RE: [TCML] HV capacitors wanted

["Lau, Gary" <Gary.Lau@xxxxxx>]

Thanks for clarifying the name.

A minor point on capacitor parts - "dielectric" refers to the insulating medium between the plates.  In a bottle cap, the dielectric is the glass bottle.  The inner "plate" is salt water.  The outer plate is typically aluminum foil, as that is a lot lighter, neater, and probably more conductive, so less lossy, than using an external salt water bath.  I would stick with the outer foil.  And any spilling of the external bath _would_ be a very bad thing, safety-wise.

Yes, commercial HV caps will be more compact and somewhat more efficient, but if money is tight, that's your best bet.  After all, that's what Tesla used.

And if you were making a Christmas list for your dad, you might add eight Cornell-Dubilier 942C20P15K caps (0.15uF@2000V).  In series, this will give you 18nF @16kV.

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Christopher Karr
> Sent: Monday, December 01, 2008 10:50 PM
> To: Tesla Pupman List
> Subject: [TCML] HV capacitors wanted
>
>
> Hello, please forget about the whole Chrishitstopher thing, as I was making a new
> email address and I didn't want a recognizable name.
>
> I have built the saltwater capacitors, before, and they were very inefficient, because
> I used aluminum foil rather than the saltwater for the outer dielectric. My dad told
> me that he didn't feel comfortable with me having high voltages running in
> saltwater, so I couldn't build the more efficient capacitor design. I may try it, soon,
> anyways, out of desperation.
>
> Anyways, I was hoping for some better capacitors that are made for high voltage by
> a company so that the losses are at a minimum with a small package size.
>
>
> __________________________________________________________________
> _______________________________
>
>
> Hi Chrishitstopher (?),
>
> Before discussing capacitor specifics, we need to be clear on the transformer
> configuration.
>
> OBIT's are typically 10kV @23mA, midpoint-grounded.  If you're planning on wiring
> the secondaries in series to achieve 20kV, it won't work.  The fact that the
> secondary midpoints are tied to the case thwarts that plan, and there's nothing one
> can do to get around it.  Instead, tie the secondaries in parallel to achieve 10kV
> @46mA.  It will still process the same amount of power, but won't fry the OBIT's.
>
> The cap size for a 10/46 power supply, assuming you have 60 Hz power and a
> static gap, is between 15 & 20 nF.
>
> If money is short, a salt water cap is the cheapest and most reliable route.  I've
> personally not ever built one, but I understand that a 12 oz beer bottle is good for
> about 0.9nF each (but YMMV).
>
> Regards, Gary Lau
> MA, USA
>
> > -----Original Message-----
> > From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> > Behalf Of Chrishitstopher Klaus
> > Sent: Monday, December 01, 2008 7:06 PM
> > To: Tesla Pupman mailing list
> > Subject: [TCML] Capacitors
> >
> >
> > Hello, everyone. I'm a fifteen-year-old coiler, and I don't have much money. I'm
> > working on my first coil (I've gotten it running, before) and my capacitors recently
> > broke. What I need is a number of capacitors or a single capacitor rated at 10nF
> > and 20kV. I'm building the Tesla Coil with two OBITs in series-parallel
> arrangement.
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