Re: SIZE of RF chokes?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi JT,

At 01:48 PM 11/19/2005, you wrote:
> You said:
>  "You may be pleased to hear that my TT-42 coil which gives 42"
> sparks from a 12/30 NST, does not use any filter.  I just use
> safety gaps."
>
> 42 inches cant be correct. According to 
> the......universal......sparklength formula, you should only get a 
> max of 37"  (  1.7*sqrt inputpower ) in watts )

John is the one that "wrote" that formula :-)))))  His TT-42 coil is 
sort of the "standard" others try for.  He has everything just 
"perfect" on it!!


> By the way now I hate your guts, considering you're using the exact 
> same transformer as I, but getting.......3 times more power coming 
> out. I dont realllly hate you but...you get the idea

"Envy" >:o)))


> With my current system in place, I get 9 to 11 inch discharges to 
> the air, and when i add a breakout point, pointed at a grounded rod 
> - I can stretch it to 15.5 inches

That does seem like something is wrong!!  I looked back over your 
other e-mails and you don't tell us a lot of details of the 
coil.  Don't worry about the Terry filter thing for now, but you 
should always use safety gaps at least.  The filter will not make 
your coil run better at all.  In fact it will decrease performance a 
few percent.

What I would like to know is all about your primary cap.  What is 
it's value and how is it made???  If it is a nice MMC, then  the low 
performance is caused by something else.  What and how is the spark 
gap made???  A bad spark gap can sure mess performance up!!!  Are you 
sure both sides of the NST are good.  If only one side of the NST is 
alive, that would explain the short sparks right there!  A full ring 
shorted safety rail or a primary too close to larger metal objects 
can sure eat up performance too!!  Of course, tuning is always super 
important...


> thats a total efficiency of about 50%
>
> OK, but using just a safety gap is BS, i saw your site dude. You use 
> a terry filter. NOt to mention, just because your coil performs 
> good, doesnt mean it will last forever. I am very happy with 15" 
> discharges if I could get my coil to last..... 5 or more years. I 
> care less about power.

A nice coil will last hundreds of years.  If it is used every day 
hard, like a public museum coil, then there will need to be some 
maintenance.  Only the new DRSSTCs have a hope of running "forever" 
without any care...  I worry that the low performance is caused by 
something that will eventually burn something up, so we should get 
that fixed for sure.


> I NEED HELP WITH A SAFETY CIRCUIT, DESIGNED TO BE VERY SPACE EFFECTIVE.
>
> (I HAVE EXACTLY A 2.5" X 3" X 3.5"  SPACE FOR A SAFETY CIRCUIT RIGHT 
> NOW. OH, AND GET THIS- I ADDED A GROUNDED CENTER TO MY SAFETY GAP, 
> AND IT STOPPED FIRING ALL TOGETHER........>>>>(WTF?????)

Just the safety gap is fine.  The Terry filter puts out a lot of heat 
and would overheat in a small enclosed space.  The filter is really 
not needed if the coil is made carefully and well which I think yours 
is.  The Terry filter is really sort of a last resort for those that 
are blowing NST all the time because they really don't know what they 
are doing.  Sort of like airbags in a car,  not needed, if you don't crash ;-)


> RESPOND ASAP

I am typing as fast as I can :o)))


> let me send an email to you, with pictures of my coil. I have tons of pictures
> Whats your email.....

Send them to me toooooo!!!

vardin@xxxxxxxxxxxxxxxxxxxxxxx

The list does not accept file attachments, but I can post your 
pictures to a website so everyone can see exactly how your coil is 
made and that would help us help you out a lot!!

Cheers,

        Terry