Originally Posted by GFC
What is their function?
They are an induction transformer that keeps your boat isolated from the shore power circuit. When you plug into shore power you are connected by the power lines to every other boat on the circuit. So if someone has a dissimilar metal problem or a ground problem you in essence have the effects of that same problem. With an AC Isolator Transformer you are not connected in any way or form to the shore power. Your AC Isolator is. The shore power and all of it's potential problems goes into your Isolator and through a transformer that then creates clean power it goes to your boat.
As an example I have two one for each 120V leg. In two years at my marina and of course every other marina that I have visited I have only just changed out my Zincs on the outside of the boat. Several boat around me go through them at least twice or three times a year.
I won't have a boat with out them. They are really not that expensive when measured in boat bucks. About $900 for each of the two that I have at 40 AMPS each. They look like they would be easy to add to any boat that did not have them.
Your Sea Ray may. My friends 2005 50' Sundancer does, it came from SeaRay with them.
Marine: Isolation and Boosting Transformers