Wind Generator controlling ideas needed

Discussion in 'The Projects Forum' started by iONic, Nov 18, 2008.

  1. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007
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    I have a treadmill motor I am working on using as a 12V battery charger. I basically have two questions regarding some of the controlling of the prop speed.

    The motor specs are:
    Electrical Rating @ 130VDC
    2.50 HP
    18 AMPS
    6700 RPM

    1) Do I assume that as long as the RPM rating is not exceeded that I would not
    overheat or damage the motor?

    2) In the case that I need or want a braking system, what might be the method
    I could use. My friend said that using a rpm detection circuit to trigger a resistor short across the motor would be a good braking system?

    Any thoughts?
     
  2. Externet

    AAC Fanatic!

    Nov 29, 2005
    758
    57
    If the speed is not exceeded but the generation has overcurrent due to a short circuit, it will get damaged.

    The best braking system is no need for a braking system by using variable pitch blades; but if you cannot implement such, get a car brakes drum/disc at the hub and actuate mechanically (as a parking brake) from the bottom of the pole to stop the windmill.

    Do not confuse braking system with speed regulation/limiting...

    Miguel
     
  3. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,677
    900
    A wind mill can rapidly burn up brakes, if used to control speed. Variable pitch would be my first choice or maybe rotating the whole head so it is at an angle to the wind. Remember that a prop pointed directly into the wind and not feathered can generate some pretty strong forces on your tower.

    John
     
  4. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007
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    For example, tipping the blade assembly from perpendicular(90 deg) to the ground to 75 deg would reduce the speed. Or from being positioned directly into the wind to a forced offset would accomplish the same thing.
     
  5. floomdoggle

    Senior Member

    Sep 1, 2008
    217
    2
    Unless you are having 60 mph winds consistently, the motor will not exceed it's rated capability. 38 percent of energy recovery is the most you can epect from a wind generator. The bearings are your worst problem. Your motor, rated at 130 volts, will probably only put out, as a generator, 24V. Maybe .5 amps at full speed.
    That said, keep on with your wind generator! Maybe one day one of these geniuses here will come up with a true sine wave generator we can all make for under $20!
    I just got my Lenz turbine wings finished today. So, I am with you.
    Dan
     
  6. floomdoggle

    Senior Member

    Sep 1, 2008
    217
    2
    Ion guy
    The thickness of your wire. inside the motor, will tell you most of what the output as a generator will be. How you are going to get this motor to spin @6700 rpm, in an average of 10MPH winds will depend on your ability to find sufficient wind, and the horsepower it produces, to sustain the rpm's of the motor. But more than that. 6700 rpm is how the motor works as a motor, not a generator.
    Good luck. And any more questions, I will be happy to answer.

    Dan
     
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