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This small wind turbine developed by High Tech Handyman in 2009
The objective was to build a wind turbine that would produce 
12 to 14 volts of useful energy at very low wind speeds, while 
at the same time, learning the basics of wind turbine design.

Learn more about the development of this wind turbine...









Bench Testing the Alternator & Electronics

I adapted a small electric motor to drive the rotor by operating it at 8v, 10v, and 12v while measuring the performance. To the far right in the pic above you can see the electronics constructed on a perf board.  I'm monitoring the AC peak to peak voltage of "Phase A" output on an oscilloscope and the DC volts across the 100 ohm resistor using a DVM. I'm also measuring the voltage across the load (small ele motor) using an analog Simpson DC voltmeter. The load is a small electric motor that spins at voltages greater than 1.5 volts.

Note: The load is critical for these measurements!
With no load, the DC voltage output can exceed 50 volts. 










Notice in the waveform above of the "Phase A" output, that the it is not a clean sine- wave. A clean sine-wave down not have those glitches. Those glitches are a result of the 1/2 inch diameter magnets that are too small in diameter in relation the the coils. Keep in mind that I eventually went to 3/4" magnets.   









In the waveform above, I was using a 1/2 inch magnet with  1.0 inch stacked on top of it for each of the 8 positions of the rotor. It's now looking more like a clean sine-wave. Here, any imperfections in the waveform are probably due to the exact placement of the magnets.









Above is another view of my bench test setup. 

Below is my test data for your review.









Notice the changes in conditions in the first and second columns as I changed the wire on the bobbins from #28 to #36 and as I changed the stacked magnets from 1/2 inch to 3/4 inch to 1.0 inch. 

To clarify, #36x2, #28x2 means; of the 4 coils in each phase, 2 coils are wound with #36 wire and 2 are wound with #28 wire. 

Also notice that I never tested with all coils wound with #36 wire. This is because I ran out of wire, so 4 of the 12 coils had to remain with #28 wire. Once I wind all 12 coils with #36 wire the voltage should increase and I expect to get more than 12 volts DC output at about 150 RPM. I'm estimating it will produce 13 to 15 volts DC at about 50 ma. That's about 0.75 watts which is a bit disappointing. I'd like to have more power. 

Question: Even if I could get 1 watt of output power from this design, does that seem reasonable for an alternator of this size operating at 150 RPM?  Do you know? 

If you know, drop me an Email!










Learn more about the development of this wind turbine...



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