Re: Primary strikes

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

Original poster: "Finn Hammer by way of Terry Fritz <twftesla-at-qwest-dot-net>" <f-h-at-c.dk>

Hello stephen!

I was interested in the same question some time back, and performed the
experiment shown on this picture:
Http://home5.inet.tele.dk/f-hammer/caparc.jpg

As you see, no harm was done. The coil is a quick MOT driven lashup.

Since the energy that the cap receives from the arc originates from
itself, and has been taxed by spark gap, and other losses, it should not
be enough to create a voltage higher than that which was originally
across it.

So a primary strike is not bad for the cap, however it may still be a
nuisance, because it can trigger the safety gap, with erretic firing as
a result.

That`s why I have strike rings on my coils anyway.

Cheers, Finn Hammer


Tesla list wrote:
> 
> Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<srward16-at-hotmail-dot-com>
> 
> Hi everyone,
> 
> I was just wondering what people think about primay strikes because my small
> coil can arc nearly consistently to my primary coil.  I was wondering how
> bad this can really be as i have seen no damage yet.  Here are my coil's
> specs:
> 
> 9000v 50ma(modified)NST
> 
> .0136uf MMC made from 2 strings of 10 in series, GE yellow snubber type
> caps.068uf each.  Each cap is 3kvdc, with the 10, i have a good 30kvdc
> rating(i really over built it!) so its very tough with my power level.
> 
> 5 gap static gap.  Linear design of the Richard quick type.  Has a fan on
> it, about .25" total width.
> 
> Flat spiral primary, 9 turns .25" cu tubing.  Inner diameter-4", outer
> diameter-12", .25" spacing in between.
> 
> Secondary is 2.3" diameter x 10" wound with 28awg.  PVC form
> 
> Toroid- i have 2, 2" cord x 12" total diameter, stacked.
> 
> I can run the coil with a twin pri/sec setup, and have no problems with
> primary arcs, and get a nice 23" spark.  But with a single coil setup, i get
> strong primary arcs about 15" long(since they bow out a bit).
> 
> So are primary strikes really that bad?  I wanted to know because i may
> de-rate my cap to about 21kvdc when i get my small SRSG to work so that i
> have a bigger capacitance.  Since i do this, could i be putting my caps in
> danger,  im sure that with a SRSG, this coil will really go nuts.  Also,
> what parts of the primary circuit are at danger(if any) from primary
> strikes?
> 
> Steve Ward.
> 
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