240V dual phase inverter?

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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #32
    Re: 240V dual phase inverter?

    played with this more this afternoon, and got no where.

    I have a 100amp panel. Both main breakers were off for all testing. It's still flipping the GFCI on the inverter with it wired normally. However, I noticed it flips the GFCI with no hot wires connected (just neutral and ground). huh wa?

    I thought maybe somewhere I crossed something up, so I took all my connectors off, and wire nutted red to red, white to white, black to black, and ground to ground. Same thing. I swapped the neutral and hot wires on the plug that goes into the inverter, and actually got a short circuit error on the inverter.

    With no hot even being connected, what would cause the GFCI on the inverter to trip?

    I guess it's time to save up and buy that transformer....
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #33
    Re: 240V dual phase inverter?
    Dill wrote: »
    played with this more this afternoon, and got no where.

    I have a 100amp panel. Both main breakers were off for all testing. It's still flipping the GFCI on the inverter with it wired normally. However, I noticed it flips the GFCI with no hot wires connected (just neutral and ground). huh wa?

    I thought maybe somewhere I crossed something up, so I took all my connectors off, and wire nutted red to red, white to white, black to black, and ground to ground. Same thing. I swapped the neutral and hot wires on the plug that goes into the inverter, and actually got a short circuit error on the inverter.

    With no hot even being connected, what would cause the GFCI on the inverter to trip?

    I guess it's time to save up and buy that transformer....
    Assuming you have a DC- grounded array, if you have a ground fault in your array, it will cause the GFCI on the inverter to trip regardless of conditions on the AC side. If the inverter is getting its reference to ground from the AC neutral/ground (they are bonded at the service), then a DC ground fault will cause a potential between DC- and ground, and when you connect the inverter to AC neutral, current flows through the GFCI in the inverter and trips it.

    Check your string voltages with the fuses pulled. If one is less than the rest by a multiple of Voc, then that 's the faulted string and the voltage will tell you where the fault is in the string.
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #34
    Re: 240V dual phase inverter?
    ggunn wrote: »
    Assuming you have a DC- grounded array, if you have a ground fault in your array, it will cause the GFCI on the inverter to trip regardless of conditions on the AC side. If the inverter is getting its reference to ground from the AC neutral/ground (they are bonded at the service), then a DC ground fault will cause a potential between DC- and ground, and when you connect the inverter to AC neutral, current flows through the GFCI in the inverter and trips it.

    Check your string voltages with the fuses pulled. If one is less than the rest by a multiple of Voc, then that 's the faulted string and the voltage will tell you where the fault is in the string.

    I've been using the inverter a lot, just not tied into the transfer switch (running extension cords) The GFCI on the inverter doesn't flip until the very instant I plug the link to the transfer switch into it, does that tell you anything?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #35
    Re: 240V dual phase inverter?

    Any other GF circuits anywhere else in the house? Connected on the hot side or not doesn't matter.

    Personally I'd disconnect the GFCI from the inverter and see if it still faults.
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #36
    Re: 240V dual phase inverter?
    Cariboocoot wrote: »
    Any other GF circuits anywhere else in the house? Connected on the hot side or not doesn't matter.

    Personally I'd disconnect the GFCI from the inverter and see if it still faults.

    yes, there is a GFCI circuit in my garage (breaker based), one in my bathroom, and one in the utility room near the panel.

    I can't disconnect the GFCI from the inverter, it's built into the AC sockets on the output.

    I will try popping the breakers out for any of the GFCI circuits in the house and unhooking the neutrals and grounds as well.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #37
    Re: 240V dual phase inverter?

    If this is a TSW inverter--There should be almost nothing you can do on the AC side that would cause the DC GFI breaker to pop... Unless you have a Neutral or Green Wire ground loop somewhere.

    Do you have the DC Ground and the AC ground tied in one common place (water pipe or ground rod)?

    To debug, put a 12 or 24 volt (or 120 volt) filament lamp across the 1 Amp DC current breaker connection (disconnect the sense Breaker--you want to keep your system running) and see if it lights. Measuring the voltage will tell you if it is your Battery Side or AC side that is causing problems (measure AC volts and DC volts--by the way, measure AC volts on your battery bank. "Simple" AC meters will use a capacitor to only measure AC voltage. True RMS reading meters will measure both AC and DC voltage when on "AC Scale").

