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# Vibrating mass, centrifugal force 175kN

## Vibrating mass, centrifugal force 175kN

(OP)
Hello.
Below description:
We have unbalanced mass (M) about 50kg which rotates with frequency 50Hz. Vibrating mass produces centrifugal force equal 175kN. Vibrating shaft is connected to the rigid frame by means of rubber vibroisolators. Schema ilustates the case. Rigid frame is not fixed to the ground.

We are afraid that so big centrifugal force can fall over construction.

Below questions:
How should we shape rigid frame to ensure stability of the construction?
Is there any equotation which will show how big force would overcome this centrifugal force(175kN, 50Hz)? We are wondering what should be weight of rigid frame.

Best regards
Artur

### RE: Vibrating mass, centrifugal force 175kN

That very much depends on the isolators. If you can ensure that the resonant modes of the shaft etc on the isolators is less than 10 Hz (say), then the unbalanced shaft will find its own centre to some extent, and not thrash the living daylights out of the frame.

It is certainly possible to work out what you ask, but it is not trivial either. I suggest you look at Thomson's Theory of Vibration book, or equivalent.

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

### RE: Vibrating mass, centrifugal force 175kN

GregLocock,

It is not clear to me how the vibration isolators are mounted. Is it possible that they will provide more displacement of the mass, resulting in more force?

--
JHG

### RE: Vibrating mass, centrifugal force 175kN

The description sounds like the isolators are between the shaft and the frame. If he gets the frequencies wrong, then it could see resonance problems. Ideally he'd use the spin drier solution.

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

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