Vibrational analysis on slow turning machine

[boozz]

Hello,

Can anyone give me some idea about known international standards written on slow turning machines? ISO 10816 gives only guidelines for fast turning machines or higher input powers (>15 kW).

The apparatus I'm talking about are slow rotating machines with speeds between 5 and 240 revs/min. Because of an inbalance (which is needed for the process) this machine has much 'low frequency' vibrations thus causing a severe vibration (Vrms values higher than 2 mm/s!).

Thanks for your replies,

Ronald

 

[electricpete]

I know this won't be what you're looking for since it's not an international standard.

NEMA MG-1 invokes a separate limit on displacement, velocity and acceleration:
2 thousandths of an inch displacement (pk-pk)
0.12 inches per second (pk-0)
0.8 g's (pk-0).

IF your vibration is at only one frequency, then you would find the displacement limit to be most restrictive below 1200cpm, the velocity limit to be most restrictive from 1200 to 24000cpm, and the acceleration limit to be most restrictive above 24000cpm.

To me this approach makes a lot of sense. For instance it is well-known that a constant velocity limit independent of frequency will not provide adequate protection for low speed machines. For example if I applied the 0.12ips limit (fairly conservative at most standards for normal machines) at 180cpm I would allow 10 mils (thousands of an inch) which most people would agree is high for most machines.

 

[micjk]

There are several sources out on the net. Here is an example of one from Lockheed Martin Michoud.

http://www.hq.nasa.gov/office/codej/codejx/Vibration_Spec.doc.

Lmmss Spec No. 9.0

Sorry Did not know how to make this a link.