Magnetic bearings are defined as what?

• A. A plain bearing with sliding contact.
• B. A hydraulic fluid support.
• C. A bearing that supports a load using magnetic levitation.
• D. A roller bearing using steel balls.

Answer: (C)

Magnetic bearings suspend a rotor in air using magnetic forces, so the load is carried by magnetic levitation rather than physical contact. This system relies on sensors to monitor position and a controller to adjust the magnetic field in real time, keeping the rotor centered and stable even at high speeds. Because there’s no contact between moving parts, there’s extremely low friction and wear, which is ideal for precision, high-speed applications.

Other bearing types rely on contact or fluid films to support loads. A plain bearing uses sliding contact between surfaces, which causes friction and wear. A hydrostatic or hydrodynamic (hydraulic fluid) bearing uses a thin film of fluid to separate surfaces, reducing wear but still involving fluid dynamics and potential leakage and load limitations. A roller bearing uses rolling elements like balls to carry the load through rolling contact, which also involves contact and wear. Magnetic bearings accomplish levitation without these forms of contact, which is why they are defined by load support through magnetic levitation.