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Re: [TCML] Largest Secondary Coil "Drivable" by Primary Circuit
For what it's worth, I've been using the same Terry Filter as I've added NSTs, from 30ma all the way up to where I am now at 240ma out of 5 NSTs. The MOVs and safety gap are voltage sensitive, so as long as the voltage stays the same, it should keep working. Though I do worry the additional current will blow something if and when it does fire again. I've been watching my tuning very closely and simulating every move I make on JavaTC, and since I started doing that my safety gaps haven't fired once....or maybe once when I miscounted the turns on my primary for the tuning tap...
As I increased power I had to cut out some of the inner turns of my primary to increase the distance between the primary and secondary windings, or they would arc. JavaTC gives you the numbers for this, so it was pretty straightforward.
I started with a 4" x 22" secondary and I'm now at a 6" x 28" secondary. When I added my second NST I switched from a static gap to an SRSG, which also changed all the tuning, etc. Then, I had to change my primary because the 6" secondary didn't fit.
I had to increase my MMC bank with each NST I added, and consequently, I had to change the primary tuning with each step as well. I started at 16.67nf and grew my MMC to 41nf. Each 30Ma I added wanted another ~13nf, so when I got to 120ma I didn't have room for the additional banks of caps, so I bought some Maxwell Pulse caps on eBay and started paralleling them with my MMC. I'm now at about 101nf with 2 Maxwells and my old MMC.
I progressed step by step, and each step in increased current and capacitance brought new issues. Though I'm happy I did it this way. I learned a lot in the process. And the most important thing I learned was if you do anything at all to help yourself, simulate, simulate, simulate. You would be surprise how many "mystery" issues disappear when you use the parameters that come out of JavaTC.
On Sep 25, 2010, at 3:11 PM, Brandon Hendershot wrote:
> Hi All,
> I was looking at my secondary today that I plan on using in my next coil,
> and it looks so small to me now!
> I'm thinking about going all out with it now! :D
> What's the largest sized secondary dia. I could possibly hope to use with my
> primary circuit?
> * 8 Amp Variac
> * Basic Terry Filter
> * 15kV 30mA NST (Can add a second identical transformer for more power. ;D)
> * Richard Quick Spark Gap w/ 200CFM 120 V A/C Quenching Fan
> * 36kV 8.75nf MMC Bank (942C20P15K Cornell Dubilier Caps) (Second MMC bank
> can be added to balance the additional NST)
> Oh! Do I need to modify my Terry Filter to accomidate the second NST??? I
> imagine not, but I'd hate to fry it!
> What's the largest anyone here's ran with a system similar to mine?
> Thanks All, I really appreciate your help!
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