    About the only thing that makes sense to me is there is a miss-wire/short on the AC side where your neutral current is actually passing through the green wire and placing significant AC current into the ground system--and leaking back through the DC GFI sense breaker. (Transfer switch miss-wired?)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #38
    Re: 240V dual phase inverter?

    For the sake of clarity, we're talking about tripping a GFCI breaker on the AC OUT of the inverter, right? Not the GFDI on the DC IN?

    Just need to be sure we're all on the same page. ;)
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #39
    Re: 240V dual phase inverter?
    Cariboocoot wrote: »
    For the sake of clarity, we're talking about tripping a GFCI breaker on the AC OUT of the inverter, right? Not the GFDI on the DC IN?

    Just need to be sure we're all on the same page. ;)

    yes, on the AC OUT which goes to the remote generator transfer switch input and a power strip in my garage. There is no GFCI on the 12VDC input on the inverter that I know of.

    Maybe some pictures would help too?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #40
    Re: 240V dual phase inverter?

    Opps, I am wrong (again :blush:)... This appears to be popping the GFI AC outlet on the inverter?

    It could be a ground/neutral swap/problem... But it can also be simply capacitive coupling in the AC wiring somewhere.

    Personally, I would pop out the GFI outlet from the inverter and just hardware or install a non-gfi outlet. You should not really have a GFI breaker in your main supply source... If you pop the GFI (kitchen sink area), you lose all of your power in the home.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #41
    Re: 240V dual phase inverter?
    BB. wrote: »
    Opps, I am wrong (again :blush:)... This appears to be popping the GFI AC outlet on the inverter?

    It could be a ground/neutral swap/problem... But it can also be simply capacitive coupling in the AC wiring somewhere.

    Personally, I would pop out the GFI outlet from the inverter and just hardware or install a non-gfi outlet. You should not really have a GFI breaker in your main supply source... If you pop the GFI (kitchen sink area), you lose all of your power in the home.

    -Bill

    that's a good idea to try, they probably put the GFCI outlet in the inverter as a CYA thing in case someone used it in a wet environment.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #42
    Re: 240V dual phase inverter?

    Bill;

    I also think this is what is going on. Two GFCI's "in a row" is a notorious trouble-making situation. They're not meant to work like that. Although we'd generally assume that with no connection on the Hot nothing should happen, the devices themselves are not that discerning. As far as they are concerned, zero current on one side and some on the other for whatever reason and in whichever direction (neutral trying to feed back to the inverter) is an imbalance and will trip the breaker. It shouldn't, but some of these GFCI's are overly sensitive.

    Dill;

    If you're wondering why they'd put such a thing in the inverter it's because the unit is designed to be a sole power source for something like an RV or cabin where that would be the only GFCI and the protection would be welcome. Gets a bit trickier when you use it as a back-up power source for existing house wiring. Time to get out the screwdriver and make some modifications. Note that such will void the warranty. Another poster here a while back had much the same problem and got the company to switch the GFCI protected inverter for one without that feature. Any hope of that?
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #43
    Re: 240V dual phase inverter?
    Cariboocoot wrote: »
    Bill;

    Dill;

    If you're wondering why they'd put such a thing in the inverter it's because the unit is designed to be a sole power source for something like an RV or cabin where that would be the only GFCI and the protection would be welcome. Gets a bit trickier when you use it as a back-up power source for existing house wiring. Time to get out the screwdriver and make some modifications. Note that such will void the warranty. Another poster here a while back had much the same problem and got the company to switch the GFCI protected inverter for one without that feature. Any hope of that?

    it makes total sense why they'd ground fault protect it. I've had the inverter since last spring, so an exchange is probably out of the question. I'll just modify it to work and report back.
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #44
    Re: 240V dual phase inverter?

    well, I swapped the GFCI outlet for a regular one, and I'm now able to power 1 side of my panel through half the transfer switch. I hooked up 1 circuit on the other side, flipped the breaker, and poof, short circuit (as I expected). Definitely will need that transformer to get a split phase signal to the other side.

