The Bucking Magnet Motor

[z.monkey]

Thanks Y'all,

I want to get away from hardware and glue...

On the Driver Ring I am going to open the hole size up, to reduce the stress on the tap.  This will reduce the holding power of the screws, so I'll probably use epoxy also.  Neither one would be used in an industrial strength device.  I want to make the magnets press fit into groove, so that the stator is like one piece, no hardware, no glue.  This will require more precise machining, and I don't quite know how I am going to do it yet.

The reason I am tapping holes here is to eliminate at least some of the hardware (nuts), and use chemicals to eliminate other hardware (lock washers).  I don't feel like any glue is industrial strength.  It seems solid now, but later after stresses in test, the glue will develop a crack, and it will grow, and the glue joint will eventually fail at the worst possible time.  I don't want to experience FMOD.  Tbird, in your wind generator the magnets are potted into place, with the resin surrounding the magnets.  In my application there would only be a thin layer between the magnet and the Stator, much less holding power, which is why I feel screws are necessary.  But, I agree that I might be able to get away with using glue only on the outer Driver Disk that is not spinning, I'm still gonna put screws in there, because that is the design, that's the plan...

Tbird, do you have a website that shows off you wind generator?  Is it a Axial Flux Alternator?

My DiaMag6 Alternator is Sort of a hybrid between the Axial Flux and Radial Flux Alternators.  However, the result is not as efficient as I hoped it would be, it does produce current, and is sufficient for this proof-of-concept device.  I explain the idiosyncrasies of my hybrid alternator in the Dia Mag Alternator thread.

[tbird]

hi z,

i didn't mean to give you the idea to use glue on the rotor, only on the stator.  IBM did that on all their dc drive motors in their early model computers.  it works fine unless there is excessive (really hot!) heat or they get bumped hard on the outside, like being dropped on a concrete floor.  to add a little extra, after the positioning is set up (5 minutes), run a small bead on the underside overhang, both sides.  when using epoxy (this stuff is epoxy), too thin a layer does make the joint weaker.  giving it a nice bead to fill between the magnet and rotor will make you think it was welded (and should look like it too).  wooden boat builders (Gold Coast Yachts, st croix) will allow up to 1/4 inch gap in their carpentry (joints, been there, seen that) without worry when filling with epoxy and suitable filler.

on the rotor, i think the bolts are the best.  nuts just cut down on a lot of tedious,  tender, intent labor.  with your mill, cutting slots (rather than drilling holes) would be easy and provide a good nest for the nuts.

if you still feel you must tap the holes, buy a set of 3 taps.  the sizes are progressively larger.  this lets you start small and work your way up.  not as big of a load each time, but takes 3 times to get 1 finished.  even with this set, i would make this a hand job.  if you were able to chuck the tap up in the mill, i could see wanting to do that.  doing it with a hand drill seems to be asking for trouble, to me.  i assume the hole is deep enough that you don't have to get a special "bottom tap", right?

i don't have a website.  i bought a kit from ed at windstuffnow.com.  here is the assy. instructions which will give you a pretty good idea of what i did.

http://www.windstuffnow.com/turbine%20kit.pdf

tom

ps  magnets are brittle.  be careful when trying to press them into something they don't want to go into.  also, they don't like too much heat either.

[z.monkey]

Your Wind Generator looks a lot like Other Power's design...

http://www.otherpower.com/trips1.html

They build the coolest stuff out of junk...

[tbird]

i think the design is real close to the same.  the magnets in ed's are made for the round rotor disk.  they are not rectangular.  it is for my boat, so i opted for lighter and cleaner, plus he had it on the shelf.  maybe a little more money, but worth it to me.

tom

[z.monkey]

Look at this goofy thing. This is the right angle chuck I got to do the inside drilling and tapping...

It looks funny, and was awkward trying to use it the first time, but I am getting used to it...