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Author Topic: The Bucking Magnet Motor  (Read 219007 times)

z.monkey

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Re: The Bucking Magnet Motor
« Reply #75 on: March 04, 2011, 01:27:28 PM »
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...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #76 on: March 05, 2011, 03:06:09 PM »
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...
Point of reference is key.  Where is neutral?  What is a slight tilt?

This design is very wrong.  Now that I have a slight bit of experience with the actual device, albeit non-functional, I can look at it from many different angles.  The cants are way too aggressive, and the clearance is way too big.  Side currents (eddy currents) from the magnets are latching the magnets between each push.  The cants need to be slightly off balance, and I swung them over to 45 degrees.  LOL!  Well, hey, its my first magnet motor...

Need to let this fester in my brain some more.  I think it will get better with time, like sharp white cheddar.  So, I am thinking the balance reference for the cants is 0 degrees, directly facing each other, so there is no vector of movement.  A slight tilt would be 5 to 10 degrees (not 45).  Then the clearance on this one is a couple hundred mills, and should be more like a tenth of that.  Reducing the cant angle will hep reduce the side current interference and magnet latching problem.  Then also getting the magnets close together should also help reduce the side currents.

So the current UABMM is scrap, unusable.  This means UABMM2 is in the works.  The plate of Aluminum that I used to make the UABMM is $10, so material cost is pretty low.  But its also the part that has the most labor, so it costs the most really.  So, now with one built, having figured out the nuances, a second one will probably take two full days of machine time.  Plus all the magnets and hardware are reusable.  This will also give me a chance to make the Driver Ring mounting system better...

Awesomes...

loosecannon

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Re: The Bucking Magnet Motor
« Reply #77 on: March 06, 2011, 07:26:33 AM »
a valiant effort indeed Z monkey.

im wondering if your current model could be modified to be a "testbed" of sorts for other magnet angles and such.

you could fab a bunch of small brackets that would allow you to mount magnets at different angles, then mount those brackets on top of your outer ring.
then you could raise the inner ring up to line up with the magnets on the outer ring.

not sure if your inner ring is useable or not, but the same idea could be applied to it.

this way, your assembly is modular and you can get much more experimentation out of a single build.

just an idea.
LC

z.monkey

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Re: The Bucking Magnet Motor
« Reply #78 on: March 06, 2011, 10:57:22 AM »
you could fab a bunch of small brackets that would allow you to mount magnets at different angles...
Variable cants?  Not a bad idea, for experimentation, and for practical use.  There needs to be a way to "throttle" the motor.  Not just for use but also for stand by.  How do we turn it off?  Pull the driver ring?  Not very practical.  I thought about using a shaft mounted brake, but that makes heat, not good for magnets.  So the other idea was to swing the magnets out of each others influence.

Well, yes this is a good idea, but we are talking about 24 magnets on the driver and another 20 on the stator.  That is a lot of brackets.  And then if we wanted to synchronize those there are more pieces to be fabricated.  Like another ring which has a slot for each magnet.  Each magnet bracket has a pin which fits in the ring slots.  As the ring turns it alters the cants of the magnets, similar to an iris mechanism.  The ring then could be connected to a linear actuator, like a lever, which could be used as a throttle.  So, when we want the motor to go, we push the lever, which pushes the magnets into place, and the motor is in a run condition.  Then pull the lever to pull the magnets out of alignment, stopping the motor.

Yes, good idea LC, but what it comes down to at the moment is labor.  It is probably going to be easier for me to make a new plate set, than it would be to  design and fabricate 44 brackets.  But the idea is definitely something to think about in future designs.  Look at what some others have done to stop their magnet motors.  Perendev uses the "clamshelled" driver ring, and also tried pins.  Yildiz uses plate sections that have to be unscrewed and removed one at a time.  These are not very practical.  It works for an experiment, but not simple enough for everyday use.  Lutec's device is a mystery to me, and appears to be electromagnetic, so they are probably using electronic controls to throttle it...

Thanks, good idea...

tbird

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Re: The Bucking Magnet Motor
« Reply #79 on: March 06, 2011, 01:19:32 PM »
hi z,

those brackets can be made fast and easy.  think decorative aluminum angle.  size to suit your needs.  mark spacing (unless you have a nice ruler on the mill), set up in mill vice and drill magnet mounting holes.  same for bracket mounting holes.  once drilled, set in miter box, with stop for length.  hack saw will make short work of separating the pieces and keep things square.

mount your rotor in the rotating table and score a line at the distance from the edge you want the brackets mounted.  same for drive ring.  you could use degrees or the points (formed by the previous machining) for distance between mounting holes, which can be tapped (easier than the first job).  since the angle alu. will be a bit thin, you may have to use a nut to hold the magnet on the bracket. 

there will be 4 magnets that you can't mount this way because of the guide pins & holes.  consider tapping the ends of those pins.  it looks like it might be a good distance (from outer edge of ring) to use as a reference for all drive ring brackets.  just turn the angle bracket 180 degrees and mount on top of pin.

i may not have covered all or been clear enough, but you are very handy when it comes to working your machine.  i'm sure you'll get the details right.

btw, it was just a thought.

tom

z.monkey

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Re: The Bucking Magnet Motor
« Reply #80 on: March 06, 2011, 02:12:48 PM »
Howdy tbird,

I see what you mean about the "L" brackets.  The variable cants would really help development.  I am going to leave the corners on the new plate set, and move the driver ring mounting points to the corners.  So, we can add a cant adjustment to those last four magnets on the driver ring...

