Re: [CAD_CAM_EDM_DRO] Re: Mariss' power supply circuit

Paul Amaranth wrote:

> > The rotors of these alternators are HUGE, of course, a solid billet
> > of steel about 18" diameter and 6 to 10 feet long! They mill a squared
> > spiral groove on the surface of the rotor, and wedge massive solid
> > copper bar into the groove for the rotating field winding. They run
> > something close to 1000 A at about 100 V on those rotor fields!
> >
> > Jon
> >
>
> Hey Jon, was that supposed to be 18 feet rather than 18 inches?

No, they all seem to run about 18" in diameter. I suspect if you
calculate the G forces at 3600 RPM with a 9" radius, they are pretty
huge. Keeping the copper bar in the slot with an insulating material
is a challenge I have no idea how to solve! An 18 foot diameter
rotor turning 3600 RPM would fly apart by itself. They have parts
in the biggest jet engines that are nearly this big (about 12'), and run
near that speed, but the materials are truly exotic, hollow Titanium,
mostly, and X-rayed about 12 different ways. The rotors have only
about .002" clearance per side to the stator, and keeping that kind
of tolerance in a self-heating heavy part spinning between widely
spaced bearings is a challenge to the best millwrights.

(I know I'm going to get it now from Bill for going off-topic, again.
Well, I'm sure they make these with CNC, does that help?)

Jon