[TCML] New Coil

[David Rieben]

Hi Miles,

A good "rule of thumb" for approximate toroid dimensions is
the dimensions of the secondary coil. (Since your secondary's
measurements are 4.4" x 22", a toroid with a 4" minor diame-
ter and a 20" major diameter would be a good ballpark size
for your coil.) Of course, the toroid's dimensions are not real-
ly that critical, just so it provides significant topload C and
electrostatic shielding for the topmost turns of the secondary
coil, as John pointed out. Making the topload toroid's dimen-
sions approximate those of the secondary coil AND placing
the topload so that its bottom is no higher above the topmost
secondary winding than its MINOR diameter should address
these requirements.

BTW, that's a nice looking coil project you have going there.

David Rieben




----- Original Message ----- 
From: "Miles Mauldin" <teslamiles at att.net>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: Thursday, March 04, 2010 6:20 AM
Subject: Re: [TCML] New Coil


I knew I wanted something to raise the toroid but didn't know how high or 
whether I was going to use a double toroid. So yes, it is too long right now 
but I can always trim down, you can;t do the reverse though. Any suggestions 
would be greatly appreciated.

12kV / 60mA NST
31nF tank
RQSG initially, plan includes changing to SRSG
1/4 copper tube flat primary of about 12-13 turns
4.4" x 22" secondary windings, 26 AWG about 1200 turns
???Top load???

Thanks!
Miles




________________________________
From: John Forcina <forcijo10 at gmail.com>
To: Tesla Coil Mailing List <tesla at pupman.com>
Sent: Wed, March 3, 2010 7:08:20 PM
Subject: Re: [TCML] New Coil

How high above the top of the secondary are you placing the topload? From
the looks of it from http://www.cmnow.com/TeslaMan/tn25.htm you are placing
it on top of that smaller piece of pipe? That is just too high and it will
provide very little Electrostatic shielding for the top of the secondary and
you will get lots of loss and corona breaking out every were.