Unbalanced inverter input

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  • Naptown
    Solar Fanatic
    • Feb 2011
    • 6880

    #1

    Unbalanced inverter input

    I have a situation where I am using 2 208V single phase inverters tieing into a 208V three phase service.
    Any one see any problems with this. The input will be unbalanced by 40A on one of the legs (higher current input) The service is a 600A.
    NABCEP certified Technical Sales Professional

    [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

    [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

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  • Mike90250
    Moderator
    • May 2009
    • 16020

    #2
    Well, it's not an inverter problem is it? More like power co is going to see un-even loading/feed on their side ? The 2 inverters output 40 amps onto 2 of the 3 pow co lines, so the inverters should have no trouble. And 40 a of imbalance on a 600 A feed, is less than 10% difference, so that's OK with me. But will the pow co ding you for it ??
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    • Naptown
      Solar Fanatic
      • Feb 2011
      • 6880

      #3
      Originally posted by Mike90250
      Well, it's not an inverter problem is it? More like power co is going to see un-even loading/feed on their side ? The 2 inverters output 40 amps onto 2 of the 3 pow co lines, so the inverters should have no trouble. And 40 a of imbalance on a 600 A feed, is less than 10% difference, so that's OK with me. But will the pow co ding you for it ??
      No it is not an inverter problem
      NABCEP certified Technical Sales Professional

      [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

      [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

      [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

      Comment

      • Sunking
        Solar Fanatic
        • Feb 2010
        • 23301

        #4
        If unbalanced yu will need to carry a grounded circuit conductor.
        MSEE, PE

        Comment

        • Naptown
          Solar Fanatic
          • Feb 2011
          • 6880

          #5
          Originally posted by Sunking
          If unbalanced yu will need to carry a grounded circuit conductor.
          Inverters are L1 L2 N
          NABCEP certified Technical Sales Professional

          [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

          [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

          [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

          Comment

          • Sunking
            Solar Fanatic
            • Feb 2010
            • 23301

            #6
            Is the service Delta or Wye?
            MSEE, PE

            Comment

            • Naptown
              Solar Fanatic
              • Feb 2011
              • 6880

              #7
              Originally posted by Sunking
              Is the service Delta or Wye?
              wye
              NABCEP certified Technical Sales Professional

              [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

              [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

              [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

              Comment

              • Sunking
                Solar Fanatic
                • Feb 2010
                • 23301

                #8
                Thought it was just checking. It should work, but the utility may not like it. Only problem you might have is high neutral current which could cause over heating.
                MSEE, PE

                Comment

                • Naptown
                  Solar Fanatic
                  • Feb 2011
                  • 6880

                  #9
                  Originally posted by Sunking
                  Thought it was just checking. It should work, but the utility may not like it. Only problem you might have is high neutral current which could cause over heating.
                  Unbalance is less than 10% of rated service. There are currently 8 3ph breakers in the panel 5 of which are unused. ( this is mostly running large 3ph heat pump package units.
                  NABCEP certified Technical Sales Professional

                  [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                  [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                  [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

                  Comment

                  • LucMan
                    Solar Fanatic
                    • Jul 2010
                    • 628

                    #10
                    How does that work with the peak demand meter as far as billable KWH?

                    Comment

                    • Naptown
                      Solar Fanatic
                      • Feb 2011
                      • 6880

                      #11
                      The same way the meter will deal with an unbalanced load. The meter reads each leg separately from what I understand. Perhaps Dereck can answer this better.
                      NABCEP certified Technical Sales Professional

                      [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                      [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                      [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

                      Comment

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