> Hi all! I'd like to run an electrical problem by you and see
> if you have any ideas...
>
> As long as I've owned my 46 MG-TC I've had a small problem with the
> charging system; normally everything works fine until the headlamps
> are turned on.
Oh, that's terminal. I'll give you $50 for the car... :-)
As a seriously helpful note, I've lately become somewhat skilled
in hot-rodding electric motors (Miq knows why!) The genuinely
hip way to balance and blueprint an electric motor is to set the
armature in a very precise lathe and take the commutator down to
the last thousandth of an inch of roundness.
You can get most (maybe 80%) of the benefits of this by simply
taking your commutator and going over it with a fine wire brush
on a Dremel. You want to make sure that the brush is fine enough
that all it does is burnish the surface, not remove metal. (And
wear eye protection! Those little brushes lose bristles, and I've
had some of them ping me on the cheek right under my safety glasses.)
If you're Truly Shriven, you might also consider rewinding the
armature, but I don't have any advice on that. But the commutator
surface does become roughened with long use, and this cuts down
both on the electrical conductivity of the brush-comm interface
as well as on the motor's high-end operation due to friction.
You can also burnish the brushes, which is the other half of the
equation when it comes to power transfer. And since a generator
is just a motor wired backwards (:-), this will help the efficiency
of the generator.
Other potential problems could be the field magnets in the generator.
I know you can "zap" (regauss) the magnets in little motors, I presume
you can have that done for a generator as well. Likewise, there is
a possibility that some contact in the lighting circuit is loose or
corroded (what? In a 47-year-old sports car?), and you've got a
voltage drop across the contacts that is drawing excessive current
and draining the battery. And as a final problem, it could just be
a tired battery; as they age, the cells become less and less able to
keep up an appropriate charging rate.
Good luck, and as I say, if you can't solve it, I'll take that old
thing off your hands for you...
--Scott "Who cares what it does, a TC *IS*, and that's enough" FIsher
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