Standby changeover Philosophy

We are following time based change over philosophy for 2x100% and 3 x 100% redundancy equipment, furthermore we have Chinese plant so we don't have well designed reliable machines.

Few days back I heard from a reliability professional that modern approach is to declare one as duty pump and use it till a situation arise, and keep the standby as standby but have its periodic run tests time to time to ensure its health. Logic behind was that once the integrity of one pump is affected the other one would be like just new, with minimum running hours, while in time based changeover both will have almost same running hours. 

Whats are your views and practices? If you support duty/standby philosophy can you please share some article/standard/reference etc, so I may convince my operations team



Original Post

  Your standby equipment, if it is rotating machinery with roller bearings, needs to be run periodically to prevent false brinelling of the bearings. Also, a periodic run is a maintenance task in RCM that is designed to identify a "hidden failure", in other words, it verifies that the machine has no problems on a periodic basis so that you can rely on it as a backup machine. 

  For any machine that has to be shut down for maintenance at some periodic interval, it makes sense to switch the equipment then, do the PM required and leave the standby machine running, switching them again at the next PM interval. This equalizes run time and gives you PM opportunities on both machines. 

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