Napoleon Engineering Services (Olean, US) are now able to supply back-up bearings for use with active magnetic bearings (AMB), where they serve as highly reliable secondary failsafe systems.
AMB are increasingly used within electrical power generation, petroleum refining, machine tooling, and natural gas pipelines. Their design incorporates the use of electromagnets, which magnetically levitate rotating shafts or other moving parts. The lack of contact between the bearings and the loads they support removes the need for lubricating systems and increases the speed at which the moving parts can operate. To ensure the success of AMB systems, a reliable backup or auxiliary bearing must be in place to enable controlled shutdown, in case of a power or control systems failure.
When using AMB to support a rotating shaft, any reduction or loss of power could cause the shaft to drop. With NES Bearings AMB back-up bearings in place, the shaft will drop 2 to 3 thousandths of an inch onto the back-up bearing system, allowing it to coast to a stop without damage to the shaft or surrounding machinery. The robust design of NES Bearings AMB back-up bearings incorporates specialty heat treatments, wear resistant material combinations, conventional or dry film lubricants and a variety of cage and internal design characteristics, all of which help to effectively manage the safe coast down of the rotating shaft.
Notes Chris Napoleon, NES Bearings president and chief engineer, “Understanding the magnitude and distribution of radial and axial loads, rotational speeds and lubrication constraints allow us to determine whether a full ball complement or caged bearing design is warranted. In some cases, standard bearings can be highly modified to meet specific application needs, resulting in manufactured AMB back-up bearings with very short lead times Other applications require more extreme design considerations, including special heat treatment processes, yielding very stable parts with extremely low residual stress. At NES Bearings, we’ve developed and manufactured many different AMB back-up bearing solutions, in sizes ranging from 1” to 14” OD, to meet a variety of needs.”