3-Phase Supply ...

The_Traveller

The_Traveller

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Just curious to know if it is possible to connect 3 of the same Inverters, on each phase, on the DB board ?

Has anyone ever tried this out ?

Are there any risks ?
 
Wouldn't the inverters need to be synchronised at the correct phase angle to prevent issues with the neutral?
 
Sinbad said:
Wouldn't the inverters need to be synchronised at the correct phase angle to prevent issues with the neutral?
Click to expand...

Yes - that's why I said 'generally' :) It has to be synced and all that, but I don't know how they do that. I do know however that a 3 Phase Inverter, is just three single phase units... Same with the PV arrays too, every phase needs its own string(s), batteries, and inverters.
 
I have a 3 phase setup documented on my blog.


One set of panels (one string of 4KW+-) -> 3 phase GTI. each phase of GTI -> multiplus -> batteries <-> mains phases.
My GTI (grid tied inverter) is 3 phase, and I have 3 separate Victron Multiplus's configured as 1 unit for the battery side.
You obviously need to sync up the phases if you go that route - I've configured my 3 Victrons to act in unison as one so its appropriately set for 3 phase.

I would probably go for a hybrid unit now though if i had to do it again, as integration is a bit of a pain in the rear.
The fronius symo 3 phase hybrids look interesting. May get one to play with at some point, as I need to do my large house install/ setup at some point.

At the time though, hybrid stuff wasn't available, so had to DIY my own solution.

Doing another install soon though, my 3rd for myself - my currently in the building stages large house will have 9KW of panels, and 20KW of LiFePO4 storage (+-14KWhr usable) for a full offgrid setup that can handle anything, including winter. Excess panels works well with small size battery, as panels are cheap. Batteries not so much :)
Why? - I really don't feel like bothering with Eskom / Muni connection at all, and I enjoy playing with this stuff.
 
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Thanks for the input guys.

I have one inverter backing up 1 of the 3 phases , but im looking to play around with another inverter to backup another phase. The inverter is identical only this time I have the option of setting the charge current to 0 so that I can use an external charger and go Solar. Thinking of buying some Lithium batteries from Isheed.
 
lsheed_cn said:
I have a 3 phase setup documented on my blog.


One set of panels (one string of 4KW+-) -> 3 phase GTI. each phase of GTI -> multiplus -> batteries <-> mains phases.
My GTI (grid tied inverter) is 3 phase, and I have 3 separate Victron Multiplus's configured as 1 unit for the battery side.
You obviously need to sync up the phases if you go that route - I've configured my 3 Victrons to act in unison as one so its appropriately set for 3 phase.
Click to expand...

I wondered? So is it three phase (120 degrees) or three separate AC lines synced in unison? :confused:

548px-3_phase_AC_waveform.svg.png
 
Is it possible to change from 3 phase supply to single phase? I have a reasonable large house but no major appliances (aircon) only a pool motor.

What would I need to change to run on single phase?
 
agentrfr said:
No he means that if you have a grid tied inverter with 3 phase coming in, you need to synch your three generated phases exactly with grid.
Click to expand...

No, the way I understand it is that 3 phase has a shared neutral, so the average current on the neutral when the phases are balanced and separated by the correct angle is zero. If the phases are in step the neutral current will be triple the current in a single phase, which is asking for trouble.
 
Shellyb1 said:
Is it possible to change from 3 phase supply to single phase? I have a reasonable large house but no major appliances (aircon) only a pool motor.

What would I need to change to run on single phase?
Click to expand...

Normally the Eskom three phase supply is 220V between the neutral and any of the three phases. Thats why in Industries it's possible to balance the 220VAC loads by sharing equal loads between the three different phases and neutral. So you just connect between the neutral and any phase. Three phase is better thought so what and why do you want to change?
 
Sinbad said:
No, the way I understand it is that 3 phase has a shared neutral, so the average current on the neutral when the phases are balanced and separated by the correct angle is zero. If the phases are in step the neutral current will be triple the current in a single phase, which is asking for trouble.
Click to expand...

Three phase equipment do not use the neutral, see my previous post.
 
Sinbad said:
Bull****. You can't have a circuit without a return.
Click to expand...

Maybe you should go read up and study on how the three phase supplies work before you call "Bull" as it' makes you look ... ...... well rather leave it there. I am in a good mood tonight. ;)
 
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