This is another Brooks-Hansen (Brooks Crompton) 7.5hp AC Induction motor conversion attempt. Why I started is another question that I have not yet found the answer to.
It has a 15cm rotor and I was aiming for eight flats, four pole, IRP using ¾†x 3/8†N38 round magnets.
Having no metal work skills or tools it was a hand hacksaw job, an exercise I suppose just to see if it could be done. On numerous occasions I wished I had not started, hard graft!
However, after several weeks of “nibbling†away I did eventually managed to cut off enough to give something resembling eight flats.
56 of the magnets were attached with Plastic Weld.
I have not had a chance to do any real data gathering yet, hopefully this will follow. The limited testing I did showed cut in for a 12V system to be about the 200rpm mark and at 300rpm approx 3A. There was little sign of cogging which was a surprise, especially as I had managed to keep the air gap much smaller than in previous attempts where cogging had been noticeable, possibly I just got lucky with the “skewing†of the magnets due to my poor workmanship?
It has been flown with an 8' wood blade set seeing 6A but unknown rpm. This was somewhat frightening so am thinking that a smaller, possibly 6' would better suit.
I don't think this has been a waste of time although I was hoping to see better output, further testing will tell but it has proven that a rotor can be hacked up without machining tools and still produce some power.
Being thick I am struggling to insert pictures so don't know if they will show up. I will try again if not!