Many ships, like mine, need a live ignition to excite the alternator rotor. I have one of those early, and reliable, Ample Power regulators from 1992.
If I turn the ignition off though, I simply do not charge.
I am puzzled as to how any other system would work? How would the alternator be regulated without a power supply? How would it charge?
I don't think it does any harm to my system to turn it off when engine is running, but I simply try never to do it. It has happened every now and again. All that happens is that the alternator amperage just drops to zero.
From an earlier post:
#19 (permalink) 3 Weeks Ago - Add Post To Favorites
Senior Member Join Date: Jul 2007
Rep Power: 5
Originally Posted by casey1999
The Yanmar manual states (and I think most engine manuals) the alternator can be damaged (rectifier I think gets damaged) if the alternator is disconnected from the battery when the alternator is spinning. Can this happen even if your alternator is self exciting? How is the rectifier actually damaged?
Two possibilities, I think?
1. If the alternator doesn't "see" battery it won't charge, no damage?
2. If it "sees" battery and tries to charge into a "no load" condition the diodes, (rectifier) can be damaged?
By mistake I ran an alternator "open" for a short time and got away with it. from what I have read I was lucky.