Aluminum roter [CLOSED]

[ghurd]

Between no answers to direct questions (at all), expensive special made magnets with no numbers, "See above" like I didn't see it, and "What's mu?"

I agree.

Hammar Tyme!

[jimovonz]

A few minutes playing with Vizimag (free download) shows that half the number of magnets in our standard configuration gives you approx 50% more flux in the gap compared to twice as many magnets in the halbach configuration. This seems logical to me as the halbach array uses alternate magnets to 'force' the flux into the disired gap rather than using an iron circuit to 'draw' the flux where we want it. I for one can't see that this is useful to our cause. I also think that some folk are missing the point that alternate magnets in the halbach array act as opposite poles rather than one complete array acting as a single pole. There may be little flux on the back side of the halbach array, but you can't use this configuration in place of a single pole as we would currently use it - there would be a lot of cancellation.

[joestue]

I did answer the question.

double the magnets, get a 1.25-1.4 increase in flux density.

NOT wasted, but only in theory will this double the output.

if the output is not doubled, then the magnets were 'wasted'

currently the magnets are the most expensive part.

[finnsawyer]

Still no drawing.  Since you seem to persist in the idea that you can make a single machine, which is not really possible as even Wondermagnets pseudo refrigerator magnet had poles similar to a horseshoe magnet, You really need to come clean or TomW will close this thread, as he has threatened.

Anyway, as to your question why half the magnets are wasted, the supposed 1.4 gain in flux gives the answer.  Whether you like it or not you will still have some sort of magnetic circuit.  Even if everything is composed of magnets except the air gap (that being the distance between the Halbach Arrays), the magnetic flux must still flow from one array through the air gap and back through the second array and eventually form a loop.  Now in the model for a magnetic circuit a magnet is analogous to a voltage source and the magnetic flux to the current.  The air gap and iron parts retard the flux and hence are analogous to resistances with the resistance of the iron parts much lower than that of the air.  All you've done, in effect, is to replace some small resistors (actually areas of small reluctance in magnetic parlance) with sources.  Well, big deal, as the air gaps are still acting like high value resistors.  By only getting a 1.4 increase in current (flux) by doubling the number of voltage sources (magnets) you are wasting the potential (joke intended) of the extra sources, as twice the number of sources driving current through twice the number of nearly identical resistors will give nearly twice the power.  

[finnsawyer]

A Halbach Array has essentially no magnetic flux on the back side.  But neither does a properly designed conventional rotor.  In the case of the iron backed rotor one would lose flux if one embeds the magnets in the iron.  Yet in the Halbach Array that is the case, as the pole magnets are embedded in the array.  So, the question is, "What would be the effect on the flux by replacing the pole magnets with blocks of iron and then gluing the pole magnets to those blocks?"  Well, in an alternator, where the flux paths are well defined it is obvious that placing half the magnets sideways really doesn't change the issue.  Each magnet will make it's contribution to the flux as though the other magnets were not there, if the iron remains on the linear part of the B-H curve.  But therein lies the problem.  Modern magnets are so powerful that the arrangement would result in magnetic saturation and a waste of magnets.

[TomW]

Glaskopte;

This story has been CLOSED.

You have not responded directly or honestly to direct, specific questions.

You are probably following some Overunity idea.

Those are absolutely not acceptable.

The combination of these 2 facts makes this story off topic and subject to sanction. Therefore it has been closed.

Tom, as Editor.

[TomW]

Glaskote;

This story has been CLOSED.

You have not responded directly or honestly to direct, specific questions.

You are probably following some Overunity idea.

Those are absolutely not acceptable.

The combination of these 2 facts makes this story off topic and subject to sanction. Therefore it has been closed.

Tom, as Editor.