Re: Strange shock

["Barton B. Anderson" <tesla123-at-pacbell-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Chris, 

This was a static discharge. Many coilers have experienced shocks off the
secondary coils. Dry weather and the coating can cause static charge levels to
build on the secondary. Just like any other static charge, friction plays a
role. Wind causes friction around the secondary. I'd almost bet there was a
nice breeze down in Santa Cruz. Depending on the conditions, the charge could
build over and over after each discharge. 

Bart 

Tesla list wrote: 
>
> Original poster: "Chris Brick" <cbrick-at-rebelbase-dot-com> 
>
> Hello coilers- 
>
> I had a strange experience on the 4th.  We ran our coil in Santa Cruz, CA 
> as fireworks since they are illegal there.  We had a nice crowd and cars 
> stopping for about an hour.  The coil ran great, at one point for almost 20 
> minutes straight with no detectable heat in the MMC and no spark length 
> degradation.  Good quality show with consistent 36" streamers to air from 
> our little 15/30 NST.  Anyhow, after the show was over I proceeded to 
> dismantle the coil as I have done a hundred times.  I removed the secondary 
> after disconnecting all the wiring and capacitors.  I received a small 
> shock from the secondary while holding it in my hands, away from everything 
> and totally disconnected.  One of my engineer friends didn't believe me so 
> he picked it up and got the same shock.  It is built on a 4". thin wall PVC 
> drain pipe, sealed, and has 1/4x20 bolts epoxyed in each end.  The larger 
> of the two shocks I got was from the bottom bolt.  The bottom of the 
> winding is connected to the bottom bolt for grounding.  The top bolt is 
> used to connect the toroid and doesn't have a connection to the 
> windings.  Any thoughts on why there would be some charge built up in the 
> secondary?  Either way, it didn't hurt and I didn't die, but I sure would 
> like to know what it was all about.  I am not too familiar with Leyden 
> Jars, but Steve the engineer had some ideas about the possible cause. 
>
> Also, those of you that are interested in rewinding a large transformer for 
> Tesla use may find it worthwhile to become friends with a local commercial 
> electrician.  I was just offered a 150KVA 240/2400 transformer for 
> $150.00.  It seems once they punch the wiring holes, they can't return them 
> to the distributor and can only sell them back at around $1 per KVA.  I am 
> going to collect a few for the cores and build myself a nice sized 
> transformer. 
>
> Thanks, 
>
> Chris