Hot alternator

Del,

Speaking of those , seems like someone sold an arc welder box.

I have been know to do things like that for experiment, but I would never sell to the public. An example is reconnecting windings in a 10 HP gasoline generator from series to parallel, then building a voltage/current exciter regulator for battery charger in my electric car. I did that in the early 80's. It worked, but was a failed experiment because it had enough noise and vibration with a one lunger, I could not concentrate enough to drive.

Diodes fail in alternators because voltage regulators do not limit alternator current. The current can be over 100A when cranking, it does not happen in a normal start, because at low speed, the alternator does not put out much. Take a running car, speed up the engine, with another car jumped, hit starter ..... diodes can go poof. Current is somewhat limited by the source impedance of alternator and associated wiring.

Back in the day before alternators, some generator systems had current limit in the voltage regulator. It could be done with alternators, but would increase cost due to current sensing.