I just want to bring up what I see as the main difference in the alternator vs the EPG when it comes to producing power and efficiencies.. We will never get fully way from the counter electromotive force.. But we can work to get rid of a good amount of CEMF while maintaining the same power out.. The goal of any generator is to create strong fluxuating B fields within the loops of coils.. You cannot create a rotor on a armature that has strong fluxuating magnetic fields within the loop because the loop obstructs the ability of a iron material to pass through.. So Stan came up with a way to get strong fluxing magnetic material to pass through the loops without the need of a rotor/armature by using a tubular passage to carry strong B field generating materials like iron. So now if we think about the alternator and what the purpose of a stator core is.. i think we can consider it a magnetic field amplifier.. it allows the rotors magnetic field to induce the needed strong magnetic field fluxuations in the center of the pickup coils.. the stator core carries an excess of CEMF to be able to work. so a stator core style generator has the inherent problem of how it goes about in getting strong B field fluxuations into the center of the pickup coils.
If you read stans EPG patent and look into the reference patents you will see a patent from batelle where they created a unit a lot like a EPG but it used solid magnetic spheres being passed through a tube with pickup coils and the magnetic spheres are being propelled by air.
The ferrite cores in coils and motors act as a cushion for the BEMF ! Take the tesla induction motor for example and the top of the art axial motors they use in cars, they all use ferrite cores to reduce torque ripple by cushioning the BEMF, the BEMF is how movement is made.
In short whenever there's movement ferrite cores act as a cushion, whenever there's no movement ferrite cores concentrate the magnetic flux.
I tried to make a motor using stan's toroidal coil principle because in paper it should work, I didn't succeed and I wasted 3 months on making FEMM simulations, the flux changes shapes all the time , it's nothing like they say it's in books.
I remember I put cylindrical magnets and toroidal coils of rectangular cross section , inside, outside, in many many positions, the only spot where there was BEMF was at the edge of the coil because there's a gradient of B flux there, there are dozens of patents from the 1950s using toroidal coils in motors, the best I could get is a motor for bicycles! The torque and power was bad, so I abandoned toroidal coils and works on axial topologies.
I did design a brand new type of motor that'll never get released but the electronics needed to drive it are too complex, in essence instead of giving it constant voltage you have to make maps of voltage for every rpm to keep the current constant instead! It has been done in research but they haven't even applied this principle in industry yet and the know how behind building strong motor power supplies is secret because there's a lot of $$$ involved now with the EV bubble. This delivers 5-10 times more power and torque than the YASA motor in the same dimensions and less weight. These oxford guys got millions in funding, it's ridiculous
