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Re: Xfmrs



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Hans,

I would hesitate sizing the core area using the current requirement of the transformer. I believe the parameters that need to be looked at are:

1. volts per turn on the primary
2. area of the core
3. frequency.

The total dphi/dt thru the core threading the primary is equal in magnitude to the volts per turn on the primary. Add frequency and you can compute the maximum phi thru this portion of the core. Max phi / area will give the flux density B. Knowing the properties of the core material will tell you how close to saturation you are. If the flux path splits (like with an EI core) the flux density at all points in the core will need to be evaluated. If too many volts per turn exist on the primary, the core will saturate even is the secondary is open circuit. Anyway, this is how I believe satuation needs to be analyzed.

Gerry R,


Original poster: "Hans Schattenmeister" <klugmann@xxxxxxxxxxx>

The process is very labor intensive. To wind a
240 volt to 15,000 volt transformer the primary
will require about 440 - 500 turns of 8 AWG wire.
and the secondary will require about 30,000 -
31,250 turns. The Iron core has to be sized
correctly for the amount of current you plan on
using. It will be hard to find. I actually have a friend who wound one.

Herr Schattenmeister





From: "Tesla list" <tesla@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Xfmrs
Date: Wed, 28 Feb 2007 17:16:29 -0700

Original poster: "Anthony R. Mollner" <penny831@xxxxxxxxxxxxx>

I have a question that I have wondered about for a long time and perhaps
someone can comment on it. How difficult is it really to "Make" a pole pig
or a transformer of some kind? I mean, why can't we wind a core, put it in a
bath of transformer oil and put it to use? Huhh, huh? Any xfmr guys out
there have an idea on that???

Tony

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Tuesday, February 27, 2007 10:08 PM
To: tesla@xxxxxxxxxx
Subject: [PHISH] Unpotting a France 12/30


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

Hello,

I have a couple of France 12/30's. I want to
un-pot one of them (some of the tar is cracked
and likely leaky) and remove a few shunts to make
a cap charger with a 5x multiplier. A newer 15/60
works just fine with some serious humming­ fast
and weighs three times the France! I am wondering
if I can keep the France in the original tank and
carefully heat it in a gas powered BBQ. Ideally,
I would like to pour molten tar out and soak the
tranny in diesel, or gasoline to dissolve the
rest. I guess I will have to remove the core to
knock out some shunts and hopefully be able to reconnect the HV bushings.

If I can leave it in the original tank, I would
melt some paraffin and Vaseline together and
repot it in that. Hopefully I can squeeze 40 or
50 ma out of it and current limit the cap input
which would likely be just right. I know this is
a well covered thread; but, has anyone
successfully done this using a similar method? I
would be open to mineral oil which probably sinks
away the heat better, but the on time should be no more than a couple
minutes.

Thanks Much,
Jim Mora

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