drove by some old excercize eqipment Stuff the other day
this was connected to a stairmaster, an old one , but very well built.

since i was the fist one to disassemble this unit.i am sure of the connections to the alternator. there was nothing connected to D+ or B+
there was a connection to terminal labeled W.
one connected to + and two connections to two terminals labeld DF.
and ground.

i spun it with one connection to + and one to ground and it showed a voltage , not much , but it was there.
as far as i could tell there was no battery in the unit but i am not positive on that.
my question is , with no power going to the field how could this produce power for the control unit , which i also have..
was this unit somehow modified to produce power at low speed?
any help would be greatly appreciated.