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whick89 avatar image
whick89 asked

Autotransformer/Isolation transformer.

Hi, I’m hoping for some clarification please. I built my system for my truck using a single Quattro 5000 230v for a trip through Africa however plans have changed and we are now going to Canada. My system is primarily solar fed, a buckboost to feed whilst moving, a generator for those dull non moving days and the ability to hook up to shore power. My problem is I’ve confused myself with which step up transformer is best suited for my build, idealistically I want the ability to plug into any shore power with the transformer then feeding my Quattro on the AC leg. I’m not worried about the HZ and all my appliances are UK specification wiring that work perfectly with my current set up but for the odd times we will be hooking up to shore power can anyone advise to the best unit?
Sorry for the simplicity of this but I’m going round and round with this one, many thanks Will.

AutotransformerIsolation Tranformer
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wkirby avatar image
wkirby answered ·

An isolation transformer is used if you want to separate the earthing systems. Especially useful on boats where you don't want a copper wire linking the hull to the shore which would cause the hull to corrode. Also used where there is a need to change the type of earthing arrangement in an installation or to create a floating system.
The input Voltage can be selected as either 115V or 230V and the output can be selected as either 115V or 230V. One of the 3600VA models has automatic selection of the input Voltage.

An Autotransformer does not offer isolation, it has a single winding with a centre tap. It is intended specifically for either a 230V input which will then offer 1x 230V output and two 115V outputs in split phase.
It can also be wired with a 115V input which would offer 230V output and two 115V outputs in split phase. The neutral current at the centre tap is limited to 28A continuous. The Autotransformer is designed to be installed in the specific configuration and is not easily re-arranged without a system re-design.

Perhaps the isolation transformer would be useful for travelling around as it is more adaptable (even automatic) to different input Voltages and you can keep the proper 230V arrangement inside the vehicle.

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whick89 avatar image whick89 commented ·
Thank you very much, so in theory both will do the job but the isolation transformer will be easier to incorporate into my existing build. Now for the fun part, I wire in a 110v hook up point to the input of the isolation transformer then piggy back the outlet into the AC1 going to my Quattro.
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kevgermany answered ·

Alternative might be to add a suitably sized 120V mains battery charger with a separate input for the 120V hook up.

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whick89 avatar image whick89 commented ·
Many thanks for your comment and yes adding an additional charger for 120v is something I thought about but incorporating this into my existing build was a different headache.
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Related Resources

Additional resources still need to be added for this topic

Victron Autotransformer product page

Victron Autotransformer data sheet

Victron Autotransformer manual