timselectric
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That drawing is incorrect.
Paralleled EG-4 6500EX on a 120V single phase system?
- Thread starter apctjb
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zanydroid
Solar Wizard
OK, so what is the difference that causes no magic smoke in a proper parallel config to double 120V capacity?
(And I’m assuming the inverters are frequency synchronized)
timselectric
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Let's try a simpler explanation.
If you place two 12v batteries in series.
You can still measure 12v at each battery. But together, you will measure 24v.
Multiply the voltage by 10, and reverse the current flow 60 times per second.
That is split-phase.
timselectric
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I don't understand your question.
Always synchronized. (In perfect phase with each other)
zanydroid
Solar Wizard
In two different configurations, you say it is 0 degrees.
(Config 1 - two in parallel, to give 120V)
(Config 2 - two in series, to give 120/240 or 240V)
There is something different in config 2, such that if you connect the hot terminals together, magic smoke goes out. If Config 1 and Config 2 are identical, giving identical 0 degree configuration will result in same behavior. But we know it is not the same, because they behave very differently
It should be because one of these configs will have one inverter flipped in the wiring.
timselectric
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0 degrees from each other.
Correct
The only difference is in how they are connected together.
If you connect two ends of a power source , it's a dead short.
Same goes for two sources in series or parallel.
Yes, the connections are different for series and parallel.
Just like every other power source. (Batteries and solar panels, for instance)
zanydroid
Solar Wizard
OK, so in the series split-phase configuration, if the inverter manufacturer insists on measuring voltage and interpreting configuration settings with the - probe at neutral, I feel we should follow their terminology and call one of those 0 degrees and one of those 180 degrees. (EG V1 = L1 - N, V2 = L2 - N). Otherwise stuff will not work. (I've been trying to find an example EG from victron on how they interpret this, but I was not able to in the allotted time).
If the inverter manufacturer insists on measuring / interpreting the settings the same direction on both legs (EG V1 = L1 - N, V2 = N - L2) then it should be 0 degrees.
What would you call (series or parallel) a split-phase inverter that can be configured in either L1/L2/N, or L1/L1/N (120V) mode, without changing any wiring inside the inverter (and it may not even be possible to change if the neutrals are bonded together on a busbar and can't be swapped). I'd prefer to refer to one of the inverters as configured in 0 degree mode for 120V and 180 degree mode for split phase because we have not done any physical rearranging of how the inverters are wired up.
If the inverter manufacturer insists on measuring / interpreting the settings the same direction on both legs (EG V1 = L1 - N, V2 = N - L2) then it should be 0 degrees.
What would you call (series or parallel) a split-phase inverter that can be configured in either L1/L2/N, or L1/L1/N (120V) mode, without changing any wiring inside the inverter (and it may not even be possible to change if the neutrals are bonded together on a busbar and can't be swapped). I'd prefer to refer to one of the inverters as configured in 0 degree mode for 120V and 180 degree mode for split phase because we have not done any physical rearranging of how the inverters are wired up.
timselectric
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You can call it anything you want. (And would be wrong)
I'm just trying to help you (and anyone else reading) understand what it is, and should be called.
Split-phase is really simple.
But for some reason people try to over complicate things.
zanydroid
Solar Wizard
The reference you've sent out on YouTube I believe is clear about the measurement polarity of the probes (if he doesn't say it explicitly, it can be seen with how he puts them on the lines). I'm not sure why that measurement direction is better than the other one.
I think it's super helpful for people to know that the 180 degree viewpoint merely happens because the measurement or programming polarity is flipped. And then they can move on / understand it more deeply.
And I think even if programming is "wrong" on how an inverter interprets the phase angle configured into it, you have to enter it wrong too to match.
timselectric
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I don't mention that, because it just confuses people more.
Unless someone brings up using a scope.
This is the only time that how measuring leads are connected, matters.
A scope is the only time that an individual half cycle is displayed on a screen.
timselectric
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It's not phase angle.
It's physical connection.
In parallel, the Lines are connected together.
In series, the Lines are positioned at either end.
When you program the inverter for "180" , it's referring to the physical connection.
Phase angle is always the same (in sync) , for series or parallel.
apctjb
Solar Enthusiast
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Totally agree.
Here is thought experiment; take 2 oscilloscopes and connect one L1 to N and the other L2 to N. Would each display a sinusoidal wave form? (Yes) And if you were to super impose one wave from on top of the other would you see just one wave form (No) or you would observe two distinct waveforms (Yes) that mirror each other about the time axis. At any given point, when one waveform is at its positive peak, the other would be at its negative peak, and vice versa.
Its a matter of perspective; from the power generation side is a single phase, which is passed through a center taped transformer to produce 2 distinct waveforms, which just happen to be 180 degrees out of sync with one in other.
