On 02/10/2010 01:41 PM, Abd ul-Rahman Lomax wrote: > At 10:24 PM 2/9/2010, Stephen A. Lawrence wrote: > > >> > Yeah, I think you are right, on that end. Energy is stored in the >> > inductor field, but with relatively long rise time. When the switch >> > opens, though, the field collapse will recover some of that energy, and >> > quickly. Usually it's dumped through a diode to protect the switch. >> >> Again, it's not a current spike, it's a voltage spike. > > That's correct. It's a *power* spike. Energy built up slowly is > recovered or dissipated quickly. > > >> In fact it's the opposite of a current spike: The current is like the >> Energizer bunny. It just keeps going, and going... no sharp spike, but >> no sharp dip either, and when you try to interrupt it, if there's no >> place else to go it'll go through an arc. And then your switch gets >> fried. > > Yes. The diode across the toroid in the Naudin schematic clamps the > voltage to the power supply voltage plus the forward drop across the > diode, perhaps a half-volt. Depending on the impedance of the supply, > the supply voltage might increase a bit during this transient. > > Bottom line, though, no convincing demonstration has been done that > there is any excess energy here. Easily, if there were, it could have > been demonstrated and measured, if it were at all as significant as > claimed. We have no numbers from anyone on energy dissipated in the > toroid circuit, and none on the energy found in the rotor and extracted > by the pickup coil. All I saw was a plot of pickup coil (voltage? > current?). With no units visible, as far as I saw, and certainly no > analysis that made sense.
Are you talking about Naudin's setup? He's plotting voltage, current, and power into the coil, and he does indeed give the units for voltage and power, though he neglects to give the units for the current. (See bottom of scope screen for voltage units -- he's putting a 6 volt roughly square wave on it.) Enough information that anyone with time on their hands could duplicate his setup and make additional measurements. But.... but.... HOLY MOSES!! I looked pretty carefully at the power curves back on 2/9/10. The red line clearly went up faster and came down faster than the blue line, as it *must*, given that the measured inductance is lower in that case. I almost snapshotted it so I could try taking the differences manually; unfortunately I didn't, and all I have is the memory of the earlier graph. But I looked just now, and the red and blue curves are almost exactly identical -- the difference between them has *vanished*. That is a significant change! I checked the dates in his images directory; he replaced that image this morning -- about 24 hours after I first looked at it. No mention on the page of the replacement, nor any explanation as to why he might have done so. Unfortunately, as I said, I didn't save his earlier image. So, it looks to me like Naudin's playing games with his measurements. His setup's interesting but I would hesitate to trust a single measurement on that page.
