"Industrial" three phase inverters for off-grid workshop.

[Hedges]

I have 3-phase 3x Sunny Island 5048US in my garage, with Sunny TriPower 30000TL-US.
It takes in one 120V phase from the grid, makes the other two phases. Also backfeeds grid from PV connected to the TriPower.
Have just been getting it going, haven't put it through its paces yet.
One of the issues I have to deal with is converting 120/208Y from Sunny Island to 480V for TriPower. But a Y-Delta transformer is not ideal; floating delta has risk of driving 480V relative to ground not just 277V. If I don't get a transformer with 277/480Y, I have to add a zig-zag transformer to 480 delta or otherwise create a neutral to ground.

https://files.sma.de/downloads/OGS_INFO-AEN120510W.pdf

For Europe or other non-US market, SMA now has a small high-frequency 3-phase hybrid. Looks like a Sunny Boy, but with both PV and battery connected, and produces 3-phase of a few kW

Sunny Tripower Smart Energy | SMA Solar

www.sma.de

Also a 75kVA 3-phase battery inverter

Sunny Tripower Storage 60 Battery Inverter | SMA Solar

The new Sunny Tripower Storage 60 is the perfect solution for commercial and industrial storage solutions. Its modularity guarantees maximum flexibility up to the MW scale. Sunny Tripower Storage offers various use cases and chances for new business models.

www.sma.de

I've seen a number of Chinese 3-phase units as well.

 

[Hedges]

Yes that is why some of us in North America are not as familiar with three phase because almost all residential here is single phase/split phase. However, thanks for reminding us that this forum is global and there are differences.

Except that having two legs of 120/208Y is pretty common, with 3-phase fed to an apartment building or condo complex.
For most people it means 208V instead of 240V for heating appliances and A/C.

But if you're clever, you can connect some transformers and get back the 3rd phase they didn't feed to your unit.
I think it'll have a few percent voltage deviation (because transformers are intentionally not the exact turns ratio their ratings suggest) but probably close enough.

 

[Ampster]

Except that having two legs of 120/208Y is pretty common, with 3-phase fed to an apartment building or condo complex.

I have an apartment in Hermosa Beach and it is definitely 240 volts. I had it trip an old Xantrex inverter when the voltage went to 250 volts. It is a residential street. The commercial next door on the Highway is fed from a different pole and transformer.

 

[chess-equality]

Victron just uploaded:

 

[houseofancients]

I am not aware of any off-grid inverter that offers 3 phase operation, i.e., a single inverter that outputs 3 phase.

This is a DIY site. Why would any of us be VERY experienced with commercial solar installations?

mpp solar makes them
deye ( sunsynk) make them too, however not sure of there is a difference between us 3 phase and eu 3 phase

 

[sunshine_eggo]

mpp solar makes them
deye ( sunsynk) make them too, however not sure of there is a difference between us 3 phase and eu 3 phase

They make single box 3 phase inverters, or are you talking about paralleling multiple units to get 3 phase?

 

[Samsonite801]

Wow, these might be a single inverter 3-phase? Also stackable. Probably cost a fortune though, looks like industrial grade...

TrueStringXL 480V Energy Storage Inverter – Reliable Power

hiqsolar.com

I also remember back when Big battery was selling those 480v used industrial inverters (where if you ordered some certain minimum amount they'd throw in the gateway controller too), doesn't look like they have them anymore though...

 

[Hedges]

mpp solar makes them
deye ( sunsynk) make them too, however not sure of there is a difference between us 3 phase and eu 3 phase

Typically US is 120/208Y or 277/480Y, 60 Hz.
EU, a common voltage is 230/400Y 50 Hz.

Many loads would work at both frequencies and 400 or 480V.

Come to think of it, 400 is to 480, and 230 is to 277, as 50 is to 60.
Same transformers and motors should work for both (lower voltage at proportionately low frequency, inductance holds off the current), just lower power at the lower voltage used for 50 Hz in EU.

The larger SMA model I linked, looks to me in the manual that it could be adjusted for both US and EU voltage/frequency.
Smaller one only listed nominal EU voltage.
But sometimes, not everything works correctly with altered settings. I've heard of some models that did not.

 

[houseofancients]

They make single box 3 phase inverters, or are you talking about paralleling multiple units to get 3 phase?

single box
MPI 10k : https://www.mppsolar.com/v3/mpi-hybrid-series-2/

 

[MaximusAnonus]

I've spent the last few days reading all I can and I came up to the conclusion that I don't really like AIOs. And also that I will have to redo my whole setup.

