At 09:47 am 27/02/2006 -0800, you wrote: >The Sprain Motor, in the context of the so-called >"Magnetic Wankel" brings up a salient point which was >never adequately addressed during the previous episode >of Takahishi a decade ago. > >That is the potential advantage of using modern >electronics to provide what (for lack of a better >term) can be called the 'selective application of >torque'. This is a subset of a putative 'low-duty >anomaly' which is arguably present in a number of >physical systems, for which there is also no real >proof - but some tantalizing hints. And when one is >operating on-the-fringe, and following the jagged >cutting-edge, then one often pays some attention to >tantalizing hints - as unproven as they may be. > >The logic (or at least the nice-sounding argument) is >this. IF an electric pulse can be translated into >torque at high efficiency (say 95%+) then - when you >compare two situations: > >1) the uniform application of torque over a complete >revolution of an axle through a 360 degree cycle - >compared with: > >2) the uneven and pulsed application of much more >torque to only a few degrees of rotation, with the >assumption that in both cases the net energy expended >is equal... > >Then, in situation #2, compared with situation #1 - >and all else being equal - there 'could be' a net >advantage (due to a combination of factors including >leverage, momentum, the Aspden effect, better >utilization of back EMf, etc.) > >I will agree that none of these, standing alone, makes >much sense (other than the Aspden effect, which might >involve the "circular polarization" of some kind of >'aether friction' but that is not a terribly robust >effect, even if it is valid.) There are also some >possible hints of anomalous energy phenomena in >low-duty cycles of electrical discharge which may >involve higher effective voltage from the same net >energy. The assumption being that uniform discharges >can inhibit the high end of a Maxwellian distribution. > >We often think of this kind of selective torque being >most evident in the the child's swing - where the >energy expended to keep moving ever higher is most >valuable only in a very short segment of each cycle. > >For another more relevant example - let's consider the >situation of a bicyclist who wants to get the most >possible boost out of lightweight battery which he/she >is using for auxiliary power. In that case, pulsing >the same amount of net energy over only the few >degrees of the cranking cycle, when the cyclist can >also best use his own physical exertion for leverage >(at about 3 O'clock and 9 O'clock of the cranking >cycle) ... this selective application of torque also >makes some sense, compared to a constant input. Both >the bicyclist and the child are using leverage, of >course, and we normally do not think of that as being >applicable to a constant rotation situation- but in >the case of the cyclist - we can see how it can >possibly be an advantage. > >Also in the sense of the Aspden-effect being >non-linear, such that a very short boost over a very >small slice of that 360 degrees, makes even more sense >if the curve of non-linearity is very steep at the >start... well, you can see where this is going. > >"Selective torque" would not favor the Sprain >implementation (any more than the previous Takahishi >version) - on the surface at least. Terry mentioned >some advantage to attraction vs. repulsion, but I have >heard the opposite argument as well. The great >difference now, over the situation a decade ago, is >the advances which have been made in fast electronics >- which can now (conceivably) make any slight effect >more interesting. > >Lets say that the Takahishi motor used a pulse over 5% >of the cycle (or 18 degrees). Lets say Sprain has >advanced this so that now he can apply the same power >to just 6 degrees of the cycle. This is interesting in >an anecdotal sense in that in two cases which I have >been involved in, there is evidence that the putative >"low-duty" advantage kicks in at 5% and is maximized >at around 2%. Admittedly, this is anecdotal and the >evidence is light - but still, I find this fascinating >- especially in the context to the Aspen effect (the >magnetic and the non-magnetic versions of that >effect). > >At any rate, there are some ways to maximize this >selective torque effect in the both Aspden and the >fully leveraged contexts - which are being neglected >by Sprain, and were missed by Takahishi as well. >Perhaps that is where he is going with the next >generation. > >Jones
I'm not quite sure what you're torquing about, Jones, but I found the swing bit so interesting that I actually googled to find exactly how it worked. <g> Frank