Single phase, split phase, its semantics really.
timselectric
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Incorrect
There is only ever one waveform.
zanydroid
Solar Wizard
This is the part that causes things to be mirrored 180 degrees.
For (one definition of) consistency it can be argued that it should be L1 to N ; N to L2. That is consistent with measuring L1-L2 that way.
timselectric
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A transformer changes voltage from input to output.
It can't create phases.
It can't create phases.
Correct. Since this simulates a split phase output it works out fine. Not just semantics of mislabeling a split phase as 2 phase. They are different in how each is generated.
ksmithaz1
Solar / EV Junkie
The confusion is because Neutral is not a leg of a "phase". It is a tap in the middle of the transformer. It appears to be "180 out" because you are taking the reading with neutral as a "common" which it is not, it is a tap. . . it's where you "SPLIT" the phase in two. There is only one magnetic wave on the winding producing +-240v L1 - L2. The wave is exactly the same on the first half of the winding as the second, however if you take a reading using N as a common, it will appear to be 180 out because you have the polarity of the scope leads 180 out. To properly look at the phase on a scope you would need to see L1->N and N->L2 thus the first trace would have L1 on the clip N on the probe. The second would need N on the clip L2 on the probe. This will likely cause a short in your cheap scope as it will want clip side of the probes to be common for both traces, thus shorting L1 to N creating smoke. If you have a scope with isolation, and you do it this way you will find the waveforms are 100% in sync.
The split phase inverter simply creates TWO 100% synchronized outputs of 120v lets call them A and B.
A-L1 connects to L1out
A-L2 and B-L1 are tied to N.
B-L2 connects to L2out.
Both A-L1 and B-L1 must rise and fall at the same time.
Both A-L2 and B-L2 must rise and fall at the same time.
This creates +-240v between A-L1 and B-L2
This simulates tapping a 240v transformer 1/2 way down the winding.
When L1 is negative for the 120v on the L1-N side of the split, N is negative for 120v on the N-L2 side of the split, and L1 would be negative for the full 240v. One wave, one spinning magnet, one-phase, tapped in the middle to grab a reduced voltage. I know it seems like there are two phases but there is only one being "shared" by tapping it in the middle to grab a different potential.
The split phase inverter simply creates TWO 100% synchronized outputs of 120v lets call them A and B.
A-L1 connects to L1out
A-L2 and B-L1 are tied to N.
B-L2 connects to L2out.
Both A-L1 and B-L1 must rise and fall at the same time.
Both A-L2 and B-L2 must rise and fall at the same time.
This creates +-240v between A-L1 and B-L2
This simulates tapping a 240v transformer 1/2 way down the winding.
When L1 is negative for the 120v on the L1-N side of the split, N is negative for 120v on the N-L2 side of the split, and L1 would be negative for the full 240v. One wave, one spinning magnet, one-phase, tapped in the middle to grab a reduced voltage. I know it seems like there are two phases but there is only one being "shared" by tapping it in the middle to grab a different potential.
ksmithaz1
Solar / EV Junkie
Which brings us to AMPS. The EG4 is capable of producing 25A (240*25 = 6000). You can pull 25A from 240. Or you can pull 50A from 120. by pulling 25A from each side of the split. You would probably want to make sure the mini-splits are on different sides, one on L1 the other on L2. Also make a modicum of effort to not skip every other slot in the panel putting everything on the same side, sounds like you didn't half-wire for the 110 so likely not a problem.
Finally, there are scientific explanations on why motors and such are more efficient at 240 than 120, it's pretty esoteric. Suffice it to say, way more often than not, they just are. I had a datacenter all the gear was 110-240 auto-ranging. We were banging pretty close to 24A @ 120v. Instead of dropping another 120, we dropped a 240v/30A. Moved all the gear draw went to a hair over 10A, so 2800W -> 2450W, about a 10-12% reduction in overall power usage. (120*24 = 2880W, 240*10 = 2400W). YMMV.
Finally, there are scientific explanations on why motors and such are more efficient at 240 than 120, it's pretty esoteric. Suffice it to say, way more often than not, they just are. I had a datacenter all the gear was 110-240 auto-ranging. We were banging pretty close to 24A @ 120v. Instead of dropping another 120, we dropped a 240v/30A. Moved all the gear draw went to a hair over 10A, so 2800W -> 2450W, about a 10-12% reduction in overall power usage. (120*24 = 2880W, 240*10 = 2400W). YMMV.
ksmithaz1
Solar / EV Junkie
And it's not really "semantics" its mechanical. One motor/generator spinning one magnet = 1 phase. Three motors spinning three magnets = 3 phase. The difference is in the wiring and the way the generator outputs are connected to the service delivery point.
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