Re: Capacitor Help

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Original poster: "MalcolmTesla" <tesla@xxxxxxxxxxxxx>

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, December 16, 2005 6:22 PM


> Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
>
> Hi Malcolm,
>
> Tesla list wrote:
>
> >Original poster: "MalcolmTesla" <tesla@xxxxxxxxxxxxx>
> >
> >Thanks.  I got the strike ring make tonight too
> >http://www.v8-ranger.com/temp/tesla/19.jpg
> >I wasn't sure if I was supposed to connect one end of it to earth or not?
>
> When using a strike ring, wire it to RF ground which is separate from
> your mains house ground. I use copper pipe hammered into the ground
> for RF ground. The bottom secondary is also attached to RF ground.

Owww this throws another wrench in the works.  A copper pipe hammered into
the ground hey...  hummm is this the only way?  I mean that's fine for
playing at home but the whole reason I started building the Tesla Coil is
because we are having a christmas tree decoration contest at work.  My team
as built a christmas tree cage from chicken wire and I'm building the Tesla
Coil (on my own dime) to go inside the tree cage.  We're not going to have a
copper pipe in the ground available there.  Is there an alternative we can
do?

> >And I made my capacitor bank or MMC as I believe it's called.  I also put
10
> >Meg 1/2 watt resistors across each cap as suggested.
> >http://www.v8-ranger.com/temp/tesla/20.jpg
> >http://www.v8-ranger.com/temp/tesla/21.jpg
>
> The MMC looks like .05uF total if using the 0.15 CD caps. Realize
> that the cap bank is set at only 12kV. I hear some build their MMC's
> to the transformers Vp, but yours is barely at an rms rating. It may
> be wise to up the rating to at least Vp.  My MMC is derated to 36kV
> which is higher than others have built their MMC's to. I kind of
> built it bullet proof, but others have done well just at a Vp rating.
> Others may have comments there.

I think Terry already answer this one further down but my caps are
940C20P1k-F which are rated at 2000 VDC 0.1 MFD.  I have 12 of them in
series which should be good for 24kv.  I have two extras so I can go to 28kv
if I have to.

> >Still need to make the safety gap across the MMC and wire up the HV
stuff.
> >Oh and winding the secondary and building  my torid are the last two
major
> >things.
> >
> >Do I adjust the safety gap across the MMC slightly larger than what ever
my
> >spark gap gets set at?  1/8" or 1/4" wider, maybe?
>
> I put my safety gap across my sparkgap. This allows the safety gap to
> act just like the sparkgap and the energy is felt across the
> inductance, unlike a cap, where a sudden discharge across a cap can
> be damaging to the cap because the discharge is felt across the cap
> (as opposed to across the primary inductance).
>
> The safety gap should be adjusted to where the transformer will not
> fire across it (it's there to protect the transformer, and if
> adjusted too wide, it then serves no purpose, and the cap discharge
> can damage the transformer secondary windings from excessive voltage,
> especially on NST's). Once installed into the system and running, you
> may have to do some "slight" adjustments. If you find your safety gap
> has to be adjusted oddly wide; stop. There may be something wrong and
> you don't want to put the transformer at further risk. This topic
> will likely come up again once your up and running.

I still don't understand.  How does the safety gap in parallel with the
regular spark gap help any unless it's connected to something else as well?