Artesyn Centellis 2000 Shelf - DC Installation and Use (June 2014) - Manual (Page 98)

FRU Installation
Centellis 2000 Shelf - DC Installation and Use (6806800G45F) 98
Exchanging Fan Trays
The exchange procedure is the same for both trays.
Unless an internal fuse has blown (not field replaceable), fan trays are never actually powered
down.
The fan rotation can be stopped by the shelf manager.
If the control board has failed, the fan will be operating at 100% speed.
Personal Injury
Rotating Fans
Inserting tools or fingers into operational fans may cause injuries.
Keep clear of the fans as long as they are rotating.