TV Dampening Properties of Centrifugal Clutch

[vonsteimel]

Greetings,
I posted a question this spring concerning Torsional Vibration & Resonance of a Ducted Fan Power Train Setup.

This is somewhat a continuation of the same issue.

We have a machinery setup powering a ducted fan (see attachment). At first we experienced severe Torsional Resonance and made some changes to correct this. After further testing it was apparent the TV issue had been resolved. Time rolls on and more changes are made for a variety of reasons as with any development project.

Now we're toward the end and there is reason to believe the centrifugal clutch (seen in "setup.jpg"), which was installed to help resolve the TV issue, is no longer needed.

My question is: How can we determine the Torsional Vibration Dampening properties of a centrifugal clutch? There are no locking mechanisms other than friction between the shoe & drum. The theory is that after the clutch has engaged it will help dampen Torsional Vibration by allowing slippage.

For instance, when the power-stroke occurs(no flywheel is used) a load is suddenly applied in the direction of rotation. If this "sudden load" comes in sync with the natural frequency of the shaft, destructive torsional vibration and resonance will follow. With the clutch installed, the "sudden load" applied to the clutch will induce a small amount of slippage before being transferred to shaft thus dampening the vibration.

NOTE: I know this is a complex Phenomenon with many contributing factors & possible solutions. Any replies/suggestions will be greatly appreciated but please keep them related to the core question: HOW TO DETERMINE THE TORSIONAL-VIBRATION DAMPENING PROPERTIES OF A CENTRIFUGAL CLUTCH.
Thank you,

CS

 

[vonsteimel]

Another attachment.

 

[GregLocock]

Measure it with toothed wheels, or a laser TV meter, if they are still available.

http://www.bksv.com/doc/bo0426.pdf

piece of cake

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[vonsteimel]

Thanks for the input.
Unfortunately the equipment belongs to an analysis firm and cannot be brought back without great expense to our small operation.

It's likely we'll bring them back one last time to analyze the final setup. Intermediate analysis between then-and-now cannot be obtained with the current budget.

Does anyone know of any studies or papers our there which are related to the dampening properties of a centrifugal clutch?

 

[MiketheEngineer]

Take it out and try it??

 

[hydtools]

Has the mass of the clutch changed the dynamics rather than any friction damping? A flywheel effect?

Ted

 

[potteryshard]

If you looked at lines painted on the halves of the centrifugal clutch with a (rented) stroboscope, it would seem like you would be able to see jittering or creepage if the clutch is indeed doing any dampening. Myself, I'd expect it to be pretty well solidly locked at anything much above pull-in speed. You might also want to look at the belt with the strobe; it may be either absorbing (or contributing) vibration.

 

[Tmoose]

Are the U-joint yokes oriented as in the sketch?
Is there any offset between the engine and jackshaft centerlines?