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Cake day: August 3rd, 2023

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  • Academic grants can work in a lot of ways. It is common for a significant chunk to be taken as overhead by the university (20-40%). This is generally smaller for senior members of the faculty who bring in more grants. The PI (primary investigator, read: dude with a reputation) tends to get 5-10% to run the program, and then another 30-40% goes to salaries for researchers working under them (read: grad students). The rest, on the order of 20%, goes to capital costs like materials, time on expensive machines, or prototypes.

    So this guy probably got paid $1-2M directly for the grants over maybe 3-5 years. Note I haven’t looked into his specific situation.



  • Electric motors actually work on a number of principles. Depending on the magnetic topology these can include multiple factors or just one.

    The classic DC motor is just a mechanical commutator (rotating switch) that alternates the polarity of pairs of electromagnets, causing pushing and pulling on the rotor to occur at appropriate times.

    AC motors are generally based on multiple electromagnets acting in unison to produce a rotating field. This is then used to twist a magnetic rotor (just like how a compass works).

    Other styles like the modern brushless motor are dependent on sensors (or equivalent devices and algorithms) to achieve the same effect as the DC motor above. The difference is that you can have more pairs of magnets (poles, pole pairs) so you can produce smooth torque by phasing at least three groups of poles that hand off to each other.

    Advanced topologies like reluctance motors use the same principle as a fridge magnet, leveraging the attraction of an electromagnet to a chunk of steel on the rotor. Again, phasing is used to smooth out the interaction.

    For more details, look up the principles of magnetic reluctance, induction (and Lorentz force), and Maxwell’s stress tensor.