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RE: [TCML] Primary Grounding was [Control Cabinet ...]



Hi David, 

I noticed the dual x-ray cable runs. Are they striped back on both ends? The
bad thing about that is the shield is floating...which makes an otherwise
very safe cable design dangerous. There was also a pic of a blue and a gray
cable twisted together. What's up with that? I may take DC's advise and put
the big PT in a separate cabinet and bring out dual cables. The isolated
primary seems like it may be the way to go assuming a large enough gap from
the primary to secondary windings. I wish there was some consensus here. The
pros seem to ground the inner turn of the primary.

Jim Mora

Did you have a safety gap across the Cap?

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of David%20Rieben
Sent: Wednesday, December 17, 2008 10:54 AM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Primary Grounding was [Control Cabinet ...]

Hi Phillip,

After reviewing my little youtube segment of my Green
Monster running, it appears me that you may indeed 
be correct about the primary not drawing as many 
strikes if it is not tied to RF ground:
http://www.youtube.com/watch?v=eWZD3M-nye8
At the time that I was running it here, I did have two se-
perate transmission lines running to the primary tank
circuit (you can see the 2 x-ray cables on the ground
in this video) and the primary was not tied to any 
ground even though the RF grounded strike rail was 
up at this time. If you review the video, you'll note that
there was only two noticable strike rail hits, so maybe
you're on to something here. I'll have to try running it
this way again and see if there is a notable decrease
in primary bound hits. I'm still not sure that the primary 
strike that you saw just before the Hipo cap died was
the cause of the cap's death, though - maybe it was
just the "straw that broke the camel's back"! 
BTW, I can still run my single eared pig in this fashion
as the tank sits on a dry plywood base inside the con-
trol panel and the pole mount brackets are fastened to
wooden 2x4's - the external tank of my pig has no con-
tact with any grounded metal.

David Rieben


----- Original Message -----

From: Phillip Slawinski 

To: Tesla Coil Mailing List 

Sent: Wed, 17 Dec 2008 16:48:03 +0000 (UTC)

Subject: Re: [TCML] Primary Grounding was [Control Cabinet ...]



Gary,



Perhaps it was not the primary strike that killed the capacitor.  It could

have just been coincidence that there was a strike to the primary.  Maybe

the Hipotronics cap was a ticking time bomb, we will probably never know.



My main point in starting this thread was to discuss whether or not

grounding the primary increases the chances that streamers will strike the

primary vs. having a primary where both ends are above ground potential.  To

me it seems like when you have a grounded strike rail, and a grounded

primary you're practically begging the streamers to hit in that area.



My experience with my 6" coil would seem to prove that having a grounded

primary does invite streamers to strike it more frequently.  There could

also be other factors that led to the primary being struck so frequently.

On the day in question it was very cold outside so David was running his

huge heater in his garage.  This heater was pointed in the general direction

of my coil.  This could have caused an updraft.  I noticed that throughout

the run the streamers were mostly reaching upward, unless they came down to

hit the primary.  It probably had enough potential to  hit the driveway, but

perhaps the updraft prevented this from happening.



-Phillip



On Wed, Dec 17, 2008 at 10:22, Lau, Gary wrote:



> Hi Phillip,

>

> I don't doubt that you saw a primary strike just prior to David's cap

> dying.  But I think it's not always easy to separate cause and effect.

>

> Conservation of energy will not allow the primary cap to be recharged by a

> streamer-strike to a higher voltage than before the gap fired.  So I don't

> think that's what killed the cap, although certainly possible that I
missed

> something.

>

> Instead, let me propose this.  What if through RSG misfiring or some other

> conspiracy of events, the cap was able to charge to a higher-than-normal

> voltage.  When the gap did fire, it would be a bigger than normal bang,

> resulting in a longer secondary streamer, and able to strike something

> (primary) normally out of reach?  The over-charging of the cap as a result

> of gap miss-fire may be the cause of the cap's demise, rather than the

> primary strike.

>

> I don't know, just an arm-chair perspective.  Corrections, discussion, and

> alternate theories are very welcome!

>

> Regards, Gary Lau

> MA, USA

>

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