Just disconnect the field wire from the alternator.
I wouldn't say that it couldn't happen but what sort of regulator failure do
you envision that would result in overcharging the batteries?

"Manlio" wrote in message
news
there is a simple way to stop the alternator delivering current when
the regulator has a failure ?
Just not to overcharge the batteries.
According to what I know the B+ cannot be open (diode break), so as
the belt cannot be pulled away due to the water pump.

Thanks for any idea.

Manlio