24V system is not gonna cut it even if I could size it properly I just don't feel comfortable with the theoretical 800A flowing through the battery to the inverters alone. I'm also beginning to be a little bit skeptical I can pull this off. The CNC itself has a 5kW spindle and each servo driver is like 750W. My lathe is like 3kW. My saw is like 2kW and so on and so on... And I have to take into consideration redundancy. With one single box doing everything I also loose everything when any single component inside shits the bed.

So right now I have
62pcs of 550W panels
64pcs of 280Ah EVE cells (which is like 55kWH of electricity)
10pcs of the EPEver Tracer10420AN MPPT chargers (these can do 48V)
2x 5kVA Multiplus (these can't do 24V)
2x 3kVA Multiplus (these can't do 24V)
1x 3kVA Quattro (these can't do 24V)

I'm certain I can sell the Victron stuff easily. So that leaves me with the panels, MPPT chargers and batteries. Used 3-Phase UPS was a really good idea but I just can't find any for sale locally. Perhaps there is a hybrid inverter (or inverter/charger whatever you wanna call it) manufacturer that makes something? It might be best to simply feed off of the batteries and solar then when they are depleted switch over to the grid. It has to be sized much bigger than the Victrons tho since it wouldn't be able to do "grid assist" AKA to draw it's rated power from the batteries and supplement it with power from the grid.

Any ideas? Googling for "hybrid inverter" or "inverter/charger" yields no real answers.

 

[houseofancients]

I've spent the last few days reading all I can and I came up to the conclusion that I don't really like AIOs. And also that I will have to redo my whole setup.

24V system is not gonna cut it even if I could size it properly I just don't feel comfortable with the theoretical 800A flowing through the battery to the inverters alone. I'm also beginning to be a little bit skeptical I can pull this off. The CNC itself has a 5kW spindle and each servo driver is like 750W. My lathe is like 3kW. My saw is like 2kW and so on and so on... And I have to take into consideration redundancy. With one single box doing everything I also loose everything when any single component inside shits the bed.

So right now I have
62pcs of 550W panels
64pcs of 280Ah EVE cells (which is like 55kWH of electricity)
10pcs of the EPEver Tracer10420AN MPPT chargers (these can do 48V)
2x 5kVA Multiplus (these can't do 24V)
2x 3kVA Multiplus (these can't do 24V)
1x 3kVA Quattro (these can't do 24V)

I'm certain I can sell the Victron stuff easily. So that leaves me with the panels, MPPT chargers and batteries. Used 3-Phase UPS was a really good idea but I just can't find any for sale locally. Perhaps there is a hybrid inverter (or inverter/charger whatever you wanna call it) manufacturer that makes something? It might be best to simply feed off of the batteries and solar then when they are depleted switch over to the grid. It has to be sized much bigger than the Victrons tho since it wouldn't be able to do "grid assist" AKA to draw it's rated power from the batteries and supplement it with power from the grid.

Any ideas? Googling for "hybrid inverter" or "inverter/charger" yields no real answers.

seeing your numbers you should go 48v

 

[Samsonite801]

I've spent the last few days reading all I can and I came up to the conclusion that I don't really like AIOs. And also that I will have to redo my whole setup.

24V system is not gonna cut it even if I could size it properly I just don't feel comfortable with the theoretical 800A flowing through the battery to the inverters alone. I'm also beginning to be a little bit skeptical I can pull this off. The CNC itself has a 5kW spindle and each servo driver is like 750W. My lathe is like 3kW. My saw is like 2kW and so on and so on... And I have to take into consideration redundancy. With one single box doing everything I also loose everything when any single component inside shits the bed.

So right now I have
62pcs of 550W panels
64pcs of 280Ah EVE cells (which is like 55kWH of electricity)
10pcs of the EPEver Tracer10420AN MPPT chargers (these can do 48V)
2x 5kVA Multiplus (these can't do 24V)
2x 3kVA Multiplus (these can't do 24V)
1x 3kVA Quattro (these can't do 24V)

I'm certain I can sell the Victron stuff easily. So that leaves me with the panels, MPPT chargers and batteries. Used 3-Phase UPS was a really good idea but I just can't find any for sale locally. Perhaps there is a hybrid inverter (or inverter/charger whatever you wanna call it) manufacturer that makes something? It might be best to simply feed off of the batteries and solar then when they are depleted switch over to the grid. It has to be sized much bigger than the Victrons tho since it wouldn't be able to do "grid assist" AKA to draw it's rated power from the batteries and supplement it with power from the grid.

