RE: realistic expectations from mini coil ??

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

Original poster: "Mccauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com> 


Jon,

Good to see you working on a minicoil.  They are very rewarding to build
and best thing about them, are
easily transportable!

I believe with a 4kV/30mA transformer, maximum arc length obtainable is
approximately 8-10 inches based on
performance of others building the same type of coil.  Gary Laus has
been hosting a low-key informal 4kV
mini-coil contest for the past two years, and the top contenders are
only getting about 13-15 inch
maximum arcs with modified 4kV/20mA transformers putting out 38mA output
current.

(If your transformer is open frame, you can easily remove some of the
magnetic shunts to increase output current.)

19 inches of output arc is very unlikely (but not impossible) with only
a 4kV/30mA NST.  Even 10 inches will be something you have to work at
for awhile.  Based on your current specs, 5" seems about right for the
coil you are specifying.

THE BIGGEST FACTOR I found in increasing arc length in my 4kV minicoil
is the size of the toroid.  To get longer arcs,
you really need to make your toroid as large as possible.

Anyways, here is my website:
http://www.easternvoltageresearch-dot-com/teslacoil4.htm

Here is Gary Lau's minicoil site (my main competitor)
http://www.laushaus-dot-com/tesla/minicoil.htm

(Both minicoils above use identical transformers Franceformer 4020SE
4kV/20mA modified to 38mA)

Dan