I'm working on a drawing now...
« Last Edit: March 06, 2011, 02:33:16 PM by z.monkey »

tbird

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Re: The Bucking Magnet Motor
« Reply #81 on: March 06, 2011, 03:31:34 PM »
this is my version of a "tbird".

tom

z.monkey

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Re: The Bucking Magnet Motor
« Reply #82 on: March 06, 2011, 04:23:47 PM »
That looks a lot more fun than mine...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #83 on: March 07, 2011, 06:21:57 PM »
So, I am thinking the balance reference for the cants is 0 degrees, directly facing each other, so there is no vector of movement.  A slight tilt would be 5 to 10 degrees (not 45)
Where is Neutral?

I forget that we're dealing with a circular object here.  Neutral is not perpendicular to the vertical axis through the center of the stator disk.  I did some doodling to see what is going on here.  If I adjust the cant to what I was thinking was the Neutral position, it is actually canted in the wrong direction (negative cant).  Were dealing with a radius so the neutral position has to be parallel with the radius.  So I measured what angle I needed to make the magnet sit flat on the radius, and that is about 7 degrees.  This means that my angles on the first UABMM are around 38 degrees and not 45 degrees, it is off set from the Neutral Position, and not relative to the vertical axis through the center of the stator disk...

I am experimenting with cant angles for the new UABMM2.  I will also probably be changing the magnet spacing and the number of magnets.  The first experiment threw a whole bunch of new variables into the equation.  Before I draw UABMM2, I need to get all these new variables worked into the puzzle...

The Neutral position of the magnets is relative to the radius of the stator.  The larger the radius of the stator the smaller the Neutral Position offset, and the smaller the radius of the stator the larger the Neutral Position offset...
« Last Edit: March 07, 2011, 07:25:11 PM by z.monkey »

z.monkey

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Re: The Bucking Magnet Motor
« Reply #84 on: March 08, 2011, 10:49:07 PM »
OK,

Made the drawing, got a couple more motor plates on order...

Also ordered the Palmgren Milling Table.  I got a deal on it too.  I've kinda been waiting on the right incentive.  So, today MSC sent me a 30% web coupon for orders over $199.  Just what I've been waiting for.  The Milling table was $315, and I get 30% off, so I paid $220, awesomes...  The best American table for about the price of the import...

I'm ready to mark up a plate, and get back to shredding metal...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #85 on: March 10, 2011, 02:59:36 AM »
Remember that whole, sloppy, cross slide table problem?

Yeah, ain't got that no moerz...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #86 on: March 18, 2011, 03:11:49 AM »
Getting a new machine table gives me an excuse to upgrade some other things...

I was clamping the Drill Press to the table with some bar clamps.  I drilled some 1/2" holes in the bench to clamp the Drill Press base with some 1/2" machine screws.

Then I clamped the Palmgren Table to the Drill Press Table with some C-Clamps, temporarily, so I can cut the holes in the adapter plate which will attach the Palmgren Table to the Drill Press Table.  There are a set of mounting points on the Palmgen Table which are a bit larger than the mounting points on the Drill Press Table.  I have a spare piece of 1/2" thick aluminum plate which is just right to join the two.  I marked up the plate and put the pilot holes in it using the temporarily mounted Palmgren Table.  Then worked them to size with a Unibit in a Hand Drill.

I need to get a 45 degree, 1/2" countersink so that I can make the bolt heads flush.  Then I can mount the new table on the drill press.  I really need to get a larger drill press so that I can utilize the full range of the new table, but for what I need to do right now, I've got plenty of space...

Its like Mini-Mill 2.0...

broli

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Re: The Bucking Magnet Motor
« Reply #87 on: March 18, 2011, 06:51:12 AM »
Nice upgrade man, but It's best you make something lovely with it for the wife (if there is one) first before attempting FE, or else it will come back to bite you in the ass big time ;D .

z.monkey

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Re: The Bucking Magnet Motor
« Reply #88 on: March 18, 2011, 10:48:41 AM »
Nice upgrade man, but It's best you make something lovely with it for the wife (if there is one) first before attempting FE, or else it will come back to bite you in the ass big time ;D .
She said "That's pretty"...
Its my motivation to make "pretty" bits of billet.  Every piece nets the same response...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #89 on: March 21, 2011, 01:21:47 AM »
I got a Countersink bit on order Friday.  Couldn't find one local...
The head of the bolt is 7/8", and the biggest bit I found here was 3/4".
Should have a the new countersink on Tuesday.

In the meanwhile, I got the Table set up for the countersink process.
I've got extra clamps in there because I've never made a 7/8" cut in
a chunk of AMS-4027, so kinda don't know what to expect with the
new table and all...

Another shot of why I need an adapter plate...

Edit:  BTW it'sa 90 degree countersink, was looking at axial angle, and not tip angle...
« Last Edit: March 21, 2011, 01:43:23 AM by z.monkey »