3 phase and Grid tie... what will happend?

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  • nordashi
    Junior Member
    • Jun 2010
    • 12

    #1

    3 phase and Grid tie... what will happend?

    Hi
    I have 3 phase in my house.
    Every phase is separated by the floors in our house.
    So P1 is used on floor 1, P2 is used on floor 2
    and P3 is used for garage, storage room, etc.
    Now my question is this:
    what will happen if I connect a grid tie inverter to p2 or p3? O.o
    Logicaly I should connect that inverter to the phase where
    most power drawing is.
  • Mike90250
    Moderator
    • May 2009
    • 16020

    #2
    All depends on how your meter works, never dealt with 3 phase G.T. personally.
    Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister

    Comment

    • Sunking
      Solar Fanatic
      • Feb 2010
      • 23301

      #3
      3 phase for a house? What size of a mansion do you live in and how many servants work for you? The answer to your question is you buy a 3-phase inverter, but I have no idea how you will balance 3 phase with a bunch of mixed single phase loads. Well actually I do but it requires some expensive transformers.
      MSEE, PE

      Comment

      • MarineLiner
        Solar Skipper
        • May 2009
        • 656

        #4
        Originally posted by nordashi
        I have 3 phase in my house.
        Every phase is separated by the floors in our house.
        So P1 is used on floor 1, P2 is used on floor 2
        and P3 is used for garage, storage room, etc.
        Now my question is this:
        what will happen if I connect a grid tie inverter to p2 or p3?
        Are you sure it's 3 phase?
        Is not it a 3 circuit breaker (fuse) box?
        Anyway, please be carefull and check: do you allowed to connect by yourself?

        Comment

        • russ
          Solar Fanatic
          • Jul 2009
          • 10360

          #5
          Depends on where you are located. I have 3 phase power - used for the water pumps and heat pump.
          [SIGPIC][/SIGPIC]

          Comment

          • MarineLiner
            Solar Skipper
            • May 2009
            • 656

            #6
            Originally posted by russ
            Depends on where you are located.
            I have 3 phase power - used for the water pumps and heat pump.
            also something like:
            P1 for water pumps,
            P2 for heat pump,
            P3 for other uses ?

            I had replaced an engine with a 1HP electro motor, to rotate an air compressor for underwater ballerina,
            wich use 3phase power, but my electrician friend do the connections.
            I did the easiest part, adjusting the air pressure switch. Ha ha ...

            Comment

            • russ
              Solar Fanatic
              • Jul 2009
              • 10360

              #7
              No - think you might not understand 3 phase - all three phases are fed to the motor of whatever you are operating.

              More efficient than single phase - similar as using HT power for larger motors. I suppose you could operate a large motor on household 120 volt power but it would be one very expensive motor and the power costs would be frightening.
              [SIGPIC][/SIGPIC]

              Comment

              • Sunking
                Solar Fanatic
                • Feb 2010
                • 23301

                #8
                Well Poly or 3 phase circuits are probable outside the scope on this forum as most are DIY types and do not have much understanding of electrical circuits.

                3 phase power is used a few different ways. Most prominently used by all commercial power generation and distribution. It allows electric companies to distribute large amounts of power on small and few conductors as possible. Enough about that as you do not need to know anymore about it with respect to generation and transmission.

                On the user side 3-phase power is the standard for large commercial and industrial users where large electric motor loads are used. 3 phase motors are far more efficient and simple than their Single phase cousins.

                In North America generally 3 phase does not enter in residential homes unless the home is really large, or a multi-residential complex like apartment or high rises. Even where it does, it is usually split out at the main distribution board and the individual loads are fed from a single phase. However where it is used the voltage is not 240/120 like single phase, it is 208/120. If your large appliances like hot water heaters, air conditioners, stoves, and ovens will have to be able to use the lower 208 voltage usually by a tap inside the unit. Not all appliances have this feature. To have true 3-phase appliances like air conditioning, hot water, etc can be had at a premium price, and if your home is large enough to justify 3-phase, you can afford the premium price IMHO. The plus is your heating and cooling bills will be lower.
                MSEE, PE

                Comment

                • nordashi
                  Junior Member
                  • Jun 2010
                  • 12

                  #9
                  Originally posted by MarineLiner
                  Are you sure it's 3 phase?
                  Is not it a 3 circuit breaker (fuse) box?
                  Anyway, please be carefull and check: do you allowed to connect by yourself?
                  Please do not underestimate my knowledge. It's a 3 phase.
                  It's not allowed, but that is not the point. Reread my post.

