Homopolar Generators (N-Machine) by Bruce de Palma

[keithturtle]

Sorry about the big pic.  I cain't find the edit function to replace it with a smaller one.

If I covered the magnets' collective face with a piece of steel, would it exhibit the opposite polarity on the exposed face?

Turtle

[Magluvin]

I dont think so turtle. The plate would act as a path to the nearest opposite poles. 
May be better to get some large ferrite speaker magnets. Some large subwoofers use them.

Mags

[Magluvin]

Actually, for 100 bux you could get 2 of these bad boys
http://cgi.ebay.com/1-Pc-N42-4-ODx2-IDx-5-H-Neodymium-Ring-Magnet_W0QQitemZ310193542112QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4838f9d3e0


Mags

[CompuTutor]

Sorry about the big pic.  I cain't find the edit function to replace it with a smaller one.

Yeah, we have something like 12 hours to correct any errors,
then we loose the right to keep our posts up to date.

Sure wish that would get turned off (Hint, hint)...

I have already made posts here I'd like to update and/or correct
as I learn from those here that have been-there/done-that.

Sad they shall always be wrong
and may mislead others into following
my (Now known to be) faulty steps.

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Nice N42 strength ring magnet. 
2" hole leaves a lot uncovered though.

Here's a 1" ID (3" OD) N42 too for smaller discs.
http://cgi.ebay.com/1-Pc-N42-3-ODx1-IDx-5-H-Neodymium-Ring-Magnet_W0QQitemZ310193983552QQ

Or bringing it right down to a 1/4" shaft,
(For small toy DC motor projects)
and up to a 2" OD disc (At a low RPM).

http://cgi.ebay.com/2-Pcs-N42-2-ODx-25-IDx0-5-H-Neodymium-Rings_W0QQitemZ310193983379QQ

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I have been looking for a disc magnet
with the smallest hole / no hole
that matches a 3-1/2" hardrive disc's OD.

I have 5400 and 7200 rpm ones to play with.

They seem to have used a spot weld style machine
on the assembly line to embed a hardened ball bearing
into the end of the shaft.
And the grounded static dissipation finger
touching it is certainly overkill too.
They spot welded a hardened pad on it too.

So one contact is already fashioned with these test units.

I figure three roller bearings at the 1/3 points
around the edge of the hardrive platter's disc
on spring fingers with matching pressure
should provide three take off points to test with.

So if anyone finds the ideal magnet
to match these hardrive platters OD
please post a link for all of us to use.

Old hardrives are ubber-inexpensive,
They are all coated in conductive material,
they all have platters near identical in size,
and the motor + drive electronics are included.

That eliminates machinists costs for test units.

**************************************************

[keithturtle]

Actually, for 100 bux you could get 2 of these bad boys
http://cgi.ebay.com/1-Pc-N42-4-ODx2-IDx-5-H-Neodymium-Ring-Magnet_W0QQitemZ310193542112QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4838f9d3e0


Mags

32 turtlebucks from the supplier

http://www.magnet4less.com/product_info.php?cPath=1_13&products_id=221

But how big a field will it create? 4" dia?   I guess I'm thinking that the overall diameter has much to do with the output as far as voltage goes.

BTW- that soft-iron sheet that transformer laminations are made from- does anyone have experience with that stuff? 
A source?  Methinks it would be better than plain old sheet metal for to smooth out the eddies, no?

Turtle