RT Journal Article
SR Electronic
T1 Ultrafast rotation of magnetically levitated macroscopic steel spheres
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP e1701519
DO 10.1126/sciadv.1701519
VO 4
IS 1
A1 Schuck, Marcel
A1 Steinert, Daniel
A1 Nussbaumer, Thomas
A1 Kolar, Johann W.
YR 2018
UL http://advances.sciencemag.org/content/4/1/e1701519.abstract
AB 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 × 108 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.