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Three-phase to single phase for home

  1. Jun 18, 2015 #1
    I live in a rural area in a third world country. Power problems are very common here.

    My house has three-phase power. It's quite big so maybe that's why my father used three-phase. It is currently distributed around the house. A phase is assigned to every section.

    Anyways, I have a problem. The voltage is very low nowadays. It's 130-155volts and it's unbearable. I can see the blades of the fan... that's how slow it's working. And lights are dim too.

    Before anyone tells me call the power company, please don't. No such thing as that and they don't care. It's a countrywide issue and they'll probably tell me you're not the only one.

    The power company did some ugly wiring in the main box of my house and I had to fix it myself so they are completely out of the question. I can't ask for help or anything.

    So let's talk physics. The voltage between each phase is 230-260 and voltage between phase and neutral is ~150volts. The voltage is really low. It's not a bad neutral or anything.

    Sorry for going into too much detail. Here's my question, instead of assigning a phase to each section of my house; is there a way to combine all phases or feed all the phases to something that gives solid 220v output? Are there any 3-phase to 1-phase stablizers? Or should I take two of the phases and step-down them to 120v and combine to get 240v?

    Please help. I don't care if it will increase my power bill. I am ready to pay more to live comfortably.
  2. jcsd
  3. Jun 18, 2015 #2

    jim hardy

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    How much current?
    Are you 60 hz or 50 ? Is frequency stable?

    Ferroresonant voltage regulating transformers do a fine job so long as frequency doesn't stray from nominal. (obviously, ferro-resonant infers frequency)
    http://www.solahevidutysales.com/power_conditioning.htm [Broken]
    one per phase , sized to your need.
    Last edited by a moderator: May 7, 2017
  4. Jun 18, 2015 #3


    Staff: Mentor

    What you are asking for sounds dangerous. Someone could be killed or injured.

    Remember that this is a public forum. Even if you believe that you could apply any wiring advice here safely, you don't know who else might read the thread and try to apply it in the future.
  5. Jun 18, 2015 #4


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    If you can afford it, buy a large sized UPS. You can skimp on the batteries (you do need some batteries as the charge flows through them and they do provide the leveling of the system). Use the UPS system to regulate your voltage. It will draw what it needs from the line at whatever lousy voltage is available. It will out put whatever settings you configure.
    No UPS system is 100% efficient, the best are around 95% or so. So you will see a 5-10% spike in your electric bill at minimum (probably more due to your own household equipment now having more power available). The UPS will provide the added benefit of riding through a brief power outage (5-10 minutes with the minimum battery configuration ie lowest cost provided system). You will have to service (most likely replace) the batteries every 3-5 years (higher cost batteries will be the ones that last 5 years or so).
    UPSs come in both single and three phase, so this seems to be a good option for you (aside from an initial cost of purchase and installation, this is costly solution). A 25-30 KVA system would provide you with an approximate 60A three phase power source (depending upon your required voltage).
    Just remember, your UPS will drop the source voltage even further (it won't care, it will suck whatever power it can, down to a brown out level). Why do I mention this? Adding a UPS might just worsen your electric companies load to the point of failure ie you will trip or fault their local system because your UPS can still pull power off of an under powered line.... all the way up to failure of the local power company's grid (resulting in no electricity for you for an extended period of time).
  6. Jun 18, 2015 #5


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    If daily sunshine is more dependable than your region's mains power, have you considered solar cells?
  7. Jun 18, 2015 #6

    jim hardy

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    Batteries? Big power electronics?

    Ferroresonant transformers are just a transformer and capacitor,

    very simple and reliable.

    but they waste considerable heat
    if you're in a cold climate that could be a plus.

    so take a look at what needs stable voltage and what doesn't.
    Are you burning up appliance motors from low voltage?
  8. Jun 18, 2015 #7

    jim hardy

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    By the way

    we do worry here about inexperienced people getting in over their heads.

    We do not know your expertise, and would like some assurance that you are aware of local building codes or will hire somebody who is.

    I worry constantly about tiny fingers around amateur electrical projects
    and as the world gets more and more litigious one is exposed to liability.

    Please understand that sort of remark raises caution flags in older people. Can you post photographs?

    Monkeying with mains power is not for amateurs.

    No insult intended, just that nobody wants to be party to a tragedy . There's a well known road paved with good intentions....
  9. Jun 18, 2015 #8


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    Agreed. @blacksky -- you need to hire a licensed electrician to help you fix your home wiring and work out a voltage stabilization strategy. This thread is closed.
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