Homebrewed Electricity > Wind
Christmas Windmill Time
taylorp035:
The steel was cheap versus the price of more magnets. My FEMM simulations suggested it was the best bang for my buck versus going with 3/8" magnets. They are also easier to bore such that they run true on the shaft.
I'll have to try the 2 coil test. I'm assuming there shouldn't be anything funny going on if I just jump 2/3rd's into my 3 coil series with alligator clips?
The lathe was the same RPM for all tests. I don't know the exact speed... it's a 1931 Sears, so it's belt driven and is one of the lower quality lathes in existence. But it was the only machine I had that could chuck up a 1" shaft.
SparWeb:
As long as you're only measuring voltage, then no real current flows. Without current, there's no torque, so nothing funny should happen.
If you have a short somewhere, then actually you will still see something funny (vibration) which would be an important sign.
Don't worry about having accurate 60 RPM. I was only asking about the consistency, and that will be consistent enough if you leave the belt on the same pulley, of course.
taylorp035:
I had some fun by running my old windmill alternator using my brushless RC car controller. It wasn't too excited by my temporary alligator clip power leads, but it spun up to ~200 RPM and had about as much torque as I could do by grabbing the 1" shaft. It was surprisingly smooth.
//www.youtube.com/watch?v=UC7rq5s8qOg
I also removed it from the nacelle tonight and got it off the shaft. I didn't think it was going to come apart in one piece considering my previous experience, but after 45 minutes, we were able to slide it off.
I was thinking, I want to redistribute the magnets so it has less cogging for future projects by making a new rotor. If any of you have an idea of a lower cogging configuration, let me know. I have 16 magnets and the current configuration had two side by side for 8 exposed magnetic poles. These lined up with the 12 coils, so there was 4 magnets at their closest points to the laminations at any given time. I was thinking of going with 13 magnets that were evenly spaced, but that would be weird with an uneven amount of +'s and -'s. I could do 14, but with vernier spacing every 7 magnets. Or I could 14 with vernier spacing over all 14.
Next up is to squeeze the new alternator into the nacelle. It's going to take a bit of cutting to make it fit since I got carried away with the size of my stator.
SparWeb:
It's holding together after all this time!
Sticking with just 8 poles, you can try variations on the exact 45 degree position of each magnet. Like 43,47,43,47,43,47,43,47. Another approach is to skew them a little. You could try a few variations of this inside the stator you have and you'd know which one is best. Then go on to other pole/coil counts.
I don't entirely understand the cogging you experience, because there isn't much iron in your stator.
taylorp035:
--- Quote ---I don't entirely understand the cogging you experience, because there isn't much iron in your stator.
--- End quote ---
It was close to a full 20 oz water bottle at the end of the blade to make it spin when I checked it out in the back yard. It's about as much torque you can apply to a 1" shaft by grabbing it with two hands. Way more torque than a 7' diameter blade set can reasonably produce from a standstill.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version