question

scmwalk avatar image
scmwalk asked

Autotransformer step up from 120v to 230v euro

I'm trying to step up volage in my boat from 120v to single leg 230v (euro) and none of the schematics show this option - all the literature (for step up) shows how to step up to 240v split phase with 2 hots.

Autotransformer
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2 Answers
Justin Cook avatar image
Justin Cook answered ·

An Isolation Transformer would probably be the way to go instead (I use one on my bench to be able to power up 230v units form US voltage): https://www.victronenergy.com/upload/documents/Datasheet-Isolation-Transformers-EN.pdf

Be aware that it's not going to change the frequency though, so if you're plugged into US 60Hz you're still going to be getting 60Hz out, which may or may not be a problem depending on your loads.

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Kevin Windrem avatar image
Kevin Windrem answered ·

You aren't going to get 230 volts from a Victron autotransformer or isolation transformer. Both are a 2:1 or in this case 1:2 so you'll get 240 volts out. Also based on what others have said on this forum that you might end up with more than 240 volts with the isolation transformer since it assumes about a 5% loss in the transformer which only occurs under heavy load. So your output may be about 250 volts.

There are transformers on the market with several taps to accommodate other than a 1:2 or 2:1 voltage factor.

As Justin said, you still will be looking at 60 Hz.

One way around all this is to run separate chargers and inverters. This way the inverter always runs and produces your target voltage AND frequency. But it does mean that the charger and inverter are always running (no pass thru).

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Justin Cook avatar image Justin Cook ♦♦ commented ·
Good point about the 1:2... I happen to have a very poorly wired outlet near my test bench that only sees about 114v anyway so I actually do get ~230v from my isolation transformer, but certainly wouldn't want to be counting on that :/
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