Re: DC secondary components

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

Original poster: "Wall Richard Wayne by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rwall-at-ix-dot-netcom-dot-com>

Jim,
 
A few years ago I mounted a disruptive TC to a plywood stand which I turned
sideways.  The coil was horizontal to earth and I placed it in east-west
direction.  I used a standard compass mounted on an insulated pole to sense the
magnetic field along side the TC.  As the coil fired the compass needle swung
east to west in the long axis of the coil.  I forget the N/S orientation of the
needle.  However, the needle was also sensitive to discharge of the coil and
moved more with bigger discharges.  My conclusion was that there was a DC
component of the TC discharge, but not necessarily before spark breakout.  For
some reason I experienced racing sparks in this configuration that the same
coil did not have in vertical position.  I became concern that even with the
insulated pole I may be exposing myself to potential HV superimposed on 60 Hz. 
So, I carried the experiment no further.  I would have like! d to do the
experiment with a rotory gap.  Technically there is a lot of inertia in a
compass needle and AC at TC frequencies should not be noticeable in needle
movement.  I'm pretty sure I reported the findings to the list and it should be
in the archives.
 
RWW