Re: Arc Over Between Secondary and Primary Coils

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Nolan,

If the tuning is off, you can get some pretty long primary to secondary
arcs (like a foot long!).  You may want to try adjusting the tuning if all
else fails.

I recently saw this problem and it is amazing how long the primary to
secondary arcs can be if the coil is out of tune.

Cheers,

	Terry


At 05:56 PM 3/15/2002 -0500, you wrote:
>Hello Everyone,
>
>    This is Nolan I have been working on a new mini tesla coil that I just
>finished building.  My mini coil specs are
>
>Secondary:  2.375 in diameter by 15in high wound with Awg 28 12.75 in long
>10 or more coats of polyurethane
>Primary: 6awg ground wire 0.25in spaced between turns max turn 8.75 1in
>spaced from secondary
>Topload: Toroid length is 9.5in and 3.375 cord, made from flexible Al tubing
>wrapped 3 times in Al tape
>Cap: Maxwell pulse discharge 0.03uf rated at 35kv
>Spark gap:  single static gap .25in carriage bolts set at 0.15in just below
>transformers max spark length
>Power Supply: Franceformer 7500kv at 60ma
>
>    My problem it that I am getting massive arc over from the middle of the
>secondary coil to the primary.  I noticed that when I had sparks coming off
>the topload to a grounded object 8in or close that there was no mid
>secondary to primary coil ark over at all.  When I move the grounded object
>away and let sparks go in to the free air I get tons of arc over.  Is this
>because the grounded object doesn't let enough energy to be stored and thus
>there is no arc over? Anyway I need a solution!  I was thinking about
>removing a turn or two from the primary, one turn would make the distance
>about 1.4in and tow turns removed would be about 1.8in, but I would be
>getting low on turns.  Would .4in or .8in more solve my ark over problem?
>If not any tips or suggestions that would help are greatly appreciated. Also
>I found that when I adjust the spark gap smaller and sand the electrodes
>every time, this greatly reduces arc over but also diminishes the spark
>length off the topload. Any ideas on spark gap? Thanks for your help!
>
>Sincerely,
>Nolan Moore
>