[TCML] MMC for 4 mot SRGTC

Sun Apr 6 18:15:23 MDT 2008

Hey David...

alright Im gonna bite on this one....Ive been running a SRSG for eons on 
the BIGPIG coil and you are stating that a BPS above and beyound 120 
results in better streamer length?

Hmm  how to approach this...   a router on a variac?  Any suggestions 
other than phase controllers?  ( I have the router and the variacs) Im 
limited to 120VAC supply for the spark gap motor...  sheesh  20Krpm from 
a router seems harsh ...definately will put the G10 disc to the ultimate 
G force test...

Scot D

David Rieben wrote:

> Hi Scott, Kris, all,
>
>
> I tend to agree with Scott on this issue. I've heard many of
> the pro's and cons regarding synch vs. asynch and IMHO,
> it comes down to a matter of preference on large, pig sized
> coils although there does defonitely appear to be an advantage
> to going synch with mid-sized coils driven by the limited avail-
> able power from NSTs. If longer sparks are what you're after,
> which is where the majority of us coilers are ;^), then the fast-
> er BPS rates afforded by an asynch RSG are a definite
> advantage with the much greater power throughput potential
> of large non-current limited transformers, like pole pigs. Some
> coilers do like to go synch with high powered coils, but from
> the spark length reports of synch vs asynch with larger coils,
> there doesn't really appear to be any advantage to "going synch"
> with a piggy powered coil. An asynch gap is also a bit sim-
> pler to construct. Also, there's the issue of securing a primary
> cap of sufficient rating to run LTR with a pole pig, as an LTR
> prerequisite would make for an impractically large and expen$ive
> capacitor. It's a lot simpler and more practical to just go asynch
> with an STR cap, utilizing a >100/120 BPS charge/dicharge cycle
> of the primary cap to increase the power throughput for longer and
> brighter sparks with large, high powered coil systems. Indeed, my
> large coil, with a 0.1 uFd primary cap seems to like 350 to 400
> BPS for the best output.
> http://www.dawntreader.net/hvgroup/david/gm.html
>
> My $.02,
> David Rieben
>
>
> ----- Original Message ----- From: "Scott Bogard" 
> <teslas-intern at hotmail.com>
> To: "Tesla Coil Mailing List" <tesla at pupman.com>
> Sent: Sunday, April 06, 2008 8:51 AM
> Subject: RE: [TCML] MMC for 4 mot SRGTC
>
>
>
> Hi Gary, Kris,
>     I use a sync gap on my 4-MOT coil.  I wish I didn't!  Granted I 
> use a ballast, but my performance is limited to about 54 inches.  4 
> MOTs can do much better, I've seen it.  You would be better off to 
> design yourself an asynch gap, and then the cap size really doesn't 
> matter as much.  My understanding is that using sync gaps requires a 
> properly sized cap for maximum performance, and my cap size was picked 
> on faulty calculations, so lesson learned, it is best to just go 
> asynch anyway.  I am in the process of designing an asynch gap, but it 
> will be a long time until I can afford to build it with school 
> expenses.  As for using .4117 uf for a cap, my guess is that would 
> eventually destroy the secondary, but I really don't know (I have had 
> burnouts with .075, let alone .4 or even .12).  Just a thought.  There 
> are others with more experience that can probably comment on this.
>
> Scott Bogard.
>
>
>> From: Gary.Lau at hp.com
>> To: tesla at pupman.com
>> Date: Sun, 6 Apr 2008 13:18:47 +0000
>> Subject: RE: [TCML] MMC for 4 mot SRGTC
>> CC:
>>
>> I have never built a MOT-based coil, so take this comment with a 
>> grain of salt, but is using a sync gap necessary?  Using a higher 
>> break rate would diminish the required cap value.  I think I've heard 
>> more async gaps used with MOT's than sync gaps.  Maybe the same with 
>> pole-pig coils.  A LTR cap there would be HUGE.
>>
>> Regards, Gary Lau
>> MA, USA
>>
>> > -----Original Message-----
>> > From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On
>> > Behalf Of Kris Grillo
>> > Sent: Saturday, April 05, 2008 11:49 AM
>> > To: tesla at pupman.com
>> > Subject: [TCML] MMC for 4 mot SRGTC
>> >
>> > I am putting together a 6" coil with 4 MOT power supply and a 120 
>> bps > sync rotary
>> > gap.  I would like to run the mots wide open (no ballast). I 
>> estimated > 8400 V .5A for
>> > the transformer output. For the MMC, JavaTC is saying I need 
>> .4117uf for > LTR!
>> > That seems huge to me. I have 60 of the 942's for 5 strings of 12 
>> right > now, and I
>> > planned on doubling that to get to .1249uf before I get it up and > 
>> running, but that is
>> > still less than resonant. I could probably swing another 84 caps to 
>> get > to 12 x 12 for
>> > a just about resonant cap, but 336 more caps for the .4117uf value 
>> is a > little out of
>> > my price range right now. Is it so important to run larger than 
>> resonant > cap with a
>> > mot driven srg coil? The mots are under oil, if that matters. Any > 
>> suggestions?
>> >
>> >
>> > ---------------------------------
>> > You rock. That's why Blockbuster's offering you one month of 
>> Blockbuster > Total
>> > Access, No Cost.
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