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- To: "Tesla List" <tesla-at-pupman-dot-com>
- Subject: Re: Just a brush
- From: "DR.RESONANCE" <DR.RESONANCE-at-next-wave-dot-net>
- Date: Thu, 6 Mar 1997 06:40:03 -0700
TO: Chris Taylor Pretend you are a TV repair technician and you get paid by the number of TV sets per hour your can repair. The fastest way to resolve your problem is substitution. Try to borrow a good cap from another experimenter and repeat your tuning experiments. This would isolate and possibly eliminate the cap as a source of trouble. You may have some leakage problems that is killing your system performance. A 30 ma transformer is quite possibly being overloaded by a .008 cap. Try using a value of .004 or .005 with a 30 ma transformer. Another quick test would be to keep your .008 cap and try driving it with a borrowed 60 ma transformer to provide more current to charge the larger cap. I presume you have tried the other tap locations on your primary -- you mentioned a five turn optimal tap on the primary. Try other locations with a cap you know has good performance. On a small coil a good place to start is by elevating the secondary inductor such that the lowest turn on the secondary inductor is 1 1/2 to 2 inches above the primary inductor. In many cases it will end up being 3-5 inches above the sec. inductor for best operation with the system running. Tune for minimum smoke! DR.RESONANCE-at-next-wave-dot-net ---------- > From: Tesla List <tesla-at-pupman-dot-com> > To: tesla-at-poodle.pupman-dot-com > Subject: Just a brush > Date: Thursday,March 06,1997 7:27 AM > > Taylor, Chris CC wrote: > > > > I have just recently completed building my first coil and fired it up > > last night. To my utter disappointment all I got was a big racket from > > the spark gap and little else. > > > > I have a 15/30 neon with a six element spark gap and a plate poly > > capacitor, (20 plates 10x8" with an 80 mil poly dielectric, theoretical > > C=0.0085 uF). I haven't got around to placing the cap in an oil bath yet > > and it doesn't arc unless the gap separation is very large, the cap then > > arcs around the edges and I shut down and reduce the gap separation. > > Would the cap be providing 0.0085 uF without the oil bath, I can't see > > why not, it is my understanding that the oil is only used to provide a > > better insulator than air around the cap. > > > > The coil also has a 1/4" copper tubing primary with 15 turns spaced at > > 1/4" in a saucer configuration, (30 degree). The secondary is 22 ga > > transformer wire on a 2.8" PVC pipe with 840 turns, (22.5" long). > > > > All I seem to be able to get from this baby is a small brush discharge > > from the tip of the secondary wire, (primary optimally tapped at turn > > 5). I have also built an 11 x 3.5" toroid which when attached does not > > produce any discharge. > > > > My questions to the lads are; > > > > What sort of diagnostics can I perform to point me in the right > > direction for larger discharges. > > > > Have I missed anything, I have used a number of the circulating formulas > > to roughly size various components. > > > > The coil is working but just doesn't seem the be very efficient. The > > lowest turn on the secondary is in line with the inner turn of the > > primary, do I need to lower the primary to get better coupling. > > > > Is my secondary too long for efficient coupling, (H/W ~ 8.5) I have read > > this may be a bit large. > > > > The addition of the torus increases the resonant frequency, do I > > increase or decrease my tank capacitance as the secondary frequency > > increases and how do I adjust the primary tap as the secondary resonant > > frequency increases. > > > > Any help would be greatly appreciated and will speed me on my way to > > coilers nirvana. > > > > Chris Taylor > > Perth, AUSTRALIA
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