RE: Current Limiting and Impedance, DC Resonant Charging

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hi Mark, Group,

I have been enjoying the thread on inductance but much of the magnetics
stuff is out of my league.

Yes, that was a typo, piggy wise: 8-10KVA and since I will be running up to
MAYBE 15KVDC, the charge inductor will need, along with the Tcoil which is a
completely another issue and the fodder of posts to come, to endure 30KV at
up to 500BPS. If I did the math correctly consistent with Richie Burnett's
excellent site: 8000max = 23 Henries and a .035 uf MMC, 10,000max = 18
Henries and a .044 uF MMC.

Perhaps, a setup such as this with a 14.4KV pig is pure folly but maybe not,
that's part of the fun. I'll have lots of stuff, hopefully not all charred
to donate back to the group in the future :-)

I have been warned to expect some serious trailing power arcs in the rotary
at less than 150 bps. Could this be do to previous core saturations? My goal
would be to run down to 100bps and chart the results up to 500bps as Burnett
has outlined in theory but I will be doing at a 50% higher voltage.

What ever I end up with: either gapped series/parallel MOT's or a design
offered as you suggest. I plan to put the Charge Inductor in clear PVC or an
acrylic fish tank and mineral oil. All suggestions much welcomed. Thanks
again.

Jim Mora
Ojai, Ca.

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Thursday, May 12, 2005 1:45 PM
To: tesla@xxxxxxxxxx
Subject: Re: Current Limiting and Impedance, DC Resonant Charging

Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>


I am finally responding to Jim Mora's post of 5/9/05.

Jim:

You said you need to build a charging reactor for 8-10VA at 21 kv.  Some
of the other discussion revolves around a pole pig so it seems to me
that this is a typo.

My charging reactor on my DC sytem runs off an MOT power supply and FW
rectifier with filter caps.  I feed the charging reactor ~ 10 KV at 180
mA so I am ~ 1.8 KVA.

My charging reactor is ~7500 turns of #30 gauge wire in 50 layers on a
paper coilform with each layer insulated with a layer of epoxy.  The
coil is mounted on a pair of U100/57/25 U-Cores(matl 3C85) and gapped at
.020" to achieve L = 31 H.  With no Gap this unit has L=160H.  I run 460
BPS so my charging circuit resonates at 230 Hz.

I started with (2) MOT secondaries in series(each had about L = 15 H)
but the windings arced internally and the Inductance began to drop over
time.  It did run that way for a number of months before the insulation
breakdown began.

Mark