A further problem here is the kickback voltage resulting from the collapse of the secondary field. Generally speaking this induces about a 300 volt spike on the primary winding, which energy must either be wasted as heat or re-used in a resonant configuration. A six cylinder gasoline auto engine at 6000 rpm needs 3 X 6000 sparks per minute max., or 300 per second, and most coils are wound to be at max efficiency at more reasonable rpm, say 3000 - 3600. Also, the resonance effect is often used in high performance ignition system coils to produce a multiple spark train which gives superior ignition or burn characteristics to the fuel-air mix; often a lean one.
Soooo, making some WAGs and estimating the resonant coil-system freq to be no more than 10 to 1 over the basic engine demand, the system resonance point would be about 1500 to 2000 Hertz. The ratio of the primary to secondary windings is about 100 to 1, and the high secondary voltage of 20,000 to 30,000 volts is produced by the extremely rapid field collapse of the secondary when the 'points' or equivalent circuit is opened or re-triggered by the hi-perf kits. By considering the dwell angle its possible to estimate the duty cycle of the coil worst case; for a six cylinder engine dwell angle - the time allowed for the coil primary to fully establish its field is, or was before magnetic or optical 'points' - up to 45 degrees, or a total of three-fourths of the entire rotation for all six firings. During the other one fourth the points were open, so for less than one twenty-fourth of each cylinder's two revolution cycle its ignition circuit discharged, for one eighth it charged. Electrical energy from the battery entered the system for up to three fourths of the time, and left it via the high tension sparks for somewhat less than one fourth. Overall, the ignition system draws perhaps 6 to 10 amps at 12 to 14 volts or between 70 and 140 watts at a max. At 100 watts continuous, a 30,000 volt DC discharge consumes 3.33 mA, to do thisover one sixth the time and collect its wits for the other 75 - 80 % it will achieve a 20 mA current pulsation, (square wave, call it 7 kV @10 mA rms). A sinusoidal 60 Hz waveform into a neon sign transformer producing 15,000 volts AC at 30 mA (rms) will consume 250 watts according to its label and will be constrained to discharge over perhaps two thirds of it's cycle for a 45 mA pulsing current consumption. A comparison shows that the wattage consumed by ignition and neon systems are in a one to two-and-a-half ratio, the voltages will probably end up at about 20kV for the ignition system vs 15 for the neon, since both discharge path and stray capacitance will suck down the ign voltage peak, and perhaps a one to four or five ratio for the current density. My very ball-park speculation, then, would be that the ignition system with well-chosen components would be about one third to one fourth as productive as the neon transformer system. All the standard disclaimers that I really don't know what I'm talking about apply here, and my fudge factors could be off at least as far as anyone elses, but its a shot at the problem from a different perspective. Malcolm Marshall Dudley wrote: > An auto spark coil would be problematic. First it would be difficult > to get the current you need, since they step the voltage up by over > 1,000:1 I believe. It would require an amp to generate a milliamp of > current on the secondary. Second, the coil is made to operate at high > frequencies (that is a rapid rise and fall time). To allow the silver > time to aggregate into particles, or move sufficiently away from the > electrode before reversal (and it will reverse, even if the waveform > is asymetrical unless you put a high voltage diode in the secondary) > would require very high voltage. > > Lets take an example. To make a gallon an hour at 60 htz requires > abou 10K volts and about 25 mA of current. With a spark coil, which > typically has a 10 microsecond pulse before the leakage inductance > shorts it out, it would require 50,000 pulses a second to maintain the > same duty cycle. But this would quickly burn the coil out, since it > is made for duty cycles of maybe 1/100 of that max. So if we run it > at 500 pulses per second, we are running at about 1% duty cycle. The > amount of current necessary would need to be about 100 times large for > the same production rate. Thus we need about 1.4 Amps of secondary > current. With the step up these have, that would require about 3,000 > amps on the input. And since the frequency is about 8 times as high, > the current needs to be about 8 times as high as well, or about 30,000 > amps. Of course if you want to make it at a slower rate, then you > could use a lower amperage, of maybe 1 amp, and make a gallon in about > 30,000 hours. > > Now I could be off by a factor of 2, or even an order of magnitude on > some of these estimates, but the result would still be the same. I > believe it would be impratical. > > Use a 15 KV neon sign transformer like I do, and it will work fine. > > Marshall > > ascottsil...@aol.com wrote: > >> Has anyone tried making a HVAC generator for CS with a 555 timer and >> an auto coil? If the waveform is symmetrical and there is no ground >> reference then pulsed DC should work just as well as AC. Just >> curious... >> >> Andy > -- The silver-list is a moderated forum for discussion of colloidal silver. Instructions for unsubscribing may be found at: http://silverlist.org To post, address your message to: silver-list@eskimo.com Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <mdev...@eskimo.com>