AMB Upgrades

Increase Operating Life, Efficiency

Extend plant operating life and improve reliability and efficiency with an upgraded active magnetic bearing (AMB) system.

Waukesha Magnetic Bearings can replace an existing AMB controller with a newer model, or perform a complete system upgrade, replacing the AMB hardware and controller.

As with any bearing retrofit, the ideal solution provides the greatest improvement in performance and efficiency with the fewest machine changes and lowest total cost.

Zephyr AMB controller interior
Zephyr digital AMB controller

Controller Upgrade

The replacement of only the AMB controller can be an attractive option for a retrofit, as the new controller is operated with the existing AMB hardware, pressure penetrators and cabling, no matter the original AMB vendor.

This scenario does not require any changes to the mechanical parts of the system so could potentially be implemented on-site.

Several constraints are imposed, however, on the controller, such as drive voltage and current, signal range of the controller position input channels, and signal range of the controller speed sensor input channels.

Controller and Hardware Upgrade

Expanding an AMB retrofit to include the AMB mechanical components as well as the controller allows optimization of the bearing windings to make full use of the controller’s power amplifier capabilities.

Retrofitting with specialty hardware, such as sealed or canned stators and sensors and corrosion-resistant auxiliary bearings, can increase the robustness of the AMB system.

The replaced hardware typically includes the magnets, position sensors, speed sensors, and auxiliary bearings, thus eliminating the controller design restrictions outlined in the previous section.

New constraints are introduced, however, to the AMB stator hardware. The stators must:

  • Fit within the same envelope as the existing bearings
  • Work with the existing pressure penetrator and cable structure
  • Work with the existing AMB rotor hardware
AMB hardware for a turboexpander retrofit

Problems AMB Upgrades Can Address

  • Trips due to aerodynamic loading
  • Corrosion, erosion or fouling of AMB components from gas content issues
  • Rotordynamic stability problems manifesting as high vibration or subsynchronous vibration
  • AMB hardware and/or controller at the end of its service life

Benefits AMB Upgrades Can Provide

  • Enhanced control of the AMB hardware
  • Improved stability margins
  • Expanded machine operating envelope
  • Reduced controller footprint in the electrical control room
  • Better access for maintenance
  • Enhanced logistics and redundancy with installed spares

Selecting an Upgrade

Explore AMB upgrade possibilities in more detail in our magnetic bearing retrofit white paper. The paper discusses the constraints of each upgrade option in general terms and in the context of a turboexpander retrofit performed in partnership with L.A. Turbine.

The paper concludes with a guide to help end users evaluate their own AMB applications for upgrade.

Download the White Paper

Magnetic Bearing Hardware

Waukesha Magnetic Bearings provides robust bearing designs for high reliability and availability in a range of operating environments. Our sealed magnetic bearings can be immersed in mildly corrosive process fluid environments, while our canned magnetic bearings are designed for immersion in the most extreme corrosive and abrasive environments.

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Magnetic Bearing Controllers

Waukesha Magnetic Bearings controllers employ complex control algorithms for optimized system performance and efficiency. In addition, remote connectivity capabilities allow for remote commissioning, monitoring, diagnostics and adjustment.

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