Why Use Magnetic Bearings?

Active magnetic bearings utilize non-contact position sensors to monitor shaft position and feed this information back to a control system. The Magnetic Bearing Controller (MBC) uses this feedback to adjust the required current to a magnetic actuator to maintain proper rotor position.

Magnetic bearings are a good match with high-speed permanent magnet (PM) motors, compressors, turbines and other high-speed rotating machinery. These devices offer a non-contact rotor support system with extremely low friction and wear. While conventional bearings (e.g. roller bearings, fluid-film bearings) physically interface with the shaft and require some form of lubrication, magnetic bearings suspend the target rotor in a magnetic field, eliminating contact wear.

Implementing magnetic bearings into your design brings numerous advantages:

  • No physical contact between rotating and stationary components means minimal friction and wear from load-bearing elements
  • AMB systems do not need lubrication systems, making them virtually maintenance-free, reducing initial costs as well as operating and maintenance costs
  • AMBs can be used in harsh environmental conditions, including extremely low temperatures, zero-gravity, and corrosive environments
  • Low power losses allow AMB supported machines to achieve higher running speeds, higher efficiencies and longer machine life than conventional bearings
  • Dynamic testing, health-monitoring, and data-logging features are integrated into the control electronics. With conventional bearing machines, these features must be externally supplied, implemented, and maintained
  • Dynamic properties (stiffness and damping) of magnetic bearings are easily measured and readily changed through built-in control firmware as part of the magnetic bearing controller. Changing the dynamic properties of conventional bearings requires a complete re-design, re-manufacture, re-test, and re-installation of the bearings, taking several weeks up to several months
  • AMBs have high static stiffness, providing precise control of the nominal shaft center under load
  • AMB supported systems allow for synchronous current minimization schemes, which virtually eliminates rotor unbalance forces transmitted to the outside structure.
  • To see more information about Calnetix AMB advantages, click here.