Re: Magnifier Report

To: tesla-at-pupman-dot-com
Subject: Re: Magnifier Report
From: Bert Hickman <bert.hickman-at-aquila-dot-com> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Sat, 10 Oct 1998 11:20:36 -0600
Approved: terryf-at-verinet-dot-com

Thanks for the update John! Comments below...

Tesla List wrote:
> 
> Original Poster: FutureT-at-aol-dot-com
> 
> All,
> 
> In new work, Lou Balint reports that he obtained a stronger longer
> spark output from his magnifier when he tuned the secondary to 1/2
> wavelength and the extra coil to 1/4 wavelength for a total 3/4
> wavelength for the secondary and extra coil combined.  This is
> compared to the usual tune point which tunes to the combined
> secondary-extra coil resonant frequency.  The new tune point gave
> about a 10% longer spark.

Hmm... interesting! This kind of makes sense, since a base-driven 1/4
wave resonator would like to "see" a current anti-node at its base.
However, since half-wave operation doubles the driver secondary's
turn-turn voltage stress, it will be interesting to see if this mode of
operation can be "scaled" to higher power/disruptive operation. Suspect
it will be a formidable challenge to provide adequate primary:secondary
insulation while maintaining a high coupling coefficient when the
secondary's maximum voltage point is at its midpoint. Sincve we get no
bootstrapping benefit off the driver output voltage, true 1/4 operation
on the tertiary coil also increases the turn-turn stress to that seen in
a 2-coil system - no "shorty" coils need apply.

> 
> He is driving the magnifier at low power using a robust signal generator,
> and he obtains about a 1" output spark.  A neon bulb array is used to
> monitor the tuning and any nodes along the coils.  Best results are
> obtained when a low voltage/low impedance node is positioned at the
> base of the extra coil.

Saw this demo'd by Lou this summer - these were extremely effective n
mapping the e-field around the driver and resonator!

> 
> Lou has also tried placing a variable tuning capacitor across
> approximately the bottom half of the secondary to assist in correctly
> positioning the low voltage node at the base of the extra coil.  This
> tends to help the coil's performance also.
> 
> John Freau

Again, scaling this would be extremely challenging for a higher power
disruptive system. Thanks again for the update,and please keep us posted
on any further interesting work that Lou's doing!

Safe coilin' to you!

-- Bert --