Application Examples of Air Core Axial Flux Motors
Introduction
There are many choices when it comes to motor architectures, so how do you know what type of motor to choose for your application? This article will describe some common application examples of where Air-core, Axial Flux motors have a unique value.
Gimbals
Air-core, Axial Flux motors deliver smooth torque in a compact design. Their inherent cog-free design provides smooth actuation at slow speeds, ideal for constant motion pointing stability. Their large diameter to height form factor also saves on axial space, reducing the gimbal’s overall volume. These motors offer the lowest axial height of any motor available from Allied Motion. Lastly, the large diameter has the innate ability to deliver the required torque in a smaller amount of required power due to the radial advantage for torque delivery.
Rotary Stages/Spindles
Turning mirrors and lenses, or rotating wafers or wafer processing tools, generally requires extreme precision. The air-core feature delivers disturbance free torque with zero cogging. The lack of cogging torque makes constant speed, measured in less than 0.1% variability at low speeds, achievable. Wafer processing hardware and laser processing equipment require a multitude of devices and mechanism, making space and weight a huge design factor. The large through hole of Air-core Axial Flux motors enables light or mechanical components to exist or pass through the motor itself, saving space and enabling compact designs.
Spindle applications generally require high speeds and are often supported using air bearing technology. With purely rotational torque coming from the top or bottom of the spindle, plus the lack of varying radial forces caused by iron to magnet attraction, Air-Core, Axial Flux motors become an ideal solution. The absence of iron in Air-core designs reduces Eddy Currents and hysteresis, providing highly efficient torque delivery at high speeds.
Large Diameter Direct Drive for MRI/CT/Imaging/Surveillance
The coil and magnet architectures of Air-core, Axial Flux motors can be made modular, easily lending themselves to large scale applications. The forcers and magnet tracks can be constructed “piece-wise”, enabling easier transportation, inspection, and overall handing, before being assembled into the final hardware. Tooling hardware can be constructed so that integration results in a large scale, direct-drive motor. Examples requiring large diameters would be MRI or CT machines, where a patient bed would exist with the center space, or surveillance/imaging equipment, where other optical equipment is often packaged in the center space.
Summary
When selecting a frameless motor, the application itself will often determine what motor architecture to choose. Applications such as gimbals, rotary stages and spindles, and anything requiring a large diameter, direct drive motor approach, are all great examples where Air-core, Axial Flux motors thrive. Sierramotion offers a variety of Axial Flux designs. For more information, contact us for more details.
