Is frictional resistance to rotation almost negligible with magnetic bearings?

[chetanladha]

Is it true that the frictional resistance to rotation is almost negligible with magnetic bearings?

Pls give your comments.

[EWH]

Yes, magnetic bearings have virtually no friction themselves, but the rotating parts need to be in vacuum to keep the whole system friction low enough to allow spinning days or weeks without losing most of the kinetic energy. For high-speed bearings in non-vacuum environments, fluid bearings may be simpler and cheaper.