Re: entire secondary

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

Original poster: "Jason Petrou by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jasonp-at-btinternet-dot-com>

Jonathon

> 1) My Idea was based on transportability (is that a word?) I want to be
able to
> take the whole thing apart and move it around. My idea was to have an
endcap
> bolted to the pri/sec base, letting me just set the secondary in the cap.
I
> would also be able to add shims to raise or lower the coil.  I see no
problems
> with this, except for grounding.  I had a few thoughts.

>       a) have the bottom of the coil (the actual bottom) covered with a
copper
> ring that would make contact with another copper ring in the end cap to
make
> the connection.
Very bad idea - a copper ring represents a shorted turn and will melt the
bottom of your secondary. Since the voltage manifests itself at the top the
fact that you have a shorted turn at the top (topload) doesnt matter cos
theres no current. However at the bottom where there is current... well you
will probably destroy your coil

>       b) a metal tab on the outside of the bottom of the sec. that would
touch
> a metal tab on the cap.
That's the best approach

>       c) a wire that I would need to manually connect with a heavy duty
> connector
Possibly... But I never attatch things to the actual secondary wire, because
once you break the wire... I would go for the tab approach. Remember, there
isnt much current leakage to ground so dont worry about heavy duty - just
inductance. I use flat copper ribbon for the primary circuit and ground
connections.

> Same Idea with the toroid. Maybe a threaded rod to raise and lower the
toroid.
Generally speaking you shoudnt have to rewaise and lower the topload except
to stop arcs coming off the top of the secondary... I would use 3 nylon
bolts thru the end cap on the secondary to hold it together.

> 2) Is sealing the PVC pipe with PU before winding necessary? I have heard
that
> you should put some PU on, and while it is wet, wind the coil, so that it
acts
> like a glue...
>   Comments?
Not really - so long as the pipe is dry and clean beforehand. What I do is
wash it with washingup liquid and detergent, then sand it down with wet&dry,
then dry it out completely with a heatgun, leave to completely dry, then
wind the coil. I have never seen people wind coils when the PU is wet - it
would be very messy and pretty much pointless I feel.

> 3) I am using a 12/60, what size form would be best, 4.5" or 6"? The mag
wire I
> have is #20, so I am leaning towards 6" so I can get the most turns
without
> exceeding the H/D ratio. (4:1 ???)
With 20 guage wire (which is a bit thick but anyway) I would go for a 6"
form... obviously. However the secondary circuit is going to be quite large,
so I would keep that topload smallish (14" total diameter, 3" Al tubing)

Best R,
Jason