Can inverter be powered with 3-phase

Discussion about adding energy storage to grid-dependent inverters using OutBack Power technology
JRHill
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Re: Can inverter be powered with 3-phase

Post by JRHill »

This whole subject might be better with those who want to argue grounding practices. To me, maybe the OB stuff can use those legs of three phase to service the system. I don't know. I'd never do it. But with power coming in from outside and the inverter passing it through won't your single phase 240v devices love the incoming power? Not.

I'm not a sparctrician But I learned that ya don't use three phase unless you are hooking it to three phase, unless you are just pulling from one leg.
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Re: Can inverter be powered with 3-phase

Post by provo »

There may be a difference in the transformer output voltages when you're being supplied with "3-phase power".

What they're doing around here probably uses different transformers, with the understanding that everyone only gets 240VAC single phase, even though the main lines out along the highway are 3-phase.
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Re: Can inverter be powered with 3-phase

Post by sbrownian »

provo wrote: Thu Apr 29, 2021 2:13 pm
Don58 wrote: Thu Apr 29, 2021 1:45 pm
There seem to me to be contradictions. Outback told me straight out that the way we had it, two legs of a three-phase source, will not work. Yet it is intended to run on household 240Vac, which if as described above is two legs of a three-phase source.
In my rural part of Calif, the neighbors and I have 2 of the 3 phases coming to the utility transformer on the pole. Say we have A and B. A few miles one way they have A and C, a few miles the other way they have B and C. The voltage on the 3 phases is whatever provides 240VAC across any 2 phases given the 120° shift and the step-down factor of the transformer. (I used to know the formula -- you can look it up.)

The 120° shift is transparent to the user. You end up with 240VAC 60Hz, and that's all that matters. The neutral comes from the transformer on the pole.
No, the 120 shift is NOT transparent to circuitry that phase locks to the 'hot' lines with a reference to neutral.

I will induce offsets in the circuitry if it is expecting 180 degrees phase shift, and that could effect the switching circuitry not turning off and on at the correct time.

One of the side effects of that is the production of heat.

According to the actual testing that Don did, he stated his inverter/charger got MUCH hotter when on the 120 vs the 180 stuff.

Pole top 7.2kv to 240 transformers 'recreate' the 180 angle between the hot leg(s) and the neutral, if you will.

(Actually, most pole tops go phase to neutral, anyway, as a 7.2kv transformer is cheaper than one wound with a primary for 12.47kv)

Three phase LOW voltage (480 / 240 /N) brings up the 120 issue.
Information, you get not; if incorrect question, you ask..
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Re: Can inverter be powered with 3-phase

Post by provo »

sbrownian wrote: Thu Apr 29, 2021 3:31 pm
No, the 120 shift is NOT transparent to circuitry that phase locks to the 'hot' lines with a reference to neutral.

I will induce offsets in the circuitry if it is expecting 180 degrees phase shift, and that could effect the switching circuitry not turning off and on at the correct time.
I stand corrected, thanks! I didn't consider the situation where someone was using two phases and the neutral that came with the 3-phase power. As you say, my pole-top xformer creates its own neutral.
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