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

[captainpecan]

Or just wind two layers around the core, one layer clockwise and the other counter clockwise?
Balance it by adding or removing one loop on the last layer.

Not a bad idea.  Maybe simply just a bifillar wind, their are a few good variations you could hook the windings up in to test.  One idea could be like a joule thief wind, but instead of the two leads running to the collector and base of a transistor, they would just go together and onto the next component.  The thing is, there is no data that I know of that is showing they are only using one winding on the toroids, so the answer could be just that simple.

[hartiberlin]

Interesting to see was, that the toroidal coils gain in inductance,
when the magnets approach.
Can we get some testers verify this ?

Well, just remembered, that Jean Louis
had already done this over here:

http://www.youtube.com/watch?v=gRdg74E0xkA

So we now know, that Steorn switches their coils ON only
shortly after top dead center and keeps them
on for about 30 degrees, until the coils have again a higher inductance.

As we now have a dL/dt term the energy equations change immense.
Have to look this up, I calculated this already a few years back
for the Newman coils.

I wonder, how Steorn accomplishes to have almost 1 Henry of inductance
just with 2 (or 4) toroidal coils, when Naudin has a simular size and  is only in a range of
1 to 12 milliHenries ?
See:
http://jnaudin.free.fr/steorn/html/inducten.htm

Does Steorn use special ferrite or mumetal cores ?

[captainpecan]

Interesting to see was, that the toroidal coils gain in inductance,
when the magnets approach.
Can we get some testers verify this ?

Actually, it is a gain in inductance when the magnets LEAVE the coils.  I was just going to post that JLNaudin had already shown this, but I just saw you figured that out already.  But I was going to make a quick note, that if you watch the demo closely, you can see that what they are calling the beginning of the pulse, does in fact appear to be a stopped rotor at TDC.  Then the end of the pulse is a little bit past.  So even picking it apart and studying very closely, they do confirm JLNaudin's results on the inductance test.  Of course Naudin tested it with one magnet and had 2 sticky spots, but the results are the same.  Any others want to see exactly the spot of the video I'm referring to where you can see them showing their pulse width, just check out part 2 http://www.youtube.com/watch?v=TtKHo9dKHtQ right at about 7:30

[Airstriker]

Does Steorn use special ferrite or mumetal cores ?

Grrrr, cannot you just read what I have written a few posts back ?!! Look at the properties of Mumetal !! Like talking to the wall ;]

[gravityblock]

1)  When reversing the pulse polarity, the rotor has the same direction of rotation.  What is biasing the rotor in one direction only with either polarity in the pulse?

The only thing I can think of that could bias the rotor in one direction only when changing the pulse polarity is for the core to have dissimilar metals in it.  For example, the top side of the core is mu-metal and the bottom side of the core is a soft iron or whatever.  It could also be diametrically where the right side is mu-metal and the left side is some other material or a combination of both.

I would love to know the answer to this question.  This could be what is responsible for the huge gains in inductance since the pulse could be at TDC or slightly past its departure as Stefan suggested and still have the same rotation direction regardless of the pulse polarity.

If there are other possible reasons why the rotor is biased in one direction only with either polarity in the pulse, then I would love to hear it.


GB