[TCML] MMC for 4 mot SRGTC

[Scott Bogard]

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?
> >
> >
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