> Has to be rated >= to the max current
> of the alternator, probably around 50 - 80 amps.
In general, alternators don't need current regulation and hence the
regulator doesn't know or care how much current the alternator can produce.
For example, older GM alternators used the same (internal) regulator from 40
amps all the way to 110 amps. For an alternator, the regulator only
controls output voltage (and perhaps the lamp on the dash).
But old DC generators (which is what I thought we were talking about) are a
different kettle of fish. They are basically identical to a DC motor, and
so if the engine is stopped (or turning very slowly), they will try to act
as motors and turn the engine. This means the 'regulator' has to disconnect
the generator from the battery when the engine is stopped, to prevent the
battery being discharged through the generator.
More importantly, DC generators will easily produce enough current to
overheat and burn up the armature, so accurate current regulation is
important. I've burned up more than I care to remember, by allowing the
current to go to 25-30 amps on a unit rated for 21 amps.
Hence my question about whether the unit in question has slip rings (and
diodes, making it an alternator), or a commutator (making it a DC
generator).
Oddly enough, my introduction to Heathkit was rebuilding a friend's kit that
didn't work (a grid dip oscillator). It worked great when I got done with
it. Taught me at least a bit about RF construction techniques as well. He
later gave me the GDO, but I have no idea where it is today. Or him, for
that matter.
-- Randall
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