20 foot diameter wind turbine

Finished wind turbine on tower




wheel hub and spindle


tapping the magnet rotor


magnet template


putting down magnets


Magnets mounted


gluing in the magnets


finished rotor

There's a magnet rotor all finished up.

rotor mounted to hub


Stator bracket

Here we're starting to assemble the alternator head. I had a few parts for this machine cutout in town with a CNC water jet machine. It costs more but you get perfect parts. The stator on this wind turbine is 28" in diameter - the stator bracket has 5 'fingers' and it's 28" in diameter. It's cut from 3/8" thick steel. In the picture, the wheel spindle is pointing down, clamped in a 3 jaw chuck and we're preparing to weld it to the stator bracket.

alternator head finished

The spindle is welded into the stator bracket and suspended in the back by a steel ring with a hole that fits around it. All that is held together with a 6" long piece of 6" sched 40 steel pipe.

alternator head finished

There is the same assemble turned over with 1 bearing on the spindle. We left it like this for quite a while and test assembled the alternator on here - because it sits nicely on a workbench. Once the rest of the chassis gets welded together the machine gets too large and heavy to handle. I'm doing this page a bit out of order though and we'll stick with the rest of the steel assembly for now.

magnet rotors on alternator head

Here we've got both magnet rotors assembed on the hub and on the spindle. We had to use jacking screws to very carefully/slowly lower the top rotor on. The force trying to pull these together is incredible. We set it up with an airgap (Distance between the magnet rotors) of about .85". The next step is to figure out the coils. We'll come up with an appropriate shape/size of coil, and then wind a test coil and poke it between the magnet rotors. We'll spin the alternator at a known speed and by looking at the voltage of the test coil, the wire gage we wound it with, the number of windings in it and the rpm, we can determine exactly how many windings we need to get the alternator to start charging at the right speed. In this case, being a 20' diameter machine - our target is about 48 Volts at 65 rpm. We'll get into that on the next page.