Re: [TCML] upgraded NPT to 15/60

[Joe Mastroianni <joe@xxxxxxxxxxxxxx>]

Hi Gary!
(Yes, NPT=NST....rented fingers...)
Thanks for the advice.  I was thinking I would have to add another string of 18 caps, to bring it to 3 parallel strings for the SRSG (according to the Tesla Map Program I need ~27.7 nF), but if you suggest 40nf  I may try that - or close to that.  I have enough caps for 4 strings of 18 so I can give that a try.  I will be using a new secondary, same primary.  But then the topload has to change as you suggest.  
Any suggestion where I might find a spun aluminum toroid that's bigger?   I think there was a suggestion on this mailing list some time ago about Ross Engineering but there was another place was O.W. Landergren and then finally John Freau himself.   Do you know if these sources are still good?  I guess on Monday I can just start calling.

Thanks!
Joe




On Jun 12, 2010, at 4:26 PM, Gary Lau wrote:

> Hi Joe,
> 
> NPT=NST??
> 
> A couple things I want to mention.  Your toroid looks kind of small for a
> 15/60 powered system.  My 15/60 coil uses a 7"x30" toroid, and every
> increase in size resulted in longer sparks.  The down side is that while the
> sparks got longer, they also got less frantic and bright, so that's a
> tradeoff.
> 
> You also mentioned using an SRSG.  It's vital to realize that you just can't
> swap out a static gap with an SRSG.  Unless you also increase the cap uF
> when going to an SRSG, you'll overvolt things considerably, or if you have
> properly set safety gaps (a MUST-HAVE with any rotary gap), they'll fire
> constantly.
> 
> With my 15/60, I found the optimal SRSG cap value to be 0.04uF (at 60 Hz).
> This is larger than most folks use with a 15/60 & SRSG, but works well for
> me.
> 
> Of course if you change the cap size with the gap type, you'll also need to
> change the primary or secondary or topload to keep things tuned, so it's not
> possible to change only the gap and see if performance improves.  It really
> involves a complete system makeover.  But it's a good time to consider
> increasing primary and secondary inductance and topload size - all
> beneficial things.
> 
> Regards, Gary Lau
> MA, USA
> 
> On Sat, Jun 12, 2010 at 6:39 PM, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:
> 
>> Same coil I showed last time.
>> Added another bank of CDE 942C20K15 caps to bring total to 36.   Two
>> parallel strings of 18.
>> Upgraded the NPT to a 15/60.
>> Spark activity is much more significant.  Where before I would only have
>> sparks at the brass breakout rod, now they're everywhere.
>> I think I'll try shining up the toroid to see if that changes the
>> characteristics.  I'll also do a night shot for contrast.  The streamers are
>> actually hitting the strike ring now, which they didn't before.
>> 
>> Tuning had to change from the 15th turn of the 1/4" flat coil of
>> refrigeration tubing to between the 11th and 12th.  I didn't do fine tuning
>> yet.
>> 
>> <http://yfrog.com/mjimg0083z>
>> 
>> I have some components for the synch rotary SG, and other showing up this
>> coming week.   We'll see how that works.
>> 
>> Cheers,
>> 
>> Joe_______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxx
>> http://www.pupman.com/mailman/listinfo/tesla
>> 
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla