----- Original Message ---- > From: Stephen A. Lawrence <[email protected]> > To: [email protected] > Sent: Thu, February 18, 2010 11:51:10 PM > Subject: Re: [Vo]:Naudin's Solid State Generator? >
> But in any case the field inside the core doesn't change the external > permanent magnet's field (or, at any rate, it doesn't have to for this > to work). > > Rather, the permanent magnet distorts the field of the core, so that the > field of the core is no longer a neat torus, and now extends outside the > toroidal coil. That's what the pickup coil is reacting to. The > "distortion" is accomplished by rotating the orientation of the core's > field such that it's no longer neat concentric rings contained within > the torus. > > In particular, during the phase when the coil is *off*, the field of the > core will be lined up with the field of the neo magnet, and will > consequently be sprawling all over the room. When the coil turns *on* > the field of the core will be (partially) rotated to follow the field of > the coil, and the portion of the core's field which is outside the torus > will be consequently reduced. So, the portion of the coil's field which > extends outside the coil varies in intensity as the coil turns on and off. > > We can be pretty sure the coil isn't succeeding in totally shielding the > core during the "on" phase, on the other hand, because the neo magnet > doesn't immediately fall off! (Or the 'on' phase may just be too short > for it to drop off before the next 'off' phase starts.) OK. I forgot about the core. > ****** > > By the way, I talked Naudin's page over briefly with the aforementioned > double E I know. He thought it was pretty funny, but didn't find it at > all puzzling. He said flatly the trick is that the current rises more > quickly when the inductance is lower, and falls more slowly when > inductance is higher; he didn't see thermal losses entering into the > budget at all. In other words, there's a back EMF alright. It just is > small, which is commensurate with the mechanical power generated by the > motor, which is also (very) small. And it happens only on the rising > and falling edges (when the "shield" moves), in the very brief space of > time during which the core material goes from unsaturated to saturated, > and it's totally swamped by the far, far higher current which is flowing > while the coil is fully energized. So, we can't see it on any of the > scope shots to date, *except* Naudin's two shots showing voltage and > current in the reference position and TDC, in which we can see the > current going up and down very slightly faster at TDC. This Steorn video http://www.youtube.com/watch?v=bSftoc9Pm1U compares the trace from a conventional pulse motor with the trace from an orbo motor. (Naudin doesn't show measurements from a conventional pulse motor). If your EE friend is correct, then Steorn is simply wrong to surmise that because the scope trace of the orbo motor does not look like the scope trace of their pulse motor, the ORBO has NO back EMF. However, might it be more accurate for them to say that there is some Back EMF, but it is not present in the amount that standard physics would predict. Also does the shot @ 6:40 provide part of the information you believed was missing? harry __________________________________________________________________ Make your browsing faster, safer, and easier with the new Internet Explorer® 8. Optimized for Yahoo! Get it Now for Free! at http://downloads.yahoo.com/ca/internetexplorer/
