Re: Over-coupled or under-insulated?

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

Original poster: "Chris Roberts by way of Terry Fritz <teslalist-at-qwest-dot-net>" <quezacotl_14000000000000-at-yahoo-dot-com>


First thing, I goofed on the primary diameter. It has two inches spacing 
all around the secondary and for some reason I thought it was 9.25. It is 
actually a 10.25 diameter, flat pancake coil. I haven't had any trouble 
with the primary sparking, (to answer the previous email) but I have about 
4 or 5 extra turns left. Win tesla says it should be tuned at turn 6. 
That's where I have it currently. The toroid has a 27 inch outermost 
diameter made with 3 inch flex tubing. It is spaced 4.5 inches above the 
uppermost winding, with the wire being slowly tapered off to prevent top 
turn corona. The sparks are all confined to the middle of the secondary, 
and it's not sparking to anywhere else, just along itself. The power supply 
is a 9/120 NST, cap is .05uf, spark gap is a vaccum RQ gap. I am using a 
variac to slowly bring up the power. Here are a couple of pics:

Here is an old picture (the wiring was replaced with thicker gauge, the 
primary was trimmed, secondary raised a LOT, etc) of the large coil with my 
mini coil on top. The secondary and toroid still look exactly the same.

<http://hot-streamer-dot-com/temp/miniattoribus.jpg>http://hot-streamer-dot-com/temp/miniattoribus.jpg 


This is a picture of the spark gap. The pipes sit with the gaps over the 
slits in the pipe. The vaccum motor on the top then pulls the air through 
the slits.

<http://hot-streamer-dot-com/temp/SG-1.jpg>http://hot-streamer-dot-com/temp/SG-1.jpg

The transformer. Pretty self-explanitory. Directly behind it you can see 
the way the secondary is supported. There are 4 threaded rods with nuts on 
them that the whole base that the secondary sits on. That way,  I can raise 
and lower the secondary at my discretion. However, I ran out of rod length 
to raise the coil up, so i ended putting a couple of boards underneath to 
raise it higher.

<http://hot-streamer-dot-com/temp/NST-1.jpg>http://hot-streamer-dot-com/temp/NST-1.jpg

So there's the five cent grand tour. (I would put all of this stuff on a 
website if I knew how) If you need any other info, be sure to ask.

  Tesla list <tesla-at-pupman-dot-com> wrote:
Original poster: "by way of Terry Fritz "

In a message dated 3/13/03 9:03:12 PM Pacific Standard Time,
tesla-at-pupman-dot-com writes:


Chris,

Where are the racing sparks? Bottom, middle or top of secondary? With
your 9.25" primary I.D. and the bottom turn of the secondary sitting just
at the top plane of the primary, the coupling should be fine. This is a
flat primary, yes? How about describing your toroid - size, shape and
distance above the top winding of the secondary. Since I don't recall,
what is the power supply? Spark gap? Primary capacitor? Are you
absolutely sure it is tuned correctly? Have you ran the math to calculate
about where the best tap point should be?

Ed Sonderman



-Chris