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troubleshooting perplexing AC shore power/inverter set up

Discussion in 'Electronics' started by incoming, Dec 11, 2023.

  1. rtrafford

    rtrafford Senior Member

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    Acme is typically a simple boost transformer. It seems to have two power feeds coming allowing you to bypass the inverter network while still using the boost. There just isn't enough information in your explanations or photos to safely direct you.
  2. rtrafford

    rtrafford Senior Member

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    Looking at your Southwire Auto Switch...I'm also a bit stumped that your two ports that should be incoming options, one for gen and one for shore seems to be labeled showing power out of one input feeding the transformer.

    So, for a moment that I am going to assume that the little arrow drawn on the shore input cable is an error, and that the shore first feeds your Acme, and then it feeds the Southward input for shore. That would mean there is an output cable on the opposite side of the switch that feeds your panel. You need to confirm this is the proper flow of power. The Southwire has two inputs on one end, and one output on the opposite side. It will always default to the generator input and uses delays. The questions you need answer are happening within the Southwire.

    First, is the Southwire receiving power from shore? Second, is the transformer within the Southwire sending signals to the contractors, or perhaps is the contactor fried into one position and refusing to shift? If you have shore power coming out of Acme and into Southwire, you can stop taking photos of the Acme. Focus on Southwire.
  3. incoming

    incoming Member

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    That test is not possible right now because the transformer is not feeding any shore power to the transfer switch. Only the generator is. This is the problem i started the thread with.
  4. incoming

    incoming Member

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    The arrows drawn on the cables are not intended to be the direction of current although now that you mention it that would have also been logical. The arrows are just pointing to the “thing” that the label says.

    Both places I’ve described the power flow in this post are accurate (post 1 and post 12)

    I’ll try a different way:

    Power comes in from shore and is split (parallel) to both (1) the main panel AC shore power / generator selector switch and (2) the transformer.

    The transformer feeds (1) the transfer switch and (2) the bypass switch. This is where the problem is, there is voltage going into the transformer, but not coming out of either output.

    The generator feeds, in parallel, (1) the transfer switch and (2) the main panel shore power / generator switch

    The transfer switch feeds the inverter.

    The inverter feeds the bypass switch

    The bypass switch feeds certain circuits on the main panel (outlets and refrigerator).
  5. rtrafford

    rtrafford Senior Member

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    So the issue is purely in Acme. You may have no issue with the switch or inverter at all. Sorry if I was confused. If I am no longer confused, you have no issue with “your inverter set up”. You have a dead transformer.
    incoming likes this.
  6. rtrafford

    rtrafford Senior Member

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    Forget everything else that you’re trying to describe in your vessel. Right now the only thing that matters here is that Acme is dead. No power out means no ability for the auto switch to sense power, therefore no switching after 3 seconds of generator shut down.

    Acme needs a rebuild or replace. My comments have all been predicated on your descriptions under your thread caption. Your thread title suggests issues within the inverter and auto switch network, and your photos show all components. Your issue seems narrow and simple. Acme.
    incoming likes this.
  7. Capt Ralph

    Capt Ralph Senior Member

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    Been thinking about a few things;
    White,black hot should be 115Vac.
    I think that is 230Vac. That white wire should be taped red.
    Now, to the transformer; 230Vac converted to 115Vac, step down.
    What the theory here is balancing the 115Vac loads from the 230 and supplying the (inverted) boat with this single 115Vac line.

    Lets talk about these 3 docks; the original, the second dock when it worked and your last dock.
    Do you remember the service voltage levels?
    230V or 208Vac??
    I have a feeling the original and the last dock are newer with 208 service, the middle dock when it worked was an older 230Vac dock.
    My (remote) SWAG is the transfer switch is looking for a good 220Vac level before it transfers over. 208 does not turn it on.
    Like some old UPSs and some old inverters did.
    Last edited: Dec 12, 2023
  8. Capt Ralph

    Capt Ralph Senior Member

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    Update
    Found some data on that RV auto switch;
    Mechanical contacts.
    Electronic time delays.
    Electronic contact control.
    90V sensing.

    I'm assuming it is looking for at least 90Vac on one of the 115Vac legs.
    Even 208Vac does provide a nice 115Vac level.
    But, due to this design, I'm still looking into this switch.
  9. rtrafford

    rtrafford Senior Member

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    It can't sense the **** power if there is no output from the Acme. My hunch is that there is a fried component in the Acme, and that is the source of all the issues. Southwire auto switch can't switch to shore power it does not sense. All issues here seem to be in the Acme.
  10. Capt Ralph

    Capt Ralph Senior Member

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    I'm not convinced of the OP flow theory. I'm kinda of thinking the transformer is working or the boats 115Vac would not work at all.
    Hands on with tracer and volt meter is required to really figure out that install.

