Open Question:

[CaptainPatent]

Neodymium Magnets - What is the best place to get mags for the least amount of money which produce a large enough magnetic field to make a viable rotor?

I have access to hard drive magnets, but I've quickly found they are polarized through the length and not through the thickness so they are absolutely not viable. I was wondering if there was another bulk or 2nd hand source.

Also - if board members don't mind me asking, what did you spend on your Neo Mags and for what dimensions? I know the price has trippled in the past few years so in many cases it will be apples-to-oranges, but I'm still curious.

[Flux]

HD magnets are polarised through the thickness. What is confusing you is that there are a pair on a steel backing plate to make one half N and the other half S. many people use them by breaking the neo bits free from the steel backing or use them as they are but their close spacing of the poles is not ideal .

in view of the price of neo, if you can't manage with HD magnets you can still build a working machine with ferrite blocks. it will be big and heavy but will compete with HD magnets unless you have a large quantity of them.

Much depends on how vitally you need the power, if it is a hobby it is quite different from being reliant on wind power in a remote place. If you really need the power the cost of neo is easier to justify.

Flux

[CaptainPatent]

I actually intend to build a smaller hobby mill at some point and if I get enough of the kinks worked out of fabrication, I may move to a much larger scale. I would like to minimize price wherever possible and I'm trying to figure out either cheap ways to obtain mags or better ways to transmit flux in the system to increase output with smaller mags.

Also - why is there such a lack of using ferrite cores in the windings? If you can decrease distance between mags with a laminated ferrite core, wouldn't you need smaller mags overall in order to produce the same flux and thus produce the same amount of output power? Couldn't you also produce more power with the same mags in a lammed core setup if you compensated by winding thicker wire for the higher amperage and reinforced the stators to compensate for the additional pull force? [Edit] - oh yeah - and of course larger blades to overcome the added cogging of the system.

With the HD mags, I'll have to take another look at the one I peeled from the steel backing. I thought that one was through the length, but maybe that was the one still on the steel backing. I'm pretty sure it was 1 piece though.

[jlt]

I have noticed The price of neo's are coming back down . Applied Magnets are showing 2x1x.5 around 8 bucks.
They were 14 bucks last month.

       The 6ft design By Hugh Piggot  only uses 8 mags .An even cheaper solution would be to use a ECM motor.

              JLT 

[electrondady1]

as flux has said there are two poles on each hd mag.
if you score them and snap them or if you cut them with a tile saw you get a conventional mag .
 but for the most part i found  a different size and thickness of magnet from each manufacturer.
this becomes problematic when trying to stack magnets or form larger  poles.

if you have a good source and don't mind spending the time  the price is right .
 

 

[ghurd]

Not ALL HD magnets have 2 poles on the same side, but almost all do.

If you have a lot of HD neos, there are several builds on thise forum that worked out well.

If you have a few left over, pretty easy (and very fun) to make a tiny functional PMA.
( http://www.otherpower.com/images/scimages/2050/3phHD.jpg )

There is a tiny neo in the voice coil plastic too.
Easy to get out, handy for other things. Sensors, fridge magnets, etc.
G-