Can I connect two parallel 230V Victron Quattro inverters to one Victron Autotransformer to create a 120/240V 60Hz split-phase electrical system?As shown in the diagram below.
Technically, yes, but you’ll be sorely disappointed at the results. The AT will overheat quickly if you try to drive more than about 3kW through it to transform the voltage. You would be better served buying a 20kVA single-phase (230V) to split-phase 120V/240V power transformer with multiple windings, not just one as in the AT.
Adding to what Ed said above:
The max current THROUGH the Victron autotransformer is 100 amps or 24KW total power. This includes true 240 volt loads. However the autotransformer is limited to 45 amps of NEUTRAL current. So your success will depend on the load balance between the two hot legs. You could connect 240 volt loads directly to the Quattro outputs which means their current would not flow through the autotransformer’s input circuit breaker. That would mean having separate load distribution for such loads without any neutral connection as water heater, HVAC, EV charger, etc.
As Ed suggests, a larger auto transformer that can handle the anticipated neutral current or better yet an isolation transformer with separate input and output windings would be better.
If this is an off-grid system then utility approval would not be a factor. If the system IS grid-connected note the 230 volt Quattros do not have a UL rating and probably won’t meet local utility requirements. I gave up on using 120 volt Quattros in a grid-connected ESS because PGE has not approved their use on their grid. Other US-based utilities may be less restrictive however. Your milage may vary.
Thanks a lot, Ed. Your answers are really helpful.
Thanks a lot, Kevin. Your answers are also very helpful.