dknespl
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balance wheel continued...
As I wrote, mass in the center where r->0 is not adding much to the total I, if I=mr^2, or we should rather write \int r^2 dm, The frequency depends on one side on the strength of the magnetic field and on the other side on the moment of inertia and they have to be "matched" in order to get required frequency, so probably you really need higher moment than that of rotating relatively small magnet only. I can imagine a construction, where the rotor would be completely made of magnet and would have large radius. It would be a magnet and a balance wheel in one part. Is it what you mean?
The advantage of larger diameter is also a finer regulation by changing the moment of inertia., i.e. relative change of moment by unscrewing the screws (changing the radius) is smaller. There are regulating screws visible in one of the concept pictures (they are not visualized on the picture above in this thread).
Regarding the disturbing effects, the great advantage is that the geometry of the balance is not changing during the oscillation (like with a single hairspring), and therefore the center of inertia doesn't move. So you don't need a tourbillon anymore.
Another advantage is, that since you do not use a spring, the amplitude can be much smaller - like that of pendulum. But then you could probably need slightly different escapement.
The positional error due to changes in friction are, I would suppose, the same as with the normal balance. Could be even better (but it is just a speculation) if the magnets keep the shaft in a stable position and don't let it fall up and down and left and right i.e. to change a position of pivots in the bearings (but probably not)..
Maybe we will be asked by TH to improve their design 
balance wheel
By: dknespl : March 28th, 2010-23:51
I think you need a kind of balance wheel. You need a moment of inertia which is weight x length of the arm (I=mr 2 ). If you would have the gyrostat made just of the magnet in the center, it would have to be much heavier in order to have the same I. Since...
ummm...
By: BDLJ : March 29th, 2010-15:38
...if you look at the design, the magnet is rotating on the same shaft as the balance wheel...and if that diagram is anything approaching scale, it's going to have a hugely larger PMOI than that cut away little wheel. So why the need for a balance wheel o...
balance wheel continued...
By: dknespl : March 29th, 2010-16:49
As I wrote, mass in the center where r->0 is not adding much to the total I, if I=mr^2, or we should rather write \int r^2 dm, The frequency depends on one side on the strength of the magnetic field and on the other side on the moment of inertia and they ...
Umm..part 2.
By: BDLJ : March 29th, 2010-19:02
"It would be a magnet and a balance wheel in one part. Is it what you mean?" Yes. Should have worded that better. Regulation via screws, If I'm interpreting you correcty, you're saying that the balance wheel is required to provide the opportunity for fine...
working prototypes
By: Thom H : April 4th, 2010-08:48
This time, there were 5 working prototypes on the Basel booth. You might say that it's a shame to show non finalised concepts, but it's the only way to make big steps. Like you can see on this forum, skeptical comments could have killed the project. Once ...
There we are...
By: Thom H : April 3rd, 2010-15:34
Point by point : No need of a balance wheel if the magnets would have a larger radius : need to be studied. It would be a complete reconstrustruction of the system and I have no idea of the answer... It's true that with a larger diameter it would be easie...
Hello Thomas..
By: BDLJ : April 4th, 2010-00:37
Thank you for spending the time to respond here. Very much appreciated and informative. The thing to see would be the images of the magnetic fields as the rotor moves, if this was modelled.....would answer a lot
Good point, Don.
By: BDLJ : April 12th, 2010-01:05
I was coming at the concept more from a proof-of-concept POV. Excellent point re: stability of field at temp. I'll have to have a look at some books to determine the variation in strength over the COSC temp range...But even fraction of a % will throw it r...
T coef
By: dknespl : April 12th, 2010-14:58
COSC criteria is 0,6 sec/day/ 0 C, which is 0.6/24/3600=~7E-6, i.e. 0.0007% change of period due to change in temperature of 1 0 C. The best current sammarium cobalt permanent magnets have RTC 0.002%, i.e. a change in magnetic flux Br per degree Centigrad...
materials
By: dknespl : April 19th, 2010-08:37
But I think, chances are, that new materials for permanent magnets will appear, that have somewhat better temperature coefficients. I think the research is going on, if not because of magnetic watch balances, the because of traveling wave tubes (radio fre...
Patent
By: dknespl : April 13th, 2010-12:58
I think it is based on patent US7396154 by TH from 2007 (but the original application is even somewhat older) . You can find it on freepatentsonline for example. There are interesting diagrams and more explanation. It also refers to some other simmilar co...
First patent
By: Thom H : April 19th, 2010-07:47
Well yes this is the first patent. And further patents with more technological solutions are pending to complete the protection of the full concept. You can see on this first patent that the original idea was quite naive ! We did the very first protoype d...
