Abstract: A bearing detection system for an electrical generator (10) includes auxiliary bearings (29) for supporting a rotating shaft (39) upon failure of main bearings (62). The auxiliary bearings (29) are mounted on the shaft and have a slight gap (64) between their outside diameters and bearing liners 33. The gap corresponds to the main bearing permissible wear. During normal functioning of the main bearing, the auxiliary bearing frame (34) rotates with the shaft and a magnet (35) with a small clearance between its face and auxiliary bearing outer ring (32) forces the synchronized rotation of inner (37) and outer (32) races. The auxiliary bearing outer ring or race (32) has a coaxial groove (31) on its outer diameter and a detection sensor (30), mounted on the bearing liner, gives a signal per rotation of the shaft to a control circuit (40).