Homopolar Generators (N-Machine) by Bruce de Palma

[ashg]

Paul R : I thought that the essence is the word "opposes".
"An induced emf always gives rise to a current whose magnetic field opposes the original change in magnetic flux".

Yes but the term "opposes" does not specify whether the the fields are truly anti-parallel and the back torque generated by such current acts directed against the action giving rise to the induced EMF.

The simplest open magnetic circuit  Homopolar generators have the unique charcteristic that the disc and magnet (permanent or electro & symetrically concentric) spin in a stationary field where the magnetic forces generated by the radial current in the disc and  in the external circuit apply forces transmitted through the open path magnetic flux. 

Its now well established (De Palma Sunburst, Trombly-Kahan, Tewari and us) that under the right magnetic circuit conditions the normally expected generator back torque on the drive motor from current generation through the disc can be substantially reduced. To that effect the homopolar can be classed as a reduced Lenz force type generator.  Generally speaking the mechanisim of back torque reduction and its engineering and optimisation have had little explanation or recognition in the public domain, to that effect that some designs of homopolar OU generators have not performed as desired.  That's exactly what we experienced. One machine had a 10% reduction in back torque and could not be classed as outside experimental error the other showed a 235% reduction in back torque which was physically obvious because the effect could be observed with shifting of the heavy output circuit cables, when the motor would speed up and the output would increase. Every homopolar machine design for reduced Lenz force, will have different performance characteristics. That happened for us and Bruce Deplama, with the Sunburst configuration working well but others not so well.  It was not necessarily the one-piece nature (magnet and disc co-rotating) of the design that caused the reduction in back torque but the physical geometry of the stationary part of the circuit and that is where the Lenz force reduction action happens. The inertial nature of the magnetic field must also play a role in this and that is not to say that there may be other conditions discovered that are essential to gain the best reduction in back-torque as well. More experimentation will confirm that but these are not cheap machines to build and experiment with and the low voltage and high current can provide some great technical challenges.

Ashg

[keithturtle]

Thanks for sharing your insights, ashg.  Sounds like you could save me lots of legwork, your having already covered the ground I am just now treading.  Maybe we could compare notes.

The units I am building don't have very tight tolerances.  I think that getting the copper very very close to the magnets will be key to extracting that tight, high energy spin at the corners, like Howard Johnson mentions, IDK.  Of course I don't know.  If I did I wouldn't be doing this.

So Trombly ain't allowed to speak, eh?   Imagine that.
" More experimentation will confirm that but these are not cheap machines to build and experiment with and the low voltage and high current can provide some great technical challenges."  Amen to that, brother.

I still haven't got my units spinning yet.   No matter, they probably won't produce any earth-shattering results

Turtle, really slow

[ggx9]

No posting for 6 months?
Hey, Turtle, after reading through much of the last 18 pages it looks like you've been around here for awhile. How is your progress?
I first heard of the N machine in the early 80's and have made some components in order to learn how it is supposed to work.
In addition to my machine shop work I have spent an enormous number of hours in study, calculations and other paperwork exercises. I have not yet attempted to duplicate the 13 1/4" diameter Sunburst machine.
Before this effort I had a background in electronics and then went on to study magnetics and the math formulas for burst RPM of flywheels. Anyone seriously interested in building one of these machines would do well to understand these formulas so you can get an idea on which parameters need to be idealized for best results. The math is fairly simple for the voltage output to be expected, the bursting speed of a flywheel and the maximum current output and why these factors have the effects that they do.
The biggest obstacle, if used, are the carbon brushes. They have mechanical drag like disk brakes on a car which turns into heat which creates several other problems. They have a voltage loss across the sliding interface with the metal surface they ride on and they have a voltage loss through the carbon itself which is not nearly as conductive as copper. The liquid brush (pure gallium or with an alloy) or the conductive belt is a must, in my opinion. The series of 18 youtube videos includes some shots of a liquid metal machine.
Precision machining and balancing along with a strong and rigid frame are essential to avoid destructive vibration through the necessarily wide RPM range. While it may not be appropriate for the  final product, a three phase motor running on a variable speed drive would be a great convenience for testing. Their prices have come way down and a unit with single phase input is available if you don't have three phase power available at your workshop.
To convert to high power (20Kw and up) of conventional 60Hz AC I would couple (on the same shaft) the N machine to a Faraday motor of similar construction (motor with magnet stationary) to provide rotating force and gear it down to a low speed 3600 or 1800 RPM AC generator, something like a gas turbine generator set due to the high RPM of the turbine and N machine.
I would like to get plans for that liquid metal N machine in the Youtube video as my next project and from there go to a large home power unit. Does anyone have more information on that machine?

[tinman]

Funny thing that this thread got a kick in the pants again today,as i was just discusing this on the magnet myth's thread.

Some intersting statements being made throughout this thread.
E.G-From Gravityblock-Electrons can also flow from the rim to the axis depending on the direction of rotation and what magnetic pole the disc is rotating through.

What magnetic pole the disk is rotating through
It rotates through a neutral field regardless which way the magnets are orientated-see pic below.North one side of the disk,and south the other side. This must mean a field flow direction through the disk-but they say nothing flows from north pole to south pole,or vice-versa.

Then there is talk that it is the electric field that causes the current flow-there is an imaginary wire created between the brush on the outer rim and the center brush on the shaft through the copper disk . OK,cool-where did this electric field come from if there was no current flow to create it in the first place?

Current must start to flow before an electric field is produced-in this case the egg comes before the chicken. Also a voltage can be measured across the disk radius before current is drawn from the HPG-->the open voltage.

I really think this deserve continued reserch,as i dont think it has yet been discovered exactly what is going on in a HPG. This will only come when you know exactly what and how magnetic fields are and work.So i think the sister thread for this thread should be the magnetic myths and misconceptions thread- http://www.overunity.com/14974/magnet-myths-and-misconceptions/msg420334/#new

[ingyenenergiagep]

U can use the disc generator for hydrogen generating from water.