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Re: Rotor BPS

Subject:  Re: Rotor BPS
  Date:  Sat, 31 May 1997 08:38:14 -0400 (EDT)
  From: richard hull <rhull-at-richmond.infi-dot-net>
    To: Tesla List <tesla-at-pupman-dot-com>


>
>Hello DR. RESONANCE, Richard Hull & All:
>
>        I have a question that I hope can be directed at both of you and
>the
>group based on comments by you,  read over the last month or so.  First,
>a short update on my situation--I've basically made little progress on
>my new coil due to the record cold and rain in south eastern
>Wisconsin--worst since 1888!
>        O.K., the point made in the post above, about the secondary
>being 4-8
>inches above the primary and I believe Richard also mentioned something
>about 3-4 weeks ago that led me to understand most of the time you
>avoided raising the primary above the very bottom of the
>secondary---that is where I am real curious. 

snip
>        Finally the question-- my present understanding is that you must
>be,
>based on the posts be elevating the secondary to a point where your K
>must drop down to a low level, guessing maybe .08, or .12???  Have I
>missed the boat here?  I had expected with what I had learned in working
>with my 8" coil tuning process that raising the primary would provide
>better output, assuming the system design allowed for the greater K. 
>Now the discussion is suggesting another point that I don't have a clear
>view/understanding of right now.  Boy, I only have 3" of clearance right
>now when I roll it out of the garage and that's without the toroid! 
>What I am wondering is that with the bigger coils, is there less
>attention to the K value and more to eliminating pri/sec arcs by
>increasing clearances?  I have a 2 1/2" air gap between the pri/sec
>windings and thought this would be O.K.
>        They are actually predicting that the rain will stop (I really
>don't
>believe it) and it will reach 75 Degrees F this weekend.  I have dropped
>the primary to be on the same plane as the lowest/first turn of the
>secondary and plan to smoke test this weekend.  If the mood strikes you,
>any comments would be of interest.  Thanks in advance!
>
>Chuck Curran
>Cedarburg, WI
>
>
Chuck,

Most really large coils can use a coupling of .25 and work fine provided
the
spark is handled adequately.  Your coupling sounds OK.

Raising the primary up around the secondary is always a dangerous game. 
The
secondary voltage on the turns rise fast.  Very fast and you are asking
for
trouble with primary/secondary arc over.

A helical archemedian spiral in an inverted cone is just the best
primary
for large coils.  A 15" diameter coil should have about a 56X12 toroid
to
shield the primary system properly and take up and distribute the power
from
such a large resonator.

On Nemesis which was almost identical to your new large system, I had
only a
1.5" separation between the first secondary turn and the inner first
primary
turn.  I never sparked over at .28 coupling.  The system did require a
ground ring around the 48" diameter primary as the arcs were quite long
and
often arced in huge circling air arcs to this point. 

If anyone insists on elevating a primary after construction, they should
be
prepared for primary-secondary arcing.  If it does not occur and the
coil
works great, they are among the blessed!

Richard Hull, TCBOR