Ultrafast rotation of magnetically levitated macroscopic steel spheres.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29326976.
- Also identified by DOI 10.1126/sciadv.1701519 and PMC identifier 5756664.
- Licence recorded as CC BY-NC.
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Abstract
Our world is increasingly powered by electricity, which is largely converted to or from mechanical energy using electric motors. Several applications have driven the miniaturization of these machines, resulting in high rotational speeds. Although speeds of several hundred thousand revolutions per minute have been used industrially, we report the realization of an electrical motor reaching 40 million rpm to explore the underlying physical boundaries. Millimeter-scale steel spheres, which are levitated and accelerated by magnetic fields inside a vacuum, are used as a rotor. Circumferential speeds exceeding 1000 m/s and centrifugal accelerations of more than 4 × 10<sup>8</sup> times gravity were reached. The results open up new research possibilities, such as the testing of materials under extreme centrifugal load, and provide insights into the development of future electric drive systems.