Vibration Mitigation in Hydraulic Pack 1

[mechatronic]

Hi!

In a recently procured Hydraulic Pack, Vibrations are observed.

It is a motor driven rotory pump. Motor is fixed on a base plate while pump was originally hanging like a cantiliver - now supported from the bottom

The Axial Vibration monitored is about 8 mm / sec while on lateral Axis we found a Vibration of 3.3 mm / Sec

The pump is directly coupled by a flexible coupling to the drive.

1. Could any one tell if there are any standards which defines permissible levels of Vibrations ( I Mean is the above mentioned vibration levels are Techically acceptable? )

2. Client is not happy with the Axial Vibrations - what could be the solution - Vendor says he wants to support the pump from sides also ( left and right side while looking from the motor end )

3. Coupling is a flexible one - what could be the problem ?

4. I am not happy with the vendors solution

Can any one guide me on Vibration levels permissible and possible solution

Regards

 

[kcj]

Is this pump bell housing mounted to a C faced motor, or mounted on the same baseplate the motor is fastened to?
Typically, the base plate, motor mount and pump mount need to be very thick and rigid. I use almost all C faced motor mounts with housing adaptor type of pump mount so haven't dealt with your style much.

If there is axial loading, I'd suspect either flexing in mounts that are soft in that direction, coupling misalignment that causes forces along the shaft axial drection, or something bent in motor or pump shafts.

In any case, the vendor should fix it. Adding braces to restrain the motions would not be acceptable to me unless they could show the reason why it was flexing in that direction. Simply restraining the motions may mask the real problems, and just transfer the loads into motor or pump bearing failures.

kcj

 

[mechatronic]

Excellent advise KCJ - Your post is very useful

Many thanks - Mechatronic

 

[zeusfaber]

There's new legal limits in the EU on permissible exposure of personnel to vibration (details here) . Even if it doesn't apply in your part of the world, it might form a benchmark to judge against.

Not well placed to help if it's just the equipment that's at risk.

A.

 

[Tmoose]

Hydraulic Institute, now ANSI has acceptance criteria for pumps of various configurations. ISO probably has something similar. For a while they were fairly scientific, limiting vibration based on frequency. Later they became more general, dealing just with overall readings. No idea what they are now.

You may need some vibration analysis to indentify frequencies of interest, and if resonance is amplifying "acceptable" vibration.

 

[21121956]

Hello everybody:

mechatronic, for vibration severity charts you can refer to the ISO 10816 (particularly ISO 10816-3).

Good luck !