Posted for Jim Sower <canarder@starband.net>:
I'm told that the difficult failure mode with internal regulators is a short
between output and field.  The alternator feeds itself.  It will run at
capacity (maybe 20 or 30 volts while it lasts) and will "... let the smoke out
of all your avionics boxes ..."  To be sure, I've never seen this happen.  All
the failures I experienced when I was in the auto repair business turned the
alternator off.  But of course I didn't witness or hear about all the failures
that happened.  Bob Nuckolls says it happens and has a way to shut down the
output cable if the voltage goes above 15 V.
I've heard that when Bob talks, Jim needs to be listenin' .... Jim S.