    Thanks for the help on this, I really appreciate it.
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #45
    Re: 240V dual phase inverter?

    as I mentioned earlier, I'm in IT. My company has several old APC 3kva rack mount UPS units we're no longer using, we upgraded to a single 10kva unit so these are just sitting.

    They have a 240V twist lock input, and output at 120V on the back. Would the transformer from this UPS work in the opposite direction?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #46
    Re: 240V dual phase inverter?

    Probably... But it might not be straight forward. Some inverters use multi-tap transformers to adjust the voltage without needing to go on inverter (saves energy).

    Also, transformers can have significant losses too in a solar system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #47
    Re: 240V dual phase inverter?

    Dill, what is the model number of those UPSs? I'm in the market for a very specific set of model numbers...
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #48
    Re: 240V dual phase inverter?

    I'll check them out and let you know tomorrow. We actually have several of them, 2 rack mount 3000kva units, and 2 floor standing 1500kva units, and a couple 2200kva, all have the 240v twist lock and 120V outputs.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #49
    Re: 240V dual phase inverter?

    Thanks. The ones I'm looking for are in the 3-6kva range, online.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #50
    Re: 240V dual phase inverter?

    SU3000RM3U

    18 characters
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #51
    Re: 240V dual phase inverter?

    Dang, not one of the ones I'm looking for. Thanks for checking.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #52
    Re: 240V dual phase inverter?
    techntrek wrote: »
    Dang, not one of the ones I'm looking for. Thanks for checking.

    yea, in looking at them closer, the twist lock plug on them are 125V, 30A plugs, not the 240V plugs I was expecting. I guess they're not really much use to me now either.

    An update, I tried to finish the transfer switch install last night (had it all tore apart troubleshooting) and the A, B, C, D, and E circuits installed without a hitch. When I put F online, short circuit. I moved it to another breaker in my panel, same thing. It figures it was the last circuit to install that had the issue. :grr I suspect this has been part of the issue all along.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #53
    Re: 240V dual phase inverter?

    Depending on their DC input voltage they might be useful as inverters if it matches your battery bank voltage. Usually APC UPSs can do a "cold start", what I would call a "black start", where they can be activated from their DC source.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #54
    Re: 240V dual phase inverter?

    I took the transfer switch apart and found the issue. When it was assembled, the 'F' circuit hot wire was pinched between two of the casing halves and 1 strand of wire shorted against the case. I pulled the wire out and replaced it, and put it back together, carefully making sure to not pinch any wires.

    When hooking it back up, I discovered 2 of the circuits I wanted to run off the switch were a multi wire branch circuit. After doing a little reading on those, I decided to leave them both off of the transfer switch as I didn't want to overload the common neutral they shared since I plan on feeding the switch with single phase power.

    Once I hooked it all back up, everything works as I originally wanted it to. I can power my furnace blower, bathroom, outlets, and anything else I want off of grid power or my inverter/generator. I'm so glad it works now and I'm not doubting my knowledge of electricity any more.

    Thanks to all that responded to this thread helping me out.
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  • Jocelyn_B
    Jocelyn_B Registered Users Posts: 1
    #55
    Re: 240V dual phase inverter?
    Dill wrote: »
    well, I swapped the GFCI outlet for a regular one, and I'm now able to power 1 side of my panel through half the transfer switch. I hooked up 1 circuit on the other side, flipped the breaker, and poof, short circuit (as I expected). Definitely will need that transformer to get a split phase signal to the other side.

    Thanks for the help on this, I really appreciate it.

    Hy Dill, I bring back to life that old thread, but, just like u. I got a PROwatt SW, mine is the 2000W version. And just like u the GFCI outlet is the main problem to connect the Inverter to my house panel, so i want to swap it for a regular one. How did it got? You just remove the front cover and swap it? Can u put it back in case of issue so u cant ship it back and still got the warranty? or its more of a custom fit and u need to modify somehow thing to make the new receptacle fit.

    One last thing, when ''(u hooked up 1 circuit on the other side, flipped the breaker, and poof, short circuit)'' I don't understand why it did, would u say it say because of ''the 'F' circuit hot wire was pinched between two of the casing halves and 1 strand of wire shorted against the case''. Thx
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