D & B, last part II

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: D & B, last part II
From: Tesla List <tesla-at-stic-dot-net>
Date: Sat, 7 Mar 1998 17:35:07 -0600
Approved: tesla-at-stic-dot-net

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From:  Greg Leyh [SMTP:lod-at-pacbell-dot-net]
Sent:  Saturday, March 07, 1998 5:24 AM
To:  Tesla List
Subject:  Re: D & B, last part II

Tesla List wrote:

> >The big Aerovox cap (1.8 uF / 60 kV ) was connected
> >between the bottom of the secondary and ground.
> 
> I would think the tuning would be substantially altered
> with such a high reactance in series with the coil
> ( using the small cap ).

It doesn't significantly alter the tuning,
since the 1.8u cap, the Csec, and the Lsec
are all in series.  The effective Csec drops
by only 1-(Csec/1.8u) x100%.

> >The rectification business was an unexpected side effect.
> >I was really trying to increase spark intensity by driving
> >some DC down the ionization channel, which was done
> >by charging up the Aerovox with a separate DC supply.
> >This DC supply was not connected when I measured the
> >rectified current.
> >
> 
> Yeah, I gathered the discharge must have been quite nice.
> You don't mention the secondary resistance and reactance;
> I'd imagine a high frequency coil to be ideal for the
> enhanced discharge effect.

This type of tomfoolery also works quite well
on my 59kHz coil, with a 14uF series cap bank.

> >I must say, though, anyone who needs to produce a real
> >lightning bolt to ground can pick up these big pulse
> >discharge caps for cheap at surplus places; and coupled with
> >a modest Tesla coil generate significant discharge current.
> 
> I'm looking for these for pulse work with NMR, are any of the
> surplus houses you mention mail order?

Capacitor alert -- I have access to a bunch of 
(used) Maxwell energy storage capacitors, with 
the following ratings:

C = 10uF
V = 60kV
Total energy per cap = 18,000J

Unfortunately, I need caps with a 20kV rating,
since I have a 24kV 100kVA cap charger.  I would
be willing to trade these 60kV caps for 20-30kV ones,
at a generous exchange rate (I'll give 2J per J!).

I can only use the newer caps though, that have 
7500J per cap or greater, due to space and weight
constraints.


-GL