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Author Topic: Dia. Mag. Alternator  (Read 190897 times)

z.monkey

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Re: Dia. Mag. Alternator
« Reply #45 on: July 08, 2010, 02:48:47 AM »
New core blocks, 0.5 inch by 0.5 inch and 0.870 +/- 0.01 inch...
The Z Axis tolerances were a lot more difficult.  I botched a couple
of blocks drilling the hole in them.  First get the block square and
plumb, then drill the hole.  Don't try and punch one side part way
and then reposition the part and find the original hole.  It just doesn't
work.  After working out the Z Axis idiosyncrasies, then I managed to
get the core blocks to fit.  Also using countersunk screws in the blocks
so there is no interference in the windings...
 

z.monkey

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Re: Dia. Mag. Alternator
« Reply #46 on: July 09, 2010, 01:27:40 PM »
OK, I got the mechanical parts assembled, with some caveats...

I was banking on the "Auto-Motoring" aspect.  Well, when we add the large blocks of steel between the magnets it tends to focus the lines of force through the blocks.  The auto-motoring still occurs but only at the very end of the 180 degree turn (flipping the poles).  When the magnets are side by side the auto-motoring magnet motors very smoothly (except for a little crossover distortion) with the driver magnet.  So with large cores in there, which are necessary for the coils, we can't rely on auto motoring, and are going to have to fall back to using gears.

A three gear setup will turn the magnets in the same way that they would auto-motor.  While this is a simple change it requires a lot of rework.  The shafts have to be lengthened to accommodate the gears.  I have to find the right size gears, and if not may need to build new end plates to accommodate the kind of gears that I can find.  Chances are that I won't be able to find the right size gear with two different size shaft holes.  So this brings up another topic which is using equal size magnets in all three positions.

Currently I have a 3/4 inch outside diameter driver magnet and the auto-motoring magnets are 5/8 inch.  The shaft on the driver is 1/4 inch, and the shaft on the auto-motoring magnet is 1/8 inch.  This means I need two different shaft sizes and two different bearing sizes.  This is problematic, in that there is a lot of extra re-calculating to design and build the end plates.  So by using equal magnets in all three positions I can streamline the redesign process.

Also, still not happy with my dimensional tolerances.  You don't really see the errors until you assemble it.  Then the lines don't quite go parallel, or its a bit twisted.  Just something that makes it look "off".  With this next set of plates I am have some mechanical assistance in making the measurements, hopefully.  I'm going to get a Bitmoore Vice to help with the positioning.  These things are neat, check it out...

http://www.harborfreight.com/5-inch-drill-press-milling-vise-94276.html

Then, at the end of the assembly process, I managed to drop the assembly on its corner (bottom picture) and bent it.  At the moment I am not worried about correcting it.  This one is never going to get wound.  Its got too many errors.  I need to lengthen the shafts to add gears.  Also need to change the magnet and shaft sizes for the outer (new name instead of auto-motoring) magnets.  This requires that I design and fabricate new end plates.  I can salvage the core blocks and structural hardware because the length of the assembly can stay the same.

Oh, also, forgot to mention the banana end plate.  When I had add the cores and magnets on only one end plate it curled like a banana.  I was able to stretch in back by adding the second end plate.  So, anyway, gonna need thicker end plates.  These magnets have big forces, and are not easy to work with, especially three at once.  The larger blocks helped this process.  The magnets are gonna stick to the largest ferrous mass they can find, in this case the core blocks.  This was easier with the core blocks in close proximity.  Before, on Diamag 2, the screws had wider clearances, which put the magnets further away from the target holes, more difficult to stab...

So, anyway, feeling sorta melancholy about this right now.  It was big work to get here, and it looks like there is bigger work on the horizon.  I'm just forkin' glad its Friday...

z.monkey

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Re: Dia. Mag. Alternator
« Reply #47 on: July 21, 2010, 12:14:54 PM »
Mk1, I'm gonna integrate the transformer lamination idea also...

But, although I have plenty of large transformers, there are none that would incorporate my design cleanly.  So what to do?  DIY, duh.  Look at the stack of Iron sheets below.  It's taken two days to cut the laminations so far, and their still solid.  Gonna need lots of holes too...

I have been picking holes in my older designs (Diamag 3).  I think I can still get the automotoring to work, but there needs to be a lot more Iron in the core.  On Diamag 3 the magnets are attracted to the little (1/2 inch) blocks.  So, even with only one magnet in there it is motoring on the blocks, meaning the poles are attracted to the metal, and want to stay oriented that way.  This makes the shaft hard to turn, unnecessary polarization.  The magnets need that attraction all the way around their path, so the core needs to completely surround the magnets.  This adds flux paths between the magnets, and I am hoping that it will allow them the automotor again.

I really do not want to put gears on this thing.  You will be shocked at the pricing.  Tiny little gears, off the shelf, are like $20 each.  Custom gears, made to order, in small quantities are like $100 each.  So, yeah, don't wanna put gears on it if I don't have to...

