Generator short?

[Thearne3]

Driving fine for 30 minutes, then big backfire, loss of power and won’t start. Heavy drain indicated on ammeter (10 amps). Driver side of terminal quite hot. I assume a short somewhere, so disconnected the terminal to cutout wire. That stopped the drain. Got home (towed by a friend) and did some checking:

1. No drain when wires normally connected to cutout are just connected to terminal box, but not cutout. No issue.
2. Checked cutout after removing from generator: no short there either.
3. Checked resistance from armature post to ground: zero resistance!

Do generators often develop a short in the windings or is it more likely the post has lost an insulator piece from the case? How is the post insulated from the case on the inside? I see an insulator ring below an insulating washer on the outside, but is there a similar insulating ring or washer on the inside of the case?

Finally, would a short in the generator cause other things to fail? Headlights (which were on) seem to be dead except for one parking light. Running tail lights all work. All lights are LED. Car still doesn’t start. Could the condenser or coil be blown?

Thanks for your advice!
Tom