Any ideas? Googling for "hybrid inverter" or "inverter/charger" yields no real answers.

Another thought...

When I was a teenager (in the early 90's), I had a friend, who's Dad had a fancy machine shop with a 2 mills, 2 lathes, large drill presses, etc, which all ran on 3-phase, but their street had only single-phase power on the lines, so he had a 'rotary phase converter', which was essentially just a large 3-phase motor re-wired so a single-phase source would turn it, and it would produce 3-phase on the leads to run all the circuits in his machine room.

All you had to do was turn on the rotary phase motor, and everything else in the room with 3-phase would run off that. This ain't new tech, they have done this method for a long time before VFD became popular..

Here's an example of one:

Just some food for thought in case it looks like an interesting solution as well to chock up in your list of potential ideas...


EDIT:
More info:

Bonus video:

 

[MaximusAnonus]

Another thought...

When I was a teenager (in the early 90's), I had a friend, who's Dad had a fancy machine shop with a 2 mills, 2 lathes, large drill presses, etc, which all ran on 3-phase, but their street had only single-phase power on the lines, so he had a 'rotary phase converter', which was essentially just a large 3-phase motor re-wired so a single-phase source would turn it, and it would produce 3-phase on the leads to run all the circuits in his machine room.

All you had to do was turn on the rotary phase motor, and everything else in the room with 3-phase would run off that. This ain't new tech, they have done this method for a long time before VFD became popular..

Here's an example of one:

Just some food for thought in case it looks like an interesting solution as well to chock up in your list of potential ideas...


EDIT:
More info:

Yeah motors can be redone. The Mitsubishi VFD/servo drivers inside the CNC machine on the other hand can't. And my CNC is my livelihood. The whole reason why I do this is to be able to run it without grid if ever the SHTF.

 

[Samsonite801]

Yeah motors can be redone. The Mitsubishi VFD/servo drivers inside the CNC machine on the other hand can't. And my CNC is my livelihood. The whole reason why I do this is to be able to run it without grid if ever the SHTF.

Yeah, the idea is that with a rotary phase converter, you're not requiring to redo any wiring in your Mitsubishi CNC, but rather you'd be adding a 3-phase motor generator ahead of the entire machine room circuit to provide 3-phase power source (adds the 3rd leg) for all of the native 3-phase equipment to run on without any modification...

Just thought I'd clarify as it seems like you might've been interpreting that the machines themselves required some kind of modification. The 3-phase machines running on this type of conversion method will have no idea they're not running on anything short of perfect 3-phase power source, same like a power company would provide...


There are also companies which make these turn-key industrial rotary phase converters:

Phase Converters 101

What is a phase converter? You've come to a great place to Start... How does a phase converter work and what size is most appropriate for my application? These are the two most common questions asked. Phase Converters Phase Conversion

www.northamericaphaseconverters.com

More refs:

https://www.google.com/search?q=3-p...ry+phase+converter&ei=7zciY-itHqaE0PEPocu-0A0

 

[Hedges]

You can run the motors off VFD, which is a lot cheaper than 3-phase inverter because it only puts PWM into motor windings. There can be issues with VFD damaging motors, however. Also, they need high voltage input. Normally that comes from AC, preferably 3-phase for higher power. Could come from batteries or PV, but then you wouldn't have proper MPPT.

Is that 120/208Y you want, or higher voltage?
Many inverters can be linked for 3-phase. Here's another one, up to 6x inverters:

Is this the poor man's grid bypass?

What i said was "Transformers are used in every system all over the world. A Transformer is how you have split-phase in your house right now" I should have said "Transformers are used in every >grid< system all over the world. A Transformer is how you have split-phase in your house right now"...

diysolarforum.com

Redundancy - with extra inverters you have redundancy. You can also make one missing phase from two others using transformers, but unless you get a bargain on a used one, cheaper high-frequency inverters cost less.

 

[MaximusAnonus]

rotary phase converter

I've seen these in videos. I've never seen them in person. I don't think they are a thing in Europe.

Almost all of the electrical motors we use here can be rewired from 400V to 240V and vice versa. I could redo all my machines to single phase power except the saw (which I could live with being plugged into normal power) and the CNC (which could be done if I swapped out the spidle and it's VFD for lower power single phase one).

