240v split phase question

Quankl

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Apr 10, 2022
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I'm looking at the Growatt/MPP/possibly EG4 Solar options now on the market.

After extensive research on panels, specs, understanding VoC, Currents etc. I realise I'm confused at split phase outputs.

Where I live we use a strange combination 115v, 50hz and also 230V 50Hz for bigger appliances. We use L1, L2, N. 3 wires in from the utility.

Now I'm seeing units being sold for USA as split phase once you have 2 in parallel.
But also I was advised that these have no low freq transformer so the 120legs can go out or sync? And I may have 115v on one side but could possibly have a difference under load on the other leg.

I'm not an electrician just an avid DIY is this how it works? In order to do split phase as I require into a panel with 2 120v legs and N,

I need

1). a split phase unit with a low freq transformer like a Growatt SPF 6000T DVM MPV.

And NOT
2) two 2 EG4 3KW models in parallel creating split phase


Any help here?

Also if this is the case, why is it that way?
 

jasonhc73

Cat herder, and dog toy tosser.
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Wichita, Kansas
I used the LV5048 two in parallel for a year. I use two LV6548's in 240V split phase presently.

They cannot go "out of phase".
 

sunshine_eggo

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I'm looking at the Growatt/MPP/possibly EG4 Solar options now on the market.

After extensive research on panels, specs, understanding VoC, Currents etc. I realise I'm confused at split phase outputs.

Where I live we use a strange combination 115v, 50hz and also 230V 50Hz for bigger appliances. We use L1, L2, N. 3 wires in from the utility.

This sounds very much like North America split phase, 120/240VAC @ 60Hz.

Now I'm seeing units being sold for USA as split phase once you have 2 in parallel.

There are also those that have native split phase support and allow 50Hz.

But also I was advised that these have no low freq transformer so the 120legs can go out or sync? And I may have 115v on one side but could possibly have a difference under load on the other leg.

Some do, and some don't, but the 120 legs should not normally go out of sync unless they're actually malfunctioning. You were advised incorrectly about the sync.

I'm not an electrician just an avid DIY is this how it works? In order to do split phase as I require into a panel with 2 120v legs and N,

I need

1). a split phase unit with a low freq transformer like a Growatt SPF 6000T DVM MPV.

And NOT
2) two 2 EG4 3KW models in parallel creating split phase

Either should meet your needs as stated. The SPF will have better surge capacity if you're powering electric motors (A/C compressor, etc.).
 

Quankl

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Joined
Apr 10, 2022
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9
So what is the major difference between two units in parallel providing a L1, N and L2 vs a low freq transformer version providing L1, N and L2.
 

BentleyJ

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Location
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This subject is confusing. Hopefully this is a simple explanation from a NON electrical engineer. The architecture for high frequency, split phase inverters is basically the same regardless of having 1 Inverter or 2 stacked. This is because inside the box of an individual split phase inverter there are actually 2 inverters that operate 180 degrees out of phase with each other. One leg of each inverter is tied together to create the neutral. Therefore if for example you have a 5kW split phase inverter then each of the 2 internal inverters can contribute only 2.5kW . This is why its necessary to balance the load(s). Its not that anything will go out of sync, it just that you cannot operate a 3kW load if its all connected to only one leg of the split phase Inverter.
In the case where 2 Inverters have to be stacked to get split phase, it requires a communication cable between the 2 to keep the phase and frequency synchronized.
 

jasonhc73

Cat herder, and dog toy tosser.
Joined
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Location
Wichita, Kansas
So what is the major difference between two units in parallel providing a L1, N and L2 vs a low freq transformer version providing L1, N and L2.
Low frequency has a giant transformer built-in.
The LV6548 I use can power my AC just fine. I run my Dewalt 120V AC miter saw easily.


The LV6548 is a 120V unit by itself. LV6548 x 2 is required to get 240V.
The LV6048 (replaced the LV5048) is 240V already by itself, paralleling is done to have more than 6K output.
 

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BentleyJ

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Riverside County, CA
Another example of this split phase electronic architecture is found in gasoline powered Inverter generators. I have a Champion 5,000W open frame style with a Nat Gas conversion. Based on observing the wiring harnesses there are 2 sets of 3 phase windings that each feed into 2 separate 120V, 2.5kW Inverters. On the output side there are 2 x 120V duplex receptacles (each duplex receptacle is fed independently from 1 of the 2 inverters) Then there is also a 4 pole twist lock receptacle that supplies 240V.
 

Quankl

New Member
Joined
Apr 10, 2022
Messages
9
This subject is confusing. Hopefully this is a simple explanation from a NON electrical engineer. The architecture for high frequency, split phase inverters is basically the same regardless of having 1 Inverter or 2 stacked. This is because inside the box of an individual split phase inverter there are actually 2 inverters that operate 180 degrees out of phase with each other. One leg of each inverter is tied together to create the neutral. Therefore if for example you have a 5kW split phase inverter then each of the 2 internal inverters can contribute only 2.5kW . This is why its necessary to balance the load(s). Its not that anything will go out of sync, it just that you cannot operate a 3kW load if its all connected to only one leg of the split phase Inverter.
In the case where 2 Inverters have to be stacked to get split phase, it requires a communication cable between the 2 to keep the phase and frequency synchronized.
Ok I believe I understand. It makes sense how you cant have a 3kw load on one leg from one 2.5kw output inverter.

And if I'm having a 1500 draw on 240 I should typically not draw 1000 additional on one leg too.


So to sum it, a 2.5kw *2 inverter (2 in 1 offering build in split phase) with a low freq inverter only has the benefit of being in one package, and I realise they also have typically higher surge ratings(maybe longer).


My other question would be about G to N bonds. I believe my power does not require that G to N bond but I have to do more research on that.

Thanks tho. Will review this thread when I get back home.
 
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