17-Year-Old Designed Electric Motor Without Rare-Earth Magnets – Slashdot


“A 17-year-old [named Robert Sansone] created a prototype of a novel synchronous reluctance motor that has greater rotational force — or torque — and efficiency than existing ones,” writes Slashdot reader hesdeadjim99 from a report via Smithsonian Magazine. “The prototype was made from 3-D printed plastic, copper wires and a steel rotor and tested using a variety of meters to measure power and a laser tachometer to determine the motor’s rotational speed. His work earned him first prize, and $75,000 in winnings, at this year’s Regeneron International Science and Engineering Fair (ISEF), the largest international high school STEM competition.” From the report: The less sustainable permanent magnet motors use materials such as neodymium, samarium and dysprosium, which are in high demand because they’re used in many different products, including headphones and earbuds, explains Heath Hofmann, a professor of electrical and computer engineering at the University of Michigan. Hofmann has worked extensively on electric vehicles, including consulting with Tesla to develop the control algorithms for its propulsion drive. […] Synchronous reluctance motors don’t use magnets. Instead, a steel rotor with air gaps cut into it aligns itself with the rotating magnetic field. Reluctance, or the magnetism of a material, is key to this process. As the rotor spins along with the rotating magnetic field, torque is produced. More torque is produced when the saliency ratio, or difference in magnetism between materials (in this case, the steel and the non-magnetic air gaps), is greater.

Instead of using air gaps, Sansone thought he could incorporate another magnetic field into a motor. This would increase this saliency ratio and, in turn, produce more torque. His design has other components, but he can’t disclose any more details because he hopes to patent the technology in the future. […] It took several prototypes before he could test his design. […] Sansone tested his motor for torque and efficiency, and then reconfigured it to run as a more traditional synchronous reluctance motor for comparison. He found that his novel design exhibited 39 percent greater torque and 31 percent greater efficiency at 300 revolutions per minute (RPM). At 750 RPM, it performed at 37 percent greater efficiency. He couldn’t test his prototype at higher revolutions per minute because the plastic pieces would overheat — a lesson he learned the hard way when one of the prototypes melted on his desk, he tells Top of the Class, a podcast produced by Crimson Education. In comparison, Tesla’s Model S motor can reach up to 18,000 RPM, explained the company’s principal motor designer Konstantinos Laskaris in a 2016 interview with Christian Ruoff of the electric vehicles magazine Charged.

Sansone validated his results in a second experiment, in which he “isolated the theoretical principle under which the novel design creates magnetic saliency,” per his project presentation. Essentially, this experiment eliminated all other variables, and confirmed that the improvements in torque and efficiency were correlated with the greater saliency ratio of his design. […] Sansone is now working on calculations and 3-D modeling for version 16 of his motor, which he plans to build out of sturdier materials so he can test it at higher revolutions per minute. If his motor continues to perform with high speed and efficiency, he says he’ll move forward with the patenting process.



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