Redundancy - with extra inverters you have redundancy. You can also make one missing phase from two others using transformers, but unless you get a bargain on a used one, cheaper high-frequency inverters cost less.

On a side note how to correctly size the power rating of the high-frequency inverters when it comes to motors and such? Should I ignore whatever peak is written in the datasheet and put all load inside the power rating?
For example the four servo drivers inside the CNC are 750W each with peak of 1300W according to their datasheet. So while I could get away with 3kW low frequency inverter with high frequency inverter I have to do 4x1300W and use at least 5200W rated inverter?

By the way who's the recommended manufacturer of hybrid inverters/chargers (something like the Victron MultiPlus)? Except the Victron of course. I don't think MPP Solar/Voltronic makes anything like that since all of their models have MPPT chargers included in the box.

 

[Hedges]

I've seen these in videos. I've never seen them in person. I don't think they are a thing in Europe.

I think if you connect single-phase to two windings of a 3-phase motor and give it a spin, you get 3-phase.
Commercial converters are probably 3-phase generator coupled to single-phase motor, but maybe they are just a single 3-phase motor with starting capacitor.

I had a Lincoln 3-phase motor-generator welder. I gave it a spin by connecting 24V of lead-acid battery to welding cables, then turned on single-phase AC.

Possibly, if your motors start up under light load, a start/run capacitor or starting capacitor and "push to start" button would get them going? No guarantees!

Almost all of the electrical motors we use here can be rewired from 400V to 240V and vice versa.

3-phase? Sounds like delta vs. Y connection of three windings.

I could redo all my machines to single phase power except the saw (which I could live with being plugged into normal power) and the CNC (which could be done if I swapped out the spidle and it's VFD for lower power single phase one).


On a side note how to correctly size the power rating of the high-frequency inverters when it comes to motors and such? Should I ignore whatever peak is written in the datasheet and put all load inside the power rating?
For example the four servo drivers inside the CNC are 750W each with peak of 1300W according to their datasheet. So while I could get away with 3kW low frequency inverter with high frequency inverter I have to do 4x1300W and use at least 5200W rated inverter?

Assuming the inverter has a surge rating that lasts for several seconds,
You can measure motor starting surge, or use LRA locked rotor amps, or assume 5x full-load current.

If your motor can be switched to "Y" windings, that would start at lower current. Then when running switch to delta windings. Assuming, of course your power source is 240 delta or maybe 120/208Y. If you've got 230/400Y, the 400V can only applied to "400V to 240V" convertible motor in the 400V ("Y", I think) configuration.

By the way who's the recommended manufacturer of hybrid inverters/chargers (something like the Victron MultiPlus)? Except the Victron of course. I don't think MPP Solar/Voltronic makes anything like that since all of their models have MPPT chargers included in the box.

I think MPP has single-phase inverters that can be stacked for 3-phase. Sure, they have MPPT built in too. That was EG-4 I linked above, also GroWatt.

 

[Hedges]

Here's thread I started on 3-phase SMA I'm putting together.

3-Phase SMA Sunny Island (15kW) + Sunny TriPower (30kW)

Showing a work-in-progress assembling 3-phase SMA system. 3x SI-5048-US are configured for 3-phase and produce 120/208Y, rated 15 kW continuous. Sunny TriPower 30000TL-US-10 is 480V delta (or 277/480Y), rated 30 kW. TriPower combiner box will be used, but for now just one string being connected...

diysolarforum.com

 

[Samsonite801]

Here's thread I started on 3-phase SMA I'm putting together.

3-Phase SMA Sunny Island (15kW) + Sunny TriPower (30kW)

Showing a work-in-progress assembling 3-phase SMA system. 3x SI-5048-US are configured for 3-phase and produce 120/208Y, rated 15 kW continuous. Sunny TriPower 30000TL-US-10 is 480V delta (or 277/480Y), rated 30 kW. TriPower combiner box will be used, but for now just one string being connected...

diysolarforum.com

Yeah, and the SMA don't have solar MPPT on them, which seems good to the OP because he seemed to want inverters without PV inputs anyways. I've seen the SMA inverters in action on the solar trailers and they look like solid units.

 

[MaximusAnonus]

Why is there so few LF inverters that can be run in parallel/3-Phase configuration while almost every HF inverter can be run in parallel/3-Phase config? ?