Choke and Step up Tran for 4 Pac mot supply

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Original poster: "tmoore by way of Terry Fritz <teslalist-at-qwest-dot-net>" <tmoorezz-at-adelphia-dot-net>

Hello All,

      I have some good news my Six inch secondary tesla coil is almost
finished, except
for some minor details. This spring when it gets worm out, I plan on making
the biggest sparks possible with my new system.  That's what this email is
about maximizing my system, I have finished my power controller, I have a
hearty 4 pac mot supply under oil, I have finished my tank circuit it has 2
Maxwell capacitors for a total of 0.06uf -at- 35kvac with a safety gap and also
a RQ spark gap with three 2 inch long by 1.125 diameter copper pieces. Also
I have a choke for current limiting to the mots that I constructed myself.
I made it from a toroidal core I removed from a 6 amp variac, it has around
5-6 layers of 12awg wire wrapped around it with four taps one per layer. It
was a while ago when I tested the mots and choke and I am going by memory.
When I hooked up the choke by itself at the max tap I believe it drew 25 to
30 amps and while it was hooked up to the 4 pac of mots it drew I believe
around 12 amps and at the lowest tap while hooked to the mots I believe it
drew 30 amps max. The choke and wire never got worm during my tests and
handled the current fine.

       What I was thinking of doing to maximizing the system was taking the
core from another 6 amp variac and wrapping 35 turns of 12awg on one side of
the core and then wrap 25 turns of 12awg on the other side or maybe put more
turns on as long as it maintains the same turn ratio for a step up
transformer. What I am trying to do is at my max power is have the trans and
cap match so that I may open the spark gap wider to allow bigger bangs. I
figure that the output voltage of my 4 pac is around 8500Vac, now the bang
size at 8500v with a 0.06uf capacitor is 2.17 joules, now if I stepped up
the voltage to 11500 with the toroidal transformer I would like to make the
bang size would be 3.97 joules, and now if I took it up to max power 3KW the
power from the 4 Pac would match the capacitor allowing for the voltage to
charge up, and if I set my spark gap to fire at 15kv the bang size would be
6.75 with aprox 440 bps. Well what I would like to know is will this step up
tran work it should but is there some thing I am not considering?? And how
many turns should I use would 25 on onside to 35 on the other be good?? Or
should I put more like 35 to 50 turns?? I know that overvolting a 120v mot
can cause saturation, but it would only be a 30% increase in voltage I
figure they can handle that. Also should I put the choke in line with the
tran and then hook the tran to the mot supply??

      One other thing I was considering doing is adding another toroid on and
have 2. The I have currently is 30 inches long and 6.5 inches high for a
total capacitance of 32.5 pF, If I add a second toroid it will measure 19 by
3.375 inches and that would measure 19.8pF. The smaller one would be
underneath with at least an inch of clearance between them. Now for my
calculations I am not sure what the total capacitance would be, would you
just add the two toroids together so it would be a total of 52.3pf or is
there some formula you need to figure out the total capacitance of the two
toroids??? Thanks for answering all my questions and takin time to helpin me
out, also if you got any tips for getting the bigger sparks that's greatly
appreciated!!!!

Sincerely,
Nolan Moore