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Neutral compensator

  1. Sep 6, 2009 #1
    I have learnt from some source that there is a device called neutral compensator .Iwould like to know about it in detail.
     
  2. jcsd
  3. Sep 6, 2009 #2

    negitron

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    It's special type of polyphase transformer (usually three-phase) which is wound in such a way as to balance the line phases as much as possible, thereby reducing the neutral current. It's connected on parallel across the load. Its phase-balancing capability also means that if you lose a phase entirely, it will regenerate the missing phase, albeit at a lower voltage than normal.
     
  4. Sep 6, 2009 #3
    A while back, I was a postdoc at MIT, and my techician and I accidentally discovered that the grounded 120 V ac outlets in our lab was actually 3 phase 120 V power, ground being the third phase. In discussing this with the utility people, the big transformer powering the building was a 3-phase delta output, and not a wye output, so they chose one of the 3 [STRIKE]wye[/STRIKE] delta legs as ground. In order to balance the load, about 1/3 of the building got each pair of outputs from the transformer [STRIKE]wye[/STRIKE] delta. We were in the 1/3 of the building that got the pair where ground was the third [STRIKE]wye[/STRIKE] delta leg. How could a polyphase transformer correct this problem?

    [Edit] three strikes [STRIKE]wye[/STRIKE] delta
     
    Last edited: Sep 6, 2009
  5. Sep 6, 2009 #4

    negitron

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    Good question; that's an.....odd setup, to say the least. I'll have to mull it over a bit. What they should have done is use a delta-wye transformer. Any idea why they didn't?
     
  6. Sep 6, 2009 #5
    Cost too much to replace.
     
  7. Sep 6, 2009 #6

    negitron

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    Apparently, this is an uncommon, but not unheard-of setup (rare enough that I'm only just finding out about it) known as a http://ecatalog.squared.com/pubs/Electrical%20Distribution/Pressure%20Switches,%20Bolt-Loc/BP/2700DB0202.pdf [Broken]. As long as everything is balanced and it's wired properly, no corrective action is needed.
     
    Last edited by a moderator: May 4, 2017
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