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Author Topic: The Bucking Magnet Motor  (Read 219035 times)

z.monkey

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Re: The Bucking Magnet Motor
« Reply #60 on: February 28, 2011, 02:37:05 AM »
Howdy LC,

Yeah, using a hand drill for these holes and taps because I don't have a way to clamp the part under my mini mill.  Also I have generally used a hand drill for taps and unibits previously.

About the balance thing, there is a bit of the tap in there to make up the difference, and I also included as much of the screw as I could...

I used epoxy instead of gorilla glue on 2 magnets.

This is a tricky thing about the balance, there are many angles and holes.  But the majority of the mass is very light and the heavy (dense) parts are the magnets and the screws around the periphery.  This will hopefully mitigate my dimensional and density infractions, but also act as a flywheel.

I can already see that I'll be making more of these, and it may take several revisions to get it right...

Make it perfect on the first try?

I have yet to do that ever...

But Revision A is generally production worthy...

So, got all the magnets installed on the Stator today...

Making a movie, up in a bit...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #61 on: February 28, 2011, 02:48:50 AM »
Finished Stator Disk movie...

http://www.youtube.com/watch?v=M4UWZ29PWA4


z.monkey

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Re: The Bucking Magnet Motor
« Reply #62 on: February 28, 2011, 03:13:52 AM »

loosecannon

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Re: The Bucking Magnet Motor
« Reply #63 on: February 28, 2011, 06:55:49 AM »
well it looks absolutely beautiful!

at this point, if the epoxy seemed to be secure enough, i might just epoxy all the magnets on to the outer ring to save lots of time and frustration.

seems like those will be even more difficult than the inner ring was.

good luck!
LC

tbird

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Re: The Bucking Magnet Motor
« Reply #64 on: February 28, 2011, 01:48:02 PM »
hi z,

just a thought for your next build.  on the rotor, instead of tapping for the screws, why not just use a nut?  while the disk is on the rotating table for drilling out the excess weight, drill a hole under (1/8 to 1/4 inch should be enough meat to hold) each surface the magnets mount on.  then you can slide the nut in and screw together.  a drop of loctite (or a locknut) will keep it from going anywhere.

for the stator, five minute j b weld should hold the magnets nicely (no spinning force).  i use it to hold (no screws) my wind gen magnets to the rotor.  of course epoxy is also poured between and around each.  never had one come off.

also i noticed awhile back you called lexan and plexiglass the same thing.  they are not.  lexan is a polycarbonate resin thermoplastic.  plexiglass is  polymethyl methacrylate.  at this link...
 
http://bbs.homeshopmachinist.net/showthread.php?t=37175

the fellow gives some tips on how to machine it.  good read.

lexan is very strong.  it is used to make bullet proof windows (http://en.wikipedia.org/wiki/Bullet-proof_glass) i use it for my windows on my boat.  a bit pricey, but very good material.  holds up much better in the sun than plexiglass too.

keep up the good work!!

tom

z.monkey

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Re: The Bucking Magnet Motor
« Reply #65 on: February 28, 2011, 05:12:56 PM »
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

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Re: The Bucking Magnet Motor
« Reply #66 on: February 28, 2011, 06:46:24 PM »
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

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Re: The Bucking Magnet Motor
« Reply #67 on: February 28, 2011, 07:17:46 PM »
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

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Re: The Bucking Magnet Motor
« Reply #68 on: February 28, 2011, 07:56:24 PM »
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

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Re: The Bucking Magnet Motor
« Reply #69 on: March 01, 2011, 12:31:05 PM »
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...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #70 on: March 01, 2011, 12:37:15 PM »
I changed the drilling and tapping strategy a bit...

I was using a 110 mil pilot hole.  Really too tight for hard material.  So I backed off to a 123.5 mil pilot hole, and the tap is a lot happier.  Also limiting the depth of the pilot hole to 550 mils, and the tap to 500 mils.  The screw only goes into the hole about 250 mils.  So this is less stress on all the tools and me altogether.  In the Stator Disk, I was making full depth taps, to the limit of the tap.  Plus there were the weight relief cutouts that caused some problems.  I probably should have waited to drill those until after the magnet screw holes were cut...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #71 on: March 02, 2011, 02:48:29 AM »
Before I finish the Driver Ring, I needed to fix up the Driver Ring support pins.  Having a threaded bolt there is going to make for a difficult insertion of the Driver Ring.  So I needed some smooth rods to slide the Driver Ring on to the rest of the assembly.  These Pins are 1/4-20 x 3" bolts that have a 2" shank.  I sawed the bolt head off and rounded off the stub so they are pins.  Then the pins need to aligned so they are parallel, and square so the Driver Ring will move freely.  I fabricated some 800 mil spacers out of 1/4" inside diameter aluminum tubes, that I just happened to have as scraps...

Edit:  The spacers set the height of teh Driver Ring...
« Last Edit: March 02, 2011, 01:16:00 PM by z.monkey »

z.monkey

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Re: The Bucking Magnet Motor
« Reply #72 on: March 04, 2011, 05:01:19 AM »
I got all the holes and taps finished with no problems on the Driver Ring.  No tool breakage...

Assembled the driver ring, and gave it an initial test.  No Self-motoring so far...

broli

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Re: The Bucking Magnet Motor
« Reply #73 on: March 04, 2011, 06:53:32 AM »
I got all the holes and taps finished with no problems on the Driver Ring.  No tool breakage...

Assembled the driver ring, and gave it an initial test.  No Self-motoring so far...

Good job anyway! It's rare to see people create things from scratch but creating things is imo a fundamental human trait. There's very little that can compare to the pride of being able to say "I created that". Whether it would spin or not that machine is already full of your energy.

z.monkey

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Re: The Bucking Magnet Motor
« Reply #74 on: March 04, 2011, 01:16:49 PM »
Good job anyway!
While I appreciate your eloquent way of saying "It sure is pretty, but it don't work."...

Frankly were not done here yet.  A couple of weeks ago I decided to take the relief cuts down to the limits.  This created a lot of extra clearance between the magnets.  I just now finished machining it.  Haven't got a chance to study, refine, and balance it yet.  That is where the magic is.  There are 44 magnets in the UABMM and they form a balance.  When you have a stall condition all these forces are equaled and at rest.  Now, by adjusting the clearances I can slightly tilt that balance, hopefully enough to cause one transition, and then a cascade, and  I am hoping that will make it go...

It does kinda want to go.  Give it a push and it does run a few revs...

We just need to add some finesse, and PFM...

Sure is damn tired tho...
« Last Edit: March 04, 2011, 02:07:16 PM by z.monkey »