Is there a rule of thumb to quickly calculate a lower bound for the mass an electric machine must have in order to source or sink a given number of watts? Such a thing ought to be possible, especially if accuracy only needs to be within a factor of 2, etc.
For example, “given that neodymium is used, and shaft turn at X hz, mass must be at least Y.”
For example, “given that neodymium is used, and shaft turn at X hz, mass must be at least Y.”