    Funny thing; Even after it gets all figured out, I would still recommend ripping all that out and starting over again,, in a safer environment.
  11. rtrafford

    rtrafford Senior Member

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    Agreed on all of this. The Acme is receiving two 110v legs from a 50 amp supply. It should be outputting two no-load legs at 114v plus or minus. He comments it is not putting out at all. My assumption is that his boat is getting shore power if he uses the manual bypass, or at worst he already knows that he has power at the Acme input. no way of knowing what is upstream of the Acme. For instance I have a breaker where the power enters the boat, first step.
  12. incoming

    incoming Member

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    a couple of clarifications- the boat receives and distributes both legs of AC power from the dock through the main panel. However, before the panel, there is a 3 wire splice that feeds the transformer, which then feeds the transfer switch and then inverter.

    also, I called wards Marine and they said failures in that acme are extremely rare, but to check the functioning of the breaker switch on the side of the unit. I’m gonna try that next.

    I agree that the acme is almost certainly the proximate cause here. I’ve known that for a while. The reason i titled the thread the way I did and posted the pictures that I did is because I’m looking for feedback on the whole set up. I’ve never seen anything like this and it doesn’t “look right” to me. The sense I’m getting is you guys feel more or less the same.
  13. rtrafford

    rtrafford Senior Member

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    Here's a bit of feedback...Acme should be in line between the incoming shore power and your panel. It should boost AC on the entire boat, not just on the inverter. Acme should have one in from shore and one out to the panel. Useful to have a bypass switch to bypass Acme in the event that Acme has an issue, or in the event that shore power is good, and Acme isn't necessary...especially for long idle times when no one is aboard...
  14. rtrafford

    rtrafford Senior Member

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    ...add, we are all trying to be helpful here...but the photos of the installation read, "hey, I just got all of this gear, and I'm going to hook it all up right here just to be sure it works."...and then was walked away from by that installer. Add that an arrow should always be indicative of flow direction. IF you have the budget, get Wards (or similarly skilled) aboard and have them set this all up properly.
  15. Capt Ralph

    Capt Ralph Senior Member

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    IMG_1583a.jpg

    Whoa, buried under some stuff but I found it still in my shop.
    24Vdc but still the same inverter.
    Anybody need one. Off of my boat 2 years ago.
    20231212_194009a.jpg
    Last edited: Dec 12, 2023
  16. wdrzal

    wdrzal Senior Member

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    Ok then go back to the original problem . No shore power.
    What is a ACME ? Isolation transformer ? we will pick up and go from there . I read the last 35 posts , the I more read the more confused I got.
  17. Capt Ralph

    Capt Ralph Senior Member

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    Relax
    I'm heading down there to figure this out. Just have to work out our schedules.
    I promised SAE hammers and a sharp chain saw.
  18. wdrzal

    wdrzal Senior Member

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    A lot of times its faster to cut it all out and start over .
  19. Capt Ralph

    Capt Ralph Senior Member

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    Wow, What a bug.
    We were on board and found the transformer strapping to just make 240 to 120Vac,,, with NO reference to a neutral level.
    Imagine a 120 VAc, 60Vac under the high and 60Vac over the bottom of the 240Vac signal.
    Yes, strapping was available for a neutral reference 120Vac but not used.
    The transfer switch, already biased with a neutral level from the gen-set (ground/neutral strap) and the output (ships neutral), only realized around 60Vac and not enough for the required stable 90Vac to enable. Good thing it never worked. Could of been an out of schedule Forth Of July..
    Yep, Worked off of the gen-set. Transformer not involved.

    When it was thought it worked, on a dock in transit, one night, that was just working from the inverter battery, nicely charged from the gen-set that day, not shore power that night.

    There is also a solar panel that trickle charges that inverter battery. This does a fine job also.

    We ended up cutting it all out. Frak that lil transformer is heavy.
    Owner young and healthy. After I cut it out, he pulled it out of the boat.
    Anybody want a 5kw transformer and/or a 120Vac transfer switch. In my truck now.

    Direct connect, now all works like a champ.

    Chain saw was not in use this visit.
    Bummer,,, I may be invited back, I'll keep the chain bar oiled for next visit.
    Last edited: Dec 19, 2023
  20. incoming

    incoming Member

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    Thanks so much for the visit captain! Sleeping much better at night knowing the AC power situation is simplified and functional. Both the AC power issues and the DC power issue (bad ground) that emerged while you were there were major head scratchers for me; I’m not sure I would have ever figured them out.