Very nice, Im impressed!
1) I work in the power transformer industry (power distribution, sub station) so I am familiar with the Wye winding, AC and sine wave, etc.. Anywho, I am hoping the plate the magnets are attached to are either aluminum or stainless thus being non-magnetic.
Nope, the rotor plate is intentionally steel. The neodymium magnets are adhered by both magnetic force and industrial grade "superglue." By design, the plate is part of the magnetic circuit. This is called an axial-flux alternator because there are two, co-rotating rotor plates, each on one side of the stationary-armature (stator). On each side of the stator, the magnets that face each other are opposite polarity. Thus, the magnetic field goes tight and straight from one magnet face on one rotor plate to the to the other magnet face on the other rotor plate, passing through the stator coils parallel with the axis of rotation...hence the name "axial-flux." The steel plates prevent the flux from extending outward from the outside surfaces of the rotors, inducing stray currents in non-current-carrying metal parts. In this case, the magnets are moving and the armature coils are stationary.
2) Just curious, why chose this design over a VAWT?
I hope this is not offensive to anyone here; but, to be blunt, vertical-axis wind turbines are very inefficient and prone to mechanical problems. There are a number of reasons for this; but, to give one simplified example...while 1/2 of the VAWT is moving with the wind, the other half of the VAWT is forced to move against the wind...think about that for a moment.
Most small-wind manufacturers send their prospective turbines to the National Renewable Energy Lab (NREL), in Denver, CO, to be tested and certified. To date, only one VAWT manufacturer (I'm aware of) has been bold (brave?) enough to send their machine to NREL for testing: Windspire. Sadly, this "best of" the VAWT machines suffered multiple breakdowns before the testing period was completed. Windspire was asked to remove their broken down equipment from the NREL grounds.
The reason all the huge, utility-scale wind farms are filled with horizontal-axis, three-bladed machines is because that has proven to be the best way to go.
3) Dont forget the 3 phase rectifier to DC (I am assuming your goal is DC output?) Its a little different than a standard setup, but the schematics make it easy to follow..
http://hackedgadgets.com/wp-content/...-rectifier.png
As shown with a Wye setup.
Yes! It's planned for charging a 48VDC battery bank. I sure hope our calculations are correct! Assumed average wind speed of 10 mph; tip-speed ratio of 5:1; M42 grade magnets; 130 turns of wire per coil; 3 coils per phase; 12 field poles in the rotor assembly...if it all works as planned, our "wild-ac" will be rectified and of suitable voltage for our battery charging needs.
From what I am seeing, you have four Wye coils so your output should be pretty steady and respectful! Even two Wye coils are good, 3 better, but 4 is ideal. If you look at the waveform of four 3 phase windings, the AC peaks should convert over to a strong and steady DC power output!!! Well done!
Thank You!
What are your plans for voltage regulation and battery charging???
We intend to use a Morningstar 48V charge controller, set up in diversion charge control mode -- when the batteries are full, the juice from the wind machine gets diverted to a "dump load," so as to always keep the wind generator loaded. When the wind is blowing, if the generator is not constantly loaded, the machine will trash itself. I made a video about this for my students -- link is below if you're interested.
I encourage you to look at PIC microcontrollers to do monitoring and charging controlling.
Keep up updated!!
EB
