I would appreciate best practices and experiences regarding "Warehousing / Storing of Rotors of various Machines" like steam turbines, compressors etc.

Thanks buddies.

Ideally, and the world is rarely ideal, I would recommend "hanging" the rotors vertically. This method of storage will remove any likelyhood of rotor bowing. Unfortunately it also takes up quite a lot of space and GREAT CARE must be exercised when lifting the rotors to this position and down again.
Obviously the rotors should be thoroughly clean and preserved during the storage.
An alternative, but much more expensive option, is to have custom made, sealed containers for each rotor, which can be vacated and slightly pressurized with a nitrogen purge. These containers can be stored either horizontal or vertical.

Relative to the comments of caveman-cheddar. Here in Philadelphia PA we have a great number of refineries who years ago stored their spare rotors horizontally. Prior to changing out a rotor they would send the stored spare to a local balance shop to have the balance verified. Almost always a correction was made and when they started the machine it was smooth for a relatively short period of time, and then the vibration would slowly increase.

What was happening was the rotor had been balanced with a bow from horizontal storage. Upon running, the bow worked itself out and the rotor was again out of balance.

It took many years to convince these refineries to store the rotors vertically, as recommended by API. As an alternative, if you must store horizontally, have it balanced prior to storage, and make sure the balance shop rolls out any bow. Then, when you replace the rotor with the spare, do not rebalance, trust that it was done properly prior to storage. If you can then slow roll the unit, the residual bow from storage will work itself out quite rapidly.

Also, if you store horizontally, use care to protect proximity probe target areas and do not let these areas become load bearing areas while in storage.

John

Motors are usually stored with lubricant in the bearings to protect them from corrosion. Periodic manual rotation helps keep the bearing coated and limits the amount of bow of horizontal rotors.

I don't know if periodic rotation is practical for the rotors you guys are talking about, but I assume it would help to limit the bow if stored horizontally.

Further to my initial suggetion, yes, one MUST check the balance of any rotor that has been in storage, whether horizontally or vertically. If it was horizontally stored, then a LONG slow-roll is also a must with runout checks to make sure any bow has been removed prior to balancing.
I would very soon stop using a workshop that didn't automatically check rotor runouts prior to balancing!

quote:

if periodic rotation is practical for the rotors you guys are talking about, but I assume it would help to limit the bow if stored horizontally.

Actually due to space and safety constraints vertical storage is generally not adopted. But bow for rotors weighing 150kg to 450 kg and upto 2.5m length could be a problem. Thats my opinion.

How much should be the rotation frequency of these rotors? Yearly, bi-annualy or else? We generally don't check balance before installation in machines and have almost nill balance problems.

What you guys suggest on how to some physical mark of rotation on rotors?

I guess you're talking small rotors here, not the ones I'm used to dealing with! Not check balance before installation? That, to me, is almost criminal. You've spent all that time and money opening the machine up, and again rebuilding it, but don't spend a couple of hours checking its heart! Very poor maintenance philosophy!