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       #Post#: 77--------------------------------------------------
       Metering watts to a GTI
       By: lynx wind Date: May 1, 2013, 9:14 pm
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       Some of you may know what happens when you connect a battery to
       a GTI.  The GTI ramps up the amp draw to maximum in a few
       seconds.  This isn't the most efficient way to run a GTI powered
       by wind.  The problem is the GTI will take as much power as it
       can and this can stall a wind turbine in moderate winds below
       the voltage threshold.
       I am working on a circuit that meters out 1-2 amps from stored
       energy derived from wind power.  This is specific to the Gull
       160.  One moment watt output might be 100 watts, the next it may
       only be 30 watts.  The GTI doesn't react this fast.
       I have tried about 10 different circuits.  Today I was testing
       something that may hold promise.  It seems to do the trick.  If
       voltage on the charged battery is high, power to the inverter is
       higher.  At the low threshold of 14 volts the circuit shuts
       down.  The circuit doesn't stall the turbine and sends a metered
       amount of amps regardless of wind speed.
       Very simple circuit comprised of a pre-packaged pulse width
       modulator, resistor and transistor.  The DC gets chopped into a
       square wave at 4700 hz.  So far I have managed to get about 20
       watts of steady power out, which is better than short spurts of
       230 watts.
       A lot of development left to go.  When I get it working well I
       will post a video.
       #Post#: 78--------------------------------------------------
       Re: Metering watts to a GTI
       By: lynx wind Date: May 2, 2013, 7:57 am
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       Success!
       The little circuit I put together meters out 10.4 watts to the
       grid continuously when the battery is at 20 volts.  This would
       equate to a Gull 160 running in a 10 mph wind.  The GTI wont
       stall the turbine and the turbine is free to run as fast as it
       wants.  Below 14 volts or 60 rpm the Gull 160 free spins ready
       for some wind power.
       This means we may not need a battery at all.  Just a capacitor
       through the circuit to GTI.
       #Post#: 81--------------------------------------------------
       Re: Metering watts to a GTI
       By: lynx wind Date: May 4, 2013, 3:22 pm
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       This the latest refinement.  I tried several versions and they
       all worked.  You can use a torroid, snap on ferrite choke, or
       ferrite rod for the core.  L1 and L2 is 14 turns L3 is 28 turns.
       When the oscillations start a magnetic field builds and
       collapses many times per second turning the transistor on and
       off.  Voltage output looks the same, but amps are throttled.
       L3 gets a AC voltage induced as the field builds and collapses.
       By shorting L3 with a ceramic capacitor no power is lost but the
       core gets more saturated as power input increases.  When the
       core saturates the transistor spends more time "on".
       To adjust this circuit once you get it running R1 to the base
       connection can be reduced to increase output.  100 ohms gave 27
       watts with 18 volts.  68 Ohms gave 48 watts at 18 volts.  You
       can increase the C1 capacitance to slow the frequency as well.
       [attachment deleted by admin]
       #Post#: 209--------------------------------------------------
       Re: Metering watts to a GTI
       By: ldissing Date: August 10, 2013, 1:51 pm
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       It would be nice if you would label that circuit with the proper
       connections (i.e. incoming power from generator, etc) and
       identifiers for the components.
       Thanks,
       Leroy
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