home made windmill grid connect ?

Discussion in 'Connecting to the Grid' started by WiscHic1, Jan 9, 2012.

  1. When i bench test my pma at 100 rpm i get 15 vdc, at 200 rpm 32 vdc 400 rpm 75 vdc wen i connect to my sun 500w dump load gti i cant get over 20 watts on my watt mizer. i have had winds at 20 mph, whats going on?
  2. windyguru

    windyguru WindyNation Expert

    Well, without knowing any specifics, I can take a guess. Open circuit voltage, like the readings you are talking about (15 VDC at 100 rpm etc) have almost nothing to do with how much power a PMA can make. For example, I could build a PMA that is the size of a penny and it could make 15 VDC at 100 rpm but the most I could expect out of it for power would be something around a few milliWatts.

    So, my first guess is that your PMA has trouble producing decent amps. Power = Volts x Amps. If you have good volts and no amps then you have hardly any power.

    My second guess is that your PMA might be good but you are using blades that are either too short for the power curve of your PMA, too long for the power curve and open circuit voltage of your PMA , or you could be using blades that just do not work well.

    Other things to consider:

    1. Tower height and the PMA's access to clean wind

    2. Wire size:


    I think for starters try bench testing your PMA when it is hooked up to the grid tie and see what kind of Watts you can get at various rpm's. Make sure you use a tachometer to measure the rpm of the PMA or else you will have no idea what the real rpm is. If you do not have a tachometer, you can get one on ebay for about 15 bucks.

    Lastly, post some pictures of your PMA and blades. Tell us as much as you can about it. This will allow everyone on the forum to give you the most beneficial help.
  3. leamywind1

    leamywind1 WindyNation Engineer

    Wind guru is right but right off the hop you are probally running a 10-30v 500w GTI and you need a 22-60 but start by wind guru's sugesstion first to really nail it.

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