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Author Topic: The Bucking Magnet Motor  (Read 218986 times)

nievesoliveras

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Re: The Bucking Magnet Motor
« Reply #30 on: October 11, 2010, 01:47:21 AM »
Thank you @thaelin. Thank you @zmonkey.

z.monkey

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Re: The Bucking Magnet Motor
« Reply #31 on: December 22, 2010, 03:03:03 AM »

Arthurs

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Re: The Bucking Magnet Motor
« Reply #32 on: January 06, 2011, 12:33:32 AM »
The result? Look forward to! ! !

z.monkey

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Re: The Bucking Magnet Motor
« Reply #33 on: January 18, 2011, 12:46:33 PM »
Pardon the delay, I have been having machine troubles...

My milling table suffered a breakdown.  Its a cross slide table, so there is hardware that moves the table.  The table screws have a keeper point which is on the moving table part, and a reference mounting point which is fixed to the base.  The reference mounting point is basically a nut.  The keeper is a rotating joint which determines the alignment of the table along the axis of the positioning screw.  The original hardware that was this keeper, rotating joint was eroding very quickly.  This resulted in a very large amount of lash on the positioning screws.  The more I used the tool, the greater the lash became, making it more difficult to use the tool, and would ultimately cause mechanical failure...

So, whats to do?  Buy a new, better quality table?  $300?  Nah...  Buy another same quality table and use it until it fails, then toss it?  Nah...  Its a cool table, I like it.  We should use scrapyard ingenuity to make it betters...

I had to let this fester in my brain to figure out the right materials.  I ultimately used some scrap iron hanging around in the shop.  I didn't have enough room inside the existing table to add the shaft collars, so I had to extend the keepers outside of the tables.  The iron scraps that I found had some existing holes that could be utilized.  I cut the pieces into appropriate lengths, and added more holes as needed.  Then bolted everything together with 3/8 inch machine screws.  The shaft collars mount on the screw shaft on both sides of the new keepers.  This improved the linear lash considerably.  I am also going to add thrust bearings on both sides of the new keepers.  I want to keep everything happy around the new keepers...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #34 on: February 09, 2011, 07:43:34 PM »
I  got a snow day, so I am starting to mill the UABMM plate.

I am using 2x4 for a sacrificial block.  The center of the plate is bolted to the 2x4 block.  Then the 2x4 block clamps into the cross slide vise.  I align each cant (magnet cutout) with the table edge, and then use the cross slides on the table to work down the cant.  After the cant is cut out I rotate the plate to the next cant position, and do it again.  This is going a lot faster than I expected.  I am cutting everything about 30 to 50 mils wide so I can finish them very precisely with a file.  I want to keep the clearances tight in the cants...

« Last Edit: February 09, 2011, 11:55:24 PM by z.monkey »

z.monkey

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Re: The Bucking Magnet Motor
« Reply #35 on: February 09, 2011, 08:04:24 PM »
Making chips...

Got any salsa?

z.monkey

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Re: The Bucking Magnet Motor
« Reply #36 on: February 09, 2011, 10:43:42 PM »
So, in around 3 hours I got more than half way around...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #37 on: February 10, 2011, 12:29:47 PM »
OK, now the driver ring is cutout.  Next we go 'round again and cut the stator disk.  Next step on the driver ring is to file down the cants and reliefs.  Then I need to drill holes for the screws that secure the magnets.  Then also tap the holes for the magnets.  I am going to use a #6-32 countersunk screw to secure the magnets to the driver ring and the stator disk.  Don't forget the Loctite when doing the final assembly.  The NIB magnets are a K&J Part Number B884DCS...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #38 on: February 12, 2011, 02:20:00 PM »
OK, got the driver ring cleaned up and fitted on the DiaMag6...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #39 on: February 13, 2011, 01:54:10 AM »
Working down the stator disk now...

broli

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Re: The Bucking Magnet Motor
« Reply #40 on: February 13, 2011, 11:10:16 AM »
This is what should define this forum, great progress. It's rare to see the evolution of an idea beyond words on this forum but this thread is a good example of it.

As for the build, is there a reason you went for aluminum and not say plexiglass or so.

z.monkey

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Re: The Bucking Magnet Motor
« Reply #41 on: February 13, 2011, 12:44:53 PM »
As for the build, is there a reason you went for aluminum and not say plexiglass or so.
Lexan (Plexiglass) cracks easy when you drill it.  A Lexan panel would have to be laser milled, and you can't make threads with a laser.  Wood is too soft, can't make the dimensional tolerances.  I need light weight and rigid which aluminum does well.  Also this is not general aluminum, its an alloy designed for use in aircraft.  This alloy (AMS4027) exceptionally light and rigid.  It has traces of Magnesium, Silicon, Copper, and Chromium in it.  So, in the end having rigid pieces and maintaining dimensional tolerances is my motivation for using this particular alloy.  It wouldn't make a very good motor if it was all floppy, and prone to cracking.  Iron (Steel) is another exceptionally rigid material, but it is ferrous, and I didn't want to throw another magnetic variable in there...

Another note on Vertical Milling.  The cross slide table that I am using is pretty floppy.  It doesn't do side cutting very well, lots of buffeting due to slop in the cross slides.  So, I had to resort to using Vertical Miliing, which is similar to drilling, except we're using a mill instead of a drill, and we have the precision positioning capability of the cross slide table.  I am positioning the table, then milling a hole.  Then I move the table about 80 mils, and cut the next hole which overlaps the first hole, cutting the webs that would normally separate two side by side holes.  You can't do that with a drill bit, held by hand.  Basically I have realized that I need a way better table.  Looking at a Palmgren table now...

http://www.palmgren.com/compound-milling-table-18-in-mtc18/

With an actual Milling Table I can do way mo-betta side cutting, which is a lot faster.  It all is dependent on the stability of the mount.  If your mount is floppy then you are going to get a lot of buffeting which makes butt ugly cuts.  With a rock solid mount all the energy of the mill is exerted on the cut, which makes nice clean, fine cuts.  It makes the process a lot cleaner, and faster, albeit you have to spend mo bux on the tool...

Buying high quality tools is always worth it in the end.  All the frustration that I have suffered with the current cross slide table could have been avoided if I had bought a better table in the beginning.  Granted this table is about 4 times as expensive.  That more than makes up for having to redesign the current table, and all the angst associated with it...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #42 on: February 13, 2011, 09:31:11 PM »
Just finished the rough cut on the stator disk.  Now I need to clean it up, drill the center hole out to 3/8" for the shaft arbor, and drill some weight relief holes...

z.monkey

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Re: The Bucking Magnet Motor
« Reply #43 on: February 14, 2011, 02:45:38 AM »
OK, good progress this week.  The UABMM has been fabricated.  I got the stator cleaned up and all the holes punched.  When I was finally done the stator was very warm, and felt soothing on my tired hands.  I was able to make all the cuts amazingly close to the markings on this one.  Maximum finished tolerance on the cants is conservatively close at around +/- 10 mils.  I'll spend a couple of days measuring, and verifying, but I am sure this is the most precise piece of metal (stator disk) I have ever fabricated.  Then I fitted everything together, and it is totally sweet...

Looks like I need to get some magnets on order...

Woot!~>  \m/___(0.o)___\m/

broli

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Re: The Bucking Magnet Motor
« Reply #44 on: February 14, 2011, 07:45:27 PM »
Congrats, I bet all the crap you endured was worth it. Irregardless of working or not, you have gained a huge amount of experience and knowledge that no armchair could ever give  :P .