I have a 230VAC source supplied by an Isolation Transformer, power then passes through a Quattro and then an Autotransformer to create 115/230v split phase. The ground relay in the AT is being controlled by the Quattro. While inverting, with the ground relay closed, all is well. The output voltages of the AT are correct as follows:
- L1 to Neutral: 115V ✅
- L2 to Neutral: 115V ✅
- L1 to L2: 230V ✅
- Neutral to Ground: 0V ✅
However, on shore power (or anytime the AT ground relay is opened) I am getting very different readings:
- L1 to Neutral: 115V ✅
- L2 to Neutral: 115V ✅
- Neutral to Ground: 115V ❌
- L1 to Ground: 230V ❌
- L2 to Ground: 0V ❌
In this installation, shore power flows in as 115V is stepped up to 230V in an Isolation Transformer (Neutral and Ground are bonded on the output side), power flows through the Quattro and into the Autotransformer. I have tested continuity between grounds and neutral through the system up until the AT. Only after the AT do I get the incorrect voltages. I have triple-checked all wiring schematics and compared with my wiring.
[UPDATED 7/19/24]
- Here is a basic single line diagram showing my system configuration. eclipse_single_line_230_115v.pdf
- Here you will find the Victron schematic, which is an exact representation of my system except that my Quattro is 48VDC, and I've added the isolation transformer on the shoreline where it's indicated: AT-1-split-phase-240V-to-120-240V-with-Quattro-240V (1).pdf
- Here is the installation manual for the Iso Transformer which says to link the N-G on the output for GFCIs to work properly. https://www.victronenergy.com/media/pg/Isolation_Transformer_2000W_and_3600W/en/index-en.html
- This installation is aboard a 42' fiberglass sailing yacht in the USA.
- A 230VAC single-phase generator is connected to AC IN 2 on the Quattro
Further tests were performed with the following results:
- Source: 115VAC Shore Power stepped up to 230VAC with Isolation Transformer.
- Isolation Transformer Output: un-bonded
- Autotransformer Output: un-bonded
- L1 to Neutral: 115V ✅
- L2 to Neutral: 115V ✅
- L1 to L2: 230V ✅
- L1 to Ground: 155V ❌
- L2 to Ground: 75V ❌
- Neutral to Ground: 47V ❌
- Source: 115VAC Shore Power stepped up to 230VAC with Isolation Transformer.
- Isolation Transformer Output: un-bonded
- Autotransformer Output: bonded
- (Is this compliant with ABYC and other conventions?) I have left the system this way and am looking for confirmation that it is correct and safe.
- L1 to Neutral: 115V ✅
- L2 to Neutral: 115V ✅
- L1 to L2: 230V ✅
- L1 to Ground: 115V ✅
- L2 to Ground: 115V ✅
- Neutral to Ground: 0V ✅
- Source: 230VAC Single Phase Generator to AC Input 2 on the Quattro
- Generator output: bonded
- Autotransformer output: un-bonded
- L1 to Neutral: 115V ✅
- L2 to Neutral: 115V ✅
- L1 to L2: 230V ✅
- L1 to Ground: 230V ❌
- L2 to Ground: 0V ❌
- Neutral to Ground: 115V ❌
- Source: 230VAC Single Phase Generator to AC Input 2 on the Quattro
- Generator output: un-bonded
- Autotransformer output: un-bonded
- L1 to Neutral: 115V ✅
- L2 to Neutral: 115V ✅
- L1 to L2: 230V ✅
- L1 to Ground: 140V ❌
- L2 to Ground: 87V ❌
- Neutral to Ground: 34V ❌
- Source: 230VAC Single Phase Generator to AC Input 2 on the Quattro
- Generator output: bonded
- Autotransformer output: bonded
- (Is this compliant with ABYC and other conventions?) I have left the system this way and am looking for confirmation that it is correct and safe.
- L1 to Neutral: 115V ✅
- L2 to Neutral: 115V ✅
- L1 to L2: 230V ✅
- L1 to Ground: 115V ✅
- L2 to Ground: 115V ✅
- Neutral to Ground: 0V ✅
Thanks to everyone, especially @KW4NP for the support. I'm learning a lot here and we have a solution figured out, I just want to make sure it's the correct one. In my head, all N-G bonds should be at each power source, including the iso transformer and the generator, but this produces the incorrect voltage across neutral and ground on the output side of the AT. Ultimately it makes sense to un-bond those and bond N-G on the output of the AT, but have we created any dangerous situation in the wiring before the AT?