many lies uncovered , more truth than they want you to know, based on low wind area,s 5-15 mph
Monday, March 21, 2016
magnetic flux, placing it right
hi everyone, I think a lot of magnet placement on rotors I see could be much better . these are my thoughts on flux and magnet placement. if you look at the picture to the side you will see a magnet flux visual test, the fuzzy looking areas are close to useless and the more packed looking areas are potentially USABLE flux. by now you already seen the much larger area compared to the magnet, this is why I think most are missing the picture when it comes to magnetic lines of flux. if one tests at least 2 magnets from the lot for there project they might rethink there design to maximise the potential output. in my opinion , most coil to magnet relations are off kilter , there is so much missing in coil, and magnet size, thickness and placement that I would guess about 35% of every one iv seen can be improved at least 20-40% if only they checked the lines of flux before assembly , things could have been moved around at the vary least to improve output. the speed the magnet moves across the coils is a major factor and might be the most important factor to try to control, this DOSE NOT mean shaft rpm, this means surface speed of the magnets. the easiest way is the diameter of the stator and rotor assembly, the larger the higher the surface speed will be. if you check a car alt you will find a surface speed of about 314 fpm, and a 36"hawt speed of about 2826 fpm at 300 rpm on a direct drive system. one can see the importance of diameter quickly. as speed and power production increase the lines of flux start to have a lag effect happen from the eddie currents and to many magnets will increase this problem, magnet placement can be one of the hardest factors to get right. most like me will be stuck using the trial and error way, the lucky ones use a scope to track every pulse and wave form. iv hade good results using .75% the coils as compaired to magnets or less in some cases, I have tried more on a couple units and always had a decrease in production, so I stick to .75% as my number . the placement will effect the time the magnets meet the coils for each of the three phases, this is a VARY important factor and might dictate a slightly staggered pattern, if this happens you will have to stagger the coils with the magnets for each phase for things to match but will net more output and cleaner power with less stator heat . on the alt type its common to see or here to angle the magnets, this can also work in other systems. turning the magnets to different angles has worked for me on several units built, not only the car alt,s. im not a big fan of using a core and especially not to transfer a south pole to the side of an adjacent magnet, it is instant cogging and counter productive for a direct drive type wind mill. I would like to build a alt type gen one day completely metal free except the magnets and copper to see the output difference, I would be willing to bet it doubles or close to it. also the bigger coils need bigger magnets as most all know, but vary few seem to know that smaller coils need smaller magnets too. this dosnt seem to be proportional from my findings but you don't use a 2"x2"x1" magnet with a 6oz coil, if you do you will produce a lot of smoke and vary little output. size matching is vary important and can only be learned by testing and recording the results, testing can use up 85% of project time but has always netted me a lot better output numbers and at lower rpm in most cases. the magnet and coils must relate to each other in so many ways, size-thickness-wire size- shape-location on the stator-winding orientation-magnet size lines of flux-gausses-angles mounted. magnets and coils are the only two items that produce the power so spend all the time on them, the rest don't matter if these two items don't relate. thanks for reading.
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flux off,
placing it right
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