noisy large rotor seasoning
noisy large rotor seasoning
(OP)
We have a 20 ton motor rotor made with large diameter shrinkfits and hundred or so shrink fitted pinned joints.
During the first few hundred revolutions on the balance machine it emitted some creaks and groans. It has been silent ever since, but has not gone thru any operating cycles.
Have others experienced rotating machinery that requires "seasoning" to run quiet?
During the first few hundred revolutions on the balance machine it emitted some creaks and groans. It has been silent ever since, but has not gone thru any operating cycles.
Have others experienced rotating machinery that requires "seasoning" to run quiet?





RE: noisy large rotor seasoning
So much for the ideal world. I know of several joints that exhibit 'green' clunks. Once they settle down they seem OK. However these are typically bolted joints, of mass produced assemblies. Equally I can think of other joints that never settle down.
Sorry not much help, but I would double check your joint forces and designs.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: noisy large rotor seasoning
Mike Halloran
Pembroke Pines, FL, USA
RE: noisy large rotor seasoning
If it is the rotor then BE VERY CAREFUL. As has been said, any noise from a rotor, particularly one with shrink fits, would tend to indicate a problem either with a fit or even possibly a shaft fracture within the shrink being held by the shrink.
Put a dial indicator on the shaft either side of the rotor mass and check for any sign of deflection. If there is a crack under there somewhere, you should pick it up. You could also do a bump test on the rotor to see if it "rings" or "thuds" but ideally you should suspend it for this, not have it on rollers.
RE: noisy large rotor seasoning
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: noisy large rotor seasoning
RE: noisy large rotor seasoning
rmw
RE: noisy large rotor seasoning
It may not happen on a restart because there is sufficient residual lubrication on the bearing/shaft surfaces to quickly form the wedge.
rmw
RE: noisy large rotor seasoning
RE: noisy large rotor seasoning
I can picture those spherical rollers being slightly axially displaced as the rotor was set down and tracking differently and objecting to being dragged a little bit sideways as they rolled.
RE: noisy large rotor seasoning
In GE we used primarily Schenck balance machines and in the turbine rotor workshop I ran these were rated at 40 tons with crowned roller bearings to match. Even with a complete Frame 5 single shaft rotor in them, round about 22 tons, we still used the supplied rollers.
I think you've also answered your own question in your last posting by stating "I can picture those spherical rollers being slightly axially displaced as the rotor was set down and tracking differently and objecting to being dragged a little bit sideways as they rolled". With this setup I'm not surprised you heard groaning noises!
RE: noisy large rotor seasoning
Our hydrodynamic bearing journals are by necessity > 25 inch diameter.
Note IRD standard products are kind of limited to 20 inch journals until capacity of 110,000 lbs. http://www.irdbalancing.com/softbearing.asp