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  • I'm a technician on a mission base in the Amazon. A few days ago we suffered a lighting strike to our electrical system when the generator was not running. The strike damaged one of our three step up transformers for our electrical distribution system. In a pinch could I run the generator only using two of it's three phases? Can I leave the third phase unloaded? I know people always say you can't but if you be sure to not exceed the rating of any one phase does it matter if the other phases are loaded or not?

    The transformers are oil cooled 75KVA pole mountable units. The high voltage sides are wired delta. If I eliminated one of the transformers could I connect just two transformers together? Is there any way to limp along with just two step up transformers and energize just two legs of the distribution system? I'm assuming I could do like this:

    ph1--(trans1)--ph2--(trans2)--ph3

    Loads would go from 1 to 2 and 2 to 3. No load would be put on 1 to 3.

    Would that work?
    Thanks!
    Greg

    Thanks!
    Greg
    Replies
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Replies

  • Ramani Aswath

    Member • Oct 15, 2011

    In a low voltage domestic three phase supply this is common. One or two phases may have light loads while the third carries a higher load. Where loads are connected phase to neutral and the neutrals are separate without possibility of break in the neutral nothing much happens. However, if the neutral breaks at some point some loads can see phase to phase voltage and suffer damage.

    If care is taken about the neutral tour scheme should work. I am not an expert in this area though.
    This article gives some info. Please see under single phase loads.
    <a href="https://en.wikipedia.org/wiki/Three-phase_electric_power" target="_blank" rel="nofollow noopener noreferrer">Three Phase Electric Power</a>
    #-Link-Snipped-#
    Please see under Three Phase Loads and Single Phase LOads here:
    #-Link-Snipped-#
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  • narayana murthy

    Member • Oct 16, 2011

    i think here appears some problem if we connect them to neural the problem in phase goes through neural and it becomes balanced as i know delta has no possibility of having neural you have to connect them to neural on some where as i don't have a practical experience i cant suggest for grounding but anyway make sure that unbalanced current should not travel to any one of phases
    what ever we can run on 2 phases but make sure that no neural current will flow to the phases
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  • takoateli

    Member • Oct 16, 2011

    Thanks for the reply! I appreciate everyone's help!
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