In testing, what should be the behavior of the galvanic isolator regarding AC superimposed current?

The behavior of a galvanic isolator is specifically designed to block galvanic current while allowing AC current to pass through. Galvanic isolation is crucial in marine environments where different metals in contact with water can lead to electrolysis, causing corrosion. A galvanic isolator serves to prevent this unwanted galvanic current—typically a DC current—from flowing between the shore power system and the vessel's electrical system.

The isolator allows AC current to flow as it is essential for the functioning of the electrical systems on board, while it effectively blocks any DC component that may lead to corrosion due to the galvanic process. This selective behavior is key to maintaining the integrity of the vessel's metal components and ensuring that marine electrical systems operate correctly without contributing to galvanic corrosion issues. Thus, the galvanic isolator fulfills its purpose when it blocks galvanic current while still permitting the necessary AC current to flow for operational needs.