On Wed, 18 Jan 2012 13:40:13 -0500, "Tom Del Rosso"
wrote:


Jim Thompson wrote:

And you're still clueless about why the dynamo won't work into an
auto-transformer.

I asked about that transformer. (Which is not an autotransformer is it? It
has 2 coils.)

It doesn't matter if it's a transformer or an autotransformer. The
point is that, at decent speeds, the alternator is a high voltage and
a high impedance, practically a current source for low-resistance
loads like lamps. A step-down transformer can boost the current into
the load by better matching impedances. So can a
rectifier-filter-buck switcher, done right.

A 2:1 step-down autotransformer might be convenient to get from
Digikey, since you could use some standard part with dual primaries or
a center-tapped secondary.

John