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shale-audio asked

Autotransformer - Do the L1 L2 out actually matter?

I have some off-grid inverters that output 240V and I use an autotransformer to Create a neutral so that I can have split phase 120V.

I noticed that it has been stated that the L1 L2 simply pass through the autotransformer and the Neutral is created. Does this mean that I can simply feed L1 and L2 into the autotransformer but then feed the same L1 L2 from the inverter rather than the autotransformer, to the panel?

This would save me from having multiple Load Center's as I could simply put a breaker for the autotransformer, and for each inverter directly into the Load Center instead of keeping them separate until after the autotransformer.


Autotransformer
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Kevin Windrem answered ·

Short answer: NO.

If you connect loads to the inverter output and feed the auto transformer from a breaker in the same load panel, you loose your neutral if the auto transformer breaker trips. This will create a situation where one side of the panel will go to a very high voltage while the other side goes to a low voltage.

You must feed the inverter into the auto transformer then from the auto transformer to the load center.

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shale-audio avatar image shale-audio commented ·

Perfect. I knew I was missing something regarding safety, but I wanted to make sure my understanding of the functionality was correct.

The Autotransformer uses the L1 L2 as reference points for creating the central tap Neutral and keeping it in range, but otherwise just passes them through. So it would work theoretically but would create a potential safety issue.


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