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Don Foreman Don Foreman is offline
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Default rotational vibration

On Wed, 12 May 2010 10:00:08 -0500, "Karl Townsend"
wrote:

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


A harmonic balancer is the mechanical equivalent of a second-order low
pass filter for electrical signals. The differential equations are
identical in form. In addition to mass (inductance) and elasticity
(capacitance) you need damping (disspation). In a harmonic balancer
this comes from losses in the elastic material (typically rubber), or
it may come from the load.