diy solar

diy solar

Autotransformers again

kabbott

New Member
Joined
Oct 24, 2021
Messages
3
Hello All,

We have a split-phase (NA type grid) but at 50 hZ.
We are having trouble in finding smaller (3 kW to 5 kW) hybrid inverters that do split-phase output.

As such, we have been investigating autotransformers and using them with EU spec (230V - 240V @ 50 hZ). The EU units in the size range are easy to find.
However we have been having less luck finding autotransformers. We have seen the Growatt ATS-US unit, Solaredge 5000, Solax and Victron (not remembering all the model numbers).

But they are all very expensive. Growatt - 250 USD, Solaredge - 400 USD, Victron 600 USD+.

Are there any other autotransformer vendors/manufacturers (5000 W range) that you would recommend (read as cheaper, but work)?
Or should I be thinking about a plain step-down transformer (240V - 120V) and ignoring all all of my 240 loads when in "backup mode".

Let me know your thoughts.

Cheers,
Kirk
 
Hello All,

We have a split-phase (NA type grid) but at 50 hZ.
We are having trouble in finding smaller (3 kW to 5 kW) hybrid inverters that do split-phase output.

As such, we have been investigating autotransformers and using them with EU spec (230V - 240V @ 50 hZ). The EU units in the size range are easy to find.
However we have been having less luck finding autotransformers. We have seen the Growatt ATS-US unit, Solaredge 5000, Solax and Victron (not remembering all the model numbers).

But they are all very expensive. Growatt - 250 USD, Solaredge - 400 USD, Victron 600 USD+.

Are there any other autotransformer vendors/manufacturers (5000 W range) that you would recommend (read as cheaper, but work)?
Or should I be thinking about a plain step-down transformer (240V - 120V) and ignoring all all of my 240 loads when in "backup mode".

Let me know your thoughts.

Cheers,
Kirk
I think Hybrid complicates the issue. Buck-Boost transformers here in USA have a set of primary connections that can be configured for 120v or 240v. These can be wired to generate split phase. If you can find some iron then it is not out of the question to wind your own autotransformer. I have wound autotransformers in an afternoon on bare steel. It is also easy to wind LF transformers from bare steel. Another option if you have a LF inverter might be to rewind the transformer to what you need. I had a 3phase 30kW 240/480 transformer from a printer that I was able to use for 3 10kW 120/240 autotransformers. It was a tape wound toroid construction. If there are any equiptment salvage operations nearby you might be able to make a deal. You might be able to talk a metals scrapper into keeping an eye out for transformer steel. You could offer him 5x scrap value and still walk away with a bargain. I expect it is shipping that jacks up the price so if you can find anything local you will be ahead. Where are you?
 
@kabbott ,

I do not have an answer for your question but I am very curious just where you have a split phase equiptment at 50 hz.
I did a career at a very major american electrical company and built stuff for the world market. I have never seen or heard of 50 hz split phase. I thought that split phase was almost exclusively north america with few other localities worldwise.

Most transformers can handle 50 or 60 hz with only minor derating. You have two types of transformers that you can use to do the task that you require, The autotransformer which has common primary and secondary (non-isolated) and a full transformer which has separate primary and secondary windings.

Autotransformers are generally more efficient than full transformers but the difference is small, a few percent
 
Back
Top