                  Originally posted by Sunking
                  3 phase for a house? What size of a mansion do you live in and how many servants work for you? The answer to your question is you buy a 3-phase inverter, but I have no idea how you will balance 3 phase with a bunch of mixed single phase loads. Well actually I do but it requires some expensive transformers.
                  Mansion? 3 phase? What are you talking about?
                  I live in Europe, and our electrical system is different.
                  There are huge transformation stations (in my small town there are 4 of them) which feed 3 phase.
                  One house is connected to 1st phase, 2nd is to the 2nd, ...
                  and that how balancing is made.

                  All cables for 3 phase are passing every house so it's cheap to connect onto 3 phase. You can have 3phase even if you had a 1 room house.
                  My 3 phase is used for mill, Hydrofor (erm water pump), metal welder, circular saw, ...


                  If you don't believe I'll make a video.
                  Lets get back to my question?

                  Comment

                  • Sunking
                    Solar Fanatic
                    • Feb 2010
                    • 23301

                    #10
                    Originally posted by nordashi
                    What are you talking about?
                    I think the question is what are you talking about?

                    Originally posted by nordashi
                    I live in Europe, and our electrical system is different.
                    I am very familiar with European electrical architecturre as I have designed many systems for clients there. Eurpoean electrical systems are no different than what we use in the USA other than the standard residential service is 220-240 single phase service operating at 50 Hz, compared to the USA 240/120 volt single phase service.

                    Originally posted by nordashi
                    There are huge transformation stations (in my small town there are 4 of them) which feed 3 phase.
                    One house is connected to 1st phase, 2nd is to the 2nd, ...
                    and that how balancing is made.
                    That is how every electrical distribution service in the world is constructed. However what you just described for residential service IS NOT 3-PHASE, It is Single Phase just like it is done on every where in the world. The distribution is 3 phase, but for your residential electrical service you are only connected to 1 of the 3 phases via a transformer to step the voltage down from say 13.2 Kv to 220 volts.

                    So go ahead and take that picture and I will show you what is really happening.
                    MSEE, PE

                    Comment

                    • MarineLiner
                      Solar Skipper
                      • May 2009
                      • 656

                      #11
                      Originally posted by nordashi
                      Please do not underestimate my knowledge. It's a 3 phase.
                      It's not allowed, but that is not the point. Reread my post.

                      Comment

                      • nordashi
                        Junior Member
                        • Jun 2010
                        • 12

                        #12
                        [QUOTE=MarineLiner;10201]

                        Comment

                        • Mike90250
                          Moderator
                          • May 2009
                          • 16020

                          #13
                          You can feed 1 phase GT inverter into 1 leg of a 3 phase circuit, but I don't knwo how the meter will interpret that, and at some point, the service transformer will become un-balanced. I'd think 10-20% of service capacity would be OK. (if you have 100A service, you an backfeed 20A on 1 leg before something complains)
                          Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                          || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                          || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                          solar: http://tinyurl.com/LMR-Solar
                          gen: http://tinyurl.com/LMR-Lister

                          Comment

                          • Sunking
                            Solar Fanatic
                            • Feb 2010
                            • 23301

                            #14
                            Originally posted by nordashi
                            While you guys was flaming me here on forum
                            I do not think anyone was flaming you, I certainly was not trying too. My comment about a mansion and servants was just humor. The reason I said that I have already explained, 3-phase service is for very large load demand are rarely used for a residence unless it is a very large home the size of a mansion, so large it would require a staff of servants to maintain and operate with separate living quarters.
                            MSEE, PE

                            Comment

                            • russ
                              Solar Fanatic
                              • Jul 2009
                              • 10360

                              #15
                              Hi Sunking, Nothing to do with solar but can you tell me what happens if the load is not balanced between the three phases say 1 amp on one leg, 2 amps on the second and 3 amps on the third?

                              Would you be drawing more through the meter than with a balanced load?

                              Thanks
                              Russ
                              [SIGPIC][/SIGPIC]

                              Comment

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