William Fraser's video: Magnetic Multistage Gear: Compound Differential

An unusual multistage magnetic gear with 3D printed parts, Neodymium magnets and brushless motor. The reduction ratio is much higher than a typical series multistage gear with similar stage ratios. A speed and torque analysis reveals large amounts of power circulating back and forth between gear stages. The analysis shows that the use of Newton's 3rd law in magnetic free body diagrams differ from that of mechanical planetary gears. 0:00 Standard multistage gear demo 2:46 Disassembly 3:43 Compound differential concept (research article) 4:36 Assembly and demonstration 5:59 Speed ratio check and explanation 7:18 Torque analysis- standard multistage 10:13 Torque analysis- compound differential 16:56 Circulating power analysis 20:38 Newton's third law for magnetic gears vs mechanical gears 23:22 Efficiency challenges 24:27 Appropriate application and efficiency remedies Magnetic gear basics: https://youtu.be/m4qPSm_8P1E Referenced research article: https://bpb-us-e2.wpmucdn.com/labs.utdallas.edu/dist/9/93/files/2021/09/Multistage.pdf