Homopolar Generators (N-Machine) by Bruce de Palma

[keithturtle]

Does anyone know what happened to Keith and his research?

Thanks for your interest.  Yeah, I'm still out here.  Got mixed up in a hydropower project, spent a whole year in that, and then the 100 year flood came and washed half of it away.  I still have the other half intact, so I'll use that dam design on the replacement side.   Fact is, you cannot build your house on sand, or your dam for that matter.  I hadn't had the time to purge the aggregate beneath and pump in cement before the big rains hit.

The Faraday disk is still on the workbench, waiting for more attention.   I bought some 1x1x4" bar ceramic magnets to create a field in and around a copper drum.  I was making good progress with my brass ends till I broke my last tap.   Something fundamentally wrong with my approach there, so it's sitting too.  Plan on using two sections of large copper gutter for the cylinder.

Life is getting in the way as well, as it always does.  No worries, I'll get back at it soon

Turtle, living up to the moniker

[tim123]

Hi Keith
  glad you're still around. I was enjoying your posts... The hydro thing sounds like a bit of a challenge...

On the HPG - i tend to agree with this, and it may prevent the design with many magnets from working:

One problem these things have is that the individual magnet fields need to merge into a single
pole face field....

What do you think?

Some links:
http://projectearth.com/ - Adam Trombly's website
http://projectearth.com/closed-path-homopolar-machine - Patent - Closed Path machine
http://projectearth.com/articles/21-homopolar-generator - An interview with him - not technical, but interesting

http://www.zamandayolculuk.com/Cetinbal/faradaydisk.htm - An analysis of the HPG - some useful info

Resonant unipolar generator
http://v3.espacenet.com/publicationDetails/originalDocument?CC=US&NR=7459823B1&KC=B1&FT=D&date=20081202&DB=EPODOC&locale=en_EP

Just reading this - it's *very* interesting too.

As I mentioned, I have a design I'd like to discuss with anyone interested - will post a diagram in a bit...

Regards, Tim

[Magluvin]

One problem these things have is that the individual magnet fields need to merge into a single
pole face field. If one simply sticks neodymium magnets to a metal disk the pole face is not unitary
and the face becomes a complex N/S pole mixture, with one pole squeezing through the other.
There is a youtube.com video where a person puts a plastic magnetic field diagnostic sheet
against a pole face configured in this way and the optical pattern shows that this occurs.
This simply means that a very low magnetic impedence return path (lower than free-space)
needs to be constructed so that only one pole transitions the gap between disks. Like a gaint
iron lamenent C. Experimenter's are loathe to create such a structure - hence their experiment's
homopolar don't work. You can see that a polar face mixture simply create an area on the
metal disk where the electrons spin in an eddy current loop contributing to lenz heating but not to
collective electron flow from center of the disk to the edges. Be ready to create a high magnetic flux
return path in homopolar instruments.

I believe I know what you are saying. The spinning ring magnet needs to be just that.  Using separate mags, the fields moves with the magnet, but ring mag, as it spins, the field doesnt spin with it.

Mags

[tim123]

Here's the idea for an axial HPG. I don't know if it'd work, but I think it should... I'd appreciate feedback from the wise members of the forum...

Benefits of the design:
- Relatively easy to build
- Can use regular sized magnets
- Power take off is much easier

Drawbacks:
- Can't close the magnetic path
- Still will be low voltage DC. (Although they'd probably be easy to put in series...)

Images attached below:
1) This shows the inner and outer magnets - i.e. the 'stator'.
Inner magnet is a rod
Outer magnet is a tube. It could simply be steel - which will naturally polarise opposite the inner magnet, or it could be pre-magnetised...

2) This shows the rotor.
It's a copper tube that fits around the inner magnet, and inside the outer one.
It has end caps which attach to the drive shaft, and from where the power is taken off

Note: I'm *assuming* that the inner magnet can rotate with the conductor - as it does in a regular HPG - but in a different axis. If it can't, then that would probably invalidate the design...

3) This shows the current flow.
Current flows out from the center of the magnetic field towards the ends, or vice-versa if rotated oppositely.
Current flows back to the center of the field - i.e. the middle of the copper pipe.

Power would be taken off / returned using slip rings or brushes - but it should be easy due to the small circumference.

That's it, let me know what you think.

Regards, Tim

[keithturtle]

"That's it, let me know what you think"

I'm not sure my input ranks with those who are wise...

Tim, does the center magnet rotate with the copper tube?   If so, is velocity differential between the two fields present, and would that negatively affect the excitation of electrons in the tube, thus limiting current output?

In my tube design, the center mag assembly floated on bearings, held in place by the attracting field outside,  whilst the tube spun in the flux sandwich.   This requires stainless and ceramic bearings, and an insulator between axle ends, from which current from each pole is extracted.

I never got beyond building the drum end retaining parts, but I still think the design is worth pursuing.   As for your drawings, they bear much resemblance to my design.   Keeping the surface velocity low at the brush contact point is critical.

I did find/purchase some electrocontuctive grease, to pack the shaft/pick-up bearings with, hoping to extract a measure of current there and thus reduce the drag on the brushes.   Multiple brushes increase drag, but if the bearings can transfer some of the current load, there will be less drag total, I would think.

Then again, I'll never know until I build it

Turtle