Re: How should we measure coil efficiency

From: 	FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: 	Monday, July 21, 1997 11:02 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: How should we measure coil efficiency

> GOODNESS = (spark length to grounded terminal)  vs. (Energy in Cpri) X BPS

Are you refering to a steady, connected spark to ground, or occasional hits?

My concern about steady sparks to ground is that they may not be truly
representative of the normal free air (or occasional to ground)
spark length performance.  Malcolm's recent work at various 
break-rates suggests this...if I'm understanding the
conclusions of his findings.  In other words, two different TCs may give 
indentical steady spark lengths to ground, but very different free air 
spark lengths, (different than each other).  (free air length, same as
occasional hits to ground length).

Break-rate is tricky, the way in which it affects spark length and
brightness seems poorly understood, since it is so dependent on 
ionization effects in the air.  Break-rate seems to affect the relationship
between "controlled" and free air sparks.

Comments welcomed,

John Freau
> This seems to be the most interesting TC figure of merit, since it measures
> how effective the coil is at building arc bridges with the energy that is
> delivered to its primary.  Long arcs seem to be the primary objective when
> building TC's, so the art is obviously in making the longest arc with a
> given amount of primary energy delivery.
> The above figure of merit is also easy to measure -- all that is required
> is a tape measure and a voltmeter.
> -GL