive over to Blighty so we can instrument it up and workout where the
resonance is :-(

Mark Rand (Did similar work on power station foundations once)
ETFM

I've never tried that. I keep the eight belts pretty tight, 1/2" deflection
in the three foot between pulley spacing. can't go tighter, I'd take out
bearings. What do you think running loose would do? Not much margin here, I
smoked all the belts once, pretty spendy to rebelt this unit.

Karl



Going looser will drop the resonant frequency of that part of the system.
Doesn't help if the field ends up smelling of burned rubber instead of
insecticide though.


Lots of ideas from lots of folk. We have faith in you :-)


regards
Mark Rand
RTFM