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Stu Fields Stu Fields is offline
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Default rotational vibration


"Karl Townsend" wrote in message
anews.com...
I'm repairing the same issue on my airblast sprayer for about the fifth
time. Own something long enough and the same problems keep repeating. the
sprayer has a vibration in it at 2500 tractor RPM, 540 PTO RPM. The
vibration is not like a tire out of balance but its a bucking forward to
reverse. When it gets a little lose, in a few more hours of run it will
damn near shake the tractor off the ground. Its also a natural harmonic
at this RPM, slow down and the vibration goes away. Unfortunately, this
REALLY reduces sprayer performance.

I'm replacing the entire PTO shaft and tightening up the clearance in the
gear box again. if everything is tight, the problem is less severe. The
is working on the symptom, not the cause.

This is a long shot, anybody know about balancing this sort of vibration
or changing the natural harmonic frequency?

Karl


Karl: I'm not clear on how your system would lose mechanical balance. And
I don't know all the variables here but it sure sounds close to my balancing
my helicopter rotor which was turning at 500rpm. With an electronic
balancer that senses where the rotating item is when the accelerometer, or
in our case the velocimeter, reading is maxed, it is relatively easy to
determine where weight needs to be added to achieve balance. This is
however a simple explanation of a single plane balancing operation. Items
with some lateral extent like the cranshaft and flywheel system of a car
have two planes to worry about. If a single plane balancer could work for
you, most helicopter operations have the equipment. My guess is that you
are quite a trip from my zip code 93527. If you were close, I do have a
balancer and some experience with it on helicopters.