Need Help With Load Sensing and Switching

Discussion in 'The Projects Forum' started by quentin7406, Mar 19, 2009.

  1. quentin7406

    Thread Starter New Member

    Mar 19, 2009
    I am interested in building a waterwheel generator capable of powering a typical home. My plan is to use a waterwheel to turn one or more DC motors to generate the power and power inverters to get usable power for home appliances. I am guessing I will probably need 2-4 kW. Because I have constant power being generated I have no need for batteries as with the standard solar panel setup and would like to avoid the cost of the batteries as well as maintenance associated with them thus the need for high currents being generated constantly with out regard to the load. My problem is what to do with the extra power. My initial thought is to bleed it off to ground but need a way to sense the load changes and switch the extra power to ground.
  2. leftyretro

    Active Member

    Nov 25, 2008

    If the load is drawing little power then there is only little power being generated. The load establishes the current, the generator establishes the voltage level and supplies the current as required by the load. All you need is to control or regulate the generator output voltage under all current loads, 0 to max rated. Ohm's law is what you need to understand.

  3. AceHomeAutomation

    New Member

    Mar 20, 2009
    Is the home not on a powergrid currently? I'm not sure of elsewhere, but in the U.S. backfeeding is being ushured in. If it's a possibility this would be a happier alternative, as you get paid for what you supply.
  4. Wendy


    Mar 24, 2008
    There is no problem generating excess power, though AHA is correct, in theory you could sell it back to the power plant (might be more hassle than it is worth though). The problem comes in if you aren't generating enough power, this is where brownouts occur, which can damage some appliences (such as refrigerators).

    The alternative is to connect to the power company grid, and sell them your excess. They would also be a backup, if for some reason your power source fails.
  5. quentin7406

    Thread Starter New Member

    Mar 19, 2009
    Thanks for the help. The cost of the grid-tie inverter is what I want to avoid Since the average cost of the the 2kW units I have found is about $2700 with a pure sine wave inverter of the same size for about half of that. Since it only generates current dependent upon load voltage regulation should not be too difficult as I have found several suitable circuits for high power voltage regulation.