Re: Practical limit to number of turns on primary ? ? ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steven Ward by way of Terry Fritz <teslalist-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

A friend of mine made a coil with about 24 turns.  It had 2 12 turn 
primaries in series.  I think he used 21 turns of it. The coil used a 12/60 
NST, RQ gap, 4.5" x 24" (28awg) secondary, a 4.5"x18" toroid.  One special 
note is that he uses for his MMC the cornel dubilier 940C, NOT 942C caps.
They are rated .15uf at 2000v.  I was worried when he said he bought them, 
he didnt know there was a differece. But surprisingly, they worked 
extremely well!  Though we didnt run the coil for too long yet.  The coil 
made 38" sparks, and the coil seemed exceedingly wild in behavior.  I dont 
know that he really lost any efficiency, but i think he gained 
some.  Compared with other coils of the same input, and spark gap, there 
was an increase in spark output of about 6" at least, and the coil appeared 
more powerful overall.
So maybe 18 turns isnt a bad thing!

Steve Ward.




>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Practical limit to number of turns on primary ? ? ?
>Date: Sun, 26 Jan 2003 19:59:18 -0700
>
>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><dhmccauley-at-spacecatlighting-dot-com>
>
>Through your tesla experiences, what is the practical limit to the number of
>turns on a primary before efficiency and performance begins to suffer?
>
>I personally have not built a primary with more than 16 turns, and it seems
>most have not built tesla coils with greater than 16 turns and most of the
>tesla cad
>programs come up with errors when you exceed 15-16 turns (i.e. Tesla Coil
>Cad V2.0).  Is there a reason for this?  I know it will effect coupling,
>primary losses, etc..., but wanted
>to hear what your experiences were with large number of turn primaries.
>
>Just FYI, my current secondary resonant will be somewhere between 70-85 kHz
>with toroid and 0.0275uF primary capacitor and over that frequency range, my
>tapping range would
>be around 14-18 turns depending on the frequency.
>
>Thanks
>
>Captain Corona