Super pole ?

[jeffpinto]

I have a six inch rotor with sharp north magnet sets (magnets side by side), just built a ten inch rotor with the super north config (ten magnet sets) 3.1 inches apart on center.
By comparison the sharp north field is much wider than the super north. The super north has such a tight and narrow field that I have figured that I can put the super north magnet sets as close as 2.1 inches apart on center (more magnets per rotor). I figure at 2.1 inches I still have a neutral zone of about 1/2 inch for switching. I am going to cut a another 10 inch wheel with 14 magnet sets. Anyone no any problems with my figuring? Any input is welcome

I will add that I did build a ten inch wheel with ten sharp north sets (side by side) 3.1 inches on center, it turned fine but there was barely a neutral zone, but it seemed to switch ok. did not get to test it on charging, could not get the magnets to stay put.

[BobZilla]

Hi Jeff,
No great words of wisdom here but your thinking is sound. The most important part regardless of your magnet pole configuration is to make sure you have that neutral zone as you have said. You seem to undersand that point already though.

A few things to consider about tightening up your spacing:

First you will be increasing your frequency by doing that (tightening up and adding more). It may be obvious but just understand that that will happen. As you experiment you will find that batteries will react in different ways to different frequency. It is a topic that could take up pages of comments but that is not the point here, just think about the effect and know it's there.

Second thing to consider is along with that increased frequency it will cause you to draw more current from your primary.

Neither of these things is good or bad, it depends on how you wish to run your machine. I am only mentioning it in case you had not thought of it and also for others who may be reading.

Good luck with your build,, post some pictures if you can.

[John_Koorn]

Hi Jeff,

I'm running a 22" bike wheel with 36 super pole North magnets on it. I don't have measurements on spacing at hand, but they're probably 2" apart or thereabouts. Runs beautifully.

I would recommend getting a bike wheel rather than cutting out a 10" rotor. The mass on the perimeter of the wheel really helps with the free spin time. Mine goes for about 52 minutes (from memory) without the coil mounted.

John K.