I have read several posts on this topic and I am still confused. I have a sailboat with US shore power inlet (2 x 120v). I am adding an european 230v shore power inlet for when I go to an european 230v 50hz marina. I would like to step down the 230v inlet to 2 x 120v (L1 & L2). My question is: having already a galvanic isolator installed for the ground wire, and assuming frequency (50 or 60hz) is not an issue for me, can the Victron Autotransformer accomplish this?
If your isolating transformer is 120/0/120 on both the input and output sides, then you don't need any additional transformer. As you assume, the frequency is not an issue, and the 230/220V will connect to L1/L2, leaving the centre (N) disconnected. The output will be 110 - 115VL1/N,L2/N.
if the isolating transformer is 230/0 (L1/L2) on the shore power side, and 120/0/120 on the isolated side, likewise this can be used with no problem.
The key phrase in Mike's post above is ISOLATION TRANSFORMER. An autotransformer will not work in this case because the neutral of the 230 volt shore power would end up as one of the HOT legs of the 120-0-120 output.
You need the center tap of the secondary winding of the isolation transformer as the neutral of the 120-0-120 service.
I have a follow up question:
I am in a simal situation, needing to connect to European shore power.
I have installed two Multiplus II 24/3000/70 - 50. Is there any concern with the 3600 Watt Auto 115/230v Isolation Transformer's 32/16 amp rating supplying Multiplus' in split phase configuration?
Thank you in advance.
Cheers.
Yes. The incoming power is one h0t leg and a neutral. The autransformer center tap will be at about 115 volts with respect to the incoming neutral and safety ground. So the neutral of your distribution panel will be at 115 volts.
An isolation transformer with a center tapped secondary is the right way to do what you want, so you can bond that center tap to safety ground and make 115-0-115.
