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Directly power house with alternator

  1. May 11, 2017 #1
    My plan is to reduce electricity use supplied by the grid by having a waterwheel partially power a house. From my simple research I've learned that hooking an alternator up to the waterwheel would work. Since a house runs on 120V AC and an alternator produces (correct me if I'm wrong) 13.8 - 14.2V AC which is then rectified to 12V DC, what do I need to have to get 120V AC?

    Is the power in an alternator rectified within the alternator itself or somewhere else in a car? What kind of current does an alternator by itself produce? I think AC, but I've heard both.

    There are so many things that don't make sense to me. Transformer, rectifier, converter, inverter? Footpound, horsepower, watts, amps, volts?? Single phase, three phase??? ELI5

    What piece of equipment do I need to step up the 12 - 14V AC an alternator produces to 120V AC that a house uses or is it even possible?

    I don't want to deal with batteries and converting to DC. That's more than I want to think about.
  2. jcsd
  3. May 11, 2017 #2


    Staff: Mentor

    An inverter will convert 12VDC from the alternator to 120VAC for the house.

    YouTube has lots of videos of back yard hydro power projects, some using alternators and some with lots of detail. I recommend that you start by watching a dozen of those.
  4. May 11, 2017 #3


    User Avatar

    Staff: Mentor

    Welcome to the PF, John.

    What you are wanting to do is pretty dangerous for someone with so little experience with electricity and electronics. What country do you live in? If you are in the US, which state do you live in? Your local electrical utility may (or may not) have a program that helps you learn your options for generating your own electricity and still interfacing with the grid. There are some specialized interface circuits that need to be used between your home's electrical generation circuits and the grid, to keep everybody safe and accurately meter what you are using from the grid and what you are supplying back to the grid.

    If you are not connecting to the grid at all, the answer to your question is to use an AC Inverter to turn your 12Vdc power into 120Vac Mains power. But there are lots of subtleties to even such a system...
    Last edited: May 11, 2017
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