FAQs

The Fusion® bearing passed vibration testing in accordance with MIL-STD-810F Method 514.5 "Minimum Integrity, Category 24."

The motor stator magnetic fields do not influence the magnetic bearings provided they are installed in a manner which magnetically isolates the bearing from the motor. This is typically accomplished by mounting the bearing stators in a non-magnetic sleeve.

Since the shaft is levitated in space with no physical contact with other rotating or stationary components, little to no maintenance is required.

The shaft will require interface surfaces for the radial magnetic bearing rotors and thrust disk. The frame will require interface housings for the magnetic bearing stators. In general, for the same load capacity, magnetic bearings are larger than fluid film bearings or rolling-element bearings.

Based on testing and analysis, we estimate the MTBF to be 80,000 hours.

Our magnetic bearings may be “canned” for operation in corrosive environments.

The moisture resistance of our bearings may be increased by using a VPI insulation coating and using connector insulators.

NovaGlide™ bearings have a rated operating temperature of 300°F. They can operate up to 400°F with some degradation in performance. We have supplied high temperature bearings with insulation systems and sensors that operate to 1000°F.

Fusion® bearings have a rated operating temperature of 140°F measured at the bearing housing.

The cost of our magnetic bearings is largely dependent on the size of the bearing and the application. The cost of the magnetic bearing system is often less than the oil lubrication system that it replaces.

Please provide Synchrony with a request for quote for a specific application so we can accurately provide you with this information.

Magnetic bearing systems are designed and optimized according to API and ISO standards.

The main factor in the decision to use NovaGlide™ or Fusion® bearings is the operating environment. NovaGlide™ bearings are typically more tolerant of process gases and temperature. However, since the NovaGlide™ bearing controller is external to the machine, multiple wire feedthroughs are required for the coil currents and the sensor signals. Fusion® bearings can operate on a minimum of two power wires and therefore the bearing integration is less complex.

NovaGlide™ bearings have a separate bearing controller and power electronics box. The typical box size for a NovaGlide™ bearing is 20 in x 12 in x 6 in. Fusion® bearings integrate the bearing controller and power electronics within the bearing.

The benefits of using magnetic bearings include higher reliability with little or no maintenance, reduced frictional losses, no contaminating or flammable lubricants and lubrication systems, reduced machine vibration and improved health monitoring and diagnostics.

The controller parameter optimization is usually a very fast process (several hours). Using the Synchrony user interface, we perform frequency sweeps of the controller system and shape the gain and phase of the controller algorithm to maximize stability. Synchrony provides the controller transfer function so that it can be used in rotordynamic modeling software. The models we use to predict the performance of the magnetic bearing are very accurate.

NovaGlide™ bearings use compliantly mounted ball bearings (single row deep groove or angular contact). The compliant mount is primarily designed to inhibit whirl and is selected and constructed to achieve the desired stiffness and damping for a given application.

Fusion® bearings use two bronze bushings per bearing as touchdown surfaces. This touchdown surface may be augmented by compliantly-mounted ball bearings if required.

No, there is no contact between the rotor components and the auxiliary bearings during normal operation.

The bearing does not shutdown in this situation but will continue to produce its maximum rated load (i.e., it will "load share" with auxiliary bearing). Once the transient load is removed, the bearing controller will automatically regain control of the shaft and center it within the magnetic bearing.

NovaGlide™ compliantly mounted ball bearings will "catch" the shaft during a total loss of power and allow the shaft to coast down. Depending on the system, it is possible for the auxiliary bearings to survive 10 or more coastdowns on the auxiliary bearings.

Synchrony does not recommend continuous operation on the auxiliary bearings.

The thrust magnetic bearing is comprised of a rotating thrust disk mounted between two stationary thrust magnets.

This is dependent on bearing size and shaft diameter but, as a reference, the
400 lb load capacity Fusion® radial magnetic bearing (which includes integrated control electronics) weighs approximately 25 lbs per bearing.

Synchrony has supplied magnetic bearings with a radial load capacity ranging from 35 lb to 3,200 lb.

Synchrony has supplied magnetic bearings with a thrust load capacity ranging from 390 lb to 12,400 lb.

Magnetic bearing size is dependent on load capacity and shaft diameter. As an example, our 400 lb load capacity Fusion® radial bearings have an axial length of 3.8 in and diameter of 7.0 in.

Yes, our magnetic bearings provide sufficient damping such that amplification factors at critical speeds are typically less than 3. Using adaptive control techniques for synchronous suppression of vibration and force, it is possible to greatly attenuate or eliminate the amplification of vibration at critical speeds.

During normal operation, the magnetic bearings levitate the shaft in space eliminating mechanical friction. Therefore, the main factor in limiting speed is strength of materials of rotor components. For our standard radial bearing, the rotor surface speed is limited to about 590 ft/s (180 m/s).

Synchrony recommends that a UPS be used to supply power to the magnetic bearings in the event of an unexpected loss in power (we offer power supplies with battery backup).

This is dependent on bearing size, but as a reference, our 400 lb load capacity Fusion® radial magnetic bearing requires a maximum of 100 W at 48 VDC per bearing.

Yes, our magnetic bearing systems utilize both radial and thrust auxiliary bearings. The gap between the rotor and the auxiliary bearing is smaller than the gap between the magnetic bearing rotor and stator and motor rotor and stator. The purpose of the auxiliary bearing is to protect these components in the event of power loss or large transient load.

The radial magnetic bearing is constructed in a similar manner to an electric motor. They are comprised of a multi-pole laminated stator, magnet wire coils and laminated rotor.

Synchrony currently supplies bearings to the following industries: aerospace and  the Department of Defense (DOD), renewable and recoverable energy, HVAC, oil and gas, and motor industries.

Yes, read about Advances in Magnetic Bearings. (388 KB PDF)