So, back to the holes.  Got some new toys.  I picked up the Bitmoore Vice and a Drill Press at Harbor Freight.  Also got a drill index with 115 bits.  I am still cutting laminations and bearing plates.  The plan is to stack up all the laminations and bearing plates, in order, and cut the main holes all at once.  This way we can get superior alignment and squareness.  I don't see any rigidity problems with a solid Iron core, but we want to make sure it all comes together nice and square.  So I plan on cutting tooling holes in the stack first.  Then remove the stack from the vice, and bolt it all together with countersinking screws in a piece of wood from the back side.  The area where the tooling holes are will later be removed for the winding slots.  Then after we drill all the pilot holes in the stack we can work on each individual layer to make the large holes for the magnets (1.125 inch) and the bearing plates (0.625 inch), and the winding slots.

The bearing plates will be 1.25 inches square and hold the individual magnets.  In this new design the bearing plates allow each magnet to be removed without disturbing the rest of the assembly.  On the Diamag 3 design once you put the windings on it, there is no more reworking.  You would have to unwind the coils to take it apart, not user friendly.  So on the new one (Diamag 6) each magnet and shaft have their own set of bearing plates.  They also have new bearings.  Before I was using punky little bearings from Mike's Hobbies.  The ball bearings are like 1/32 inch, punky...  The new bearings are a Dayton part, from Grainger, and a load rated at 335 pounds, so no problems there.  New magnets also, moving up to a 1 inch diameter Neo-Dia-Mag, K&J Magnetics part number RX04X0DIA...

So, my previous prediction of bigger work on the horizon is true.  Cutting those steel plates is a lot of work.  I'm sawing straighter lines now anyway...

Mk1

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Re: Dia. Mag. Alternator
« Reply #48 on: July 22, 2010, 01:52:33 AM »
@Z

Nice tools ! I like the way you work !


z.monkey

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Re: Dia. Mag. Alternator
« Reply #49 on: July 22, 2010, 02:00:22 AM »
Diamag 6
The Stack

I had to cut a few more plates this morning.  Then I was able to assemble "The Stack".  I used clamping on three axis' to hold the stack of plates still while I drilled the tooling holes.  1/4-20 countersunk machine screws hold all the plates together in the Z axis for the precision cuts.  The X axis is held by the machine vice.  I am going to let the combination secure the Y axis, but if it doesn't feel right I'll add the large wood clamp also.

Also, clearance, just barely enough.  I was worried about the Z axis clearance between the drill bit, in the resting position, and the top of the stack.  I have about 3/16 inch.  really close.  My original plan would not have worked.  I realized it was a problem when I assembled the drill press and put the Bitmoore vice on it...

So, you know, spin control...

Charlie_V

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Re: Dia. Mag. Alternator
« Reply #50 on: July 23, 2010, 04:04:46 AM »
I find that if the coil diameter matches close to the diameter of the magnet, you'll get the most voltage per change. Smaller wire doesn't always help either (especially for a generator) since the smaller wire size greatly increases the wire resistance. 

I looked at the magnet focusing patent, that's just a form of halbech array.

z.monkey

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Re: Dia. Mag. Alternator
« Reply #51 on: July 23, 2010, 12:05:34 PM »
The core size is equal to the magnet diameter now, 1 inch.

This idea came about after studying axial flux alternators.  There are magnets on both sides of the coils.  A traditional alternator only has a magnet on the inside of the coils, nothing on the outside.  Then also I was curious about the diametrically magnetized magnets.  So trying to build a simple representation of the idea I simplified and miniaturized the concept and here we are.  It is relatively simple compared to either a automotive alternator or a axial flux alternator, but the same concept.  I really have never looked into a Halbeck Array, need to give it a look see...

Charlie_V

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Re: Dia. Mag. Alternator
« Reply #52 on: July 23, 2010, 02:51:58 PM »
Halbech arrays just increase the magnetic field in one direction and suppress the field in another.  So you can make the north pole almost double in strength while reducing the south pole to almost nothing.

giantkiller

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Re: Dia. Mag. Alternator
« Reply #53 on: July 24, 2010, 06:55:47 PM »
An addendum:
The diamagnetic configuration aligns this config with magnetic shearing, same as Bedini.
The Patent 5,929,732 has its poles opposite side of the axis instead of on the opposite sides of the diameter or cylinder.

z.monkey

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Re: Dia. Mag. Alternator
« Reply #54 on: July 26, 2010, 01:08:43 PM »
I guess that adds some credence to my design.  LOL!

Here's is a shot right before the first cut.
I am really happy with the Bitmoore vise.
My dimensional tolerances are better than ever...

z.monkey

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Re: Dia. Mag. Alternator
« Reply #55 on: July 30, 2010, 01:34:04 PM »
I made a lot of holes this week.  Gonna make some more too...

