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Re: [TCML] Coil V5 - first light

Hi Brent,
Well put. To clarify when I say less energy per bang I'm implying use of a smaller cap to accommodate a higher break rate, so more but smaller breaks, same average power. Good thoughts nonetheless, Interesting secondary geometry (is it a magnifier?) do you have some pictures of your system, I'd love to see them, 6 feet is pretty darn good for 4kW, and a system that runs for 12 years is a real accomplishment, I'd like to see construction details for implementation in my future designs. A magnifier is my next tesla project on my list, for now I've been concentrating on plasma stuff, learning a bit of glassblowing. 

Scott Bogard.

On 10/23/2010 2:50 PM, bturner@xxxxxxxx wrote:

Some comments -

Tight coupling and high break rates results in approximating CW operation
- this is what Tesla was doing with the magnifier system. A high-power CW
'master oscillator' end-feeding the free-resonant 'extra coil'.

Faster break rates don't really dimish the discharge energy unless the
break rate is faster than the 'ring-up' time in the secondary. (Hence WHY
maggies use tight coupling AND high break rates - not a matter of maximum
secondary voltage, rather, maximum secondary CURRENT.) Another thing that
is often overlooked in RSG's is the conduction -- dwell -- time. THAT is
more important than the break rate in reference to coupling and ring-up
times. Match the dwell angle to the ring-up time and the efficiency starts
to really climb.

I am now running my system at 600 bps(!) full synchronous, 0.06uf, 12Kv
input. I still get effective ring-up, no drop in voltage, but the high rep
rate packs a whole lot more energy per second into the discharges - BRIGHT
WHITE arcs to ground and 6+ feet in length. Not bad for 4Kw input, and the
secondary coil is only 10" diameter and 20" in winding height (2:1)...
Hasn't broken down yet in over 12 years of operation...

- brent turner




Remember Joe, with higher BPS you can shoot for a much higher coupling.
   Yet another reason I hate SRSG, I used to get racing arcs with a loose
0.12 coupling, with my ASRSG, I don't and my coupling is a whopping 0.16
(the primary sits a half inch ABOVE the bottom of the secondary!)  This
higher coupling makes your arcs sooo much brighter it isn't even funny,
I can see them in near daylight!  Keep this in mind, higher break rate,
smaller bangs, less energy per bang, bye bye racing sparks.  Remember
every change you make transforms the coil into a whole different animal,
throw established knowledge out of the window and test to form new
assumptions, just don't forget what you've learned so you can retest old
assumptions on different configurations.

Scott Bogard.


On 10/23/2010 11:00 AM, Joe Mastroianni wrote:

Hi David,

JavaTC suggests the optimal coupling is in the 0.14 range.  However, for
my prior, now extinct secondary, I got killer arcs when I got close to
that.  Could have been cause by other issues - like the fact I put
0.12uF of cap in the tank. (now running 0.06uF)   But I'm wary of higher
k.  Every time I mess with getting close to 0.14 or 0.13, I get badness.

I am going to measure the k directly, today, and will post the numbers.

Cheers,
Joe




On Oct 23, 2010, at 4:24 AM, David Rieben wrote:


Hi Joe,

Although this has nothing to do with your Dolphs "bubbling up
on you", I did notice that your physical primary/secondary coupling
looks rather loose to me. Your calculated k = .09 is probably "in
the ballpark" but to my understanding, around .12 to .15 is usually
considered in the optimal range for medium to larger SG driven
coils. IIRC, the top plane of the copper tubing primary of my
Green Monster coil system lies only about 1.5" below the level
of my lowest seondary turn and this seems to work great for me
(no racing sparks but plenty of good energy transfer).

David Rieben


----- Original Message ----- From: "Joe
Mastroianni"<joe@xxxxxxxxxxxxxx>
To: "Tesla Coil Mailing List"<tesla@xxxxxxxxxx>
Sent: Friday, October 22, 2010 8:18 PM
Subject: [TCML] Coil V5 - first light


http://yfrog.com/n2rrfj

8.5" x 34" secondary.  919 turns of heavy build 20ga.  6" x 24" toroid
Using the same dreaded ribbon primary because I didn't want to have to
build a new one yet.  Spacing between the top of the ribbon and the
first turn of the secondary is 3.75".  k=0.09 calculated (not yet
measured).  ARSG.  Pig running at about 30A.
Sparks seem to be in the 6-7' range, but have yet to mount the larger
toroid I'm working on.

Basically, needed to replace my 6.25"x24" secondary that burned last
weekend.

Problem with this secondary is that the Dolphs bubbled up on me.  It
went on w/o bubbles, and they emerged later.   I coated all week, at
least 1 coat per day.   Could it have happened because it is much
colder out then when I wound my prior secondaries?

Cheers,
Joe_______________________________________________
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