Practical issues in a 3-ph load with open neutral

Discussion in 'General Electronics Chat' started by powersys2005, Jan 15, 2010.

  1. powersys2005

    Thread Starter New Member

    Jan 3, 2010
    29
    0
    I would like to discuss the underlined sentences in the text below.

    [1] As triple harmonic currents have zero phase sequence they cannot exist in a three-phase balanced form unless there is a neutral return path.

    [2] The rectifiers normally included in UPS equipments are of the three-phase bridge type; at there is no neutral connection there will be no significant triplen harmonic currents.


    Questions:
    [Q1] Kindly refer to [1] above. If the three-phase system (Y-connected and without neutral return path) is unbalanced, will triple harmonic currents appear in phase or line currents?

    [Q2] Kindly refer to [2] above. The author said "no significant", which means a three-phase (Y-connected) with no neutral connection can has "little" triple harmonic currents. If my interpretation is correct, would someone please advise how these "little" triplen harmonics occurs?


    Thanks

    [​IMG]
     
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  2. powersys2005

    Thread Starter New Member

    Jan 3, 2010
    29
    0
    Kindly advise. Thanks.
     
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