This is the stack with a lot of pilot holes in it.  The center three holes are for the magnets, and will get bored out to 1.125 inches.  The piece of wood with the bolts sticking out of it is the jig for boring the large holes.  I'll take each plate from the stack and bolt it to the jig.  Then clamp the jig in a vise.  Then use a uni-bit to widen to 1/4 inch pilot holes to 1.125 inches.  Then we have two more groups of holes for the bearing plates and for the stiffeners / mounting holes.  The bearing plates are designed to use 10-32 hardware (3/16 inch holes) and are on the perimeter of the magnet holes.  The stiffener and mounting holes use 1/4-20 hardware (1/4 inch holes) and are around the edge of the stack.  At the bottom of the picture are the new neo-dia-mags.  These are going to stay in their package, far away from the machine area until I am ready to do the final assembly.

I have had a problem with the neo-dia-mags picking up the machine dust and I cannot remove all of it.  I don't want the machine dust contaminating the rotating parts.  The plan is to finish machining the stack, and then coat the plates with a "laminate", in this case some clear epoxy spray paint I think will do it.  In addition to separating the plates the laminate is to seal the steel plates so they don't rust, and to cut down on the machine dust contamination.  The idea is to get all the parts into a finished state and then assemble the magnetic parts in a clean area which is far away from the machine shop.  I am still probably a week away from the final assembly.

This version is considerably more work and expense than I had planned.  I had estimated that to build an alternator like this would cost $200.  The magnets (3) for this version were $45, the bearings (6) were $60, the steel sheets (2.5) were about $20, and then the tooling cost (drill press, Bitmoore vise, drill index, and hand drill batteries) was around $360.  But labor is by far the greatest expense.  I have spent two weeks working on it so far, and its going to take another week, at least...

At least I'm not bored, hehe, get bored, lol, uulgh...

Mk1

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Re: Dia. Mag. Alternator
« Reply #56 on: July 30, 2010, 01:41:31 PM »
@Z

Nice work man !

I think however that you will find your self wishing for bigger pieces of metal there is not much room for the coil , once the magnets are in the core it self is a magnet , you can put the away a bit to have more wire.

But we will see , great work again!

Mark

z.monkey

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Re: Dia. Mag. Alternator
« Reply #57 on: August 11, 2010, 01:56:30 AM »
Thx Mk1!

This is boring...  hehe...

Finally got back to the metal shop today.  I had built a jig to bore the holes around 10 days ago.  Basically just a 2x4 that I planned to squeeze in the jaws of the Workmate.  So I experienced some slippage trying to bore the  magnet holes.  So I revised the jig to be a surface clamped device so that it would have support from the bottom.  The first two steel plates are a little funny, but after I got the jig stabilized, and a process figured out, then I starting boring some nice holes.  I have a couple extra plates in the stack.  I can adjust the spacing between the plates to use fewer plates and increase the magnetic conductivity between the plates until it is optimum.  I can adjust the holes as needed with the high speed micro grinder thingy...

Here are a few pics of the day...

z.monkey

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Re: Dia. Mag. Alternator
« Reply #58 on: August 13, 2010, 12:58:25 AM »
The boring part is over...

Now moving on to cutting the slots for the windings...

z.monkey

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Re: Dia. Mag. Alternator
« Reply #59 on: August 23, 2010, 01:03:16 PM »
This weekend was stellar.  Zen and the art of cutting steel.  Man it was hot too.  I mean the outside temperature, 104 F on Sunday.  I finished fitting the plates last Friday, and have been getting ready to cut the slots.  Each vertical slot took about 20 minutes to cut with a hacksaw.  Once I got these 8 cuts in I can take apart the stack and to the rout in the bottom of the slots.

This rout is the main reason I got the Bitmoore Vise.  I am using a 1/8 inch end/side mill to make the rout.  I take each individual plate and bolt it on the the large hole tooling jig that I used to bore the large diameter holes.  Then put the jig in the Bitmoore Vise.  We are doing this on the drill press, so the table is the Z Axis.  So I position the table to where the mill is just below the bottom of the plate, cutting into the wood a little.  Lock the table, Lock the Vise, tension the X and Y adjustment tables, then rout the slot.  I am still getting used to the process.  If you don't have all the things locked and tensioned the table will do funny things when you start to cut.  Also cutting to fast causes tension on the table and the spindle and the mill goes in funny directions.  But, once I figured out the quirks, then I started cutting some decent routs.  I am scratching a line in the steel with an hardened scribe, so the line is permanent.  I can cut right down the line, and leave the line there, within a few mils...

You can see below the first plate routs are kinda curvy.  This is moving too fast, and not knowing the quirks.  This is an outer plate, so that area will be filed down to form a chase for the wire.  From a side view the core will look like a square with round chamfered corners.  I don't want the windings on corners.  I am thinking about getting a radiused mill to do these chamfers.  Also, someday, I would like to do this whole operation on a mill.  An automated 3 Axis Mill could probably cut one of these plates in an hour, where it takes me weeks to do it with hand tools.