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Old 10-03-2019, 05:00 AM   #15
Whodgins
Senior Member
 
City: Antalya, Turkey
Country: Canada
Vessel Name: mv Möbius
Vessel Model: XPM78 eXtreme eXploration Passage Maker, Naval Yachts
Join Date: Sep 2016
Posts: 103
Quote:
Originally Posted by twistedtree View Post
Great stuff, as always. And what would a reply be without a few questions? ......

I’m curious how you envision operating on 60hz shore power with a 50hz boat? Assuming your inverters are programmed to 50hz, they will only
Lock on to 50hz shore power. Alternately you can open up the acceptable input frequency really wide to accept both 50 and 60hz. But if you do that then the 60hz shore power will pass through yielding 60hz on board rather than your native 50hz. This implies that all the onboard loads are 50/60hz agnostic.
Hi Peter, thanks for stopping by as I'm sure things are very busy for you as well as your new build progresses.

Great question and I will cover this in more depth in coming Tech Talk posts on the blog but short answer (for me) is as follows. Given that we very rarely ever have shore power and when we do it is usually when we are leaving the boat for some time, the first way we deal with 50/60Hz supply is via the different inverters. The three 220 inverters will be 50Hz and the two 120V will be 60Hz, so this will cover us in probably more than 95% of the time.

On those occasions when we do plug into shore power, all of it comes aboard through the Isolation Transformer which gives us the ability to chose and match any voltage we want for input/output from 120-240V, but of course does not directly address your question about Hz. What we are doing to have both Hz onboard when on shore power is to have the shore power supply ONLY the charge side of the inverters and have ALL AC output coming from the inverters only. This is why in the Electrical Summary article on the blog, I've characterised our electrical system and our boat as being "Battery Based". With no generator and no shore power supplied AC onboard, we have no "inverter only" load switch as everything is "inverter only". In this setup, shore power is only used to run the battery chargers, which can accept 50 and 60Hz and then all the AC (and DC) comes from the batteries.

In the little diagram I made for the Electrical System Overview article, you can see that coming out of the Isolation Transformer, the AC power goes directly to the AC input of the inverter/chargers and is only used for the charger side of the MultiPlus units, not passed directly through.

Your question has pointed out to me that I forgot to label the diagram in the TT post to have the Hz for the AC outputs so I will go and update that. Thanks.

I fully understand that this type of setup would not make sense for many/most boats as they are much more often plugged into shore power or running a genset, but for our use case this is what we think will work best.

Make sense to you? Raise any concerns? I would certainly welcome and appreciate any and all questions and suggestions you would have as you are certainly for more experienced and expert in such matters.

Thanks!
Wayne
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