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  1. #21

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    lol top you must hand those out quit a bit to have em in a pdf file. How many of em actually get turned back in to ya?

  2. #22
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    Never seen one filled out yet. The key is to keep a straight face when you hand them the report. Tell them Employee Relations needs the paperwork filled out for there records

  3. #23
    fio1022 Guest

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    Quote Originally Posted by dbrown20
    The maximum safe output of the bank operating in this manner is 58% of a 3 pot Wye/Delta bank. The system is grossly unbalanced, both electrostatically and electromagnetically."

    dbrown20
    To get back to the subject.
    Is there 2 or 3 seperate phases coming out of an open delta?If there is only 2,how do these 3 phase motors start rotating and could't that do damage over time to customers equipment?
    I know this is above and beyond what I need to know to be a good lineman,but I always like to know how things work.
    It's just my nature

  4. #24
    Ryan Guest

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    Hey sorry topgroove, I mistook you for someone else.
    Apologies.
    I wish everyone used there real names.

  5. #25
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    take a look at this diagram again, You'll see how you can get three phases of secondary voltage using only two transformers. Its why its called open wye open delta. Its perfect for a customer who only has a small three phase load.

    http://www.dropshots.com/day.php?use...7&ctime=184203

    After you click on the link above ckick the image again and it will make it more clear.
    Last edited by topgroove; 07-10-2006 at 07:32 PM.

  6. #26
    fio1022 Guest

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    I understand how it is wired,I don't understand how you can get 3 phases out when only 2 are going in.

  7. #27
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    That's why a trampbag has handles.....
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    Fio1022
    There are 3 phases, exactly like a closed delta. It is difficult to wrap your head around the concept until you have actually hooked up a dozen or so, but it is 3 wire and phases in with a closed Delta bank. If you draw a Delta, a triangle, on paper in pencil then erase one side of the Delta you get an open Delta. You can measure across all three points, a to b – b to c – c to a, but the one side is missing. In a Delta all sides are of equal length and so what you can measure physically you can also measure electrically with a volt meter. Example 240v – 240v – 240v.

    On the primary side you simply need to energise the H coils, with a completed circuit, either with a Wye or Delta connection. The open Delta is on the secondary side.

    All thanks to Nicolas Tesla.
    Have Trampbag, Will Travel

    Everyone who comes here brings a little joy.

    Some when they come in. Others when they leave.

  8. #28
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    All thanks to Nicolas Tesla. now theres one guy in history who never got any respect.I bet Edison never had any thing nice to say about him.

  9. #29
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    Thumbs up

    By the way, I love the feelings thing.
    Have Trampbag, Will Travel

    Everyone who comes here brings a little joy.

    Some when they come in. Others when they leave.

  10. #30
    playtime Guest

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    Quote Originally Posted by fio1022
    To get back to the subject.
    Is there 2 or 3 seperate phases coming out of an open delta?If there is only 2,how do these 3 phase motors start rotating and could't that do damage over time to customers equipment?
    I know this is above and beyond what I need to know to be a good lineman,but I always like to know how things work.
    It's just my nature
    2 tubs, 2 phases.
    X3 of transformer 1 We'll call this A(240 volt leg) X1 of trans 1 and X3 of trans 2 tied together we'll call this B(240 volt leg) X1 of trans 2 we'll call this C(240 volt leg). Now if you get your trusty Voltmeter out A to B= 480 volt. B to C= 480 volt. C to A= 480 volt. For this example say each tub is a 50 kva (2X50kva=100kva rating of bank.) this connection is only rated at 86% of the 100kva or 86kva. The 58% number comes from the total of a 3 tub bank ( ex. 50 kva X 3= 150 kva) 86 kva is 58% of 150kva.

    Make sure you remove the bonding strap from the tank to the X2 bushing on transformer 2.

    This is used by alot of REC's or RUS's for safety reasons. It cuts down on backfeeds.
    Last edited by playtime; 07-11-2006 at 07:22 AM.

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