Maintaining current output even under load

Discussion in 'Windtura Generators' started by fabieville, Aug 15, 2010.

  1. fabieville

    fabieville WindyNation Engineer

    How can I maintain the current output of my wind turbine even under load from a discharge battery. Say for example my turbine would give me 5 amp while free spinning/open circuit at 300 RPM and then when i apply the battery to be charge at that same rpm I cant get the 5 amp I am getting about 2 instead. What can I do to maintain or even get close to the 5 amp while under load from the battery?
  2. windyguru

    windyguru WindyNation Expert

    Hi, I am not exactly certain what you are saying because you can not measure amps coming from the generator when it is not under load. If the generator is free-spinning, the only thing you could measure is open circuit voltage. No load = no power = no amps.

    Also, if your battery is completely discharged, you might have to give it an initial charge by hooking it up to a battery charger. If it can not maintain its voltage after charging, then the battery is bad.
  3. fabieville

    fabieville WindyNation Engineer

    what i mean is how can you make a wind turbine deliver just what it is producing to the battery. Instead of having such a pull down from the battery?Somewhat like how the MPPT ( maximum powerpoint tracking) circuits operate on the solar panel. If you know how the popular circuit that name Mini Maximiser works then is just the same principle i would want to apply to a wind turbine.
  4. Hector

    Hector WindyNation Engineer

    Just as the Windyguru said, in order to have a current flowing to your load, you need a close circuit in first place.
    Now, answering your question, how to keep a steady "Amp" rate when your load is applied?

    Some notes about this:
    1. Electrical motors and Electrical Generator are similar in their operational behaviors, a generator is just a mirror image of a motor, the key word here is "mirror".

    2. On an electrical motor, the more you increase the mechanical load applied to the motor, the more electrical current it will demand.
    Now applied to the generator,

    3. The more electrical current you "demand from your generator", the more torque (Mechanical force) it will need to produce that current.
    If you increase your electrical load (By connecting more apliances you generator system), the current demand will increase too and the torque needed to move the generator (or the torque needed to generate that current) will have to be bigger too. how much? it depend on your load and the generator you are using.

    At NO LOAD situation, the torque needed will be very small, the more you increase your load the more the torque needed to spin the generator will be, therefore the more wind or water you will need. Check the followinf chart for a general idea on how those variables relates to each other when applied to a motor / Generator...


    The chart above is from this site: "Understanding D.C. Motor Characteristics"
    Just keep in mind this chart is for a motor, in order to apply it to a generator consider the power as the output produced not the work consumed. if you put this chart infront of a mirror that will be your chart for a generator. In order to apply it to a generator just read it from right to left.

    In this case 600RPM will be the NO LOAD speed and 0 RPM will be the full load speed.

    The short answer to: how to keep a steady current value is to match the torque who moves the rotor on your generator to the current needed, each time you increase your load.

    Hope this answer can be useful to you.

    Best regards,
    Hector Cuchilla
    El Salvador, C.A.

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