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Re: Latest magnifier results

Subject:       Re: Latest magnifier results
       Date:   Tue, 10 Jun 1997 00:25:46 -0700
       From:   Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization:  Stoneridge Engineering
         To:   Tesla List <tesla-at-pupman-dot-com>
 References:    1


Tesla List wrote:
> 
> Subject:  Latest magnifier results
>   Date:   Sun, 8 Jun 1997 09:15:37 +0000
>   From:  "Bert Pool" <bertpool-at-flash-dot-net>
>     To:   Tesla List <tesla-at-pupman-dot-com>, jgore-at-onramp-dot-net
>     CC:   bemery-at-why-dot-net
> 
> Wild Bill Emery and I built a new primary for our magnifier Saturday.
> We increased its diameter by a total of four inches which reduced
> coupling to an acceptable degree (nope, we have not yet measured the
> actual value).  This night's run we tested the new FOUR layer
> secondary and a new TWO layer resonator coil.  Did it work?
> 
> We are proud new entrants into the grand order of 10+ foot spark
> makers.  We couldn't be more excited.  Well, ok, if we'd gotten 15
> foot sparks, then we'd have been more excited.
> 
> We found that we could directly replace the 8.44 inch by 24 inch
> single layer resonator with the two layer resonator without retuning
> whatsoever.  The two layer coil does perform better than the single
> layer coil, though not to a dramatic degree.  We might see a bigger
> difference when we move up to larger capacitive top loadings.  We
> are getting constant ground strikes from our toroid, which is
> mounted over seven feet high.  Longest measured strike to ground was
> 10 feet, though we have streamers probably longer than that.  The
> neighbors loved it.  We even had neighbors on other streets load
> up their pickups with their kids and drive by to watch.
> 
> Our variac stcak suffered a very violent demise, complete with
> fireball and acrid smoke.  We crawled into the power cabinet and
> bypassed the variac so we were running directly off the contactors.
> "Variac?  What variac?  We don't need no stinking variac!"  Instant
> on, instant off.  Worked great.  We tripped our 60 amp circuit
> breaker countless times, usually when the output spark hit the
> transmission line and triggered a safety gap firing.
> 
> We experimented with using a piece of 10 inch wide aluminum flashing
> as a transmission line.  I expected horrendous corona off the edges.
> Nope, works very well, we saw no transmission line corona at all.  It
> seems that the same physics which allow flashing to serve as a good
> low impedence ground conductor also allow it to serve as an admirable
> low impedence high voltage transmission line for magnifier work.
> Downside:  it tens to flap a bit in light breezes.
> 
> Next on the agenda: a new 100 amp breaker has to be installed, and
> we'll try moving up on the top load capacitance.  We designed a new
> way of stacking our 36 by 8 inch toroids, so we'll probably next
> attempt two toroids.  We'll also be moving up our tank capacitance
> from 0.015 ufd to 0.03 ufd.  We're gonna leave the variac bypassed
> for now.
> 
> Bert Pool
> bertpool-at-flash-dot-net

Bert & Bill,

Thanks for the great update! Too bad about the variac though... OUCH!
Looks like you'll need to hit the Hamfest circuit to score another one
cheaply. Should make for interesting running going from zero to full
bore by hitting the contactor!

It is surprising that you didn't see any corona coming off the
transmission line, especially after your previous report about the power
arcs to ground! One thought - if you rolled the outside edges of the
strip transmission line, maybe you could kill two birds... make it
stiffer and also reduce incidence of corona - a cross section:

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Congratulations in hitting the 10 foot mark, even if it was a little
painful!

-- Bert H --