in this video, the guy basically says 400hz motors have 7-10X the power of 60hz motors for the same physical size. Is that true? if so, why has the modern world (except for aircraft) standardized on the 60hz (or 50hz) motor? What would be the down side(s) of using a 400hz motor as an EV motor? I've yet to hear of any EVs using a 400hz motor, which would seem idea if the guy in the video is right.