Alternator 1 or 3 wire

[fishnfool101380]

Looking for advice, I recently began a project (1978 Wellcraft Nova 250) and am discovering that a boat project is much more involved than I had recently thought... I am constantly finding myself searching for answers or how too's for hours on end. Well I have came to a point where I need to reach out and ask for help.

I want to purchase a 100 amp alternator but as I began to shop around I found that there are several wiring configurations. I have two question #1 is my old alternator a "3 wire alternator" ? (picture below)

#2 Is there a downside to switching to a 1 wire self exciting type of alternator?

Thank you in advance, I am sure I will be here often to bug all of you throughout this project

 

[bruceb58]

I have no idea what all your connections are but that doesn't really matter.

Buy a 3 wire alternator. All you need is voltage to the field(excite) that is active when you turn your key on(you probably already have that going to your present alternator). The sense line can just hook up to the alternator output and of course the alternator output connects to either your starter, battery or output of your battery turn off switch.

 

[fishnfool101380]

Thank you Bruce. I could not have asked for a more clear descriptive answer. Very much appreciated