Project: Self-build alternator for a Lister 6/1

[mobile_bob]

then there is another variant i ran across that could be adapted to the torogen
that being the induction alternator
it needs no expensive magnets, because it uses field coils
it needs no slip rings or brushes because both the field and armature coils are fixed and no rotating

if one were to explore this route, i would probably go for 25hz generation because it affords the use
of thicker laminations, i would also use plain hot rolled steel sheet and have the laminations water, laser or
even plasma cut.  the lamintations could be cut with the slot already done, so when they are stacked
the rotor slot is already in place.

anything  60hz and under allows the use of more readily available surplus 3 phase bridge rectifiers

the rotor plate could be laser cut with slots to register the laminated pole piece that form the inductive element
that passes through the toroid slots,

from what i have seen of inductive alternators the wave form is a bit misshapen, but we don't care about a perfect
sinewave if you are going to rectify anyway.

the only automotive alternator that uses the inductive method is those made by electrodyne corp. of which are
incredibly well built long life machines of very high output and very good efficiency.

with this design one would need a regulator, but i bet an automotive type could be pressed into service, as well as the
higher end 3 step controllers could also be used.

the toroids could also be made from steel strapping if two things are understood
1. the strapping would need to be annealed, not a difficult project in itself it just needs heated to ~650-700 degree's
and allowed to cool slowly, and

2. this type of steel will age, in that over time its hysterysis qualities will increase, as would be the case with hot rolled low
carbon steel sheet, but this might be acceptable for a prototype and we don't know how much the hysterysis effects might
decrease the efficiency anyway,, probably not by more than a few percent anyway.

3. the laminations being made of steel strapping wound into a toroid core would have the laminations 90 degrees off of
optimum, so i would expect a bit higher eddy current losses. how much effect this might have is anyone guess, but
i would not expect a huge hit in efficiency in any event. Much of this could be eliminated by canting the toroids at an angle
of perhaps 45 degree's from the more typical radial orientation.

in a rather large scale alternator (still micro compared to industry standards, but huge in our circle) i would still bet that
reaching 80% efficiency is attainable at some point in the output curve of the alternator. in theory after the prototype has
been built and tested and proven to reach 80% efficiency one could then make a decision whether or not replacing the toroid
cores with silicon steel alloy (the stuff modern motor and alternator cores are made of) with the anticipation of perhaps reaching
well into the mid 80's percentile in efficiency.

it is assumed this would be a three phase machine, rectified to charge a battery bank

bob g