Re: DIY HV transformer

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Christoph Bohr" <cb@xxxxxxxxxxxxxxx>

Hello Mark.

Thanks for your reply.
I already opened a core just as you describe it and the
E and the I part of the core really seprate nicely while
the remaining welds hold the laminnations together.
Unfortunately this transformer had both windings ruined.
But I still have a bigger one I will try to modify this way.
It has also a primary failure, but on one of the outer layers.
I think it should be OK to remove some turns there...
I will carry out these tasks in the next few days and
report what happened.

best regards

Christoph

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Wednesday, July 13, 2005 8:29 PM
Subject: RE: DIY HV transformer


> Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>
>
>
> Christopher:
>
> If one of your MOT secondaries is now shorted then it is obviously
> ruined.  You can convert your ruined MOT to a ballast inductor.  Most
> MOT's are made of E and I cores.  The E's and I's are all in the same
> stack respectively(typically) and welded together along either side.  If
> you saw the weld out then the I cores will separate from the E's.  Note:
> make a thin saw cut down the center of the weld so the weld remains
> intact to hold the separated E's and I's together(or add new weld on
> either side of the the originals).  Once apart, remove the secondary
> coil and use the primary as the inductor coil.  You can gap the E and I
> stack with plastic shims to vary the inductance.  I can give you some
> rough #'s on inductance and gap for a given core if you want.
>
> Mark
>
>
> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Tuesday, July 12, 2005 1:00 PM
> To: tesla@xxxxxxxxxx
> Subject: DIY HV transformer
>
>
> Original poster: "Christoph Bohr" <cb@xxxxxxxxxxxxxxx>
>
> Hello everyone.
>
> As you may have noticed during the last few days, I had some trouble
> with my 6-mot-stack, which finally lead to a failure mode that makes
> diagnosis very difficult, so I wanted to try something else: Wind my own
> transformer:
> first pictures of the winding process can be seen here:
> http://www.luebke-lands.de/tesla19.html
> along with some basic specs.
>
> The transformer is intended to be run unter oil, but another problem
> arises:
>
> The core material I am winding this transformer on, is the core of my
> former ballast coil, which means I no longer have one. Now, can I
> incooperate some shunts or airgap to limit the current so that I don't
> have to build another ballast coil? The core is basicaly rectangular,
> with each of the coils on one leg left and right... Maybe someone has an
> idea here. Maybe even with shunts, that can be moved by means of some
> mechanism while the transformer is still under oil....
>
> I'm thankfull for any suggestions.
>
> best regards
>
> Christoph
>
>
>