Re: Spacing??? Too much?

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Pyrotrons-at-aol-dot-com>

Hi Erik.

I would go with a 1/4" spacing between turns on your primary coil. A 1" 
spacing between coils should be adequate for even a roughly tuned system.

A side note: From my experience, increasing the size of the secondary coil 
does not increase your sparklength by much, if at all. I ran a 6" secondary 
coil with a 9kV 30mA NST, and couldn't get more than 7" out of it (I was just 
toying around). I then wound a 3" x 10" coil, and I'm getting 10" out of it 
quite easily. What I'm saying is, I would go with a smaller secondary (I've 
found that 3" coils are a good size for 270VA input). That is, unless you 
plan to run more power in the future. Dave Wightman ran his 8" coil at the 
Y2K Texas Teslathon and got like, 8-10 foot arcs with something like 7-10kVA 
in. Very impressive up against his coil's size! He has to use those "creepage 
disks" though to keep it from flashing over. That coil is amazing.

Anyhow, I always use a 1" spacing for coils whether they're low or high 
power. It has always worked fine ; )

For 3/8" tubing I use a 3/8" spacing. For 1/4" tubing I use a 1/4" spacing. 
IMO it just looks better like this, but thats personal preference. 

As far as coupling goes, less t-t spacing will result in tighter coupling 
between the coils. On my most recent low-power coil, the primary has a .15" 
t-t spacing and is wound with #12 house wire. It is a flat spiral 
configuration - - - and it overcouples!! Racing sparks, flashovers, etc. I 
have to raise the secondary coil to keep it from destruction.

Take good care - good luck w/ your new 7".

Justin Hays
KC5PNP
Email: pyrotrons-at-aol-dot-com
Webpage: http://www.angelfire-dot-com/tx4/electricbuzz/mainpage.html