On 02/18/2010 08:39 PM, Harry Veeder wrote: > > > > > ----- Original Message ---- >> From: Stephen A. Lawrence <[email protected]> To: >> [email protected] Sent: Thu, February 18, 2010 2:10:30 PM >> Subject: Re: [Vo]:Naudin's Solid State Generator? >> >> >> >> On 02/18/2010 01:11 PM, Harry Veeder wrote: >>>
>>> And if it is a generator more heat will be dissipated? >> >> Right -- as much, or more; if it's a generator it may be 0% >> efficient. But if it's just a transformer its efficiency must be >> greater than 0. >> >> :-) >> >> By the way -- it's *not* the case that the presence of the pickup >> coil must make it dissipate less heat in the core, any more than >> it's the case that the presence of a receiver 20 miles downrange >> makes the transmitter at an AM radio station run cooler. >> >> Just because it looks like a transformer rather than a transmitter >> doesn't mean it behaves that way. (I've long since backed off from >> any claim that I fully understand this thing -- and that's why it's >> still so interesting, of course.) >> > > Naudin has posted two more videos where he holds the magnet away from > the torodial coils so that the pickup coil is between the magnet and > the toroidal coil: > > http://www.youtube.com/watch?v=2Nd9IuVJ3ww > > and with a nanocrystalline alloy for the core: > http://www.youtube.com/watch?v=AdEd8jX0fZA > > This time the current drops when the magnet is brought closer. Haven't had time to look at these yet; will do that tomorrow. > > > I am still puzzled how the magnetic field inside manages to vary the > permanent magnet's field magnetic outside the core. The logic of > combining a contained field to a pervasive field doesn't make sense > to me. > > I presume the core is emitting EM radiation. Does that play a role? Well, sure, at some level. It's how the two halves of a transformer communicate with each other, really. In fact it's the only way a magnetic field ever changes -- the change, which propagates at C, is EM radiation. We may or may not need to worry about that to understand this, but it's there, at some level. 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.) ****** 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. My friend also told me all about his recent haemotoxicity, brought on by a bad reaction to augmentin (prescribed for a sinus infection, of all the trivial things), which prevented his answering any sooner on this... beware unnecessary surgery, and beware unnecessary antibiotics.
