Elements of a magnetic bearing system include electromagnets, sensors, digital processors, power amplifiers, and cabling. Synchrony's approach to fault tolerance is to design highly integrated systems that have multiple processors, redundant sensors, and extra electromagnets connected by cables to matching power amplifiers. Upon a failure of a component, the fault tolerant magnetic bearing automatically re-configures itself and continues to operate. Using an innovative architecture, fault tolerance is achieved with only a modest increase in size and cost of the overall magnetic bearing system.

Where would this level of protection be necessary?

Originally, this architecture was developed for the US Air Force for next generation aero-engine applications. Industrial applications can also now benefit from this technology, including large turbomachines found in the Oil & Gas and Power Generation sectors. Some examples include applications where downtime is extremely expensive (such as compressors used in petrochemical plants) and applications where a machine is difficult or impossible to service in the event of a failure (such as subsea compressors). Fault tolerance allows the rotating machine to continue to operate until maintenance can be scheduled. Magnetic bearings can help achieve a level of reliability never before possible.

• Displace fossil fuels with other sources of energy, such as nuclear, wind, geothermal, and solar
• Reduce the consumption of energy by reducing energy-intensive activities
• Improve the utilization of energy by increasing the efficiency of machines and processes

Improved efficiency is the low-hanging fruit because it typically does not involve radical changes in our energy infrastructure. For instance, according to NEMA, electric motors account for nearly 70% of the electricity consumed in the U.S. industrial manufacturing sector. Many of those motors drive turbomachines such as pumps, blowers, and compressors commonly found in industrial processes. Even small efficiency improvements translate to large reductions in energy consumption. Magnetic bearings and high speed motors can help to reduce the energy consumption in your factory in these ways:

• Reduce bearing losses. Using magnetic forces to support and position rotating shafts eliminates the viscous friction from lubricants in motors and turbomachines.
• Eliminate gearbox losses. Directly connecting a high speed motor to a high speed turbomachine eliminates the power consumed by gears, bearings, and pinions.
• Improve aerodynamic efficiency. Increasing the speed of the turbomachine and allowing the speed to vary with operating conditions improves the overall aerodynamic efficiency of the turbomachine.

These improvements in efficiency have been already accepted in applications such as refrigerant compressors and aeration blowers, where efficiency improvements greater than 10% are achievable.

• Limited damping. The vibrational characteristics of a rotating machine close to or at its critical speeds (resonances) are determined by the amount of damping (dissipation) introduced by the bearings. A magnetic bearing can electronically optimize this damping to reduce the vibration at critical speeds. An air bearing will typically have much less damping, which will restrict the operating speed range of the machine, and may require a more complicated balancing process.
• Manufacturing tolerances. The forces in an air bearing are created due to the small clearance between the rotating and stationary surfaces, often times less than 0.001 in for a journal diameter of about 1 in. Because bearing forces are reduced at larger clearances, it is necessary to maintain this small clearance even for much larger shafts. The net result is that it becomes difficult or impossible to manufacture the bearing for larger machines with the required precision. The clearances in a magnetic bearing are between 10 and 20 times larger, which make them suitable for larger machines.
• Intolerance to contaminants. Because of the very small clearances, the performance of the bearing is adversely affected by contaminants in the air. This precludes use of the air bearing in many industrial environments unless special provisions are made to ensure the environment surrounding the air bearing is clean. The performance of a magnetic bearing is relatively insensitive to these contaminants.
• Load capacity varies with speed. For typical operating conditions, t]]> This Sunday, The New York Times ran a story on Synchrony and our Fusion® bearing. The reporter, Anne Eisenberg, did a wonderful job explaining magnetic bearings to the general public and how the Fusion bearing is different from other types of magnetic bearings. The article also included insightful comments from Eric Maslen (University of Virginia), Dave Trumper (MIT), Bill Pizzichil (Baldor), and Jigger Jumonville (Atlas-Copco consultant).

  The article ran on Sunday, January 3, 2010, and by Monday night we have had well over 2000 visits to our synchrony.com web site, including many inquiries regarding our products and our company. Many that have contacted us share our belief that the acceptance of magnetic bearings is accelerating due to improvements in simplicity, size, performance, and value.

  It is certainly an exciting time to be at Synchrony.

  The entire article is available Online here.

   

  ]]> At Synchrony, we are passionate about massively increasing the use of magnetic bearings for a broad range of applications. We believe our approach to improving the performance, simplicity, size, and economics allows the machine designer to use magnetic bearings for applications that were previously not feasible. One example is pumps, which are found in large facilities such as oil refineries in quantities of thousands. Bearing failures currently limit the reliability and life of pumps for many applications. There are many other opportunities for magnetic bearings to pay dividends in pumps.

  At Synchrony, we have seen increased interest in using magnetic bearings to replace oil-lubricated bearings in pumps. For pumps currently supported on ball bearings, magnetic bearings offer improvements in machine vibration and reliability. For pumps supported on fluid film bearings and fed with pressurized oil, magnetic bearings allow the complete elimination of the oil lubrication system, including the oil reservoir, pumps, filters, heat exchangers, and piping. Often, the economics to replace a fluid-film bearing with magnetic bearings can be justified solely on the acquisition cost of the oil lubrication system. In addition, magnetic bearings offer higher efficiency, improved control of vibration, reductions in maintenance, improvements in reliability, and elimination of the cost and hazards of handling, storing, and disposing of oil.

  Synchrony's Fusion® bearings were designed to be easily integrated into machines such as pumps and motors. With all the control electronics embedded into the bearing, the requirements for wiring, connectors, and space for an external controller are all greatly diminished. Available in a range of standard sizes, the task of retrofitting an existing machine or integrating into a new machine is greatly reduced in scope and cost.

  For a pump that is driven by an electric motor, the motor rotor can also be supported on magnetic bearings. The entire machine train can now be completely free of oil, and the efficiency, vibration, r]]> Clean. Efficient. Reliable. These attributes are often used to describe magnetic bearings. With no need for lubricants, with no mechanical wear or friction, and with the capability to tailor bearing characteristics to optimize performance, it's no wonder that there's growing excitement about using magnetic bearings in high performance machinery. This is especially true today, where there is much focus on improving the utilization of energy using eco-friendly technologies.

  The truth is, the advantages of magnetic bearings have been known for a long time. The principle of using electromagnets, sensors, and active electronics to suspend objects without mechanical contact was demonstrated by Jesse Beams at the University of Virginia back in the 1950s. Despite the long history of magnetic bearings, today only a small fraction of rotating machinery is supplied with magnetic bearings. What's the reluctance towards the widespread use of this technology?

  We believe that in the past, the acceptance of magnetic bearings was impeded because the bearings did not meet basic engineering criteria related to performance, simplicity, size, and cost:

  Performance. Magnetic bearings must be unconditionally stable for just about any operating condition of the host machine. This includes conditions of high dynamic loading caused by surge, stall, ingestion of liquid slugs, cavitation, motor electrical faults, and other transient conditions.

  Simplicity. Magnetic bearings must be easily integrated into new and existing designs of rotating machinery. To facilitate this integration, the bearings should be offered in standard sizes, be easy to mechanically and electrically integrate into the machine, and be accurately modeled using standard techniques. Additionally, the bearings should be simple to optimize and operate, and interface with other plant systems for process control, health monitoring, and trending. The size, quantity, and length of cables between the controller and the magnetic bearings should be kept to a minimum. The overall complexity of the magnetic bearing should be hidden from the mac]]>