Magnetic Suspension Backup Bearings: Types and Selection Tips

Magnetic suspension backup bearings (also called catcher or protection bearings) are a critical safety component in magnetic levitation systems. They provide mechanical support to the rotor during power loss or system failure, preventing rotor-stator contact and catastrophic damage in equipment like maglev blowers and turbo-machines.

Common Types Used as Backup Bearings

1.Angular Contact Ball Bearings

These are widely used due to their high-speed capability and axial load capacity. Common series include 70 and 72. Specialized models such as CXFSV71905ACQQ/P4ADFLTB, CXFSV71907ACQQ/P4ADFLTB, and CXFSV71908ACQQ/P4ADFLTB are designed for impact resistance and stable run-down performance.

2.Deep Groove Ball Bearings
Thin-section types from series like 618 or 819 are used where space is limited. Examples include CXFV61909QQ/P4ALTB and CXFV61910QQ/P4ALTB, which offer reliable backup support for high-speed rotors.

Key Selection Guidelines

1.Prioritize impact strength

The bearing must survive the sudden drop of the rotor. Standard bearings may fail instantly under shock loads. Choose bearings specifically engineered for high impact resistance.

2.Address lubrication during standby

Backup bearings often remain idle for long periods, leading to grease degradation. Use specialty greases for long-term storage or apply solid lubricant coatings (e.g., PTFE or DLC) on bearing surfaces.

3.Match design to application needs

Options include full-complement (no cage) for higher load capacity, hybrid ceramic balls for reduced heat, or standard steel for cost efficiency. Select based on expected drop events, system dynamics, and budget—not one-size-fits-all assumptions.

4.Apply corrosion protection

Stationary bearings are prone to rust. Anti-corrosion coatings (such as zinc or nickel) on rings help maintain readiness and extend service life.

5.Balance precision and cost

High precision (e.g., P4, ABEC 7) improves coast-down smoothness but increases cost. For most backup roles, moderate precision that meets functional requirements is sufficient and more economical.

Conclusion

Selecting the right backup bearing requires understanding your system’s failure mode and operational environment. Partner with a manufacturer experienced in magnetic suspension applications to ensure reliability without overspending.