Sorry I took so long to reply to this -- been busy. I tried to watch the referenced video this morning but YouTube is being agonizingly slow -- or there's a bad link in the net somewhere -- and it ran the first part horribly slowly and something eventually gave up, timed out, and wouldn't show me the rest at all. So, I managed to watch the first part of the video but didn't get to the shot at 6:40. Can you summarize what it showed?
Anyhow, I've addressed what I can, below: On 02/21/2010 03:17 PM, Harry Veeder wrote: > > ----- Original Message ---- >> From: Stephen A. Lawrence <[email protected]> [ ... ] >> >> 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. Several things. -- The fact that the trace of the Orbo and the trace of a pulse motor are different doesn't seem especially relevant to anything. They're different, we know that already. It's a straw man. -- I think my EE friend is wrong. After working through a gedanken experiment involving massive simplifications of the circuit by using, among other things, superconducting wires in a number of places :-), I concluded that the difference in current rise time can't account for the mechanical energy output. But I've been swamped with mundane stuff since and haven't gotten around to calling him to find out why my analysis is NG (so for now I believe my result). -- There **IS** a back EMF which appears when the magnet is moved away from the coil! It's small -- VERY small -- so it doesn't show up in any of the traces we've seen, where its effects are totally overwhelmed by the "sustaining current" going through the coil and turning into heat. Or, at any rate, theory says that back EMF must be there, because the field produced by the (saturated) core ROTATES when the external magnets are removed, with the result that the component of the field which is concentric with the torus must INCREASE (very slightly). The thing which is interesting is that this EMF is in the correct direction to result in extra energy being pumped into the system when the motor is in operation. However, I don't have a handle on the magnitude of this EMF and I have no idea if it can account for the energy output of the motor. (At this point I'm not even sure that the magnitude of this "magnet motion" EMF behaves "properly" as we increase the amount of current in the coil.) -- As far as I know there is *nothing* about the Steorn motor which does not follow the theories of standard physics, and *nothing* Sean or Naudin has shown has indicated otherwise. The weird behavior of the toroidal coils is predicted, absolutely, by the standard models, and I'm quite sure these motors could be simulated using appropriate software. The problem is saturation (which is in the standard model) and toroidal coils (which are in the standard model) are, in the details of their behavior, hideously confusing. As far as I know, they have made no effort to measure the very tiny back EMF which is predicted by standard physics, so there's no way we can conclude that it's not coming out as predicted! They also have made no effort to calculate the energy injected into the system by that back EMF, so, again, there's no way we can conclude that the energy in does not equal the energy out. Anyway I've got to go, I'm spending time I don't have here, unfortunately... > > Also does the shot @ 6:40 provide part of the information you > believed was missing? Got a half baked You-tube window on the screen, which won't show me that part of the video. I may try again later. > > 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/ > >
