STEORN DEMO LIVE & STREAM in Dublin, December 15th, 10 AM

[0c]

Not to slight anyone...  I am sure there are many experts in the field here already.  But it has been recommended to me that we listen to Overconfident.  I think he is 0c on this board.  I've seen some promising posts by him so far on other boards.

I wouldn't consider myself an expert, no formal education or anything like that. But I do have some insights into magnetism, many of which have been experimentally confirmed. I hope I can contribute something worthwhile to this effort.

The relationship of a ferrite material's relative permeability to saturation due to a PM field is what I thought was needed for the first step.  And I've yet to find it.  Anyone have reference info for this?

The core data you are most likely to find does not deal with the problems in this device. Most coils and cores are designed for use as filters, transformers, or RF equipment; applications where saturation is a distinct disadvantage and should be avoided at all costs. You won't find the information you are looking for there.

You should be looking for information regarding "Magnetic Amplifiers" or "Saturable Core Reactors". Of course, most of the books and papers on those topics are held in university libraries and professional magnetics societies and hard for laymen (like me) to get hold of. Here is an introductory "Neets" module on Saturable Core Reactors:
http://www.tpub.com/content/neets/14180/css/14180_135.htm

and another on Magnetic Amplifiers
http://www.tpub.com/content/neets/14180/css/14180_140.htm

The following graph from the link above illustrates the general relationship between permeability and saturation:
http://www.tpub.com/content/neets/14180/img/14180_135_1.jpg

For the type of application we are dealing with here, the important relationships are between permeability and saturation. Please study the permeability curve in the graph. The high point on the permeability curve is where magnetic attraction will be the strongest and we can get the most torque as the magnet approaches the core.

When the magnet is at its closest point, we want to reduce the attraction so there is little resistance to further rotation, so we need to further saturate the core and reduce its permeability. It will be virtually impossible to reduce permeability completely. Fortunately, that's not required, as long as it is significantly less than it was in the attraction phase.

I have mentioned elsewhere about "magnetic bias". By using materials with high remanence, we can increase the permeability when no power is applied to the coil. Take 1010 steel as an example (look up the magnetic properties), you'll see it has a high remanence.

It will take less input power to drive 1010 from remanence into saturation than it would to drive it from zero B all the way up to saturation. With ferrites and other materials without any remanence, you would always be starting from zero.

Hope this makes sense,
0c

[onthecuttingedge2005]

some suggestions, incorporate magnetic bearings on the rotor, build the rotor inside an ideal jar, remove the air inside the jar with a food jar vacuum sealer or better yet with a high performance vacuum pump.

this will minimize the drag on the rotor and will increase efficiency. aerodynamic drag and bearing friction should be dropped to as close to zero as possible.

[mondrasek]

Thanks 0c.  I'll have a look at those reference materials as soon as life allows.

I thought that graph was most interesting.  I actually saw you post that "somewhere else" and have looked at it several times since.

So, a couple quick questions regarding:

I have mentioned elsewhere about "magnetic bias". By using materials with high remanence, we can increase the permeability when no power is applied to the coil. Take 1010 steel as an example (look up the magnetic properties), you'll see it has a high remanence.

It will take less input power to drive 1010 from remanence into saturation than it would to drive it from zero B all the way up to saturation. With ferrites and other materials without any remanence, you would always be starting from zero.

Should we not try to bias ferrite with external magnets as TK, Ossie, etc. have already shown (to raise permeability) rather than switch to a material like 1010?  Or is the total power to saturate (say to ~95%) the steel vs. ferrite from max permeability less?

Sorry in advance if the answer is in the referenced links.  But isn't the quick exchange of information what conversations (and forums) are all about?

Thanks again,

M.

[mondrasek]

some suggestions, incorporate magnetic bearings on the rotor, build the rotor inside an ideal jar, remove the air inside the jar with a food jar vacuum sealer or better yet with a high performance vacuum pump.

this will minimize the drag on the rotor and will increase efficiency. aerodynamic drag and bearing friction should be dropped to as close to zero as possible.

Excellent suggestions for increasing efficiency.  But a bit premature imo.  And here is my reasoning for that:

So far we have not seen evidence of OU.  In fact, we have seen some that shows possibly very low efficiency.  That is because no one is measuring all of the input and outputs.

There have been many good replications and measurements of input electrical power.  But there are two outputs that have not been measured simultaneously.  Those are the rotor torque (finally measured by TK), and the heat and/or electrical energy recoverable from the toroid coils (measured somewhat by a few).  Without both of those measurements (rotor torque *and* heat/recovered coil energy) we have no data to support claims of OU.  Only if the total of those outputs is greater than the input are we in OU territory.  And then optimizations to the nth degree, that would include the more advanced level of placing the unit in a vacuum, would seem appropriate to me.  Right now I suggest we get rid of the gross inefficiencies that may have occurred due to lack of proper material specification for the major components.

Again, just my opinion.

[gravityblock]

I look at permeability as being 100% attraction and 0% saturation.  The permeability is just the inverse of saturation.  When the core is 100% saturated, then it will have 0% attraction.  When it is 0% saturated then it will be 100% attractive.  This is why you don't want to use opposite poles with the dual magnets.  This will cause the core to increase towards saturation as the rotor magnets approach and the speed gain decreases as it gets closer to the core.  This is a CEMF on the approach.  When using like poles with the dual magnets, the like poles do not increase the core towards saturation and it doesn't lose it's attractiveness, thus the rotor magnets can obtain its greatest total speed during it's approach to TDC.

Being able to saturate the core very quickly with a fast rise time in current and with magnetic viscosity decreases the energy needed from the pulse to increase the core towards saturation so it begins to lose its attractiveness.  The faster the core increases towards saturation, the closer to TDC the rotor magnets can get before the pulse is needed and this will increase the speed gains.

Here are the key components and factors in this device

1)  A core being able to saturate very fast (Magnetic viscosity)
2)  A core that has a high attractiveness at 0% saturation.
3)  A fast rise time in current to saturate the core as quickly as possible.
4)  Dual magnets with like poles to use Newtons Third law to defeat the CEMF on both the approach and departure.


GB