Edmund Scientific Tesla Coil

To: tesla-at-pupman-dot-com
Subject: Edmund Scientific Tesla Coil
From: "Steve Young" <youngs-at-konnections-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Tue, 28 Dec 1999 13:16:28 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi list,
 
Just wondering if any of the list have had experience with the litle Tesla
Coil sold by the Edmund Scientific Company.  See it at
http://www.edmundscientific-dot-com/Products/DisplayProduct.cfm?productid=1024
 
What is unique about it, outside of the high price tag, is that it uses a
"kicking coil" instead of the usual step-up transformer to power it.  For
more on kicking coils, see "High Frequency Apparatus" by Thomas Stanley
Curtis, published by Lindsay Publications.  There is a whole chapter
devoted to kicking coil apparatus.
 
As you can see by the web site photo, it produces a fairly wimpy output.  I
was just wondering if anyone has added a toroid and more primary turns to
see if the output could be beefed-up some?
 
Anyway, it might be a consideration for someone's first coil to experiment
with.  The primary circuit is all at line voltage, which can kill but is
safer than NSTs or pole pigs for beginners.
 
For those wondering what on earth a "kicking coil" is, basically it is an
iron core coil, such as an ordinary relay coil, and a vibrating set of
contact points (such as normally closed contacts on a relay).  It works
just like an old style electromechanical buzzer or doorbell.  Basically, it
is an induction coil without a secondary.  The voltage step-up is the
result of the inductive "kick" as the magnetic field collapses when the
points open.
 
The circuit is as follows:  AC input goes to series connected iron core
coil, vibrating points, TC primary, then to other AC input.  Capacitor is
across bottom of primary and junction of iron core coil and points.  With
points open, the iron core coil "kick" charges the cap.  With points
closed, the cap discharges into TC primary and the iron core coil is
energized from the AC input, which opens the points again.
 
Smoother operation would result from running the kicking coil from DC as
there would be no "beating" effects between the AC line frequency and the
frequency of the vibrating contacts.
 
Anyway, I believe some list members would be interested in the experience
of others with this little coil, or with any others powered by a "kicking
coil", especially a larger setup.
 
--Steve Young