Bill and Bill, 
I spoke to a Motorcycle Electrics technician yesterday, said he had used Harley (Accell) alternators on various racing applications that rev up to 8-9000 rpm with no problems. He recommended the use of the 45 amp regulator on the 25 amp alternator as it was more robust and better design. I did not mention 'buck converter' as that term is new to me. He also said that it was only the balanced magnet annulus that spins and had no history of mechanical failure. 
Thanks for your input here, WD, I too, know just enough to be dangerous! FWIW, Dave McC 

 

Dave,

 I have no trouble with the design of these parts, but I avoid EE tasks as what happens is that I get into the project and then miss something that a EE takes for granted because they do this sort of thing all the time. I can easily work to someone's schematics though.

 OK now about the alternator; several things have to work to be able to use these things. Since the alternator is usually on the outside of the assembly most do not have a large center opening that we can say pass the e-shaft through. For a E-shaft concentric alternator we need a HOLE about 40mm (at least) to fit the shaft through regardless of which end of the engine we run the alternator on. We also need to mount the alternator windings to the engines cases safely. This is doubly true of the magnetic rotating assembly. The large center hole is the area I expect the most trouble with.

Bil Jepson