Spare equipment sitting on storage racks question - when to rotate the pumps/motors etc.

Any info out there ?

Cheers

Colin.

Hi Colin,

There are some general principles you can apply, but I cant offer a recipe.

1. If the shafts are slender with respect to rotor weight and span of bearings, the rotors MUST be turned, assuming they are stored horizontally. Obviously, if vertical storage (of shaft) is possible, that is ideal and does not need turning. For the rest, a 270 degree turn is optimal. The timing depends on your evaluation of shaft slenderness. 6-monthly should be enough in most cases, but 3-monthly is good for really slender shafts.
2. For large rotors such as those of steam and gas turbines vertical storage is recommended, if possible in a container filled with dry nitrogen at 5-10mm water column pressure. If they cant be stored vertically, consider turning them over every 2 months.
3. Motor shafts are generally quite stiff. In most cases they dont need to be turned. If you suspect they are not stiff or too heavy, turn them over every 6 months.
4. These actions should be entered as routines in your CMMS, so that you know for sure that they are actually done and not merely on the wish list.
5. Vertical storage means truly vertical, either by hanging freely or kept in a container. Resting the shaft end againt a rack or wall at a small angle is not OK.

V.Narayan

Email reply from Paul Barringer

Colin:

Looking for information on ReliabilityWeb.com is always a good source of information. Terry O’Hanlon has a wealth of information at his finger tips.

One good source of information is found in the reading list at http://www.barringer1.com/read.htm
Nonoperating Reliability Databook from RAC

You will find that when most things don’t operate the failure rate is 10 to 30 times higher than when operated.

When pumps, motors, etc. sit on the shelf, you need to regularly rotate the shafts to avoid 1) corrosion and 2) false brinnelling of the bearing surfaces.

When pumps, motors, etc. are installed you need to also activate them regularly to avoid the same problems noted above AND more specifically to keep your humans on their toes for how to start up and bring down equipment without killing the system. That means you need a written procedure (that is followed!) and you need frequent drills, else your operators will demonstrate MTBSE. In well disciplined plants the time between exercises can be 1-2 months, in other plants it should be 1-2 weeks—it all depends on the discipline to keep men/machines in a simpatico arrangement.

Furthermore, remember that your installation/use practices can have significant effects on both in storage and in use life. See:



[URL=Pump Practices and Component Life Multipliers]http://www.barringer1.com/aug97prb.htm[/URL]

Demonstrated Life Of Pump Components From Pump Practices

How Much Life Is Lost From Specific Pump Practices


Hope this answers your questions.

----

Paul Barringer
Barringer & Associates, Inc.
Phone: 281-852-6810
FAX: 281-852-3749
Web: http://www.barringer1.com

Vee did good on addressing rotor mass but anitfriction bearings should be turned regularly or bound to lock bearings. But this generally leaves the floating bearing with different tension that the fixed bearing.

A small motor driving a gearbox of output ~5 RPM can be utilized. Place the motors in a row and have a chain drive 50 motors. Set on a timer and run 5 min/da and/or twice a day. the bearings will get lubed and the ball won't break through the lube film promoting false brinnelling.