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3 phase turns ratio formula

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    3 phase turns ratio formula

    What is the turns ratio for a delta wye 138000/12470 XFMR. What is the proper formula? Thanks

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    Kalbi_Rob is offline Experienced Member Pro Subscriber
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    Quote Originally Posted by Js20981 View Post
    What is the turns ratio for a delta wye 138000/12470 XFMR. What is the proper formula? Thanks
    First step is to only use phase to ground voltages.
    For Delta, Line-to-Line = Phase-to-Ground voltages.
    For Wye, SQRT(3) * Line-to-Line = Phase-to-Ground voltages. Vp=12470/SQRT(3)=12470/1.732=7199.8V

    TTR=138000V/7200V=~19.166

    Math should be correct minus rounding errors.

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    as the previous post already explained
    These questions are hard to answer.

    Even NETA is vague on the exams.

    Given 138,000 to 12470
    They do not tell you the connections( I protested these questions)



    138,000 probably a line to line voltage so you would assume a delta
    12470 probably a wye voltage. 12470/square root 3=7199.56=7200

    138,000/7200=19.1666

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