Pump-Motor Vibration Mounting

[umairnazar]

Hello everyone;
How are you all?
I learn every time I mail in this forum regarding issues concerning hydraulics.
I have one more issue to be assisted. In our hydraulic system when we install hydraulic pump with electric motor, we usually couple the motor with pump and mount it on tank directly without using any rubber mounts.
I think we should use. When we have to select the mounts, we need to know the natural frequency of the system. But the natural frequency of the pump-motor is not given in catalogs. (Correct me if I am wrong).
How do we select the right mount for our system?
Also when we have to make a stand for a manifold of hydraulic valves, we should use mounts for it also. How to select the mounts for that as well? How will we find the frequency of the manifold with 06 or 07 valves mounted over it?
Waiting for your kind suggestion
Regards
M Umair Nazar

[smedsgenbo]

Hello dear fellow!

It's good that you learn some from reading here. I hope I will so too.... and everybody else of course.

My experience with the vibrationdampers for "sliding" in between the bell housing and the top of the tank is not very good, so to say. I can't see they work at all. And now I want to tell you why!
The tank-lid has to be stiff enough in the first place.
A lot of the vibration caused comes from the fluid and not from the pump/motor combination. Fluid borne noise can be eliminated to a certain extend by making the passage for the oil as smooth as possible. In other words, start throwing away elbows at the assembly.
It is my oppinion that, if the lid is stiff, the manifold-support brackets are strong and stiff and placed on the tank with enough fasteners then a hose connection between the pump outlet and the manifold will eliminate 95% of vibration.
There are other things to take into consideration. The coupling for example. Is it rigid or is it rigid enough. The coupling manufacturer KTR supports it's couplings with as many as 7 different spiders. Each with different properties to elliminate vibration or noise.
As if you have done all the above already and just need to take the last step to install vibration damper, then let the supplier of the vibration damper do the calculation for you. I'm very sure they will do that as a service if you buy their products.