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Thread: OCPD Brain Freeze!

  1. #21
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    Quote Originally Posted by Smart $ View Post
    I understand.

    So the 416:480 transformer is not a problem, even though uncommon?

    And what about using three 240:480 1 xfmrs?
    That will work just fine too, as long as you wire them to convert a 480 delta to a 240 wye, with corresponding phase shift/vector group.
    More often they will be wired to convert a 480 delta to a 240 delta, which we do not need here, but either configuration is possible, depending on the result you are trying to achieve.

  2. #22
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    Quote Originally Posted by GoldDigger View Post
    That will work just fine too, as long as you wire them to convert a 480 delta to a 240 wye, with corresponding phase shift/vector group...
    That'd amount to 416Y/240, which is why I suggested it in the first place.
    I will have achieved my life's goal if I die with a smile on my face.

  3. #23
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    Why not simply feed every 3 inverters into a single core transformer with a 240 volt delta primary with a 277/480 or 120/208 Wye secondary depending upon what is needed?
    Wayne A. From: N.W.Indiana
    Be Fair, Be Safe
    Just don't be fairly safe

  4. #24
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    Possibly because the inverters have already been purchased and have a two wire 240V output?
    And for a grid tied inverter which side of the transformer is the primary?


    Tapatalk!

  5. #25
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    Quote Originally Posted by Smart $ View Post
    That don't sound right. If you have a 240Y/132V system, the line-to-neutral voltage is 132V... not 240V. FWIW, I've not seen such a system... though I can see how the inverters could be that way on a standard 240/120 3 4W system... but would you run the inverter's neutral to the panel (i.e. distribution panel, not AC combiner panel)?

    Also, wouldn't the breaker then be based on 12kW/132V assuming the neutral point is grounded...???
    actully it's 240/139v and very common to find this wire up on many generators and now a few transformers to allow a lower voltage grounding point insted of using a delta configuration.

    sqrt3/240.748 is 139
    Wayne A. From: N.W.Indiana
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  6. #26
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    Quote Originally Posted by hurk27 View Post
    actully it's 240/139v and very common to find this wire up on many generators and now a few transformers to allow a lower voltage grounding point insted of using a delta configuration.

    sqrt3/240.748 is 139
    I was just quoting 132V value posted by GD. Didn't check accuracy...

    BTW & FWIW, the 240V is the standard... 139V would be the rounded value.
    I will have achieved my life's goal if I die with a smile on my face.

  7. #27
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    Quote Originally Posted by hurk27 View Post
    Why not simply feed every 3 inverters into a single core transformer with a 240 volt delta primary with a 277/480 or 120/208 Wye secondary depending upon what is needed?
    As noted by GD, two wire connection.

    Needs one side grounded for GF reference.
    I will have achieved my life's goal if I die with a smile on my face.

  8. #28
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    Quote Originally Posted by GoldDigger View Post
    Possibly because the inverters have already been purchased and have a two wire 240V output?
    And for a grid tied inverter which side of the transformer is the primary?


    Tapatalk!
    In my world, I see the energy flow *to* the grid as primary. So, 480 is our secondary with 416 as primary side (facing inverter).

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