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Re: Nathan's Saga Update...
Tesla List wrote:
>
> Original Poster: "Nathan Ball" <nateburg-at-hotmail-dot-com>
>
> Terry,and All,
>
<SNIP>
>
> I soon found that I am inducing current into the motor windings, because the
> plug in at the other end of the cord where I was started getting corona
> discharge and melting itself to the carpet.
>
> So I am pretty sure I'm getting induction to the motor- but does anybody
> else have experience with this? I havn't noticed any change when I use the
> rotary (At least when my power supplies were reliable enough to run the
> coil). Does anybody else have problems with induction of current into their
> motor windings?
Nathan,
The high voltage is not coming from the motor windings, it's most likely
coming from the power cord. Any length of wire in the immediate
vicinity, and the metal in the motor body itself, will capacitively
couple to the near e-field of your coil and will act like an antenna.
You're picking up HV RF from your high fields near your system. This is
especially bothersome if the system's not breaking out. Any loose
lengths of wire in the vicinity of your coil should have a safe path to
shunt any stray RF to ground, or should be tightly rolled up to reduce
its "pickup" length.
>
> I tried running it with my old toroid, a 3" by 14" foil taped dryer duct.
> It got no noticable improvement, but the streamer was very stringy, not so
> crackly and jagged like the other ones.
>
> The difference between the 15/30 and the 15/60 is very noticeable. There is
> not much of a distance increase, but the 60 gets much hotter, louder, and
> robust discharge than the 30 does. When I used the rotary before, though,
> loudness and brightness of the gap increased dramatically and coil ouput was
> longer, although still weak.
>
> When I tried the coil on 16 turns instead of 15 the primary, the output got
> slightly longer, although at that point the spark gap was firing quite
> sporadically.
You need to bring the system into tune first, then ramp the power up.
The best way to do this is to lay a short piece of wire on top of the
toroid, with one end projecting outwards a bit from the toroid. This
will create a breakout point for streamers to start. Close down your
static gaps so that the system fires smoothly. Run the system in the
dark, carefully looking at the output streamer length, and also looking
for any signs of abnormal corona or flashovers. Once you've got a feel
for the streamer length, shut the system down and add a bit more primary
inductance (no more than 1/4 of a turn max!) and try again. If the
streamer length increases, add another 1/4 turn and try again. If it
decreases, reduce the tap by 1/4 turn. If you have a well constructed
secondary, a good RF ground, and a good primary cap, you _should_ have
fairly sharp tuning point (indicating a hi-Q system). Once you're close,
change by +/- 1/8 turn to tweak it into tune.
Once you've tapped the system for best tune, you can then begin playing
with coupling and spark gap length (power level). You want to make sure
that your system is properly set up and in tune before pouring the coals
to it or using the rotary sparkgap. Increase the static gap and look for
signs of abnormal corona (such as a "Christmas tree" of corona from the
top of secondary to primary), or any inter-turn flashovers. Inter-turn
flashovers may indicate overcoupling, and a need to raise the secondary
versus the primary. You can then reduce the amount of overhang that your
breakout wire has on the toroid, or (hopefully) remove it altogether as
the toroid starts breaking out on its own.
Once you've got the gaps set for desired output power and you see no
problems, try lowering the secondary versus the primary no more than
1/4" at a time. If the output decreases, or you see sporadic interturn
flashovers on the secondary, raise it up a bit. Your system should then
be ready for running wuth the synchronous gap. Since the effective
energy level per bang may be higher with the sync rotary, you may need
to raise the secondary a bit if you see any signs of overcoupling.
Finally, you may find that you need to add a bit more primary inductance
at full power to compensate for the added capacitance from streamer
loading.
>
> I havn't done anything else this evening, but will hope to hear some input
> soon from you guys out there, so you can help me procrastinate my chemistry
> lab writeup some more this weekend. ;-)
>
> Thanks,
> Nathan
>
> PS. Are any of you experienced in Tesla Coil Exorcisms? I really think I
> should get some of these evil demons out of my coil... They're the best
> explanation I have for the poor performance now!
>
> Hopefully I will go to my dad's office and scan in some pictures soon so you
> people can see my actual coil, and maybe that will help you help me. -N
>
> ______________________________________________________
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Try the above, and it should do the trick! Safe coilin' to you, Nathan!
-- Bert --