On rational reactions – and other ones – of overloaded magnetic gears

Experiments exploring the coupling of two rotating spherical magnets reveal a cogging-free coupling for two specific angles between the input and output rotation axes (see enclosed movie). The striking difference between these two phase-locked modes of operation is the reversed sense of rotation of the driven magnet. For other angles, the cogging leads to a more complex dynamical behaviour. The experimental results can be understood by a mathematical model based on pure dipole-dipole interaction, with the addition of adequate friction terms. Like all magnetic couplings, the setup contains intrinsic overload protection. The dynamic answer of the gear with cogging to an overload shows a plethora of modes of the driven magnet which can be explored interactively with the enclosed Python script. The talk is based on: Hartung, S., Rehberg, I. Dynamics of a magnetic gear with two cogging-free operation modes. Arch Appl Mech 91, 1423–1435 (2021). https://doi.org/10.1007/s00419-020-01830-z