Figure 4 shows integrated magnetic bearings supporting a 250-horsepower industrial motor. The integration was achieved by modifying the shaft and the bearing housings to accommodate the radial bearings. An optional thrust bearing provides axial load capacity for applications such as vertical motors.
Compact Magnetic Bearing Controller. Figure 5 presents a compact magnetic bearing controller that can be located close to or directly on a rotating machine. The controller includes all signal conditioning, digital processing, power amplification, and high-speed network communications. Despite its small size, each power amplifier is rated at 7,500 VA. Machine mounting the controller eliminates long cable runs for the coil and sensor wires, simplifies connectors, reduces EMI, and eliminates special sensor tuning.
The controller box may be purged if located in an explosive environment. The external connections to the controller include DC power cables and an Ethernet network cable. Also included in the compact controller are spare I/O and spare processing power, which facilitate the industrial trend toward locally controlled, intelligent machinery.
Through technical advances, magnetic bearings now offer advantages for a much broader range of machines and applications. Design innovations related to miniaturization, integration, and standardization continue to increase the general acceptance of magnetic bearings for many new and existing applications, setting the standard for better, smaller, and greener.
This article was written by Dr. Victor Iannello, ScD, founder and CEO of Synchrony, Salem, VA. For more information, visit http://info.hotims.com/28054-321.