question

Hi Anita. Try signing/logging in to Victron Professional. https://professional.victronenergy.com/accounts/sign-up/ Hopefully my data gets scrubbed outta that link, I can't remove it from here. There's training stuff in there that I can't speak for, but might help..

And my Google has learnt my habits. Everything I type that it can link with Victron it will cough. The depth of info is incredible.

Have fun.. :)

Okay, I think I have enough information to provide you an answer, however let me first start by stating for the record, that I am neither a licensed electrician, nor Victron equipment installer, merely an avid DIYer with a talent for electricity. If anyone with such certifications wishes to correct anything I have said here, please do...

That being said, what you are describing sounds like a fairly typically 4-Wire (plus GND depending) Wye installation. Before attempting to configure this, please familiarize yourself with the requirements and stipulations of installing a 3-phase/parallel system: https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems

Assuming you are following those guidelines regarding DC wiring, etc... to perform the actual configuration of the VE.Bus system you are attempting to install, I think it would be appropriate to start with the VE Quick Configure Utility at first (bear with me). Using this utility, start with a "new VE Bus System", select 3-Phase, click "Show Picture", and ensure you have the communication wiring between all the components wired as shown, click next, ensure all inverters are in the "off" position, any AC Input has been shutoff, AND any AC Output has been disconnected as well! Pick the right COM port your MK3 USB is using (I can help with this if you need it), click next and follow the instructions. The first inverter you switch on will become your L1, second will be the L2 and so on. This will be important for your phase rotation, I recommend you label them, more on this later though.. Once all three units have been powered on and recognized by the utility, click done and save. You should now have a 3-phase system running off of DC power. Take a multimeter and measure voltages across L1+L2, L2+L3, L1+L3, L1+N, L2+N and L3+N. Ensure these are consistent with each other. I believe the default will be 230V on each phase-to-N, and around 400V phase-to-phase. This can be adjusted after the fact using VE Configure as needed, but this may be what you are looking for already. To get specific, you mentioned each individual phase will be 230V, however you mentioned phase to-phase is 380V, which I do not think is totally accurate. Based on my math, and how 3-phase works, the phase-to-phase voltage should equate to (L1-to-GND voltage) * (Square root of 3). If your single phase voltage is 230V, phase-to-phase should be ~400V, however if single phase voltage is 220V, then phase-to-phase would be ~380V. So basically this is up to you what you want it to be, but to adjust it, you would alter the Output Voltage in the "Inverter" settings tab of each unit (they MUST be all 3 set the same, else I suspect bad things will happen), set to 220V if you want phase-to-phase=380V, or 230V if you want phase-to-phase=400V.

At this point I would advise you test a 3-phase load, while still running in inverter mode off the DC bus. Most 3-phase loads will be unaffected by the rotation with the exception of a motor. If you have a motor I would test this to make sure it spins the right direction. You should simply be able to connect the load's L1 to inverter L1, L2 to L2, etc.. If however the motor spins backward, it may be looking for an A-C-B rotation. I think you should be able to swap the motors L2 and L3 to correct this.

Assuming that all goes well, now its time to try your AC Input. Shutoff the AC Output again before doing so. Now, if your genset outputs three-phase in a wye split, you should again be able to connect the genset L1 out to Inverter L1 AC In, and so on. Tie the genset N together with all three inverter N, and same with GND if there is one. Before starting the generator, connect to your GX device, go to your MultiPlus (there will be only one listed even though there physically are 3, that's okay), scroll down and view the error screen; this hopefully will help you if it doesn't like the AC input... Now it's time to cross your fingers and fire up the gen. If all goes well, in about a minute after the voltage stabilizes, you should hear a very loud click, as the internal transfer switch in the inverters activate... Otherwise, check your GX to see what the error is, most likely it will be the phase rotation if the output happens to be A-C-B. In this case you should be able to again just swap the L2 and L3 hopefully (after shutting off the gen!). Now try it all together! See if the AC Output loads work as expected when the AC Input is active.

Hope this helps! I followed a very similar procedure when configuring a split-phase (2-phase) 180* setup.